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* [PATCH V2 0/3] Add MSystems Disk-On-Chip G3 support
@ 2011-12-22 15:51 Robert Jarzmik
  2011-12-22 15:51 ` [PATCH V2 1/3] lib: add BCH encoding/decoding Robert Jarzmik
                   ` (3 more replies)
  0 siblings, 4 replies; 7+ messages in thread
From: Robert Jarzmik @ 2011-12-22 15:51 UTC (permalink / raw)
  To: barebox

This patchset brings support for M-Systems disk-on-chip G3
chips. Almost all code is taken from linux kernel (bitrev,
bch, docg3), and slightly amended for barebox.

This patchset relies on a previous patchset "drivers/mtd:
add a core" included in barebox.git/next, and is rebased on
top of it.

This patchset won't bring hopefully, as it doesn't change
anything outside of its own scope.

Cheers.

Robert Jarzmik (3):
  lib: add BCH encoding/decoding
  lib: add bitrev utility
  drivers/mtd: add docg3 chip

 drivers/mtd/Kconfig          |    1 +
 drivers/mtd/Makefile         |    1 +
 drivers/mtd/devices/Kconfig  |   16 +
 drivers/mtd/devices/Makefile |    5 +
 drivers/mtd/devices/docg3.c  | 1196 ++++++++++++++++++++++++++++++++++++
 drivers/mtd/devices/docg3.h  |  283 +++++++++
 include/linux/bch.h          |   79 +++
 include/linux/bitrev.h       |   16 +
 lib/Kconfig                  |    7 +
 lib/Makefile                 |    2 +
 lib/bch.c                    | 1366 ++++++++++++++++++++++++++++++++++++++++++
 lib/bitrev.c                 |   68 +++
 12 files changed, 3040 insertions(+), 0 deletions(-)
 create mode 100644 drivers/mtd/devices/Kconfig
 create mode 100644 drivers/mtd/devices/Makefile
 create mode 100644 drivers/mtd/devices/docg3.c
 create mode 100644 drivers/mtd/devices/docg3.h
 create mode 100644 include/linux/bch.h
 create mode 100644 include/linux/bitrev.h
 create mode 100644 lib/bch.c
 create mode 100644 lib/bitrev.c

-- 
1.7.5.4


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^ permalink raw reply	[flat|nested] 7+ messages in thread

* [PATCH V2 1/3] lib: add BCH encoding/decoding
  2011-12-22 15:51 [PATCH V2 0/3] Add MSystems Disk-On-Chip G3 support Robert Jarzmik
@ 2011-12-22 15:51 ` Robert Jarzmik
  2011-12-22 15:51 ` [PATCH V2 2/3] lib: add bitrev utility Robert Jarzmik
                   ` (2 subsequent siblings)
  3 siblings, 0 replies; 7+ messages in thread
From: Robert Jarzmik @ 2011-12-22 15:51 UTC (permalink / raw)
  To: barebox

As flash memories need BCH correcting codes, add the BCH
library, taken from the linux kernel.

Signed-off-by: Robert Jarzmik <robert.jarzmik@free.fr>
---
 include/linux/bch.h |   79 +++
 lib/Kconfig         |    4 +
 lib/Makefile        |    1 +
 lib/bch.c           | 1366 +++++++++++++++++++++++++++++++++++++++++++++++++++
 4 files changed, 1450 insertions(+), 0 deletions(-)
 create mode 100644 include/linux/bch.h
 create mode 100644 lib/bch.c

