From: Sebastian Block <basti@linux-source.de>
To: barebox@lists.infradead.org
Subject: [PATCH v2] mtd: add mtdram device (which build mtd over ram area - useful for FRAM oder MRAM)
Date: Sat, 06 Sep 2014 13:21:03 +0200 [thread overview]
Message-ID: <540AEE1F.5030504@linux-source.de> (raw)
In-Reply-To: <20140901080611.GE5352@pengutronix.de>
Change since v1 (Sascha, thanks for review):
* use xzalloc instead of kzalloc and control check
* correct help and names
* fix coding style issue
* remove verbose and unneeded messages
This adds support for MTD in RAM devices (like FRAM or MRAM).
Signed-off-by: Sebastian Block <basti@linux-source.de>
---
drivers/mtd/devices/Kconfig | 5 ++
drivers/mtd/devices/Makefile | 1 +
drivers/mtd/devices/mtdram.c | 124 +++++++++++++++++++++++++++++++++++++++++++
3 files changed, 130 insertions(+)
create mode 100644 drivers/mtd/devices/mtdram.c
diff --git a/drivers/mtd/devices/Kconfig b/drivers/mtd/devices/Kconfig
index 61278a2..7f9c306 100644
--- a/drivers/mtd/devices/Kconfig
+++ b/drivers/mtd/devices/Kconfig
@@ -58,4 +58,9 @@ config MTD_DOCG3
M-Systems and now Sandisk. The support is very experimental,
and doesn't give access to any write operations.
+config MTD_MTDRAM
+ tristate "Support for NVRAM devices (FRAM, MRAM, ...)"
+ help
+ This enables non volatile RAM to used as MTD devices.
+
endmenu
diff --git a/drivers/mtd/devices/Makefile b/drivers/mtd/devices/Makefile
index bf1f8a9..bc1960e 100644
--- a/drivers/mtd/devices/Makefile
+++ b/drivers/mtd/devices/Makefile
@@ -5,3 +5,4 @@
obj-$(CONFIG_MTD_DATAFLASH) += mtd_dataflash.o
obj-$(CONFIG_MTD_DOCG3) += docg3.o
obj-$(CONFIG_MTD_M25P80) += m25p80.o
+obj-$(CONFIG_MTD_MTDRAM) += mtdram.o
diff --git a/drivers/mtd/devices/mtdram.c b/drivers/mtd/devices/mtdram.c
new file mode 100644
index 0000000..47c5ad7
--- /dev/null
+++ b/drivers/mtd/devices/mtdram.c
+ *
+ * Author: Sebastian Block <basti@linux-source.de>
+ * Copyright (c) 2014
+ *
+ * Some parts are based on mtdram.c found in Linux kernel
+ * by Alexander Larsson <alex@cendio.se>
+ * and Joern Engel <joern@wh.fh-wedel.de>.
+ *
+ * This code 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.
+ *
+ */
+#include <common.h>
+#include <environment.h>
+#include <errno.h>
+#include <init.h>
+#include <io.h>
+#include <linux/mtd/mtd.h>
+#include <malloc.h>
+#include <of.h>
+
+struct mtdram_priv_data {
+ struct mtd_info mtd;
+ void *base;
+};
+
+static int ram_erase(struct mtd_info *mtd, struct erase_info *instr)
+{
+ memset((char *)mtd->priv + instr->addr, 0xff, instr->len);
+ instr->state = MTD_ERASE_DONE;
+ mtd_erase_callback(instr);
+ return 0;
+}
+
+static int ram_write(struct mtd_info *mtd, loff_t to, size_t len, size_t *retlen, const u_char *buf)
+{
+ memcpy((char*)mtd->priv + to, buf, len);
+ *retlen = len;
+ return 0;
+}
+
+static int ram_read(struct mtd_info *mtd, loff_t from, size_t len, size_t *retlen, u_char *buf)
+{
+ memcpy(buf, mtd->priv + from, len);
+ *retlen = len;
+ return 0;
+}
+
+static int mtdram_probe(struct device_d *dev)
+{
+ void __iomem *base;
+ int device_id;
+ struct mtd_info *mtd;
+ struct resource *res;
+ loff_t size;
+ int ret = 0;
+
+ mtd = xzalloc(sizeof(struct mtd_info), GFP_KERNEL);
+
+ device_id = DEVICE_ID_SINGLE;
+ if (dev->device_node) {
+ const char *alias = of_alias_get(dev->device_node);
+ if (alias)
+ mtd->name = xstrdup(alias);
+ }
+
+ if (!mtd->name) {
+ device_id = DEVICE_ID_DYNAMIC;
+ mtd->name = "mtdram";
+ }
+
+ base = dev_request_mem_region(dev, 0);
+ if (!base) {
+ ret = -EBUSY;
+ goto nobase;
+ }
+
+ res = dev_get_resource(dev, IORESOURCE_MEM, 0);
+ size = (unsigned long) resource_size(res);
+ mtd->priv = base;
+
+ mtd->type = MTD_RAM;
+ mtd->writesize = 1;
+ mtd->writebufsize = 64;
+ mtd->flags = MTD_CAP_RAM;
+ mtd->size = size;
+
+ mtd->read = ram_read;
+ mtd->write = ram_write;
+ mtd->erase = ram_erase;
+ mtd->erasesize = 1;
+
+ mtd->parent = dev;
+
+ ret = add_mtd_device(mtd, mtd->name, device_id);
+ return ret;
+
+nobase:
+ kfree(mtd);
+nomem1:
+ return ret;
+}
+
+static __maybe_unused struct of_device_id mtdram_dt_ids[] = {
+ {
+ .compatible = "mtd-ram",
+ }, {
+ /* sentinel */
+ }
+};
+
+static struct driver_d mtdram_driver = {
+ .name = "mtdram",
+ .probe = mtdram_probe,
+ .of_compatible = DRV_OF_COMPAT(mtdram_dt_ids),
+};
+device_platform_driver(mtdram_driver);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Sebastian Block");
+MODULE_DESCRIPTION("MTD RAM driver for NVRAMs");
--
1.9.1
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next prev parent reply other threads:[~2014-09-06 11:21 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-08-28 8:59 [PATCH] " basti
2014-08-28 11:51 ` Alexander Aring
2014-08-28 11:58 ` Alexander Aring
2014-09-01 8:06 ` Sascha Hauer
2014-09-06 11:21 ` Sebastian Block [this message]
2014-09-08 6:23 ` [PATCH v2] " Sascha Hauer
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