From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from exprod5og110.obsmtp.com ([64.18.0.20]) by merlin.infradead.org with smtps (Exim 4.80.1 #2 (Red Hat Linux)) id 1UrtcX-0002LN-Rg for barebox@lists.infradead.org; Wed, 26 Jun 2013 17:35:08 +0000 From: Renaud Barbier Date: Wed, 26 Jun 2013 18:33:43 +0100 Message-Id: <1372268027-15271-5-git-send-email-renaud.barbier@ge.com> In-Reply-To: <1372157137-7602-1-git-send-email-renaud.barbier@ge.com> References: <1372157137-7602-1-git-send-email-renaud.barbier@ge.com> List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "barebox" Errors-To: barebox-bounces+u.kleine-koenig=pengutronix.de@lists.infradead.org Subject: [PATCH 4/8] ppc 8xxx: DIMM parameters calculation To: barebox@lists.infradead.org This code calculates the DIMM characteritics i.e DIMM organization parameters and timings for DDR2 memory based on SPD data. It also provides a function to find out the lowest common DIMM parameters to be used for all DIMMs. This code is based on the equivalent files in directory arch/powerpc/cpu/mpc8xxx/ddr from U-Boot version git-a71d45d. Signed-off-by: Renaud Barbier --- arch/ppc/ddr-8xxx/ddr2_dimm_params.c | 303 +++++++++++++++++++++++++++++ arch/ppc/ddr-8xxx/lc_common_dimm_params.c | 214 ++++++++++++++++++++ 2 files changed, 517 insertions(+), 0 deletions(-) create mode 100644 arch/ppc/ddr-8xxx/ddr2_dimm_params.c create mode 100644 arch/ppc/ddr-8xxx/lc_common_dimm_params.c diff --git a/arch/ppc/ddr-8xxx/ddr2_dimm_params.c b/arch/ppc/ddr-8xxx/ddr2_dimm_params.c new file mode 100644 index 0000000..b36a888 --- /dev/null +++ b/arch/ppc/ddr-8xxx/ddr2_dimm_params.c @@ -0,0 +1,303 @@ +/* + * Copyright 2008 Freescale Semiconductor, Inc. + * + * 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. + */ + +#include +#include +#include "ddr.h" +/* + * Calculate the Density of each Physical Rank. + * Returned size is in bytes. + * + * Table comes from Byte 31 of JEDEC SPD Spec. + * + * DDR II + * Bit Size Size + * --- ----- + * 7 high 512MB + * 6 256MB + * 5 128MB + * 4 16GB + * 3 8GB + * 2 4GB + * 1 2GB + * 0 low 1GB + * + * Reorder Table to be linear by stripping the bottom + * 2 or 5 bits off and shifting them up to the top. + * + */ +static uint64_t compute_ranksize(uint32_t mem_type, unsigned char row_dens) +{ + uint64_t bsize; + + bsize = ((row_dens >> 5) | ((row_dens & 31) << 3)); + bsize <<= 27ULL; + + return bsize; +} + +/* + * Convert a two-nibble BCD value into a cycle time. + * While the spec calls for nano-seconds, picos are returned. + */ +static uint32_t convert_bcd_tenths_to_cycle_time_ps(uint32_t spd_val) +{ + uint32_t tenths_ps[16] = { + 0, + 100, + 200, + 300, + 400, + 500, + 600, + 700, + 800, + 900, + 250, + 330, + 660, + 750, + 0, + 0 + }; + uint32_t whole_ns = (spd_val & 0xF0) >> 4; + uint32_t tenth_ns = spd_val & 0x0F; + uint32_t ps = (whole_ns * 1000) + tenths_ps[tenth_ns]; + + return ps; +} + +static uint32_t convert_bcd_hundredths_to_cycle_time_ps(uint32_t spd_val) +{ + uint32_t tenth_ns = (spd_val & 0xF0) >> 4; + uint32_t hundredth_ns = spd_val & 0x0F; + uint32_t ps = (tenth_ns * 100) + (hundredth_ns * 10); + + return ps; +} + +static uint32_t byte40_table_ps[8] = { + 0, + 250, + 330, + 500, + 660, + 750, + 0, + 