diff --git a/include/linux/bch.h b/include/linux/bch.h
new file mode 100644
index 0000000..295b4ef
--- /dev/null
+++ b/include/linux/bch.h
@@ -0,0 +1,79 @@
+/*
+ * Generic binary BCH encoding/decoding library
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 as published by
+ * the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
+ * more details.
+ *
+ * You should have received a copy of the GNU General Public License along with
+ * this program; if not, write to the Free Software Foundation, Inc., 51
+ * Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Copyright © 2011 Parrot S.A.
+ *
+ * Author: Ivan Djelic <ivan.djelic@parrot.com>
+ *
+ * Description:
+ *
+ * This library provides runtime configurable encoding/decoding of binary
+ * Bose-Chaudhuri-Hocquenghem (BCH) codes.
+*/
+#ifndef _BCH_H
+#define _BCH_H
+
+#include <linux/types.h>
+
+/**
+ * struct bch_control - BCH control structure
+ * @m:          Galois field order
+ * @n:          maximum codeword size in bits (= 2^m-1)
+ * @t:          error correction capability in bits
+ * @ecc_bits:   ecc exact size in bits, i.e. generator polynomial degree (<=m*t)
+ * @ecc_bytes:  ecc max size (m*t bits) in bytes
+ * @a_pow_tab:  Galois field GF(2^m) exponentiation lookup table
+ * @a_log_tab:  Galois field GF(2^m) log lookup table
+ * @mod8_tab:   remainder generator polynomial lookup tables
+ * @ecc_buf:    ecc parity words buffer
+ * @ecc_buf2:   ecc parity words buffer
+ * @xi_tab:     GF(2^m) base for solving degree 2 polynomial roots
+ * @syn:        syndrome buffer
+ * @cache:      log-based polynomial representation buffer
+ * @elp:        error locator polynomial
+ * @poly_2t:    temporary polynomials of degree 2t
+ */
+struct bch_control {
+	unsigned int    m;
+	unsigned int    n;
+	unsigned int    t;
+	unsigned int    ecc_bits;
+	unsigned int    ecc_bytes;
+/* private: */
+	uint16_t       *a_pow_tab;
+	uint16_t       *a_log_tab;
+	uint32_t       *mod8_tab;
+	uint32_t       *ecc_buf;
+	uint32_t       *ecc_buf2;
+	unsigned int   *xi_tab;
+	unsigned int   *syn;
+	int            *cache;
+	struct gf_poly *elp;
+	struct gf_poly *poly_2t[4];
+};
+
+struct bch_control *init_bch(int m, int t, unsigned int prim_poly);
+
+void free_bch(struct bch_control *bch);
+
+void encode_bch(struct bch_control *bch, const uint8_t *data,
+		unsigned int len, uint8_t *ecc);
+
+int decode_bch(struct bch_control *bch, const uint8_t *data, unsigned int len,
+	       const uint8_t *recv_ecc, const uint8_t *calc_ecc,
+	       const unsigned int *syn, unsigned int *errloc);
+
+#endif /* _BCH_H */
diff --git a/lib/Kconfig b/lib/Kconfig
index e16dd35..83ac1ac 100644
--- a/lib/Kconfig
+++ b/lib/Kconfig
@@ -19,4 +19,8 @@ config FDT
 config OFTREE
 	select FDT
 	bool
+
+config BCH
+       bool
+
 endmenu
diff --git a/lib/Makefile b/lib/Makefile
index ae76b4c..04c5487 100644
--- a/lib/Makefile
+++ b/lib/Makefile
@@ -31,3 +31,4 @@ obj-$(CONFIG_LZO_DECOMPRESS)		+= decompress_unlzo.o
 obj-$(CONFIG_PROCESS_ESCAPE_SEQUENCE)	+= process_escape_sequence.o
 obj-$(CONFIG_FDT)	+= fdt/
 obj-y			+= uncompress.o
+obj-$(CONFIG_BCH)	+= bch.o
diff --git a/lib/bch.c b/lib/bch.c
new file mode 100644
index 0000000..5797c3f
--- /dev/null
+++ b/lib/bch.c
@@ -0,0 +1,1366 @@
+/*
+ * Generic binary BCH encoding/decoding library
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 as published by
+ * the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
+ * more details.
+ *
+ * Copyright © 2011 Parrot S.A.
+ *
+ * Author: Ivan Djelic <ivan.djelic@parrot.com>
+ *
+ * Description:
+ *
+ * This library provides runtime configurable encoding/decoding of binary
+ * Bose-Chaudhuri-Hocquenghem (BCH) codes.
+ *
+ * Call init_bch to get a pointer to a newly allocated bch_control structure for
+ * the given m (Galois field order), t (error correction capability) and
+ * (optional) primitive polynomial parameters.
+ *
+ * Call encode_bch to compute and store ecc parity bytes to a given buffer.
+ * Call decode_bch to detect and locate errors in received data.
+ *
+ * On systems supporting hw BCH features, intermediate results may be provided
+ * to decode_bch in order to skip certain steps. See decode_bch() documentation
+ * for details.
+ *
+ * Option CONFIG_BCH_CONST_PARAMS can be used to force fixed values of
+ * parameters m and t; thus allowing extra compiler optimizations and providing
+ * better (up to 2x) encoding performance. Using this option makes sense when
+ * (m,t) are fixed and known in advance, e.g. when using BCH error correction
+ * on a particular NAND flash device.
+ *
+ * Algorithmic details:
+ *
+ * Encoding is performed by processing 32 input bits in parallel, using 4
+ * remainder lookup tables.
+ *
+ * The final stage of decoding involves the following internal steps:
+ * a. Syndrome computation
+ * b. Error locator polynomial computation using Berlekamp-Massey algorithm
+ * c. Error locator root finding (by far the most expensive step)
+ *
+ * In this implementation, step c is not performed using the usual Chien search.
+ * Instead, an alternative approach described in [1] is used. It consists in
+ * factoring the error locator polynomial using the Berlekamp Trace algorithm
+ * (BTA) down to a certain degree (4), after which ad hoc low-degree polynomial
+ * solving techniques [2] are used. The resulting algorithm, called BTZ, yields
+ * much better performance than Chien search for usual (m,t) values (typically
+ * m >= 13, t < 32, see [1]).
+ *
+ * [1] B. Biswas, V. Herbert. Efficient root finding of polynomials over fields
+ * of characteristic 2, in: Western European Workshop on Research in Cryptology
+ * - WEWoRC 2009, Graz, Austria, LNCS, Springer, July 2009, to appear.
+ * [2] [Zin96] V.A. Zinoviev. On the solution of equations of degree 10 over
+ * finite fields GF(2^q). In Rapport de recherche INRIA no 2829, 1996.
+ *
+ * Taken from the linux kernel.
+ */
+
+#include <common.h>
+#include <errno.h>
+#include <init.h>
+#include <malloc.h>
+#include <linux/kernel.h>
+#include <linux/bitops.h>
+#include <asm/byteorder.h>
+#include <linux/bch.h>
+
+#if defined(CONFIG_BCH_CONST_PARAMS)
+#define GF_M(_p)               (CONFIG_BCH_CONST_M)
+#define GF_T(_p)               (CONFIG_BCH_CONST_T)
+#define GF_N(_p)               ((1 << (CONFIG_BCH_CONST_M))-1)
+#else
+#define GF_M(_p)               ((_p)->m)
+#define GF_T(_p)               ((_p)->t)
+#define GF_N(_p)               ((_p)->n)
+#endif
+
+#define BCH_ECC_WORDS(_p)      DIV_ROUND_UP(GF_M(_p)*GF_T(_p), 32)
+#define BCH_ECC_BYTES(_p)      DIV_ROUND_UP(GF_M(_p)*GF_T(_p), 8)
+
+#ifndef dbg
+#define dbg(_fmt, args...)     do {} while (0)
+#endif
+
+/*
+ * represent a polynomial over GF(2^m)
+ */
+struct gf_poly {
+	unsigned int deg;    /* polynomial degree */
+	unsigned int c[0];   /* polynomial terms */
+};
+
+/* given its degree, compute a polynomial size in bytes */
+#define GF_POLY_SZ(_d) (sizeof(struct gf_poly)+((_d)+1)*sizeof(unsigned int))
+
+/* polynomial of degree 1 */
+struct gf_poly_deg1 {
+	struct gf_poly poly;
+	unsigned int   c[2];
+};
+
+/*
+ * same as encode_bch(), but process input data one byte at a time
+ */
+static void encode_bch_unaligned(struct bch_control *bch,
+				 const unsigned char *data, unsigned int len,
+				 uint32_t *ecc)
+{
+	int i;
+	const uint32_t *p;
+	const int l = BCH_ECC_WORDS(bch)-1;
+
+	while (len--) {
+		p = bch->mod8_tab + (l+1)*(((ecc[0] >> 24)^(*data++)) & 0xff);
+
+		for (i = 0; i < l; i++)
+			ecc[i] = ((ecc[i] << 8)|(ecc[i+1] >> 24))^(*p++);
+
+		ecc[l] = (ecc[l] << 8)^(*p);
+	}
+}
+
+/*
+ * convert ecc bytes to aligned, zero-padded 32-bit ecc words
+ */
+static void load_ecc8(struct bch_control *bch, uint32_t *dst,
+		      const uint8_t *src)
+{
+	uint8_t pad[4] = {0, 0, 0, 0};
+	unsigned int i, nwords = BCH_ECC_WORDS(bch)-1;
+
+	for (i = 0; i < nwords; i++, src += 4)
+		dst[i] = (src[0] << 24)|(src[1] << 16)|(src[2] << 8)|src[3];
+
+	memcpy(pad, src, BCH_ECC_BYTES(bch)-4*nwords);
+	dst[nwords] = (pad[0] << 24)|(pad[1] << 16)|(pad[2] << 8)|pad[3];
+}
+
+/*
+ * convert 32-bit ecc words to ecc bytes
+ */
+static void store_ecc8(struct bch_control *bch, uint8_t *dst,
+		       const uint32_t *src)
+{
+	uint8_t pad[4];
+	unsigned int i, nwords = BCH_ECC_WORDS(bch)-1;
+
+	for (i = 0; i < nwords; i++) {
+		*dst++ = (src[i] >> 24);
+		*dst++ = (src[i] >> 16) & 0xff;
+		*dst++ = (src[i] >>  8) & 0xff;
+		*dst++ = (src[i] >>  0) & 0xff;
+	}
+	pad[0] = (src[nwords] >> 24);
+	pad[1] = (src[nwords] >> 16) & 0xff;
+	pad[2] = (src[nwords] >>  8) & 0xff;
+	pad[3] = (src[nwords] >>  0) & 0xff;
+	memcpy(dst, pad, BCH_ECC_BYTES(bch)-4*nwords);
+}
+
+/**
+ * encode_bch - calculate BCH ecc parity of data
+ * @bch:   BCH control structure
+ * @data:  data to encode
+ * @len:   data length in bytes
+ * @ecc:   ecc parity data, must be initialized by caller
+ *
+ * The @ecc parity array is used both as input and output parameter, in order to
+ * allow incremental computations. It should be of the size indicated by member
+ * @ecc_bytes of @bch, and should be initialized to 0 before the first call.
+ *
+ * The exact number of computed ecc parity bits is given by member @ecc_bits of
+ * @bch; it may be less than m*t for large values of t.
+ */
+void encode_bch(struct bch_control *bch, const uint8_t *data,
+		unsigned int len, uint8_t *ecc)
+{
+	const unsigned int l = BCH_ECC_WORDS(bch)-1;
+	unsigned int i, mlen;
+	unsigned long m;
+	uint32_t w, r[l+1];
+	const uint32_t * const tab0 = bch->mod8_tab;
+	const uint32_t * const tab1 = tab0 + 256*(l+1);
+	const uint32_t * const tab2 = tab1 + 256*(l+1);
+	const uint32_t * const tab3 = tab2 + 256*(l+1);
+	const uint32_t *pdata, *p0, *p1, *p2, *p3;
+
+	if (ecc) {
+		/* load ecc parity bytes into internal 32-bit buffer */
+		load_ecc8(bch, bch->ecc_buf, ecc);
+	} else {
+		memset(bch->ecc_buf, 0, sizeof(r));
+	}
+
+	/* process first unaligned data bytes */
+	m = ((unsigned long)data) & 3;
+	if (m) {
+		mlen = (len < (4-m)) ? len : 4-m;
+		encode_bch_unaligned(bch, data, mlen, bch->ecc_buf);
+		data += mlen;
+		len  -= mlen;
+	}
+
+	/* process 32-bit aligned data words */
+	pdata = (uint32_t *)data;
+	mlen  = len/4;
+	data += 4*mlen;
+	len  -= 4*mlen;
+	memcpy(r, bch->ecc_buf, sizeof(r));
+
+	/*
+	 * split each 32-bit word into 4 polynomials of weight 8 as follows:
+	 *
+	 * 31 ...24  23 ...16  15 ... 8  7 ... 0
+	 * xxxxxxxx  yyyyyyyy  zzzzzzzz  tttttttt
+	 *                               tttttttt  mod g = r0 (precomputed)
+	 *                     zzzzzzzz  00000000  mod g = r1 (precomputed)
+	 *           yyyyyyyy  00000000  00000000  mod g = r2 (precomputed)
+	 * xxxxxxxx  00000000  00000000  00000000  mod g = r3 (precomputed)
+	 * xxxxxxxx  yyyyyyyy  zzzzzzzz  tttttttt  mod g = r0^r1^r2^r3
+	 */
+	while (mlen--) {
+		/* input data is read in big-endian format */
+		w = r[0]^cpu_to_be32(*pdata++);
+		p0 = tab0 + (l+1)*((w >>  0) & 0xff);
+		p1 = tab1 + (l+1)*((w >>  8) & 0xff);
+		p2 = tab2 + (l+1)*((w >> 16) & 0xff);
+		p3 = tab3 + (l+1)*((w >> 24) & 0xff);
+
+		for (i = 0; i < l; i++)
+			r[i] = r[i+1]^p0[i]^p1[i]^p2[i]^p3[i];
+
+		r[l] = p0[l]^p1[l]^p2[l]^p3[l];
+	}
+	memcpy(bch->ecc_buf, r, sizeof(r));
+
+	/* process last unaligned bytes */
+	if (len)
+		encode_bch_unaligned(bch, data, len, bch->ecc_buf);
+
+	/* store ecc parity bytes into original parity buffer */
+	if (ecc)
+		store_ecc8(bch, ecc, bch->ecc_buf);
+}
+EXPORT_SYMBOL_GPL(encode_bch);
+
+static inline int modulo(struct bch_control *bch, unsigned int v)
+{
+	const unsigned int n = GF_N(bch);
+	while (v >= n) {
+		v -= n;
+		v = (v & n) + (v >> GF_M(bch));
+	}
+	return v;
+}
+
+/*
+ * shorter and faster modulo function, only works when v < 2N.
+ */
+static inline int mod_s(struct bch_control *bch, unsigned int v)
+{
+	const unsigned int n = GF_N(bch);
+	return (v < n) ? v : v-n;
+}
+
+static inline int deg(unsigned int poly)
+{
+	/* polynomial degree is the most-significant bit index */
+	return fls(poly)-1;
+}
+
+static inline int parity(unsigned int x)
+{
+	/*
+	 * public domain code snippet, lifted from
+	 * http://www-graphics.stanford.edu/~seander/bithacks.html
+	 */
+	x ^= x >> 1;
+	x ^= x >> 2;
+	x = (x & 0x11111111U) * 0x11111111U;
+	return (x >> 28) & 1;
+}
+
+/* Galois field basic operations: multiply, divide, inverse, etc. */
+
+static inline unsigned int gf_mul(struct bch_control *bch, unsigned int a,
+				  unsigned int b)
+{
+	return (a && b) ? bch->a_pow_tab[mod_s(bch, bch->a_log_tab[a]+
+					       bch->a_log_tab[b])] : 0;
+}
+
+static inline unsigned int gf_sqr(struct bch_control *bch, unsigned int a)
+{
+	return a ? bch->a_pow_tab[mod_s(bch, 2*bch->a_log_tab[a])] : 0;
+}
+
+static inline unsigned int gf_div(struct bch_control *bch, unsigned int a,
+				  unsigned int b)
+{
+	return a ? bch->a_pow_tab[mod_s(bch, bch->a_log_tab[a]+
+					GF_N(bch)-bch->a_log_tab[b])] : 0;
+}
+
+static inline unsigned int gf_inv(struct bch_control *bch, unsigned int a)
+{
+	return bch->a_pow_tab[GF_N(bch)-bch->a_log_tab[a]];
+}
+
+static inline unsigned int a_pow(struct bch_control *bch, int i)
+{
+	return bch->a_pow_tab[modulo(bch, i)];
+}
+
+static inline int a_log(struct bch_control *bch, unsigned int x)
+{
+	return bch->a_log_tab[x];
+}
+
+static inline int a_ilog(struct bch_control *bch, unsigned int x)
+{
+	return mod_s(bch, GF_N(bch)-bch->a_log_tab[x]);
+}
+
+/*
+ * compute 2t syndromes of ecc polynomial, i.e. ecc(a^j) for j=1..2t
+ */
+static void compute_syndromes(struct bch_control *bch, uint32_t *ecc,
+			      unsigned int *syn)
+{
+	int i, j, s;
+	unsigned int m;
+	uint32_t poly;
+	const int t = GF_T(bch);
+
+	s = bch->ecc_bits;
+
+	/* make sure extra bits in last ecc word are cleared */
+	m = ((unsigned int)s) & 31;
+	if (m)
+		ecc[s/32] &= ~((1u << (32-m))-1);
+	memset(syn, 0, 2*t*sizeof(*syn));
+
+	/* compute v(a^j) for j=1 .. 2t-1 */
+	do {
+		poly = *ecc++;
+		s -= 32;
+		while (poly) {
+			i = deg(poly);
+			for (j = 0; j < 2*t; j += 2)
+				syn[j] ^= a_pow(bch, (j+1)*(i+s));
+
+			poly ^= (1 << i);
+		}
+	} while (s > 0);
+
+	/* v(a^(2j)) = v(a^j)^2 */
+	for (j = 0; j < t; j++)
+		syn[2*j+1] = gf_sqr(bch, syn[j]);
+}
+
+static void gf_poly_copy(struct gf_poly *dst, struct gf_poly *src)
+{
+	memcpy(dst, src, GF_POLY_SZ(src->deg));
+}
+
+static int compute_error_locator_polynomial(struct bch_control *bch,
+					    const unsigned int *syn)
+{
+	const unsigned int t = GF_T(bch);
+	const unsigned int n = GF_N(bch);
+	unsigned int i, j, tmp, l, pd = 1, d = syn[0];
+	struct gf_poly *elp = bch->elp;
+	struct gf_poly *pelp = bch->poly_2t[0];
+	struct gf_poly *elp_copy = bch->poly_2t[1];
+	int k, pp = -1;
+
+	memset(pelp, 0, GF_POLY_SZ(2*t));
+	memset(elp, 0, GF_POLY_SZ(2*t));
+
+	pelp->deg = 0;
+	pelp->c[0] = 1;
+	elp->deg = 0;
+	elp->c[0] = 1;
+
+	/* use simplified binary Berlekamp-Massey algorithm */
+	for (i = 0; (i < t) && (elp->deg <= t); i++) {
+		if (d) {
+			k = 2*i-pp;
+			gf_poly_copy(elp_copy, elp);
+			/* e[i+1](X) = e[i](X)+di*dp^-1*X^2(i-p)*e[p](X) */
+			tmp = a_log(bch, d)+n-a_log(bch, pd);
+			for (j = 0; j <= pelp->deg; j++) {
+				if (pelp->c[j]) {
+					l = a_log(bch, pelp->c[j]);
+					elp->c[j+k] ^= a_pow(bch, tmp+l);
+				}
+			}
+			/* compute l[i+1] = max(l[i]->c[l[p]+2*(i-p]) */
+			tmp = pelp->deg+k;
+			if (tmp > elp->deg) {
+				elp->deg = tmp;
+				gf_poly_copy(pelp, elp_copy);
+				pd = d;
+				pp = 2*i;
+			}
+		}
+		/* di+1 = S(2i+3)+elp[i+1].1*S(2i+2)+...+elp[i+1].lS(2i+3-l) */
+		if (i < t-1) {
+			d = syn[2*i+2];
+			for (j = 1; j <= elp->deg; j++)
+				d ^= gf_mul(bch, elp->c[j], syn[2*i+2-j]);
+		}
+	}
+	dbg("elp=%s\n", gf_poly_str(elp));
+	return (elp->deg > t) ? -1 : (int)elp->deg;
+}
+
+/*
+ * solve a m x m linear system in GF(2) with an expected number of solutions,
+ * and return the number of found solutions
+ */
+static int solve_linear_system(struct bch_control *bch, unsigned int *rows,
+			       unsigned int *sol, int nsol)
+{
+	const int m = GF_M(bch);
+	unsigned int tmp, mask;
+	int rem, c, r, p, k, param[m];
+
+	k = 0;
+	mask = 1 << m;
+
+	/* Gaussian elimination */
+	for (c = 0; c < m; c++) {
+		rem = 0;
+		p = c-k;
+		/* find suitable row for elimination */
+		for (r = p; r < m; r++) {
+			if (rows[r] & mask) {
+				if (r != p) {
+					tmp = rows[r];
+					rows[r] = rows[p];
+					rows[p] = tmp;
+				}
+				rem = r+1;
+				break;
+			}
+		}
+		if (rem) {
+			/* perform elimination on remaining rows */
+			tmp = rows[p];
+			for (r = rem; r < m; r++) {
+				if (rows[r] & mask)
+					rows[r] ^= tmp;
+			}
+		} else {
+			/* elimination not needed, store defective row index */
+			param[k++] = c;
+		}
+		mask >>= 1;
+	}
+	/* rewrite system, inserting fake parameter rows */
+	if (k > 0) {
+		p = k;
+		for (r = m-1; r >= 0; r--) {
+			if ((r > m-1-k) && rows[r])
+				/* system has no solution */
+				return 0;
+
+			rows[r] = (p && (r == param[p-1])) ?
+				p--, 1u << (m-r) : rows[r-p];
+		}
+	}
+
+	if (nsol != (1 << k))
+		/* unexpected number of solutions */
+		return 0;
+
+	for (p = 0; p < nsol; p++) {
+		/* set parameters for p-th solution */
+		for (c = 0; c < k; c++)
+			rows[param[c]] = (rows[param[c]] & ~1)|((p >> c) & 1);
+
+		/* compute unique solution */
+		tmp = 0;
+		for (r = m-1; r >= 0; r--) {
+			mask = rows[r] & (tmp|1);
+			tmp |= parity(mask) << (m-r);
+		}
+		sol[p] = tmp >> 1;
+	}
+	return nsol;
+}
+
+/*
+ * this function builds and solves a linear system for finding roots of a degree
+ * 4 affine monic polynomial X^4+aX^2+bX+c over GF(2^m).
+ */
+static int find_affine4_roots(struct bch_control *bch, unsigned int a,
+			      unsigned int b, unsigned int c,
+			      unsigned int *roots)
+{
+	int i, j, k;
+	const int m = GF_M(bch);
+	unsigned int mask = 0xff, t, rows[16] = {0,};
+
+	j = a_log(bch, b);
+	k = a_log(bch, a);
+	rows[0] = c;
+
+	/* buid linear system to solve X^4+aX^2+bX+c = 0 */
+	for (i = 0; i < m; i++) {
+		rows[i+1] = bch->a_pow_tab[4*i]^
+			(a ? bch->a_pow_tab[mod_s(bch, k)] : 0)^
+			(b ? bch->a_pow_tab[mod_s(bch, j)] : 0);
+		j++;
+		k += 2;
+	}
+	/*
+	 * transpose 16x16 matrix before passing it to linear solver
+	 * warning: this code assumes m < 16
+	 */
+	for (j = 8; j != 0; j >>= 1, mask ^= (mask << j)) {
+		for (k = 0; k < 16; k = (k+j+1) & ~j) {
+			t = ((rows[k] >> j)^rows[k+j]) & mask;
+			rows[k] ^= (t << j);
+			rows[k+j] ^= t;
+		}
+	}
+	return solve_linear_system(bch, rows, roots, 4);
+}
+
+/*
+ * compute root r of a degree 1 polynomial over GF(2^m) (returned as log(1/r))
+ */
+static int find_poly_deg1_roots(struct bch_control *bch, struct gf_poly *poly,
+				unsigned int *roots)
+{
+	int n = 0;
+
+	if (poly->c[0])
+		/* poly[X] = bX+c with c!=0, root=c/b */
+		roots[n++] = mod_s(bch, GF_N(bch)-bch->a_log_tab[poly->c[0]]+
+				   bch->a_log_tab[poly->c[1]]);
+	return n;
+}
+
+/*
+ * compute roots of a degree 2 polynomial over GF(2^m)
+ */
+static int find_poly_deg2_roots(struct bch_control *bch, struct gf_poly *poly,
+				unsigned int *roots)
+{
+	int n = 0, i, l0, l1, l2;
+	unsigned int u, v, r;
+
+	if (poly->c[0] && poly->c[1]) {
+
+		l0 = bch->a_log_tab[poly->c[0]];
+		l1 = bch->a_log_tab[poly->c[1]];
+		l2 = bch->a_log_tab[poly->c[2]];
+
+		/* using z=a/bX, transform aX^2+bX+c into z^2+z+u (u=ac/b^2) */
+		u = a_pow(bch, l0+l2+2*(GF_N(bch)-l1));
+		/*
+		 * let u = sum(li.a^i) i=0..m-1; then compute r = sum(li.xi):
+		 * r^2+r = sum(li.(xi^2+xi)) = sum(li.(a^i+Tr(a^i).a^k)) =
+		 * u + sum(li.Tr(a^i).a^k) = u+a^k.Tr(sum(li.a^i)) = u+a^k.Tr(u)
+		 * i.e. r and r+1 are roots iff Tr(u)=0
+		 */
+		r = 0;
+		v = u;
+		while (v) {
+			i = deg(v);
+			r ^= bch->xi_tab[i];
+			v ^= (1 << i);
+		}
+		/* verify root */
+		if ((gf_sqr(bch, r)^r) == u) {
+			/* reverse z=a/bX transformation and compute log(1/r) */
+			roots[n++] = modulo(bch, 2*GF_N(bch)-l1-
+					    bch->a_log_tab[r]+l2);
+			roots[n++] = modulo(bch, 2*GF_N(bch)-l1-
+					    bch->a_log_tab[r^1]+l2);
+		}
+	}
+	return n;
+}
+
+/*
+ * compute roots of a degree 3 polynomial over GF(2^m)
+ */
+static int find_poly_deg3_roots(struct bch_control *bch, struct gf_poly *poly,
+				unsigned int *roots)
+{
+	int i, n = 0;
+	unsigned int a, b, c, a2, b2, c2, e3, tmp[4];
+
+	if (poly->c[0]) {
+		/* transform polynomial into monic X^3 + a2X^2 + b2X + c2 */
+		e3 = poly->c[3];
+		c2 = gf_div(bch, poly->c[0], e3);
