297 lines
8.0 KiB
C
297 lines
8.0 KiB
C
/*
|
|
* 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 <common.h>
|
|
#include <asm/fsl_ddr_sdram.h>
|
|
#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 != SPD_MEMTYPE_DDR2)
|
|
goto error;
|
|
|
|
retval = ddr2_spd_checksum_pass(spd);
|
|
if (retval)
|
|
goto error;
|
|
|
|
/*
|
|
* 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;
|
|
}
|