0 +}; + +static uint32_t +compute_trfc_ps_from_spd(unsigned char trctrfc_ext, unsigned char trfc) +{ + uint32_t trfc_ps; + + trfc_ps = (((trctrfc_ext & 0x1) * 256) + trfc) * 1000; + trfc_ps += byte40_table_ps[(trctrfc_ext >> 1) & 0x7]; + + return trfc_ps; +} + +static uint32_t +compute_trc_ps_from_spd(unsigned char trctrfc_ext, unsigned char trc) +{ + uint32_t trc_ps; + + trc_ps = (trc * 1000); + trc_ps += byte40_table_ps[(trctrfc_ext >> 4) & 0x7]; + + return trc_ps; +} + +/* + * Determine Refresh Rate. + * Table from SPD Spec, Byte 12, converted to picoseconds and + * filled in with "default" normal values. + */ +static uint32_t determine_refresh_rate_ps(const uint32_t spd_refresh) +{ + uint32_t refresh_time_ps[8] = { + 15625000, /* 0 Normal 1.00x */ + 3900000, /* 1 Reduced .25x */ + 7800000, /* 2 Extended .50x */ + 31300000, /* 3 Extended 2.00x */ + 62500000, /* 4 Extended 4.00x */ + 125000000, /* 5 Extended 8.00x */ + 15625000, /* 6 Normal 1.00x filler */ + 15625000, /* 7 Normal 1.00x filler */ + }; + + return refresh_time_ps[spd_refresh & 0x7]; +} + +/* + * The purpose of this function is to compute a suitable + * CAS latency given the DRAM clock period. The SPD only + * defines at most 3 CAS latencies. Typically the slower in + * frequency the DIMM runs at, the shorter its CAS latency can. + * be. If the DIMM is operating at a sufficiently low frequency, + * it may be able to run at a CAS latency shorter than the + * shortest SPD-defined CAS latency. + * + * If a CAS latency is not found, 0 is returned. + * + * Do this by finding in the standard speed table the longest + * tCKmin that doesn't exceed the value of mclk_ps (tCK). + * + * An assumption made is that the SDRAM device allows the + * CL to be programmed for a value that is lower than those + * advertised by the SPD. This is not always the case, + * as those modes not defined in the SPD are optional. + * + * CAS latency de-rating based upon values JEDEC Standard No. 79-2C + * Table 40, "DDR2 SDRAM standard speed bins and tCK, tRCD, tRP, tRAS, + * and tRC for corresponding bin" + * + * ordinal 2, ddr2_speed_bins[1] contains tCK for CL=3 + * Not certain if any good value exists for CL=2 + */ + /* CL2 CL3 CL4 CL5 CL6 CL7 */ +uint16_t ddr2_speed_bins[] = { 0, 5000, 3750, 3000, 2500, 1875 }; + +uint32_t compute_derated_DDR2_CAS_latency(uint32_t mclk_ps) +{ + const uint32_t num_speed_bins = ARRAY_SIZE(ddr2_speed_bins); + uint32_t lowest_tCKmin_found = 0, lowest_tCKmin_CL = 0, i, x; + + for (i = 0; i < num_speed_bins; i++) { + x = ddr2_speed_bins[i]; + if (x && (x <= mclk_ps) && (x >= lowest_tCKmin_found)) { + lowest_tCKmin_found = x; + lowest_tCKmin_CL = i + 2; + } + } + + return lowest_tCKmin_CL; +} + +/* + * compute_dimm_parameters for DDR2 SPD + * + * Compute DIMM parameters based upon the SPD information in SPD. + * Writes the results to the dimm_params_s structure pointed by pdimm. + */ +uint32_t +compute_dimm_parameters(const generic_spd_eeprom_t *spdin, + struct dimm_params_s *pdimm) +{ + const struct ddr2_spd_eeprom_s *spd = spdin; + uint32_t retval; + + if (!spd->mem_type) { + memset(pdimm, 0, sizeof(struct dimm_params_s)); + goto error; + } + + if (spd->mem_type != SPD_MEMTYPE_DDR2) + goto error; + + retval = ddr2_spd_checksum_pass(spd); + if (retval) + goto spd_err; + + /* + * The part name in ASCII in the SPD EEPROM is not null terminated. + * Guarantee null termination here by presetting all bytes to 0 + * and copying the part name in ASCII from the SPD onto it + */ + memset(pdimm->mpart, 0, sizeof(pdimm->mpart)); + memcpy(pdimm->mpart, spd->mpart, sizeof(pdimm->mpart) - 1); + + /* DIMM organization parameters */ + pdimm->n_ranks = (spd->mod_ranks & 0x7) + 1; + pdimm->rank_density = compute_ranksize(spd->mem_type, spd->rank_dens); + pdimm->capacity = pdimm->n_ranks * pdimm->rank_density; + pdimm->data_width = spd->dataw; + pdimm->primary_sdram_width = spd->primw; + pdimm->ec_sdram_width = spd->ecw; + + /* These are all the types defined by the JEDEC DDR2 SPD 1.3 spec */ + switch (spd->dimm_type) { + case DDR2_SPD_DIMMTYPE_RDIMM: + case DDR2_SPD_DIMMTYPE_72B_SO_RDIMM: + case DDR2_SPD_DIMMTYPE_MINI_RDIMM: + /* Registered/buffered DIMMs */ + pdimm->registered_dimm = 1; + break; + + case DDR2_SPD_DIMMTYPE_UDIMM: + case DDR2_SPD_DIMMTYPE_SO_DIMM: + case DDR2_SPD_DIMMTYPE_MICRO_DIMM: + case DDR2_SPD_DIMMTYPE_MINI_UDIMM: + /* Unbuffered DIMMs */ + pdimm->registered_dimm = 0; + break; + + case DDR2_SPD_DIMMTYPE_72B_SO_CDIMM: + default: + goto error; + } + + pdimm->n_row_addr = spd->nrow_addr; + pdimm->n_col_addr = spd->ncol_addr; + pdimm->n_banks_per_sdram_device = spd->nbanks; + pdimm->edc_config = spd->config; + pdimm->burst_lengths_bitmask = spd->burstl; + pdimm->row_density = spd->rank_dens; + + /* + * Calculate the Maximum Data Rate based on the Minimum Cycle time. + * The SPD clk_cycle field (tCKmin) is measured in tenths of + * nanoseconds and represented as BCD. + */ + pdimm->tCKmin_X_ps + = convert_bcd_tenths_to_cycle_time_ps(spd->clk_cycle); + pdimm->tCKmin_X_minus_1_ps + = convert_bcd_tenths_to_cycle_time_ps(spd->clk_cycle2); + pdimm->tCKmin_X_minus_2_ps + = convert_bcd_tenths_to_cycle_time_ps(spd->clk_cycle3); + pdimm->tCKmax_ps = convert_bcd_tenths_to_cycle_time_ps(spd->tckmax); + + /* + * Compute CAS latencies defined by SPD + * The SPD caslat_X should have at least 1 and at most 3 bits set. + * + * If cas_lat after masking is 0, the __ilog2 function returns + * 255 into the variable. This behavior is abused once. + */ + pdimm->caslat_X = __ilog2(spd->cas_lat); + pdimm->caslat_X_minus_1 = __ilog2(spd->cas_lat + & ~(1 << pdimm->caslat_X)); + pdimm->caslat_X_minus_2 = __ilog2(spd->cas_lat & ~(1 << pdimm->caslat_X) + & ~(1 << pdimm->caslat_X_minus_1)); + pdimm->caslat_lowest_derated + = compute_derated_DDR2_CAS_latency(get_memory_clk_period_ps()); + pdimm->tRCD_ps = spd->trcd * 250; + pdimm->tRP_ps = spd->trp * 250; + pdimm->tRAS_ps = spd->tras * 1000; + pdimm->tWR_ps = spd->twr * 250; + pdimm->tWTR_ps = spd->twtr * 250; + pdimm->tRFC_ps = compute_trfc_ps_from_spd(spd->trctrfc_ext, spd->trfc); + pdimm->tRRD_ps = spd->trrd * 250; + pdimm->tRC_ps = compute_trc_ps_from_spd(spd->trctrfc_ext, spd->trc); + pdimm->refresh_rate_ps = determine_refresh_rate_ps(spd->refresh); + pdimm->tIS_ps = convert_bcd_hundredths_to_cycle_time_ps(spd->ca_setup); + pdimm->tIH_ps = convert_bcd_hundredths_to_cycle_time_ps(spd->ca_hold); + pdimm->tDS_ps + = convert_bcd_hundredths_to_cycle_time_ps(spd->data_setup); + pdimm->tDH_ps = convert_bcd_hundredths_to_cycle_time_ps(spd->data_hold); + pdimm->tRTP_ps = spd->trtp * 250; + pdimm->tDQSQ_max_ps = spd->tdqsq * 10; + pdimm->tQHS_ps = spd->tqhs * 10; + + return 0; +error: + return 1; +spd_err: + return 2; +} diff --git a/arch/ppc/ddr-8xxx/lc_common_dimm_params.c b/arch/ppc/ddr-8xxx/lc_common_dimm_params.c new file mode 100644 index 0000000..a1addb0 --- /dev/null +++ b/arch/ppc/ddr-8xxx/lc_common_dimm_params.c @@ -0,0 +1,214 @@ +/* + * Copyright 2008-2012 Freescale Semiconductor, Inc. + * + * 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. + */ + +#include +#include +#include + +#include "ddr.h" + +static unsigned int common_burst_length( + const struct dimm_params_s *dimm_params, + const unsigned int number_of_dimms) +{ + unsigned int i, temp; + + temp = 0xff; + for (i = 0; i < number_of_dimms; i++) + if (dimm_params[i].n_ranks) + temp &= dimm_params[i].burst_lengths_bitmask; + + return temp; +} + +/* Compute a CAS latency suitable for all DIMMs */ +static unsigned int compute_lowest_caslat( + const struct dimm_params_s *dimm_params, + const unsigned int number_of_dimms) +{ + uint32_t temp1, temp2, i, not_ok, lowest_good_caslat, + tCKmin_X_minus_1_ps, tCKmin_X_minus_2_ps; + const unsigned int mclk_ps = get_memory_clk_period_ps(); + + /* + * Step 1: find CAS latency common to all DIMMs using bitwise + * operation. + */ + temp1 = 0xFF; + for (i = 0; i < number_of_dimms; i++) + if (dimm_params[i].n_ranks) { + temp2 = 0; + temp2 |= 1 << dimm_params[i].caslat_X; + temp2 |= 1 << dimm_params[i].caslat_X_minus_1; + temp2 |= 1 << dimm_params[i].caslat_X_minus_2; + /* + * FIXME: If there was no entry for X-2 (X-1) in + * the SPD, then caslat_X_minus_2 + * (caslat_X_minus_1) contains either 255 or + * 0xFFFFFFFF because that's what the __ilog2 + * function returns for an input of 0. + * On 32-bit PowerPC, left shift counts with bit + * 26 set (that the value of 255 or 0xFFFFFFFF + * will have), cause the destination register to + * be 0. That is why this works. + */ + temp1 &= temp2; + } + + /* + * Step 2: check each common CAS latency against tCK of each + * DIMM's SPD. + */ + lowest_good_caslat = 0; + temp2 = 0; + while (temp1) { + not_ok = 0; + temp2 = __ilog2(temp1); + + for (i = 0; i < number_of_dimms; i++) { + if (!dimm_params[i].n_ranks) + continue; + + if (dimm_params[i].caslat_X == temp2) { + if (mclk_ps >= dimm_params[i].tCKmin_X_ps) + continue; + else + not_ok++; + } + + if (dimm_params[i].caslat_X_minus_1 == temp2) { + tCKmin_X_minus_1_ps = + dimm_params[i].tCKmin_X_minus_1_ps; + if (mclk_ps >= tCKmin_X_minus_1_ps) + continue; + else + not_ok++; + } + + if (dimm_params[i].caslat_X_minus_2 == temp2) { + tCKmin_X_minus_2_ps + = dimm_params[i].tCKmin_X_minus_2_ps; + if (mclk_ps >= tCKmin_X_minus_2_ps) + continue; + else + not_ok++; + } + } + + if (!not_ok) + lowest_good_caslat = temp2; + + temp1 &= ~(1 << temp2); + } + return lowest_good_caslat; +} + +/* + * compute_lowest_common_dimm_parameters() + * + * Determine the worst-case DIMM timing parameters from the set of DIMMs + * whose parameters have been computed into the array pointed to + * by dimm_params. + */ +unsigned int +compute_lowest_common_dimm_parameters(const struct