+		b2 = gf_div(bch, poly->c[1], e3);
+		a2 = gf_div(bch, poly->c[2], e3);
+
+		/* (X+a2)(X^3+a2X^2+b2X+c2) = X^4+aX^2+bX+c (affine) */
+		c = gf_mul(bch, a2, c2);           /* c = a2c2      */
+		b = gf_mul(bch, a2, b2)^c2;        /* b = a2b2 + c2 */
+		a = gf_sqr(bch, a2)^b2;            /* a = a2^2 + b2 */
+
+		/* find the 4 roots of this affine polynomial */
+		if (find_affine4_roots(bch, a, b, c, tmp) == 4) {
+			/* remove a2 from final list of roots */
+			for (i = 0; i < 4; i++) {
+				if (tmp[i] != a2)
+					roots[n++] = a_ilog(bch, tmp[i]);
+			}
+		}
+	}
+	return n;
+}
+
+/*
+ * compute roots of a degree 4 polynomial over GF(2^m)
+ */
+static int find_poly_deg4_roots(struct bch_control *bch, struct gf_poly *poly,
+				unsigned int *roots)
+{
+	int i, l, n = 0;
+	unsigned int a, b, c, d, e = 0, f, a2, b2, c2, e4;
+
+	if (poly->c[0] == 0)
+		return 0;
+
+	/* transform polynomial into monic X^4 + aX^3 + bX^2 + cX + d */
+	e4 = poly->c[4];
+	d = gf_div(bch, poly->c[0], e4);
+	c = gf_div(bch, poly->c[1], e4);
+	b = gf_div(bch, poly->c[2], e4);
+	a = gf_div(bch, poly->c[3], e4);
+
+	/* use Y=1/X transformation to get an affine polynomial */
+	if (a) {
+		/* first, eliminate cX by using z=X+e with ae^2+c=0 */
+		if (c) {
+			/* compute e such that e^2 = c/a */
+			f = gf_div(bch, c, a);
+			l = a_log(bch, f);
+			l += (l & 1) ? GF_N(bch) : 0;
+			e = a_pow(bch, l/2);
+			/*
+			 * use transformation z=X+e:
+			 * z^4+e^4 + a(z^3+ez^2+e^2z+e^3) + b(z^2+e^2) +cz+ce+d
+			 * z^4 + az^3 + (ae+b)z^2 + (ae^2+c)z+e^4+be^2+ae^3+ce+d
+			 * z^4 + az^3 + (ae+b)z^2 + e^4+be^2+d
+			 * z^4 + az^3 +     b'z^2 + d'
+			 */
+			d = a_pow(bch, 2*l)^gf_mul(bch, b, f)^d;
+			b = gf_mul(bch, a, e)^b;
+		}
+		/* now, use Y=1/X to get Y^4 + b/dY^2 + a/dY + 1/d */
+		if (d == 0)
+			/* assume all roots have multiplicity 1 */
+			return 0;
+
+		c2 = gf_inv(bch, d);
+		b2 = gf_div(bch, a, d);
+		a2 = gf_div(bch, b, d);
+	} else {
+		/* polynomial is already affine */
+		c2 = d;
+		b2 = c;
+		a2 = b;
+	}
+	/* find the 4 roots of this affine polynomial */
+	if (find_affine4_roots(bch, a2, b2, c2, roots) == 4) {
+		for (i = 0; i < 4; i++) {
+			/* post-process roots (reverse transformations) */
+			f = a ? gf_inv(bch, roots[i]) : roots[i];
+			roots[i] = a_ilog(bch, f^e);
+		}
+		n = 4;
+	}
+	return n;
+}
+
+/*
+ * build monic, log-based representation of a polynomial
+ */
+static void gf_poly_logrep(struct bch_control *bch,
+			   const struct gf_poly *a, int *rep)
+{
+	int i, d = a->deg, l = GF_N(bch)-a_log(bch, a->c[a->deg]);
+
+	/* represent 0 values with -1; warning, rep[d] is not set to 1 */
+	for (i = 0; i < d; i++)
+		rep[i] = a->c[i] ? mod_s(bch, a_log(bch, a->c[i])+l) : -1;
+}
+
+/*
+ * compute polynomial Euclidean division remainder in GF(2^m)[X]
+ */
+static void gf_poly_mod(struct bch_control *bch, struct gf_poly *a,
+			const struct gf_poly *b, int *rep)
+{
+	int la, p, m;
+	unsigned int i, j, *c = a->c;
+	const unsigned int d = b->deg;
+
+	if (a->deg < d)
+		return;
+
+	/* reuse or compute log representation of denominator */
+	if (!rep) {
+		rep = bch->cache;
+		gf_poly_logrep(bch, b, rep);
+	}
+
+	for (j = a->deg; j >= d; j--) {
+		if (c[j]) {
+			la = a_log(bch, c[j]);
+			p = j-d;
+			for (i = 0; i < d; i++, p++) {
+				m = rep[i];
+				if (m >= 0)
+					c[p] ^= bch->a_pow_tab[mod_s(bch,
+								     m+la)];
+			}
+		}
+	}
+	a->deg = d-1;
+	while (!c[a->deg] && a->deg)
+		a->deg--;
+}
+
+/*
+ * compute polynomial Euclidean division quotient in GF(2^m)[X]
+ */
+static void gf_poly_div(struct bch_control *bch, struct gf_poly *a,
+			const struct gf_poly *b, struct gf_poly *q)
+{
+	if (a->deg >= b->deg) {
+		q->deg = a->deg-b->deg;
+		/* compute a mod b (modifies a) */
+		gf_poly_mod(bch, a, b, NULL);
+		/* quotient is stored in upper part of polynomial a */
+		memcpy(q->c, &a->c[b->deg], (1+q->deg)*sizeof(unsigned int));
+	} else {
+		q->deg = 0;
+		q->c[0] = 0;
+	}
+}
+
+/*
+ * compute polynomial GCD (Greatest Common Divisor) in GF(2^m)[X]
+ */
+static struct gf_poly *gf_poly_gcd(struct bch_control *bch, struct gf_poly *a,
+				   struct gf_poly *b)
+{
+	struct gf_poly *tmp;
+
+	dbg("gcd(%s,%s)=", gf_poly_str(a), gf_poly_str(b));
+
+	if (a->deg < b->deg) {
+		tmp = b;
+		b = a;
+		a = tmp;
+	}
+
+	while (b->deg > 0) {
+		gf_poly_mod(bch, a, b, NULL);
+		tmp = b;
+		b = a;
+		a = tmp;
+	}
+
+	dbg("%s\n", gf_poly_str(a));
+
+	return a;
+}
+
+/*
+ * Given a polynomial f and an integer k, compute Tr(a^kX) mod f
+ * This is used in Berlekamp Trace algorithm for splitting polynomials
+ */
+static void compute_trace_bk_mod(struct bch_control *bch, int k,
+				 const struct gf_poly *f, struct gf_poly *z,
+				 struct gf_poly *out)
+{
+	const int m = GF_M(bch);
+	int i, j;
+
+	/* z contains z^2j mod f */
+	z->deg = 1;
+	z->c[0] = 0;
+	z->c[1] = bch->a_pow_tab[k];
+
+	out->deg = 0;
+	memset(out, 0, GF_POLY_SZ(f->deg));
+
+	/* compute f log representation only once */
+	gf_poly_logrep(bch, f, bch->cache);
+
+	for (i = 0; i < m; i++) {
+		/* add a^(k*2^i)(z^(2^i) mod f) and compute (z^(2^i) mod f)^2 */
+		for (j = z->deg; j >= 0; j--) {
+			out->c[j] ^= z->c[j];
+			z->c[2*j] = gf_sqr(bch, z->c[j]);
+			z->c[2*j+1] = 0;
+		}
+		if (z->deg > out->deg)
+			out->deg = z->deg;
+
+		if (i < m-1) {
+			z->deg *= 2;
+			/* z^(2(i+1)) mod f = (z^(2^i) mod f)^2 mod f */
+			gf_poly_mod(bch, z, f, bch->cache);
+		}
+	}
+	while (!out->c[out->deg] && out->deg)
+		out->deg--;
+
+	dbg("Tr(a^%d.X) mod f = %s\n", k, gf_poly_str(out));
+}
+
+/*
+ * factor a polynomial using Berlekamp Trace algorithm (BTA)
+ */
+static void factor_polynomial(struct bch_control *bch, int k, struct gf_poly *f,
+			      struct gf_poly **g, struct gf_poly **h)
+{
+	struct gf_poly *f2 = bch->poly_2t[0];
+	struct gf_poly *q  = bch->poly_2t[1];
+	struct gf_poly *tk = bch->poly_2t[2];
+	struct gf_poly *z  = bch->poly_2t[3];
+	struct gf_poly *gcd;
+
+	dbg("factoring %s...\n", gf_poly_str(f));
+
+	*g = f;
+	*h = NULL;
+
+	/* tk = Tr(a^k.X) mod f */
+	compute_trace_bk_mod(bch, k, f, z, tk);
+
+	if (tk->deg > 0) {
+		/* compute g = gcd(f, tk) (destructive operation) */
+		gf_poly_copy(f2, f);
+		gcd = gf_poly_gcd(bch, f2, tk);
+		if (gcd->deg < f->deg) {
+			/* compute h=f/gcd(f,tk); this will modify f and q */
+			gf_poly_div(bch, f, gcd, q);
+			/* store g and h in-place (clobbering f) */
+			*h = &((struct gf_poly_deg1 *)f)[gcd->deg].poly;
+			gf_poly_copy(*g, gcd);
+			gf_poly_copy(*h, q);
+		}
+	}
+}
+
+/*
+ * find roots of a polynomial, using BTZ algorithm; see the beginning of this
+ * file for details
+ */
+static int find_poly_roots(struct bch_control *bch, unsigned int k,
+			   struct gf_poly *poly, unsigned int *roots)
+{
+	int cnt;
+	struct gf_poly *f1, *f2;
+
+	switch (poly->deg) {
+		/* handle low degree polynomials with ad hoc techniques */
+	case 1:
+		cnt = find_poly_deg1_roots(bch, poly, roots);
+		break;
+	case 2:
+		cnt = find_poly_deg2_roots(bch, poly, roots);
+		break;
+	case 3:
+		cnt = find_poly_deg3_roots(bch, poly, roots);
+		break;
+	case 4:
+		cnt = find_poly_deg4_roots(bch, poly, roots);
+		break;
+	default:
+		/* factor polynomial using Berlekamp Trace Algorithm (BTA) */
+		cnt = 0;
+		if (poly->deg && (k <= GF_M(bch))) {
+			factor_polynomial(bch, k, poly, &f1, &f2);
+			if (f1)
+				cnt += find_poly_roots(bch, k+1, f1, roots);
+			if (f2)
+				cnt += find_poly_roots(bch, k+1, f2, roots+cnt);
+		}
+		break;
+	}
+	return cnt;
+}
+
+#if defined(USE_CHIEN_SEARCH)
+/*
+ * exhaustive root search (Chien) implementation - not used, included only for
+ * reference/comparison tests
+ */
+static int chien_search(struct bch_control *bch, unsigned int len,
+			struct gf_poly *p, unsigned int *roots)
+{
+	int m;
+	unsigned int i, j, syn, syn0, count = 0;
+	const unsigned int k = 8*len+bch->ecc_bits;
+
+	/* use a log-based representation of polynomial */
+	gf_poly_logrep(bch, p, bch->cache);
+	bch->cache[p->deg] = 0;
+	syn0 = gf_div(bch, p->c[0], p->c[p->deg]);
+
+	for (i = GF_N(bch)-k+1; i <= GF_N(bch); i++) {
+		/* compute elp(a^i) */
+		for (j = 1, syn = syn0; j <= p->deg; j++) {
+			m = bch->cache[j];
+			if (m >= 0)
+				syn ^= a_pow(bch, m+j*i);
+		}
+		if (syn == 0) {
+			roots[count++] = GF_N(bch)-i;
+			if (count == p->deg)
+				break;
+		}
+	}
+	return (count == p->deg) ? count : 0;
+}
+#define find_poly_roots(_p, _k, _elp, _loc) chien_search(_p, len, _elp, _loc)
+#endif /* USE_CHIEN_SEARCH */
+
+/**
+ * decode_bch - decode received codeword and find bit error locations
+ * @bch:      BCH control structure
+ * @data:     received data, ignored if @calc_ecc is provided
+ * @len:      data length in bytes, must always be provided
+ * @recv_ecc: received ecc, if NULL then assume it was XORed in @calc_ecc
+ * @calc_ecc: calculated ecc, if NULL then calc_ecc is computed from @data
+ * @syn:      hw computed syndrome data (if NULL, syndrome is calculated)
+ * @errloc:   output array of error locations
+ *
+ * Returns:
+ *  The number of errors found, or -EBADMSG if decoding failed, or -EINVAL if
+ *  invalid parameters were provided
+ *
+ * Depending on the available hw BCH support and the need to compute @calc_ecc
+ * separately (using encode_bch()), this function should be called with one of
+ * the following parameter configurations -
+ *
+ * by providing @data and @recv_ecc only:
+ *   decode_bch(@bch, @data, @len, @recv_ecc, NULL, NULL, @errloc)
+ *
+ * by providing @recv_ecc and @calc_ecc:
+ *   decode_bch(@bch, NULL, @len, @recv_ecc, @calc_ecc, NULL, @errloc)
+ *
+ * by providing ecc = recv_ecc XOR calc_ecc:
+ *   decode_bch(@bch, NULL, @len, NULL, ecc, NULL, @errloc)
+ *
+ * by providing syndrome results @syn:
+ *   decode_bch(@bch, NULL, @len, NULL, NULL, @syn, @errloc)
+ *
+ * Once decode_bch() has successfully returned with a positive value, error
+ * locations returned in array @errloc should be interpreted as follows -
+ *
+ * if (errloc[n] >= 8*len), then n-th error is located in ecc (no need for
+ * data correction)
+ *
+ * if (errloc[n] < 8*len), then n-th error is located in data and can be
+ * corrected with statement data[errloc[n]/8] ^= 1 << (errloc[n] % 8);
+ *
+ * Note that this function does not perform any data correction by itself, it
+ * merely indicates error locations.
+ */
+int decode_bch(struct bch_control *bch, const uint8_t *data, unsigned int len,
+	       const uint8_t *recv_ecc, const uint8_t *calc_ecc,
+	       const unsigned int *syn, unsigned int *errloc)
+{
+	const unsigned int ecc_words = BCH_ECC_WORDS(bch);
+	unsigned int nbits;
+	int i, err, nroots;
+	uint32_t sum;
+
+	/* sanity check: make sure data length can be handled */
+	if (8*len > (bch->n-bch->ecc_bits))
+		return -EINVAL;
+
+	/* if caller does not provide syndromes, compute them */
+	if (!syn) {
+		if (!calc_ecc) {
+			/* compute received data ecc into an internal buffer */
+			if (!data || !recv_ecc)
+				return -EINVAL;
+			encode_bch(bch, data, len, NULL);
+		} else {
+			/* load provided calculated ecc */
+			load_ecc8(bch, bch->ecc_buf, calc_ecc);
+		}
+		/* load received ecc or assume it was XORed in calc_ecc */
+		if (recv_ecc) {
+			load_ecc8(bch, bch->ecc_buf2, recv_ecc);
+			/* XOR received and calculated ecc */
+			for (i = 0, sum = 0; i < (int)ecc_words; i++) {
+				bch->ecc_buf[i] ^= bch->ecc_buf2[i];
+				sum |= bch->ecc_buf[i];
+			}
+			if (!sum)
+				/* no error found */
+				return 0;
+		}
+		compute_syndromes(bch, bch->ecc_buf, bch->syn);
+		syn = bch->syn;
+	}
+
+	err = compute_error_locator_polynomial(bch, syn);
+	if (err > 0) {
+		nroots = find_poly_roots(bch, 1, bch->elp, errloc);
+		if (err != nroots)
+			err = -1;
+	}
+	if (err > 0) {
+		/* post-process raw error locations for easier correction */
+		nbits = (len*8)+bch->ecc_bits;
+		for (i = 0; i < err; i++) {
+			if (errloc[i] >= nbits) {
+				err = -1;
+				break;
+			}
+			errloc[i] = nbits-1-errloc[i];
+			errloc[i] = (errloc[i] & ~7)|(7-(errloc[i] & 7));
+		}
+	}
+	return (err >= 0) ? err : -EBADMSG;
+}
+EXPORT_SYMBOL_GPL(decode_bch);
+
+/*
+ * generate Galois field lookup tables
+ */
+static int build_gf_tables(struct bch_control *bch, unsigned int poly)
+{
+	unsigned int i, x = 1;
+	const unsigned int k = 1 << deg(poly);
+
+	/* primitive polynomial must be of degree m */
+	if (k != (1u << GF_M(bch)))
+		return -1;
+
+	for (i = 0; i < GF_N(bch); i++) {
+		bch->a_pow_tab[i] = x;
+		bch->a_log_tab[x] = i;
+		if (i && (x == 1))
+			/* polynomial is not primitive (a^i=1 with 0<i<2^m-1) */
+			return -1;
+		x <<= 1;
+		if (x & k)
+			x ^= poly;
+	}
+	bch->a_pow_tab[GF_N(bch)] = 1;
+	bch->a_log_tab[0] = 0;
+
+	return 0;
+}
+
+/*
+ * compute generator polynomial remainder tables for fast encoding
+ */
+static void build_mod8_tables(struct bch_control *bch, const uint32_t *g)
+{
+	int i, j, b, d;
+	uint32_t data, hi, lo, *tab;
+	const int l = BCH_ECC_WORDS(bch);
+	const int plen = DIV_ROUND_UP(bch->ecc_bits+1, 32);
+	const int ecclen = DIV_ROUND_UP(bch->ecc_bits, 32);
+
+	memset(bch->mod8_tab, 0, 4*256*l*sizeof(*bch->mod8_tab));
+
+	for (i = 0; i < 256; i++) {
+		/* p(X)=i is a small polynomial of weight <= 8 */
+		for (b = 0; b < 4; b++) {
+			/* we want to compute (p(X).X^(8*b+deg(g))) mod g(X) */
+			tab = bch->mod8_tab + (b*256+i)*l;
+			data = i << (8*b);
+			while (data) {
+				d = deg(data);
+				/* subtract X^d.g(X) from p(X).X^(8*b+deg(g)) */
+				data ^= g[0] >> (31-d);
+				for (j = 0; j < ecclen; j++) {
+					hi = (d < 31) ? g[j] << (d+1) : 0;
+					lo = (j+1 < plen) ?
+						g[j+1] >> (31-d) : 0;
+					tab[j] ^= hi|lo;
+				}
+			}
+		}
+	}
+}
+
+/*
+ * build a base for factoring degree 2 polynomials
+ */
+static int build_deg2_base(struct bch_control *bch)
+{
+	const int m = GF_M(bch);
+	int i, j, r;
+	unsigned int sum, x, y, remaining, ak = 0, xi[m];
+
+	/* find k s.t. Tr(a^k) = 1 and 0 <= k < m */
+	for (i = 0; i < m; i++) {
+		for (j = 0, sum = 0; j < m; j++)
+			sum ^= a_pow(bch, i*(1 << j));
+
+		if (sum) {
+			ak = bch->a_pow_tab[i];
+			break;
+		}
+	}
+	/* find xi, i=0..m-1 such that xi^2+xi = a^i+Tr(a^i).a^k */
+	remaining = m;
+	memset(xi, 0, sizeof(xi));
+
+	for (x = 0; (x <= GF_N(bch)) && remaining; x++) {
+		y = gf_sqr(bch, x)^x;
+		for (i = 0; i < 2; i++) {
+			r = a_log(bch, y);
+			if (y && (r < m) && !xi[r]) {
+				bch->xi_tab[r] = x;
+				xi[r] = 1;
+				remaining--;
+				dbg("x%d = %x\n", r, x);
+				break;
+			}
+			y ^= ak;
+		}
+	}
+	/* should not happen but check anyway */
+	return remaining ? -1 : 0;
+}
+
+static void *bch_alloc(size_t size, int *err)
+{
+	void *ptr;
+
+	ptr = kmalloc(size, GFP_KERNEL);
+	if (ptr == NULL)
+		*err = 1;
+	return ptr;
+}
+
+/*
+ * compute generator polynomial for given (m,t) parameters.
+ */
+static uint32_t *compute_generator_polynomial(struct bch_control *bch)
+{
+	const unsigned int m = GF_M(bch);
+	const unsigned int t = GF_T(bch);
+	int n, err = 0;
+	unsigned int i, j, nbits, r, word, *roots;
+	struct gf_poly *g;
+	uint32_t *genpoly;
+
+	g = bch_alloc(GF_POLY_SZ(m*t), &err);
+	roots = bch_alloc((bch->n+1)*sizeof(*roots), &err);
+	genpoly = bch_alloc(DIV_ROUND_UP(m*t+1, 32)*sizeof(*genpoly), &err);
+
+	if (err) {
+		kfree(genpoly);
+		genpoly = NULL;
+		goto finish;
+	}
+
+	/* enumerate all roots of g(X) */
+	memset(roots , 0, (bch->n+1)*sizeof(*roots));
+	for (i = 0; i < t; i++) {
+		for (j = 0, r = 2*i+1; j < m; j++) {
+			roots[r] = 1;
+			r = mod_s(bch, 2*r);
+		}
+	}
+	/* build generator polynomial g(X) */
+	g->deg = 0;
+	g->c[0] = 1;
+	for (i = 0; i < GF_N(bch); i++) {
+		if (roots[i]) {
+			/* multiply g(X) by (X+root) */
+			r = bch->a_pow_tab[i];
+			g->c[g->deg+1] = 1;
+			for (j = g->deg; j > 0; j--)
+				g->c[j] = gf_mul(bch, g->c[j], r)^g->c[j-1];
+
+			g->c[0] = gf_mul(bch, g->c[0], r);
+			g->deg++;
+		}
+	}
+	/* store left-justified binary representation of g(X) */
+	n = g->deg+1;
+	i = 0;
+
+	while (n > 0) {
+		nbits = (n > 32) ? 32 : n;
+		for (j = 0, word = 0; j < nbits; j++) {
+			if (g->c[n-1-j])
+				word |= 1u << (31-j);
+		}
+		genpoly[i++] = word;
+		n -= nbits;
+	}
+	bch->ecc_bits = g->deg;
+
+finish:
+	kfree(g);
+	kfree(roots);
+
+	return genpoly;
+}
+
+/**
+ * init_bch - initialize a BCH encoder/decoder
+ * @m:          Galois field order, should be in the range 5-15
+ * @t:          maximum error correction capability, in bits
+ * @prim_poly:  user-provided primitive polynomial (or 0 to use default)
+ *
+ * Returns:
+ *  a newly allocated BCH control structure if successful, NULL otherwise
+ *
+ * This initialization can take some time, as lookup tables are built for fast
+ * encoding/decoding; make sure not to call this function from a time critical
+ * path. Usually, init_bch() should be called on module/driver init and
+ * free_bch() should be called to release memory on exit.
+ *
+ * You may provide your own primitive polynomial of degree @m in argument
+ * @prim_poly, or let init_bch() use its default polynomial.
+ *
+ * Once init_bch() has successfully returned a pointer to a newly allocated
+ * BCH control structure, ecc length in bytes is given by member @ecc_bytes of
+ * the structure.
+ */
+struct bch_control *init_bch(int m, int t, unsigned int prim_poly)
+{
+	int err = 0;
+	unsigned int i, words;
+	uint32_t *genpoly;
+	struct bch_control *bch = NULL;
+
+	const int min_m = 5;
+	const int max_m = 15;
+
+	/* default primitive polynomials */
+	static const unsigned int prim_poly_tab[] = {
+		0x25, 0x43, 0x83, 0x11d, 0x211, 0x409, 0x805, 0x1053, 0x201b,
+		0x402b, 0x8003,
+	};
+
+#if defined(CONFIG_BCH_CONST_PARAMS)
+	if ((m != (CONFIG_BCH_CONST_M)) || (t != (CONFIG_BCH_CONST_T))) {
+		printk(KERN_ERR "bch encoder/decoder was configured to support "
+		       "parameters m=%d, t=%d only!\n",
+		       CONFIG_BCH_CONST_M, CONFIG_BCH_CONST_T);
+		goto fail;
+	}
+#endif
+	if ((m < min_m) || (m > max_m))
+		/*
+		 * values of m greater than 15 are not currently supported;
+		 * supporting m > 15 would require changing table base type
+		 * (uint16_t) and a small patch in matrix transposition
+		 */
+		goto fail;
+
+	/* sanity checks */
+	if ((t < 1) || (m*t >= ((1 << m)-1)))
+		/* invalid t value */
+		goto fail;
+
+	/* select a primitive polynomial for generating GF(2^m) */
+	if (prim_poly == 0)
+		prim_poly = prim_poly_tab[m-min_m];
+
+	bch = kzalloc(sizeof(*bch), GFP_KERNEL);
+	if (bch == NULL)
+		goto fail;
+
+	bch->m = m;
+	bch->t = t;
+	bch->n = (1 << m)-1;
+	words  = DIV_ROUND_UP(m*t, 32);
+	bch->ecc_bytes = DIV_ROUND_UP(m*t, 8);
+	bch->a_pow_tab = bch_alloc((1+bch->n)*sizeof(*bch->a_pow_tab), &err);
+	bch->a_log_tab = bch_alloc((1+bch->n)*sizeof(*bch->a_log_tab), &err);
+	bch->mod8_tab  = bch_alloc(words*1024*sizeof(*bch->mod8_tab), &err);
+	bch->ecc_buf   = bch_alloc(words*sizeof(*bch->ecc_buf), &err);
+	bch->ecc_buf2  = bch_alloc(words*sizeof(*bch->ecc_buf2), &err);
+	bch->xi_tab    = bch_alloc(m*sizeof(*bch->xi_tab), &err);
+	bch->syn       = bch_alloc(2*t*sizeof(*bch->syn), &err);
+	bch->cache     = bch_alloc(2*t*sizeof(*bch->cache), &err);
+	bch->elp       = bch_alloc((t+1)*sizeof(struct gf_poly_deg1), &err);
+
+	for (i = 0; i < ARRAY_SIZE(bch->poly_2t); i++)
+		bch->poly_2t[i] = bch_alloc(GF_POLY_SZ(2*t), &err);
+
+	if (err)
+		goto fail;
+
+	err = build_gf_tables(bch, prim_poly);
+	if (err)
+		goto fail;
+
+	/* use generator polynomial for computing encoding tables */
+	genpoly = compute_generator_polynomial(bch);
+	if (genpoly == NULL)
+		goto fail;
+
+	build_mod8_tables(bch, genpoly);
+	kfree(genpoly);
+
+	err = build_deg2_base(bch);
+	if (err)
+		goto fail;
+
+	return bch;
+
+fail:
+	free_bch(bch);
+	return NULL;
+}
+EXPORT_SYMBOL_GPL(init_bch);
+
+/**
+ *  free_bch - free the BCH control structure
+ *  @bch:    BCH control structure to release
+ */
+void free_bch(struct bch_control *bch)
+{
+	unsigned int i;
+
+	if (bch) {
+		kfree(bch->a_pow_tab);
+		kfree(bch->a_log_tab);
+		kfree(bch->mod8_tab);
+		kfree(bch->ecc_buf);
+		kfree(bch->ecc_buf2);
+		kfree(bch->xi_tab);
+		kfree(bch->syn);
+		kfree(bch->cache);
+		kfree(bch->elp);
+
+		for (i = 0; i < ARRAY_SIZE(bch->poly_2t); i++)
+			kfree(bch->poly_2t[i]);
+
+		kfree(bch);
+	}
+}
+EXPORT_SYMBOL_GPL(free_bch);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Ivan Djelic <ivan.djelic@parrot.com>");
+MODULE_DESCRIPTION("Binary BCH encoder/decoder");
-- 
1.7.5.4


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^ permalink raw reply	[flat|nested] 7+ messages in thread

* [PATCH V2 2/3] lib: add bitrev utility
  2011-12-22 15:51 [PATCH V2 0/3] Add MSystems Disk-On-Chip G3 support Robert Jarzmik
  2011-12-22 15:51 ` [PATCH V2 1/3] lib: add BCH encoding/decoding Robert Jarzmik
@ 2011-12-22 15:51 ` Robert Jarzmik
  2011-12-22 15:51 ` [PATCH V2 3/3] drivers/mtd: add docg3 chip Robert Jarzmik
  2012-01-05 23:11 ` [PATCH V2 0/3] Add MSystems Disk-On-Chip G3 support Robert Jarzmik
  3 siblings, 0 replies; 7+ messages in thread
From: Robert Jarzmik @ 2011-12-22 15:51 UTC (permalink / raw)
  To: barebox

Add bit reversing utility, taken from the linux kernel.

Signed-off-by: Robert Jarzmik <robert.jarzmik@free.fr>
---
 include/linux/bitrev.h |   16 +++++++++++
 lib/Kconfig            |    3 ++
 lib/Makefile           |    1 +
 lib/bitrev.c           |   68 ++++++++++++++++++++++++++++++++++++++++++++++++
 4 files changed, 88 insertions(+), 0 deletions(-)
 create mode 100644 include/linux/bitrev.h
 create mode 100644 lib/bitrev.c

diff --git a/include/linux/bitrev.h b/include/linux/bitrev.h
new file mode 100644
index 0000000..7ffe03f
--- /dev/null
+++ b/include/linux/bitrev.h
@@ -0,0 +1,16 @@
+#ifndef _LINUX_BITREV_H
+#define _LINUX_BITREV_H
+
+#include <linux/types.h>
+
+extern u8 const byte_rev_table[256];
+
+static inline u8 bitrev8(u8 byte)
+{
+	return byte_rev_table[byte];
+}
+
+extern u16 bitrev16(u16 in);
+extern u32 bitrev32(u32 in);
+
+#endif /* _LINUX_BITREV_H */
diff --git a/lib/Kconfig b/lib/Kconfig
index 83ac1ac..3339a9a 100644
--- a/lib/Kconfig
+++ b/lib/Kconfig
@@ -23,4 +23,7 @@ config OFTREE
 config BCH
        bool
 
+config BITREV
+       bool
+
 endmenu
diff --git a/lib/Makefile b/lib/Makefile
index 04c5487..7799e69 100644
--- a/lib/Makefile
+++ b/lib/Makefile
@@ -32,3 +32,4 @@ obj-$(CONFIG_PROCESS_ESCAPE_SEQUENCE)	+= process_escape_sequence.o
 obj-$(CONFIG_FDT)	+= fdt/
 obj-y			+= uncompress.o
 obj-$(CONFIG_BCH)	+= bch.o
+obj-$(CONFIG_BITREV)	+= bitrev.o
diff --git a/lib/bitrev.c b/lib/bitrev.c
new file mode 100644
index 0000000..2662760
--- /dev/null
+++ b/lib/bitrev.c
@@ -0,0 +1,68 @@
+/*
+ * Bit reversal module
+ *
+ * Copyright (C) Akinobu Mita
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * Taken from linux kernel.
+ */
+#include <linux/types.h>
+#include <linux/bitrev.h>
+
+const u8 byte_rev_table[256] = {
+	0x00, 0x80, 0x40, 0xc0, 0x20, 0xa0, 0x60, 0xe0,
+	0x10, 0x90, 0x50, 0xd0, 0x30, 0xb0, 0x70, 0xf0,
+	0x08, 0x88, 0x48, 0xc8, 0x28, 0xa8, 0x68, 0xe8,
+	0x18, 0x98, 0x58, 0xd8, 0x38, 0xb8, 0x78, 0xf8,
+	0x04, 0x84, 0x44, 0xc4, 0x24, 0xa4, 0x64, 0xe4,
+	0x14, 0x94, 0x54, 0xd4, 0x34, 0xb4, 0x74, 0xf4,
+	0x0c, 0x8c, 0x4c, 0xcc, 0x2c, 0xac, 0x6c, 0xec,
+	0x1c, 0x9c, 0x5c, 0xdc, 0x3c, 0xbc, 0x7c, 0xfc,
+	0x02, 0x82, 0x42, 0xc2, 0x22, 0xa2, 0x62, 0xe2,
+	0x12, 0x92, 0x52, 0xd2, 0x32, 0xb2, 0x72, 0xf2,
+	0x0a, 0x8a, 0x4a, 0xca, 0x2a, 0xaa, 0x6a, 0xea,
+	0x1a, 0x9a, 0x5a, 0xda, 0x3a, 0xba, 0x7a, 0xfa,
+	0x06, 0x86, 0x46, 0xc6, 0x26, 0xa6, 0x66, 0xe6,
+	0x16, 0x96, 0x56, 0xd6, 0x36, 0xb6, 0x76, 0xf6,
+	0x0e, 0x8e, 0x4e, 0xce, 0x2e, 0xae, 0x6e, 0xee,
+	0x1e, 0x9e, 0x5e, 0xde, 0x3e, 0xbe, 0x7e, 0xfe,
+	0x01, 0x81, 0x41, 0xc1, 0x21, 0xa1, 0x61, 0xe1,
+	0x11, 0x91, 0x51, 0xd1, 0x31, 0xb1, 0x71, 0xf1,
+	0x09, 0x89, 0x49, 0xc9, 0x29, 0xa9, 0x69, 0xe9,
+	0x19, 0x99, 0x59, 0xd9, 0x39, 0xb9, 0x79, 0xf9,
+	0x05, 0x85, 0x45, 0xc5, 0x25, 0xa5, 0x65, 0xe5,
+	0x15, 0x95, 0x55, 0xd5, 0x35, 0xb5, 0x75, 0xf5,
+	0x0d, 0x8d, 0x4d, 0xcd, 0x2d, 0xad, 0x6d, 0xed,
+	0x1d, 0x9d, 0x5d, 0xdd, 0x3d, 0xbd, 0x7d, 0xfd,
+	0x03, 0x83, 0x43, 0xc3, 0x23, 0xa3, 0x63, 0xe3,
+	0x13, 0x93, 0x53, 0xd3, 0x33, 0xb3, 0x73, 0xf3,
+	0x0b, 0x8b, 0x4b, 0xcb, 0x2b, 0xab, 0x6b, 0xeb,
+	0x1b, 0x9b, 0x5b, 0xdb, 0x3b, 0xbb, 0x7b, 0xfb,
+	0x07, 0x87, 0x47, 0xc7, 0x27, 0xa7, 0x67, 0xe7,
+	0x17, 0x97, 0x57, 0xd7, 0x37, 0xb7, 0x77, 0xf7,
+	0x0f, 0x8f, 0x4f, 0xcf, 0x2f, 0xaf, 0x6f, 0xef,
+	0x1f, 0x9f, 0x5f, 0xdf, 0x3f, 0xbf, 0x7f, 0xff,
+};
+
+u16 bitrev16(u16 x)
+{
+	return (bitrev8(x & 0xff) << 8) | bitrev8(x >> 8);
+}
+
+/**
+ * bitrev32 - reverse the order of bits in a u32 value
+ * @x: value to be bit-reversed
+ */
+u32 bitrev32(u32 x)
+{
+	return (bitrev16(x & 0xffff) << 16) | bitrev16(x >> 16);
+}
-- 
1.7.5.4


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^ permalink raw reply	[flat|nested] 7+ messages in thread

* [PATCH V2 3/3] drivers/mtd: add docg3 chip
  2011-12-22 15:51 [PATCH V2 0/3] Add MSystems Disk-On-Chip G3 support Robert Jarzmik
  2011-12-22 15:51 ` [PATCH V2 1/3] lib: add BCH encoding/decoding Robert Jarzmik
  2011-12-22 15:51 ` [PATCH V2 2/3] lib: add bitrev utility Robert Jarzmik
@ 2011-12-22 15:51 ` Robert Jarzmik
  2012-01-05 23:11 ` [PATCH V2 0/3] Add MSystems Disk-On-Chip G3 support Robert Jarzmik
  3 siblings, 0 replies; 7+ messages in thread
From: Robert Jarzmik @ 2011-12-22 15:51 UTC (permalink / raw)
  To: barebox

Add the MSystem disk-on-chip G3 support, taken from the
linux kernel with few amendments to bring it into barebox.