dimm_params_s *dimm, + struct common_timing_params_s *out, + const unsigned int number_of_dimms) +{ + const uint32_t mclk_ps = get_memory_clk_period_ps(); + uint32_t temp1, i; + struct common_timing_params_s tmp = {0}; + + tmp.tCKmax_ps = 0xFFFFFFFF; + temp1 = 0; + for (i = 0; i < number_of_dimms; i++) { + if (dimm[i].n_ranks == 0) { + temp1++; + continue; + } + + /* + * Find minimum tCKmax_ps to find fastest slow speed, + * i.e., this is the slowest the whole system can go. + */ + tmp.tCKmax_ps = min(tmp.tCKmax_ps, dimm[i].tCKmax_ps); + + /* Find maximum value to determine slowest speed, delay, etc */ + tmp.tCKmin_X_ps = max(tmp.tCKmin_X_ps, dimm[i].tCKmin_X_ps); + tmp.tCKmax_max_ps = max(tmp.tCKmax_max_ps, dimm[i].tCKmax_ps); + tmp.tRCD_ps = max(tmp.tRCD_ps, dimm[i].tRCD_ps); + tmp.tRP_ps = max(tmp.tRP_ps, dimm[i].tRP_ps); + tmp.tRAS_ps = max(tmp.tRAS_ps, dimm[i].tRAS_ps); + tmp.tWR_ps = max(tmp.tWR_ps, dimm[i].tWR_ps); + tmp.tWTR_ps = max(tmp.tWTR_ps, dimm[i].tWTR_ps); + tmp.tRFC_ps = max(tmp.tRFC_ps, dimm[i].tRFC_ps); + tmp.tRRD_ps = max(tmp.tRRD_ps, dimm[i].tRRD_ps); + tmp.tRC_ps = max(tmp.tRC_ps, dimm[i].tRC_ps); + tmp.tIS_ps = max(tmp.tIS_ps, dimm[i].tIS_ps); + tmp.tIH_ps = max(tmp.tIH_ps, dimm[i].tIH_ps); + tmp.tDS_ps = max(tmp.tDS_ps, dimm[i].tDS_ps); + tmp.tDH_ps = max(tmp.tDH_ps, dimm[i].tDH_ps); + tmp.tRTP_ps = max(tmp.tRTP_ps, dimm[i].tRTP_ps); + tmp.tQHS_ps = max(tmp.tQHS_ps, dimm[i].tQHS_ps); + tmp.refresh_rate_ps = max(tmp.refresh_rate_ps, + dimm[i].refresh_rate_ps); + /* Find maximum tDQSQ_max_ps to find slowest timing. */ + tmp.tDQSQ_max_ps = max(tmp.tDQSQ_max_ps, dimm[i].tDQSQ_max_ps); + } + tmp.ndimms_present = number_of_dimms - temp1; + + if (temp1 == number_of_dimms) + return 0; + + temp1 = common_burst_length(dimm, number_of_dimms); + tmp.all_DIMMs_burst_lengths_bitmask = temp1; + tmp.all_DIMMs_registered = 0; + + tmp.lowest_common_SPD_caslat = compute_lowest_caslat(dimm, + number_of_dimms); + /* + * Compute a common 'de-rated' CAS latency. + * + * The strategy here is to find the *highest* de-rated cas latency + * with the assumption that all of the DIMMs will support a de-rated + * CAS latency higher than or equal to their lowest de-rated value. + */ + temp1 = 0; + for (i = 0; i < number_of_dimms; i++) + temp1 = max(temp1, dimm[i].caslat_lowest_derated); + tmp.highest_common_derated_caslat = temp1; + + temp1 = 1; + for (i = 0; i < number_of_dimms; i++) + if (dimm[i].n_ranks && + !(dimm[i].edc_config & EDC_ECC)) { + temp1 = 0; + break; + } + tmp.all_DIMMs_ECC_capable = temp1; + + if (mclk_ps > tmp.tCKmax_max_ps) + return 1; + + /* + * AL must be less or equal to tRCD. Typically, AL would + * be AL = tRCD - 1; + * + * When ODT read or write is enabled the sum of CAS latency + + * additive latency must be at least 3 cycles. + * + */ + if ((tmp.lowest_common_SPD_caslat < 4) && (picos_to_mclk(tmp.tRCD_ps) > + tmp.lowest_common_SPD_caslat)) + tmp.additive_latency = picos_to_mclk(tmp.tRCD_ps) - + tmp.lowest_common_SPD_caslat; + + memcpy(out, &tmp, sizeof(struct common_timing_params_s)); + + return 0; +} -- 1.7.1 _______________________________________________ barebox mailing list barebox@lists.infradead.org http://lists.infradead.org/mailman/listinfo/barebox