Signed-off-by: Robert Jarzmik <robert.jarzmik@free.fr>

---
Since V1:
 - fix: docg3: align OOB stack to 4 bytes boundary
   drivers/mtd/Makefile: add self-contained devices
 - fix: add surrounding #ifdef MTD_WRITE for size
   optimization
---
 drivers/mtd/Kconfig          |    1 +
 drivers/mtd/Makefile         |    1 +
 drivers/mtd/devices/Kconfig  |   16 +
 drivers/mtd/devices/Makefile |    5 +
 drivers/mtd/devices/docg3.c  | 1196 ++++++++++++++++++++++++++++++++++++++++++
 drivers/mtd/devices/docg3.h  |  283 ++++++++++
 6 files changed, 1502 insertions(+), 0 deletions(-)
 create mode 100644 drivers/mtd/devices/Kconfig
 create mode 100644 drivers/mtd/devices/Makefile
 create mode 100644 drivers/mtd/devices/docg3.c
 create mode 100644 drivers/mtd/devices/docg3.h

diff --git a/drivers/mtd/Kconfig b/drivers/mtd/Kconfig
index 9137cde..69ababc 100644
--- a/drivers/mtd/Kconfig
+++ b/drivers/mtd/Kconfig
@@ -20,6 +20,7 @@ config MTD_RAW_DEVICE
 	default n
 	prompt "mtdraw device to read/write both data+oob"
 
+source "drivers/mtd/devices/Kconfig"
 source "drivers/mtd/nand/Kconfig"
 source "drivers/mtd/ubi/Kconfig"
 
diff --git a/drivers/mtd/Makefile b/drivers/mtd/Makefile
index 67741f4..4f97d9a 100644
--- a/drivers/mtd/Makefile
+++ b/drivers/mtd/Makefile
@@ -1,5 +1,6 @@
 obj-$(CONFIG_NAND)			+= nand/
 obj-$(CONFIG_UBI)			+= ubi/
+obj-y					+= devices/
 obj-$(CONFIG_PARTITION_NEED_MTD)	+= partition.o
 obj-$(CONFIG_MTD)			+= core.o
 obj-$(CONFIG_MTD_OOB_DEVICE)		+= mtdoob.o
diff --git a/drivers/mtd/devices/Kconfig b/drivers/mtd/devices/Kconfig
new file mode 100644
index 0000000..e6d747c
--- /dev/null
+++ b/drivers/mtd/devices/Kconfig
@@ -0,0 +1,16 @@
+menu "Self contained MTD devices"
+	depends on MTD!=n
+
+config MTD_DOCG3
+	bool "M-Systems Disk-On-Chip G3"
+	select BCH
+	select BITREV
+	---help---
+	  This provides an MTD device driver for the M-Systems DiskOnChip
+	  G3 devices.
+
+	  The driver provides access to G3 DiskOnChip, distributed by
+	  M-Systems and now Sandisk. The support is very experimental,
+	  and doesn't give access to any write operations.
+
+endmenu
diff --git a/drivers/mtd/devices/Makefile b/drivers/mtd/devices/Makefile
new file mode 100644
index 0000000..164a72e
--- /dev/null
+++ b/drivers/mtd/devices/Makefile
@@ -0,0 +1,5 @@
+#
+# Makefile for the self containted memory technology device drivers.
+#
+
+obj-$(CONFIG_MTD_DOCG3)		+= docg3.o
diff --git a/drivers/mtd/devices/docg3.c b/drivers/mtd/devices/docg3.c
new file mode 100644
index 0000000..f7e33dc
--- /dev/null
+++ b/drivers/mtd/devices/docg3.c
@@ -0,0 +1,1196 @@
+/*
+ * Handles the M-Systems DiskOnChip G3 chip
+ *
+ * Copyright (C) 2011 Robert Jarzmik
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * Taken from linux kernel.
+ */
+
+#include <common.h>
+#include <init.h>
+#include <driver.h>
+#include <errno.h>
+#include <malloc.h>
+#include <io.h>
+#include <linux/kernel.h>
+#include <linux/mtd/mtd.h>
+#include <linux/err.h>
+#include <linux/bitrev.h>
+#include <linux/bch.h>
+
+#include "docg3.h"
+
+static unsigned reliable_mode;
+
+/**
+ * struct docg3_bch - BCH engine
+ */
+static struct bch_control *docg3_bch;
+struct mtd_info *docg3_floors[DOC_MAX_NBFLOORS];
+
+static inline u8 doc_readb(struct docg3 *docg3, u16 reg)
+{
+	u8 val = readb(docg3->base + reg);
+
+	doc_dbg("readb(%04x) -> %02x\n", reg, val);
+	return val;
+}
+
+static inline u16 doc_readw(struct docg3 *docg3, u16 reg)
+{
+	u16 val = readw(docg3->base + reg);
+
+	doc_dbg("readb(%04x) -> %04x\n", reg, val);
+	return val;
+}
+
+static inline void doc_writeb(struct docg3 *docg3, u8 val, u16 reg)
+{
+	doc_dbg("writeb(%02x into %04x)\n", val, reg);
+	writeb(val, docg3->base + reg);
+}
+
+static inline void doc_writew(struct docg3 *docg3, u16 val, u16 reg)
+{
+	doc_dbg("writew(%04x into %04x)\n", val, reg);
+	writew(val, docg3->base + reg);
+}
+
+static inline void doc_flash_command(struct docg3 *docg3, u8 cmd)
+{
+	doc_writeb(docg3, cmd, DOC_FLASHCOMMAND);
+}
+
+static inline void doc_flash_sequence(struct docg3 *docg3, u8 seq)
+{
+	doc_writeb(docg3, seq, DOC_FLASHSEQUENCE);
+}
+
+static inline void doc_flash_address(struct docg3 *docg3, u8 addr)
+{
+	doc_writeb(docg3, addr, DOC_FLASHADDRESS);
+}
+
+static int doc_register_readb(struct docg3 *docg3, int reg)
+{
+	u8 val;
+
+	doc_writew(docg3, reg, DOC_READADDRESS);
+	val = doc_readb(docg3, reg);
+	doc_vdbg("Read register %04x : %02x\n", reg, val);
+	return val;
+}
+
+static int doc_register_readw(struct docg3 *docg3, int reg)
+{
+	u16 val;
+
+	doc_writew(docg3, reg, DOC_READADDRESS);
+	val = doc_readw(docg3, reg);
+	doc_vdbg("Read register %04x : %04x\n", reg, val);
+	return val;
+}
+
+static void doc_delay(struct docg3 *docg3, int nbNOPs)
+{
+	int i;
+
+	doc_vdbg("NOP x %d\n", nbNOPs);
+	for (i = 0; i < nbNOPs; i++)
+		doc_writeb(docg3, 0, DOC_NOP);
+}
+
+static int is_prot_seq_error(struct docg3 *docg3)
+{
+	int ctrl;
+
+	ctrl = doc_register_readb(docg3, DOC_FLASHCONTROL);
+	return ctrl & (DOC_CTRL_PROTECTION_ERROR | DOC_CTRL_SEQUENCE_ERROR);
+}
+
+static int doc_is_ready(struct docg3 *docg3)
+{
+	int ctrl;
+
+	ctrl = doc_register_readb(docg3, DOC_FLASHCONTROL);
+	return ctrl & DOC_CTRL_FLASHREADY;
+}
+
+static int doc_wait_ready(struct docg3 *docg3)
+{
+	int maxWaitCycles = 100;
+
+	do {
+		doc_delay(docg3, 4);
+	} while (!doc_is_ready(docg3) && maxWaitCycles--);
+	doc_delay(docg3, 2);
+	if (maxWaitCycles > 0)
+		return 0;
+	else
+		return -EIO;
+}
+
+static int doc_reset_seq(struct docg3 *docg3)
+{
+	int ret;
+
+	doc_writeb(docg3, 0x10, DOC_FLASHCONTROL);
+	doc_flash_sequence(docg3, DOC_SEQ_RESET);
+	doc_flash_command(docg3, DOC_CMD_RESET);
+	doc_delay(docg3, 2);
+	ret = doc_wait_ready(docg3);
+
+	doc_dbg("doc_reset_seq() -> isReady=%s\n", ret ? "false" : "true");
+	return ret;
+}
+
+static void doc_read_data_area(struct docg3 *docg3, void *buf, int len,
+			       int first)
+{
+	int i, cdr, len4;
+	u16 data16, *dst16;
+	u8 data8, *dst8;
+
+	doc_dbg("doc_read_data_area(buf=%p, len=%d)\n", buf, len);
+	cdr = len & 0x3;
+	len4 = len - cdr;
+
+	if (first)
+		doc_writew(docg3, DOC_IOSPACE_DATA, DOC_READADDRESS);
+	dst16 = buf;
+	for (i = 0; i < len4; i += 2) {
+		data16 = doc_readw(docg3, DOC_IOSPACE_DATA);
+		if (dst16) {
+			*dst16 = data16;
+			dst16++;
+		}
+	}
+
+	if (cdr) {
+		doc_writew(docg3, DOC_IOSPACE_DATA | DOC_READADDR_ONE_BYTE,
+			   DOC_READADDRESS);
+		doc_delay(docg3, 1);
+		dst8 = (u8 *)dst16;
+		for (i = 0; i < cdr; i++) {
+			data8 = doc_readb(docg3, DOC_IOSPACE_DATA);
+			if (dst8) {
+				*dst8 = data8;
+				dst8++;
+			}
+		}
+	}
+}
+
+static void doc_set_reliable_mode(struct docg3 *docg3)
+{
+	static char *strmode[] = { "normal", "fast", "reliable", "invalid" };
+
+	doc_dbg("doc_set_reliable_mode(%s)\n", strmode[docg3->reliable]);
+	switch (docg3->reliable) {
+	case 0:
+		break;
+	case 1:
+		doc_flash_sequence(docg3, DOC_SEQ_SET_FASTMODE);
+		doc_flash_command(docg3, DOC_CMD_FAST_MODE);
+		break;
+	case 2:
+		doc_flash_sequence(docg3, DOC_SEQ_SET_RELIABLEMODE);
+		doc_flash_command(docg3, DOC_CMD_FAST_MODE);
+		doc_flash_command(docg3, DOC_CMD_RELIABLE_MODE);
+		break;
+	default:
+		doc_err("doc_set_reliable_mode(): invalid mode\n");
+		break;
+	}
+	doc_delay(docg3, 2);
+}
+
+static void doc_set_asic_mode(struct docg3 *docg3, u8 mode)
+{
+	int i;
+
+	for (i = 0; i < 12; i++)
+		doc_readb(docg3, DOC_IOSPACE_IPL);
+
+	mode |= DOC_ASICMODE_MDWREN;
+	doc_dbg("doc_set_asic_mode(%02x)\n", mode);
+	doc_writeb(docg3, mode, DOC_ASICMODE);
+	doc_writeb(docg3, ~mode, DOC_ASICMODECONFIRM);
+	doc_delay(docg3, 1);
+}
+
+static void doc_set_device_id(struct docg3 *docg3, int id)
+{
+	u8 ctrl;
+
+	doc_dbg("doc_set_device_id(%d)\n", id);
+	doc_writeb(docg3, id, DOC_DEVICESELECT);
+	ctrl = doc_register_readb(docg3, DOC_FLASHCONTROL);
+
+	ctrl &= ~DOC_CTRL_VIOLATION;
+	ctrl |= DOC_CTRL_CE;
+	doc_writeb(docg3, ctrl, DOC_FLASHCONTROL);
+}
+
+static int doc_set_extra_page_mode(struct docg3 *docg3)
+{
+	int fctrl;
+
+	doc_dbg("doc_set_extra_page_mode()\n");
+	doc_flash_sequence(docg3, DOC_SEQ_PAGE_SIZE_532);
+	doc_flash_command(docg3, DOC_CMD_PAGE_SIZE_532);
+	doc_delay(docg3, 2);
+
+	fctrl = doc_register_readb(docg3, DOC_FLASHCONTROL);
+	if (fctrl & (DOC_CTRL_PROTECTION_ERROR | DOC_CTRL_SEQUENCE_ERROR))
+		return -EIO;
+	else
+		return 0;
+}
+
+static void doc_setup_addr_sector(struct docg3 *docg3, int sector)
+{
+	doc_delay(docg3, 1);
+	doc_flash_address(docg3, sector & 0xff);
+	doc_flash_address(docg3, (sector >> 8) & 0xff);
+	doc_flash_address(docg3, (sector >> 16) & 0xff);
+	doc_delay(docg3, 1);
+}
+
+static int doc_read_seek(struct docg3 *docg3, int block0, int block1, int page,
+			 int wear, int ofs)
+{
+	int sector, ret = 0;
+
+	doc_dbg("doc_seek(blocks=(%d,%d), page=%d, ofs=%d, wear=%d)\n",
+		block0, block1, page, ofs, wear);
+
+	if (!wear && (ofs < 2 * DOC_LAYOUT_PAGE_SIZE)) {
+		doc_flash_sequence(docg3, DOC_SEQ_SET_PLANE1);
+		doc_flash_command(docg3, DOC_CMD_READ_PLANE1);
+		doc_delay(docg3, 2);
+	} else {
+		doc_flash_sequence(docg3, DOC_SEQ_SET_PLANE2);
+		doc_flash_command(docg3, DOC_CMD_READ_PLANE2);
+		doc_delay(docg3, 2);
+	}
+
+	doc_set_reliable_mode(docg3);
+	if (wear)
+		ret = doc_set_extra_page_mode(docg3);
+	if (ret)
+		goto out;
+
+	doc_flash_sequence(docg3, DOC_SEQ_READ);
+	sector = (block0 << DOC_ADDR_BLOCK_SHIFT) + (page & DOC_ADDR_PAGE_MASK);
+	doc_flash_command(docg3, DOC_CMD_PROG_BLOCK_ADDR);
+	doc_setup_addr_sector(docg3, sector);
+
+	sector = (block1 << DOC_ADDR_BLOCK_SHIFT) + (page & DOC_ADDR_PAGE_MASK);
+	doc_flash_command(docg3, DOC_CMD_PROG_BLOCK_ADDR);
+	doc_setup_addr_sector(docg3, sector);
+	doc_delay(docg3, 1);
+
+out:
+	return ret;
+}
+
+static int doc_read_page_ecc_init(struct docg3 *docg3, int len)
+{
+	doc_writew(docg3, DOC_ECCCONF0_READ_MODE
+		   | DOC_ECCCONF0_BCH_ENABLE | DOC_ECCCONF0_HAMMING_ENABLE
+		   | (len & DOC_ECCCONF0_DATA_BYTES_MASK),
+		   DOC_ECCCONF0);
+	doc_delay(docg3, 4);
+	doc_register_readb(docg3, DOC_FLASHCONTROL);
+	return doc_wait_ready(docg3);
+}
+
+static void doc_hamming_ecc_init(struct docg3 *docg3, int nb_bytes)
+{
+	u8 ecc_conf1;
+
+	ecc_conf1 = doc_register_readb(docg3, DOC_ECCCONF1);
+	ecc_conf1 &= ~DOC_ECCCONF1_HAMMING_BITS_MASK;
+	ecc_conf1 |= (nb_bytes & DOC_ECCCONF1_HAMMING_BITS_MASK);
+	doc_writeb(docg3, ecc_conf1, DOC_ECCCONF1);
+}
+
+static int doc_ecc_bch_fix_data(struct docg3 *docg3, void *buf, u8 *hwecc)
+{
+	u8 ecc[DOC_ECC_BCH_SIZE];
+	int errorpos[DOC_ECC_BCH_T], i, numerrs;
+
+	for (i = 0; i < DOC_ECC_BCH_SIZE; i++)
+		ecc[i] = bitrev8(hwecc[i]);
+	numerrs = decode_bch(docg3_bch, NULL, DOC_ECC_BCH_COVERED_BYTES,
+			     NULL, ecc, NULL, errorpos);
+	BUG_ON(numerrs == -EINVAL);
+	if (numerrs < 0)
+		goto out;
+
+	for (i = 0; i < numerrs; i++)
+		errorpos[i] = (errorpos[i] & ~7) | (7 - (errorpos[i] & 7));
+	for (i = 0; i < numerrs; i++)
+		if (errorpos[i] < DOC_ECC_BCH_COVERED_BYTES*8)
+			/* error is located in data, correct it */
+			change_bit(errorpos[i], buf);
+out:
+	doc_dbg("doc_ecc_bch_fix_data: flipped %d bits\n", numerrs);
+	return numerrs;
+}
+
+static int doc_read_page_prepare(struct docg3 *docg3, int block0, int block1,
+				 int page, int offset)
+{
+	int wear_area = 0, ret = 0;
+
+	doc_dbg("doc_read_page_prepare(blocks=(%d,%d), page=%d, ofsInPage=%d)\n",
+		block0, block1, page, offset);
+	if (offset >= DOC_LAYOUT_WEAR_OFFSET)
+		wear_area = 1;
+	if (!wear_area && offset > (DOC_LAYOUT_PAGE_OOB_SIZE * 2))
+		return -EINVAL;
+
+	doc_set_device_id(docg3, docg3->device_id);
+	ret = doc_reset_seq(docg3);
+	if (ret)
+		goto err;
+
+	/* Program the flash address block and page */
+	ret = doc_read_seek(docg3, block0, block1, page, wear_area, offset);
+	if (ret)
+		goto err;
+
+	doc_flash_command(docg3, DOC_CMD_READ_ALL_PLANES);
+	doc_delay(docg3, 2);
+	doc_wait_ready(docg3);
+
+	doc_flash_command(docg3, DOC_CMD_SET_ADDR_READ);
+	doc_delay(docg3, 1);
+	if (offset >= DOC_LAYOUT_PAGE_SIZE * 2)
+		offset -= 2 * DOC_LAYOUT_PAGE_SIZE;
+	doc_flash_address(docg3, offset >> 2);
+	doc_delay(docg3, 1);
+	doc_wait_ready(docg3);
+
+	doc_flash_command(docg3, DOC_CMD_READ_FLASH);
+
+	return 0;
+err:
+	doc_writeb(docg3, 0, DOC_DATAEND);
+	doc_delay(docg3, 2);
+	return -EIO;
+}
+
+static int doc_read_page_getbytes(struct docg3 *docg3, int len, u_char *buf,
+				  int first)
+{
+	doc_read_data_area(docg3, buf, len, first);
+	doc_delay(docg3, 2);
+	return len;
+}
+
+static void doc_get_bch_hw_ecc(struct docg3 *docg3, u8 *hwecc)
+{
+	int i;
+
+	for (i = 0; i < DOC_ECC_BCH_SIZE; i++)
+		hwecc[i] = doc_register_readb(docg3, DOC_BCH_HW_ECC(i));
+}
+
+static void doc_page_finish(struct docg3 *docg3)
+{
+	doc_writeb(docg3, 0, DOC_DATAEND);
+	doc_delay(docg3, 2);
+}
+
+static void doc_read_page_finish(struct docg3 *docg3)
+{
+	doc_page_finish(docg3);
+	doc_set_device_id(docg3, 0);
+}
+
+static void calc_block_sector(loff_t from, int *block0, int *block1, int *page,
+			      int *ofs, int reliable)
+{
+	uint sector, pages_biblock;
+
+	pages_biblock = DOC_LAYOUT_PAGES_PER_BLOCK * DOC_LAYOUT_NBPLANES;
+	if (reliable == 1 || reliable == 2)
+		pages_biblock /= 2;
+
+	sector = from / DOC_LAYOUT_PAGE_SIZE;
+	*block0 = sector / pages_biblock * DOC_LAYOUT_NBPLANES;
+	*block1 = *block0 + 1;
+	*page = sector % pages_biblock;
+	*page /= DOC_LAYOUT_NBPLANES;
+	if (reliable == 1 || reliable == 2)
+		*page *= 2;
+	if (sector % 2)
+		*ofs = DOC_LAYOUT_PAGE_OOB_SIZE;
+	else
+		*ofs = 0;
+}
+
+static int doc_read_oob(struct mtd_info *mtd, loff_t from,
+			struct mtd_oob_ops *ops)
+{
+	struct docg3 *docg3 = mtd->priv;
+	int block0, block1, page, ret, ofs = 0;
+	u8 *oobbuf = ops->oobbuf;
+	u8 *buf = ops->datbuf;
+	size_t len, ooblen, nbdata, nboob;
+	u8 hwecc[DOC_ECC_BCH_SIZE], eccconf1;
+
+	if (buf)
+		len = ops->len;
+	else
+		len = 0;
+	if (oobbuf)
+		ooblen = ops->ooblen;
+	else
+		ooblen = 0;
+
+	if (oobbuf && ops->mode == MTD_OOB_PLACE)
+		oobbuf += ops->ooboffs;
+
+	doc_dbg("doc_read_oob(from=%lld, mode=%d, data=(%p:%zu), oob=(%p:%zu))\n",
+		from, ops->mode, buf, len, oobbuf, ooblen);
+	if ((len % DOC_LAYOUT_PAGE_SIZE) || (ooblen % DOC_LAYOUT_OOB_SIZE) ||
+	    (from % DOC_LAYOUT_PAGE_SIZE))
+		return -EINVAL;
+
+	ret = -EINVAL;
+	calc_block_sector(from + len, &block0, &block1, &page, &ofs,
+			  docg3->reliable);
+	if (block1 > docg3->max_block)
+		goto err;
+
+	ops->oobretlen = 0;
+	ops->retlen = 0;
+	ret = 0;
+	while (!ret && (len > 0 || ooblen > 0)) {
+		calc_block_sector(from, &block0, &block1, &page, &ofs,
+			docg3->reliable);
+		nbdata = min_t(size_t, len, (size_t)DOC_LAYOUT_PAGE_SIZE);
+		nboob = min_t(size_t, ooblen, (size_t)DOC_LAYOUT_OOB_SIZE);
+		ret = doc_read_page_prepare(docg3, block0, block1, page, ofs);
+		if (ret < 0)
+			goto err;
+		ret = doc_read_page_ecc_init(docg3, DOC_ECC_BCH_TOTAL_BYTES);
+		if (ret < 0)
+			goto err_in_read;
+		ret = doc_read_page_getbytes(docg3, nbdata, buf, 1);
+		if (ret < nbdata)
+			goto err_in_read;
+		doc_read_page_getbytes(docg3, DOC_LAYOUT_PAGE_SIZE - nbdata,
+				       NULL, 0);
+		ret = doc_read_page_getbytes(docg3, nboob, oobbuf, 0);
+		if (ret < nboob)
+			goto err_in_read;
+		doc_read_page_getbytes(docg3, DOC_LAYOUT_OOB_SIZE - nboob,
+				       NULL, 0);
+
+		doc_get_bch_hw_ecc(docg3, hwecc);
+		eccconf1 = doc_register_readb(docg3, DOC_ECCCONF1);
+
+		if (nboob >= DOC_LAYOUT_OOB_SIZE) {
+			doc_dbg("OOB - INFO: %02x:%02x:%02x:%02x:%02x:%02x:%02x\n",
+				oobbuf[0], oobbuf[1], oobbuf[2], oobbuf[3],
+				oobbuf[4], oobbuf[5], oobbuf[6]);
+			doc_dbg("OOB - HAMMING: %02x\n", oobbuf[7]);
+			doc_dbg("OOB - BCH_ECC: %02x:%02x:%02x:%02x:%02x:%02x:%02x\n",
+				oobbuf[8], oobbuf[9], oobbuf[10], oobbuf[11],
+				oobbuf[12], oobbuf[13], oobbuf[14]);
+			doc_dbg("OOB - UNUSED: %02x\n", oobbuf[15]);
+		}
+		doc_dbg("ECC checks: ECCConf1=%x\n", eccconf1);
+		doc_dbg("ECC HW_ECC: %02x:%02x:%02x:%02x:%02x:%02x:%02x\n",
+			hwecc[0], hwecc[1], hwecc[2], hwecc[3], hwecc[4],
+			hwecc[5], hwecc[6]);
+
+		ret = -EIO;
+		if (is_prot_seq_error(docg3))
+			goto err_in_read;
+		ret = 0;
+		if ((block0 >= DOC_LAYOUT_BLOCK_FIRST_DATA) &&
+		    (eccconf1 & DOC_ECCCONF1_BCH_SYNDROM_ERR) &&
+		    (eccconf1 & DOC_ECCCONF1_PAGE_IS_WRITTEN) &&
+		    (ops->mode != MTD_OOB_RAW) &&
+		    (nbdata == DOC_LAYOUT_PAGE_SIZE)) {
+			ret = doc_ecc_bch_fix_data(docg3, buf, hwecc);
+			if (ret < 0) {
+				mtd->ecc_stats.failed++;
+				ret = -EBADMSG;
+			}
+			if (ret > 0) {
+				mtd->ecc_stats.corrected += ret;
+				ret = -EUCLEAN;
+			}
+		}
+
+		doc_read_page_finish(docg3);
+		ops->retlen += nbdata;
+		ops->oobretlen += nboob;
+		buf += nbdata;
+		oobbuf += nboob;
+		len -= nbdata;
+		ooblen -= nboob;
+		from += DOC_LAYOUT_PAGE_SIZE;
+	}
+
+	return ret;
+err_in_read:
+	doc_read_page_finish(docg3);
+err:
+	return ret;
+}
+
+static int doc_read(struct mtd_info *mtd, loff_t from, size_t len,
+	     size_t *retlen, u_char *buf)
+{
+	struct mtd_oob_ops ops;
+	size_t ret;
+
+	memset(&ops, 0, sizeof(ops));
+	ops.datbuf = buf;
+	ops.len = len;
+	ops.mode = MTD_OOB_AUTO;
+
+	ret = doc_read_oob(mtd, from, &ops);
+	*retlen = ops.retlen;
+	return ret;
+}
+
+static int doc_reload_bbt(struct docg3 *docg3)
+{
+	int block = DOC_LAYOUT_BLOCK_BBT;
+	int ret = 0, nbpages, page;
+	u_char *buf = docg3->bbt;
+
+	nbpages = DIV_ROUND_UP(docg3->max_block + 1, 8 * DOC_LAYOUT_PAGE_SIZE);
+	for (page = 0; !ret && (page < nbpages); page++) {
+		ret = doc_read_page_prepare(docg3, block, block + 1,
+					    page + DOC_LAYOUT_PAGE_BBT, 0);
+		if (!ret)
+			ret = doc_read_page_ecc_init(docg3,
+						     DOC_LAYOUT_PAGE_SIZE);
+		if (!ret)
+			doc_read_page_getbytes(docg3, DOC_LAYOUT_PAGE_SIZE,
+					       buf, 1);
+		buf += DOC_LAYOUT_PAGE_SIZE;
+	}
+	doc_read_page_finish(docg3);
+	return ret;
+}
+
+static int doc_block_isbad(struct mtd_info *mtd, loff_t from)
+{
+	struct docg3 *docg3 = mtd->priv;
+	int block0, block1, page, ofs, is_good;
+
+	calc_block_sector(from, &block0, &block1, &page, &ofs,
+		docg3->reliable);
+	doc_dbg("doc_block_isbad(from=%lld) => block=(%d,%d), page=%d, ofs=%d\n",
+		from, block0, block1, page, ofs);
+
+	if (block0 < DOC_LAYOUT_BLOCK_FIRST_DATA)
+		return 0;
+	if (block1 > docg3->max_block)
+		return -EINVAL;
+
+	is_good = docg3->bbt[block0 >> 3] & (1 << (block0 & 0x7));
+	return !is_good;
+}
+
+#ifdef MTD_WRITE
+static int doc_guess_autoecc(struct mtd_oob_ops *ops)
+{
+	int autoecc;
+
+	switch (ops->mode) {
+	case MTD_OOB_PLACE:
+	case MTD_OOB_AUTO:
+		autoecc = 1;
+		break;
+	case MTD_OOB_RAW:
+		autoecc = 0;
+		break;
+	default:
+		autoecc = -EINVAL;
+	}
+	return autoecc;
+}
+
+static void doc_fill_autooob(u8 *dst, u8 *oobsrc)
+{
+	memcpy(dst, oobsrc, DOC_LAYOUT_OOB_PAGEINFO_SZ);
+	dst[DOC_LAYOUT_OOB_UNUSED_OFS] = oobsrc[DOC_LAYOUT_OOB_PAGEINFO_SZ];
+}
+
+static int doc_backup_oob(struct docg3 *docg3, loff_t to,
+			  struct mtd_oob_ops *ops)
+{
+	int ooblen = ops->ooblen, autoecc;
+
+	if (ooblen != DOC_LAYOUT_OOB_SIZE)
+		return -EINVAL;
+	autoecc = doc_guess_autoecc(ops);
+	if (autoecc < 0)
+		return autoecc;
+
+	docg3->oob_write_ofs = to;
+	docg3->oob_autoecc = autoecc;
+	if (ops->mode == MTD_OOB_AUTO) {
+		doc_fill_autooob(docg3->oob_write_buf, ops->oobbuf);
+		ops->oobretlen = 8;
+	} else {
+		memcpy(docg3->oob_write_buf, ops->oobbuf, DOC_LAYOUT_OOB_SIZE);
+		ops->oobretlen = DOC_LAYOUT_OOB_SIZE;
+	}
+	return 0;
+}
+
+static void doc_write_data_area(struct docg3 *docg3, const void *buf, int len)
+{
+	int i, cdr, len4;
+	u16 *src16;
+	u8 *src8;
+
+	doc_dbg("doc_write_data_area(buf=%p, len=%d)\n", buf, len);
+	cdr = len & 0x3;
+	len4 = len - cdr;
+
+	doc_writew(docg3, DOC_IOSPACE_DATA, DOC_READADDRESS);
+	src16 = (u16 *)buf;
+	for (i = 0; i < len4; i += 2) {
+		doc_writew(docg3, *src16, DOC_IOSPACE_DATA);
+		src16++;
+	}
+
+	src8 = (u8 *)src16;
+	for (i = 0; i < cdr; i++) {
+		doc_writew(docg3, DOC_IOSPACE_DATA | DOC_READADDR_ONE_BYTE,
+			   DOC_READADDRESS);
+		doc_writeb(docg3, *src8, DOC_IOSPACE_DATA);
+		src8++;
+	}
+}
+
+static void doc_setup_writeaddr_sector(struct docg3 *docg3, int sector, int ofs)
+{
+	ofs = ofs >> 2;
+	doc_delay(docg3, 1);
+	doc_flash_address(docg3, ofs & 0xff);
+	doc_flash_address(docg3, sector & 0xff);
+	doc_flash_address(docg3, (sector >> 8) & 0xff);
+	doc_flash_address(docg3, (sector >> 16) & 0xff);
+	doc_delay(docg3, 1);
+}
+
+static int doc_write_seek(struct docg3 *docg3, int block0, int block1, int page,
+			 int ofs)
+{
+	int ret = 0, sector;
+
+	doc_dbg("doc_write_seek(blocks=(%d,%d), page=%d, ofs=%d)\n",
+		block0, block1, page, ofs);
+
+	doc_set_reliable_mode(docg3);
+
+	if (ofs < 2 * DOC_LAYOUT_PAGE_SIZE) {
+		doc_flash_sequence(docg3, DOC_SEQ_SET_PLANE1);
+		doc_flash_command(docg3, DOC_CMD_READ_PLANE1);
+		doc_delay(docg3, 2);
+	} else {
+		doc_flash_sequence(docg3, DOC_SEQ_SET_PLANE2);
+		doc_flash_command(docg3, DOC_CMD_READ_PLANE2);
+		doc_delay(docg3, 2);
+	}
+
+	doc_flash_sequence(docg3, DOC_SEQ_PAGE_SETUP);
+	doc_flash_command(docg3, DOC_CMD_PROG_CYCLE1);
+
+	sector = (block0 << DOC_ADDR_BLOCK_SHIFT) + (page & DOC_ADDR_PAGE_MASK);
+	doc_setup_writeaddr_sector(docg3, sector, ofs);
+
+	doc_flash_command(docg3, DOC_CMD_PROG_CYCLE3);
+	doc_delay(docg3, 2);
+	ret = doc_wait_ready(docg3);
+	if (ret)
+		goto out;
+
+	doc_flash_command(docg3, DOC_CMD_PROG_CYCLE1);
+	sector = (block1 << DOC_ADDR_BLOCK_SHIFT) + (page & DOC_ADDR_PAGE_MASK);
+	doc_setup_writeaddr_sector(docg3, sector, ofs);
+	doc_delay(docg3, 1);
+
+out:
+	return ret;
+}
+
+static int doc_write_page_ecc_init(struct docg3 *docg3, int len)
+{
+	doc_writew(docg3, DOC_ECCCONF0_WRITE_MODE
+		   | DOC_ECCCONF0_BCH_ENABLE | DOC_ECCCONF0_HAMMING_ENABLE
+		   | (len & DOC_ECCCONF0_DATA_BYTES_MASK),
+		   DOC_ECCCONF0);
+	doc_delay(docg3, 4);
+	doc_register_readb(docg3, DOC_FLASHCONTROL);
+	return doc_wait_ready(docg3);
+}
+
+static void doc_write_page_putbytes(struct docg3 *docg3, int len,
+				    const u_char *buf)
+{
+	doc_write_data_area(docg3, buf, len);
+	doc_delay(docg3, 2);
+}
+
+static void doc_ecc_disable(struct docg3 *docg3)
+{
+	doc_writew(docg3, DOC_ECCCONF0_READ_MODE, DOC_ECCCONF0);
+	doc_delay(docg3, 4);
+}
+
+static int doc_get_op_status(struct docg3 *docg3)
+{
+	u8 status;
+
+	doc_flash_sequence(docg3, DOC_SEQ_PLANES_STATUS);
+	doc_flash_command(docg3, DOC_CMD_PLANES_STATUS);
+	doc_delay(docg3, 5);
+
+	doc_ecc_disable(docg3);
+	doc_read_data_area(docg3, &status, 1, 1);
+	return status;
+}
+
+static int doc_write_erase_wait_status(struct docg3 *docg3)
+{
+	int status, ret = 0;
+
+	if (!doc_is_ready(docg3))
+		mdelay(3000);
+	if (!doc_is_ready(docg3)) {
+		doc_dbg("Timeout reached and the chip is still not ready\n");
+		ret = -EAGAIN;
+		goto out;
+	}
+
+	status = doc_get_op_status(docg3);
+	if (status & DOC_PLANES_STATUS_FAIL) {
+		doc_dbg("Erase/Write failed on (a) plane(s), status = %x\n",
+			status);
+		ret = -EIO;
+	}
+
+out:
+	doc_page_finish(docg3);
+	return ret;
+}
+
+static int doc_erase_block(struct docg3 *docg3, int block0, int block1)
+{
+	int ret, sector;
+
+	doc_dbg("doc_erase_block(blocks=(%d,%d))\n", block0, block1);
+	ret = doc_reset_seq(docg3);
+	if (ret)
+		return -EIO;
+
+	doc_set_reliable_mode(docg3);
+	doc_flash_sequence(docg3, DOC_SEQ_ERASE);
+
+	sector = block0 << DOC_ADDR_BLOCK_SHIFT;
+	doc_flash_command(docg3, DOC_CMD_PROG_BLOCK_ADDR);
+	doc_setup_addr_sector(docg3, sector);
+	sector = block1 << DOC_ADDR_BLOCK_SHIFT;
+	doc_flash_command(docg3, DOC_CMD_PROG_BLOCK_ADDR);
+	doc_setup_addr_sector(docg3, sector);
+	doc_delay(docg3, 1);
+
+	doc_flash_command(docg3, DOC_CMD_ERASECYCLE2);
+	doc_delay(docg3, 2);
+
+	if (is_prot_seq_error(docg3)) {
+		doc_err("Erase blocks %d,%d error\n", block0, block1);
+		return -EIO;
+	}
+
+	return doc_write_erase_wait_status(docg3);
+}
+
+static int doc_erase(struct mtd_info *mtd, struct erase_info *info)
+{
+	struct docg3 *docg3 = mtd->priv;
+	uint64_t len;
+	int block0, block1, page, ret, ofs = 0;
+
+	doc_dbg("doc_erase(from=%d, len=%d\n", info->addr, info->len);
+	doc_set_device_id(docg3, docg3->device_id);
+
+	info->state = MTD_ERASE_PENDING;
+	calc_block_sector(info->addr + info->len, &block0, &block1, &page,
+			  &ofs, docg3->reliable);
+	ret = -EINVAL;
+	if (block1 > docg3->max_block || page || ofs)
+		goto reset_err;
+
+	ret = 0;
+	calc_block_sector(info->addr, &block0, &block1, &page, &ofs,
+			  docg3->reliable);
+	doc_set_reliable_mode(docg3);
+	for (len = info->len; !ret && len > 0; len -= mtd->erasesize) {
+		info->state = MTD_ERASING;
+		ret = doc_erase_block(docg3, block0, block1);
+		block0 += 2;
+		block1 += 2;
+	}
+
+	if (ret)
+		goto reset_err;
+
+	info->state = MTD_ERASE_DONE;
+	return 0;
+
+reset_err:
+	info->state = MTD_ERASE_FAILED;
+	return ret;
+}
+
+static int doc_write_page(struct docg3 *docg3, loff_t to, const u_char *buf,
+			  const u_char *oob, int autoecc)
+{
+	int block0, block1, page, ret, ofs = 0;
+	u8 hwecc[DOC_ECC_BCH_SIZE], hamming;
+
+	doc_dbg("doc_write_page(to=%lld)\n", to);
+	calc_block_sector(to, &block0, &block1, &page, &ofs, docg3->reliable);
+
+	doc_set_device_id(docg3, docg3->device_id);
+	ret = doc_reset_seq(docg3);
+	if (ret)
+		goto err;
+
+	/* Program the flash address block and page */
+	ret = doc_write_seek(docg3, block0, block1, page, ofs);
+	if (ret)
+		goto err;
+
+	doc_write_page_ecc_init(docg3, DOC_ECC_BCH_TOTAL_BYTES);
+	doc_delay(docg3, 2);
+	doc_write_page_putbytes(docg3, DOC_LAYOUT_PAGE_SIZE, buf);
+
+	if (oob && autoecc) {
+		doc_write_page_putbytes(docg3, DOC_LAYOUT_OOB_PAGEINFO_SZ, oob);
+		doc_delay(docg3, 2);
+		oob += DOC_LAYOUT_OOB_UNUSED_OFS;
+
+		hamming = doc_register_readb(docg3, DOC_HAMMINGPARITY);
+		doc_delay(docg3, 2);
+		doc_write_page_putbytes(docg3, DOC_LAYOUT_OOB_HAMMING_SZ,
+					&hamming);
+		doc_delay(docg3, 2);
+
+		doc_get_bch_hw_ecc(docg3, hwecc);
+		doc_write_page_putbytes(docg3, DOC_LAYOUT_OOB_BCH_SZ, hwecc);
+		doc_delay(docg3, 2);
+
+		doc_write_page_putbytes(docg3, DOC_LAYOUT_OOB_UNUSED_SZ, oob);
+	}
+	if (oob && !autoecc)
+		doc_write_page_putbytes(docg3, DOC_LAYOUT_OOB_SIZE, oob);
+
+	doc_delay(docg3, 2);
+	doc_page_finish(docg3);
+	doc_delay(docg3, 2);
+	doc_flash_command(docg3, DOC_CMD_PROG_CYCLE2);
+	doc_delay(docg3, 2);
+
+	/*
+	 * The wait status will perform another doc_page_finish() call, but that
+	 * seems to please the docg3, so leave it.
+	 */
+	ret = doc_write_erase_wait_status(docg3);
+	return ret;
+err:
+	doc_read_page_finish(docg3);
+	return ret;
+}
+
+static int doc_write_oob(struct mtd_info *mtd, loff_t ofs,
+			 struct mtd_oob_ops *ops)
+{
+	struct docg3 *docg3 = mtd->priv;
+	int block0, block1, page, ret, pofs = 0, autoecc, oobdelta;
+	u8 *oobbuf = ops->oobbuf;
+	u8 *buf = ops->datbuf;
+	size_t len, ooblen;
+	u8 oob[DOC_LAYOUT_OOB_SIZE] __aligned(4);
+
+	if (buf)
+		len = ops->len;
+	else
+		len = 0;
+	if (oobbuf)
+		ooblen = ops->ooblen;
+	else
+		ooblen = 0;
+
+	if (oobbuf && ops->mode == MTD_OOB_PLACE)
+		oobbuf += ops->ooboffs;
+
+	doc_dbg("doc_write_oob(from=%lld, mode=%d, data=(%p:%zu), oob=(%p:%zu))\n",
+		ofs, ops->mode, buf, len, oobbuf, ooblen);
+	switch (ops->mode) {
+	case MTD_OOB_PLACE:
+	case MTD_OOB_RAW:
+		oobdelta = mtd->oobsize;
+		break;
+	case MTD_OOB_AUTO:
+		oobdelta = mtd->ecclayout->oobavail;
+		break;
+	default:
+		oobdelta = 0;
+	}
+	if ((len % DOC_LAYOUT_PAGE_SIZE) || (ooblen % oobdelta) ||
+	    (ofs % DOC_LAYOUT_PAGE_SIZE))
+		return -EINVAL;
+	if (len && ooblen &&
+	    (len / DOC_LAYOUT_PAGE_SIZE) != (ooblen / oobdelta))
+		return -EINVAL;
+
+	ret = -EINVAL;
+	calc_block_sector(ofs + len, &block0, &block1, &page, &pofs,
+			  docg3->reliable);
+	if (block1 > docg3->max_block)
+		goto err;
+
+	ops->oobretlen = 0;
+	ops->retlen = 0;
+	ret = 0;
+	if (len == 0 && ooblen == 0)
+		return -EINVAL;
+	if (len == 0 && ooblen > 0)
+		return doc_backup_oob(docg3, ofs, ops);
+
+	autoecc = doc_guess_autoecc(ops);
+	if (autoecc < 0)
+		return autoecc;
+
+	while (!ret && len > 0) {
+		memset(oob, 0, sizeof(oob));
+		if (ofs == docg3->oob_write_ofs)
+			memcpy(oob, docg3->oob_write_buf, DOC_LAYOUT_OOB_SIZE);
+		else if (ooblen > 0 && ops->mode == MTD_OOB_AUTO)
+			doc_fill_autooob(oob, oobbuf);
+		else if (ooblen > 0)
+			memcpy(oob, oobbuf, DOC_LAYOUT_OOB_SIZE);
+		ret = doc_write_page(docg3, ofs, buf, oob, autoecc);
+
+		ofs += DOC_LAYOUT_PAGE_SIZE;
+		len -= DOC_LAYOUT_PAGE_SIZE;
+		buf += DOC_LAYOUT_PAGE_SIZE;
+		if (ooblen) {
+			oobbuf += oobdelta;
+			ooblen -= oobdelta;
+			ops->oobretlen += oobdelta;
+		}
+		ops->retlen += DOC_LAYOUT_PAGE_SIZE;
+	}
+err:
+	doc_set_device_id(docg3, 0);
+	return ret;
+}
+
+static int doc_write(struct mtd_info *mtd, loff_t to, size_t len,
+		     size_t *retlen, const u_char *buf)
+{
+	struct docg3 *docg3 = mtd->priv;
+	int ret;
+	struct mtd_oob_ops ops;
+
+	doc_dbg("doc_write(to=%lld, len=%zu)\n", to, len);
+	ops.datbuf = (char *)buf;
+	ops.len = len;
+	ops.mode = MTD_OOB_PLACE;
+	ops.oobbuf = NULL;
+	ops.ooblen = 0;
+	ops.ooboffs = 0;
+
+	ret = doc_write_oob(mtd, to, &ops);
+	*retlen = ops.retlen;
+	return ret;
+}
+#endif
+
+static void __init doc_set_driver_info(int chip_id, struct mtd_info *mtd)
+{
+	struct docg3 *docg3 = mtd->priv;
+	int cfg;
+
+	cfg = doc_register_readb(docg3, DOC_CONFIGURATION);
+	docg3->if_cfg = (cfg & DOC_CONF_IF_CFG ? 1 : 0);
+	docg3->reliable = reliable_mode;
+
+	switch (chip_id) {
+	case DOC_CHIPID_G3:
+		mtd->name = asprintf("DiskOnChip G3 floor %d",
+				      docg3->device_id);
+		docg3->max_block = 2047;
+		break;
+	}
+	mtd->type = MTD_NANDFLASH;
+	mtd->flags = MTD_CAP_NANDFLASH;
+	mtd->size = (docg3->max_block + 1) * DOC_LAYOUT_BLOCK_SIZE;
+	if (docg3->reliable == 2)
+		mtd->size /= 2;
+	mtd->erasesize = DOC_LAYOUT_BLOCK_SIZE * DOC_LAYOUT_NBPLANES;
+	if (docg3->reliable == 2)
+		mtd->erasesize /= 2;
+	mtd->writesize = DOC_LAYOUT_PAGE_SIZE;
+	mtd->oobsize = DOC_LAYOUT_OOB_SIZE;
+	mtd->read = doc_read;
+	mtd->read_oob = doc_read_oob;
+	mtd->block_isbad = doc_block_isbad;
+#ifdef MTD_WRITE
+	mtd->erase = doc_erase;
+	mtd->write = doc_write;
+	mtd->write_oob = doc_write_oob;
+#endif
+}
+
+static struct mtd_info *doc_probe_device(void __iomem *base, int floor,
+					 struct device_d *dev)
+{
+	int ret, bbt_nbpages;
+	u16 chip_id, chip_id_inv;
+	struct docg3 *docg3;
+	struct mtd_info *mtd;
+
+	ret = -ENOMEM;
+	docg3 = kzalloc(sizeof(struct docg3), GFP_KERNEL);
+	if (!docg3)
+		goto nomem1;
+	mtd = kzalloc(sizeof(struct mtd_info), GFP_KERNEL);
+	if (!mtd)
+		goto nomem2;
+	mtd->priv = docg3;
+	bbt_nbpages = DIV_ROUND_UP(docg3->max_block + 1,
+				   8 * DOC_LAYOUT_PAGE_SIZE);
+	docg3->bbt = kzalloc(bbt_nbpages * DOC_LAYOUT_PAGE_SIZE, GFP_KERNEL);
+	if (!docg3->bbt)
+		goto nomem3;
+
+	docg3->dev = dev;
+	docg3->device_id = floor;
+	docg3->base = base;
+	doc_set_device_id(docg3, docg3->device_id);
+	if (!floor)
+		doc_set_asic_mode(docg3, DOC_ASICMODE_RESET);
+	doc_set_asic_mode(docg3, DOC_ASICMODE_NORMAL);
+
+	chip_id = doc_register_readw(docg3, DOC_CHIPID);
+	chip_id_inv = doc_register_readw(docg3, DOC_CHIPID_INV);
+
+	ret = 0;
+	if (chip_id != (u16)(~chip_id_inv))
+		goto nomem3;
+
+	switch (chip_id) {
+	case DOC_CHIPID_G3:
+		doc_info("Found a G3 DiskOnChip at addr %p, floor %d\n",
+			 base, floor);
+		break;
+	default:
+		doc_err("Chip id %04x is not a DiskOnChip G3 chip\n", chip_id);
+		goto nomem3;
+	}
+
+	doc_set_driver_info(chip_id, mtd);
+
+	doc_hamming_ecc_init(docg3, DOC_LAYOUT_OOB_PAGEINFO_SZ);
+	doc_reload_bbt(docg3);
+	return mtd;
+
+nomem3:
+	kfree(mtd);
+nomem2:
+	kfree(docg3);
+nomem1:
+	return ERR_PTR(ret);
+}
+
+static int __init docg3_probe(struct device_d *dev)
+{
+	struct mtd_info *mtd;
+	void __iomem *base;
+	int ret, floor, found = 0;
+
+	base = dev_request_mem_region(dev, 0);
+
+	ret = -ENOMEM;
+	docg3_bch = init_bch(DOC_ECC_BCH_M, DOC_ECC_BCH_T,
+			     DOC_ECC_BCH_PRIMPOLY);
+	if (!docg3_bch)
+		goto nomem2;
+
+	/* for (floor = 0; floor < DOC_MAX_NBFLOORS; floor++) { */
+	for (floor = 0; floor < 2; floor++) {
+		mtd = doc_probe_device(base, floor, dev);
+		if (IS_ERR(mtd)) {
+			ret = PTR_ERR(mtd);
+			goto err_probe;
+		}
+		if (!mtd) {
+			if (floor == 0)
+				goto notfound;
+			else
+				continue;
+		}
+		docg3_floors[floor] = mtd;
+		ret = add_mtd_device(mtd, NULL);
+		if (ret)
+			goto err_probe;
+		found++;
+	}
+
+	if (ret)
+		goto err_probe;
+	if (!found)
+		goto notfound;
+
+	return 0;
+
+notfound:
+	ret = -ENODEV;
+	dev_info(dev, "No supported DiskOnChip found\n");
+err_probe:
+	free_bch(docg3_bch);
+nomem2:
+	return ret;
+}
+
+static struct driver_d  g3_driver = {
+	.name	= "docg3",
+	.probe	= docg3_probe,
+};
+
+static int __init docg3_init(void)
+{
+	return register_driver(&g3_driver);
+}
+
+device_initcall(docg3_init);
diff --git a/drivers/mtd/devices/docg3.h b/drivers/mtd/devices/docg3.h
new file mode 100644
index 0000000..97eafe3
--- /dev/null
+++ b/drivers/mtd/devices/docg3.h
@@ -0,0 +1,283 @@
+/*
+ * Handles the M-Systems DiskOnChip G3 chip
+ *
+ * Copyright (C) 2011 Robert Jarzmik
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ */
+
+#ifndef _MTD_DOCG3_H
+#define _MTD_DOCG3_H
+
+/*
+ * Flash memory areas :
+ *   - 0x0000 .. 0x07ff : IPL
+ *   - 0x0800 .. 0x0fff : Data area
+ *   - 0x1000 .. 0x17ff : Registers
+ *   - 0x1800 .. 0x1fff : Unknown
+ */
+#define DOC_IOSPACE_IPL			0x0000
+#define DOC_IOSPACE_DATA		0x0800
+#define DOC_IOSPACE_SIZE		0x2000
+
+/*
+ * DOC G3 layout and adressing scheme
+ *   A page address for the block "b", plane "P" and page "p":
+ *   address = [bbbb bPpp pppp]
+ */
+
+#define DOC_ADDR_PAGE_MASK		0x3f
+#define DOC_ADDR_BLOCK_SHIFT		6
+#define DOC_LAYOUT_NBPLANES		2
+#define DOC_LAYOUT_PAGES_PER_BLOCK	64
+#define DOC_LAYOUT_PAGE_SIZE		512
+#define DOC_LAYOUT_OOB_SIZE		16
+#define DOC_LAYOUT_WEAR_SIZE		8
+#define DOC_LAYOUT_PAGE_OOB_SIZE				\
+	(DOC_LAYOUT_PAGE_SIZE + DOC_LAYOUT_OOB_SIZE)
+#define DOC_LAYOUT_WEAR_OFFSET		(DOC_LAYOUT_PAGE_OOB_SIZE * 2)
+#define DOC_LAYOUT_BLOCK_SIZE					\
+	(DOC_LAYOUT_PAGES_PER_BLOCK * DOC_LAYOUT_PAGE_SIZE)
+
+/*
+ * ECC related constants
+ */
+#define DOC_ECC_BCH_M			14
+#define DOC_ECC_BCH_T			4
+#define DOC_ECC_BCH_PRIMPOLY		0x4443
+#define DOC_ECC_BCH_SIZE		7
+#define DOC_ECC_BCH_COVERED_BYTES				\
+	(DOC_LAYOUT_PAGE_SIZE + DOC_LAYOUT_OOB_PAGEINFO_SZ +	\
+	 DOC_LAYOUT_OOB_HAMMING_SZ)
+#define DOC_ECC_BCH_TOTAL_BYTES					\
+	(DOC_ECC_BCH_COVERED_BYTES + DOC_LAYOUT_OOB_BCH_SZ)
+
+/*
+ * Blocks distribution
+ */
+#define DOC_LAYOUT_BLOCK_BBT		0
+#define DOC_LAYOUT_BLOCK_OTP		0
+#define DOC_LAYOUT_BLOCK_FIRST_DATA	6
+
+#define DOC_LAYOUT_PAGE_BBT		4
+
+/*
+ * Extra page OOB (16 bytes wide) layout
+ */
+#define DOC_LAYOUT_OOB_PAGEINFO_OFS	0
+#define DOC_LAYOUT_OOB_HAMMING_OFS	7
+#define DOC_LAYOUT_OOB_BCH_OFS		8
+#define DOC_LAYOUT_OOB_UNUSED_OFS	15
+#define DOC_LAYOUT_OOB_PAGEINFO_SZ	7
+#define DOC_LAYOUT_OOB_HAMMING_SZ	1
+#define DOC_LAYOUT_OOB_BCH_SZ		7
+#define DOC_LAYOUT_OOB_UNUSED_SZ	1
+
+
+#define DOC_CHIPID_G3			0x200
+#define DOC_ERASE_MARK			0xaa
+#define DOC_MAX_NBFLOORS		4
+/*
+ * Flash registers
+ */
+#define DOC_CHIPID			0x1000
+#define DOC_TEST			0x1004
+#define DOC_BUSLOCK			0x1006
+#define DOC_ENDIANCONTROL		0x1008
+#define DOC_DEVICESELECT		0x100a
+#define DOC_ASICMODE			0x100c
+#define DOC_CONFIGURATION		0x100e
+#define DOC_INTERRUPTCONTROL		0x1010
+#define DOC_READADDRESS			0x101a
+#define DOC_DATAEND			0x101e
+#define DOC_INTERRUPTSTATUS		0x1020
+
+#define DOC_FLASHSEQUENCE		0x1032
+#define DOC_FLASHCOMMAND		0x1034
+#define DOC_FLASHADDRESS		0x1036
+#define DOC_FLASHCONTROL		0x1038
+#define DOC_NOP				0x103e
+
+#define DOC_ECCCONF0			0x1040
+#define DOC_ECCCONF1			0x1042
+#define DOC_ECCPRESET			0x1044
+#define DOC_HAMMINGPARITY		0x1046
+#define DOC_BCH_HW_ECC(idx)		(0x1048 + idx)
+
+#define DOC_PROTECTION			0x1056
+#define DOC_DPS0_KEY			0x105c
+#define DOC_DPS1_KEY			0x105e
+#define DOC_DPS0_ADDRLOW		0x1060
+#define DOC_DPS0_ADDRHIGH		0x1062
+#define DOC_DPS1_ADDRLOW		0x1064
+#define DOC_DPS1_ADDRHIGH		0x1066
+#define DOC_DPS0_STATUS			0x106c
+#define DOC_DPS1_STATUS			0x106e
+
+#define DOC_ASICMODECONFIRM		0x1072
+#define DOC_CHIPID_INV			0x1074
+#define DOC_POWERMODE			0x107c
+
+/*
+ * Flash sequences
+ * A sequence is preset before one or more commands are input to the chip.
+ */
+#define DOC_SEQ_RESET			0x00
+#define DOC_SEQ_PAGE_SIZE_532		0x03
+#define DOC_SEQ_SET_FASTMODE		0x05
+#define DOC_SEQ_SET_RELIABLEMODE	0x09
+#define DOC_SEQ_READ			0x12
+#define DOC_SEQ_SET_PLANE1		0x0e
+#define DOC_SEQ_SET_PLANE2		0x10
+#define DOC_SEQ_PAGE_SETUP		0x1d
+#define DOC_SEQ_ERASE			0x27
+#define DOC_SEQ_PLANES_STATUS		0x31
+
+/*
+ * Flash commands
+ */
+#define DOC_CMD_READ_PLANE1		0x00
+#define DOC_CMD_SET_ADDR_READ		0x05
+#define DOC_CMD_READ_ALL_PLANES		0x30
+#define DOC_CMD_READ_PLANE2		0x50
+#define DOC_CMD_READ_FLASH		0xe0
+#define DOC_CMD_PAGE_SIZE_532		0x3c
+
+#define DOC_CMD_PROG_BLOCK_ADDR		0x60
+#define DOC_CMD_PROG_CYCLE1		0x80
+#define DOC_CMD_PROG_CYCLE2		0x10
+#define DOC_CMD_PROG_CYCLE3		0x11
+#define DOC_CMD_ERASECYCLE2		0xd0
+#define DOC_CMD_READ_STATUS		0x70
+#define DOC_CMD_PLANES_STATUS		0x71
+
+#define DOC_CMD_RELIABLE_MODE		0x22
+#define DOC_CMD_FAST_MODE		0xa2
+
+#define DOC_CMD_RESET			0xff
+
+/*
+ * Flash register : DOC_FLASHCONTROL
+ */
+#define DOC_CTRL_VIOLATION		0x20
+#define DOC_CTRL_CE			0x10
+#define DOC_CTRL_UNKNOWN_BITS		0x08
+#define DOC_CTRL_PROTECTION_ERROR	0x04
+#define DOC_CTRL_SEQUENCE_ERROR		0x02
+#define DOC_CTRL_FLASHREADY		0x01
+
+/*
+ * Flash register : DOC_ASICMODE
+ */
+#define DOC_ASICMODE_RESET		0x00
+#define DOC_ASICMODE_NORMAL		0x01
+#define DOC_ASICMODE_POWERDOWN		0x02
+#define DOC_ASICMODE_MDWREN		0x04
+#define DOC_ASICMODE_BDETCT_RESET	0x08
+#define DOC_ASICMODE_RSTIN_RESET	0x10
+#define DOC_ASICMODE_RAM_WE		0x20
+
+/*
+ * Flash register : DOC_ECCCONF0
+ */
+#define DOC_ECCCONF0_WRITE_MODE		0x0000
+#define DOC_ECCCONF0_READ_MODE		0x8000
+#define DOC_ECCCONF0_AUTO_ECC_ENABLE	0x4000
+#define DOC_ECCCONF0_HAMMING_ENABLE	0x1000
+#define DOC_ECCCONF0_BCH_ENABLE		0x0800
+#define DOC_ECCCONF0_DATA_BYTES_MASK	0x07ff
+
+/*
+ * Flash register : DOC_ECCCONF1
+ */
+#define DOC_ECCCONF1_BCH_SYNDROM_ERR	0x80
+#define DOC_ECCCONF1_UNKOWN1		0x40
+#define DOC_ECCCONF1_PAGE_IS_WRITTEN	0x20
+#define DOC_ECCCONF1_UNKOWN3		0x10
+#define DOC_ECCCONF1_HAMMING_BITS_MASK	0x0f
+
+/*
+ * Flash register : DOC_PROTECTION
+ */
+#define DOC_PROTECT_FOUNDRY_OTP_LOCK	0x01
+#define DOC_PROTECT_CUSTOMER_OTP_LOCK	0x02
+#define DOC_PROTECT_LOCK_INPUT		0x04
+#define DOC_PROTECT_STICKY_LOCK		0x08
+#define DOC_PROTECT_PROTECTION_ENABLED	0x10
+#define DOC_PROTECT_IPL_DOWNLOAD_LOCK	0x20
+#define DOC_PROTECT_PROTECTION_ERROR	0x80
+
+/*
+ * Flash register : DOC_DPS0_STATUS and DOC_DPS1_STATUS
+ */
+#define DOC_DPS_OTP_PROTECTED		0x01
+#define DOC_DPS_READ_PROTECTED		0x02
+#define DOC_DPS_WRITE_PROTECTED		0x04
+#define DOC_DPS_HW_LOCK_ENABLED		0x08
+#define DOC_DPS_KEY_OK			0x80
+
+/*
+ * Flash register : DOC_CONFIGURATION
+ */
+#define DOC_CONF_IF_CFG			0x80
+#define DOC_CONF_MAX_ID_MASK		0x30
+#define DOC_CONF_VCCQ_3V		0x01
+
+/*
+ * Flash register : DOC_READADDRESS
+ */
+#define DOC_READADDR_INC		0x8000
+#define DOC_READADDR_ONE_BYTE		0x4000
+#define DOC_READADDR_ADDR_MASK		0x1fff
+
+/*
+ * Flash register : DOC_POWERMODE
+ */
+#define DOC_POWERDOWN_READY		0x80
+
+/*
+ * Status of erase and write operation
+ */
+#define DOC_PLANES_STATUS_FAIL		0x01
+#define DOC_PLANES_STATUS_PLANE0_KO	0x02
+#define DOC_PLANES_STATUS_PLANE1_KO	0x04
+
+/*
+ * DPS key management
+ *
+ * Each floor of docg3 has 2 protection areas: DPS0 and DPS1. These areas span
+ * across block boundaries, and define whether these blocks can be read or
+ * written.
+ * The definition is dynamically stored in page 0 of blocks (2,3) for DPS0, and
+ * page 0 of blocks (4,5) for DPS1.
+ */
+#define DOC_LAYOUT_DPS_KEY_LENGTH	8
+
+struct docg3 {
+	struct device_d *dev;
+	void __iomem *base;
+	unsigned int device_id:4;
+	unsigned int if_cfg:1;
+	unsigned int reliable:2;
+	int max_block;
+	u8 *bbt;
+	loff_t oob_write_ofs;
+	int oob_autoecc;
+	u8 oob_write_buf[DOC_LAYOUT_OOB_SIZE];
+};
+
+#define doc_err(fmt, arg...) dev_err(docg3->dev, fmt, ## arg)
+#define doc_info(fmt, arg...) dev_info(docg3->dev, fmt, ## arg)
+#define doc_dbg(fmt, arg...) dev_dbg(docg3->dev, fmt, ## arg)
+#define doc_vdbg(fmt, arg...) dev_dbg(docg3->dev, fmt, ## arg)
+
+#endif
-- 
1.7.5.4


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^ permalink raw reply	[flat|nested] 7+ messages in thread

* Re: [PATCH V2 0/3] Add MSystems Disk-On-Chip G3 support
  2011-12-22 15:51 [PATCH V2 0/3] Add MSystems Disk-On-Chip G3 support Robert Jarzmik
                   ` (2 preceding siblings ...)
  2011-12-22 15:51 ` [PATCH V2 3/3] drivers/mtd: add docg3 chip Robert Jarzmik
@ 2012-01-05 23:11 ` Robert Jarzmik
  2012-01-06  9:06   ` Sascha Hauer
  3 siblings, 1 reply; 7+ messages in thread
From: Robert Jarzmik @ 2012-01-05 23:11 UTC (permalink / raw)
  To: Sascha Hauer; +Cc: barebox

Robert Jarzmik <robert.jarzmik@free.fr> writes:
> This patchset brings support for M-Systems disk-on-chip G3
> chips. Almost all code is taken from linux kernel (bitrev,
> bch, docg3), and slightly amended for barebox.

Hi Sascha, happy new year.

Do you intend to review / merge this serie ?

Cheers.

--
Robert

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^ permalink raw reply	[flat|nested] 7+ messages in thread

* Re: [PATCH V2 0/3] Add MSystems Disk-On-Chip G3 support
  2012-01-05 23:11 ` [PATCH V2 0/3] Add MSystems Disk-On-Chip G3 support Robert Jarzmik
@ 2012-01-06  9:06   ` Sascha Hauer
  2012-01-09  6:49     ` Robert Jarzmik
  0 siblings, 1 reply; 7+ messages in thread
From: Sascha Hauer @ 2012-01-06  9:06 UTC (permalink / raw)
  To: Robert Jarzmik; +Cc: barebox

Hi Robert,

On Fri, Jan 06, 2012 at 12:11:13AM +0100, Robert Jarzmik wrote:
> Robert Jarzmik <robert.jarzmik@free.fr> writes:
> > This patchset brings support for M-Systems disk-on-chip G3
> > chips. Almost all code is taken from linux kernel (bitrev,
> > bch, docg3), and slightly amended for barebox.
> 
> Hi Sascha, happy new year.

Happy new year ;)

> 
> Do you intend to review / merge this serie ?

I already did. Have a look at current master.

Sascha


-- 
Pengutronix e.K.                           |                             |
Industrial Linux Solutions                 | http://www.pengutronix.de/  |
Peiner Str. 6-8, 31137 Hildesheim, Germany | Phone: +49-5121-206917-0    |
Amtsgericht Hildesheim, HRA 2686           | Fax:   +49-5121-206917-5555 |

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^ permalink raw reply	[flat|nested] 7+ messages in thread

* Re: [PATCH V2 0/3] Add MSystems Disk-On-Chip G3 support
  2012-01-06  9:06   ` Sascha Hauer
@ 2012-01-09  6:49     ` Robert Jarzmik
  0 siblings, 0 replies; 7+ messages in thread
From: Robert Jarzmik @ 2012-01-09  6:49 UTC (permalink / raw)
  To: Sascha Hauer; +Cc: barebox

Sascha Hauer <s.hauer@pengutronix.de> writes:

>> Do you intend to review / merge this serie ?
> I already did. Have a look at current master.
Oh great, thanks.

Now everything is in place, and I'll send the mioa701 board support :)

Cheers.

-- 
Robert

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^ permalink raw reply	[flat|nested] 7+ messages in thread

end of thread, other threads:[~2012-01-09  6:49 UTC | newest]

Thread overview: 7+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2011-12-22 15:51 [PATCH V2 0/3] Add MSystems Disk-On-Chip G3 support Robert Jarzmik
2011-12-22 15:51 ` [PATCH V2 1/3] lib: add BCH encoding/decoding Robert Jarzmik
2011-12-22 15:51 ` [PATCH V2 2/3] lib: add bitrev utility Robert Jarzmik
2011-12-22 15:51 ` [PATCH V2 3/3] drivers/mtd: add docg3 chip Robert Jarzmik
2012-01-05 23:11 ` [PATCH V2 0/3] Add MSystems Disk-On-Chip G3 support Robert Jarzmik
2012-01-06  9:06   ` Sascha Hauer
2012-01-09  6:49     ` Robert Jarzmik

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