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* Copyright 2014 Freescale Semiconductor, Inc.
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* calculate the organization and timing parameter
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* from ddr3 spd, please refer to the spec
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* JEDEC standard No.21-C 4_01_02_12R23A.pdf
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#include <fsl_ddr_sdram.h>
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* Calculate the Density of each Physical Rank.
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* Returned size is in bytes.
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* sdram capacity(bit) / 8 * primary bus width / sdram width
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* * Logical Ranks per DIMM
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* where: sdram capacity = spd byte4[3:0]
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* primary bus width = spd byte13[2:0]
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* sdram width = spd byte12[2:0]
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* Logical Ranks per DIMM = spd byte12[5:3] for SDP, DDP, QDP
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* spd byte12{5:3] * spd byte6[6:4] for 3DS
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* To simplify each rank size = total DIMM size / Number of Package Ranks
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* where Number of Package Ranks = spd byte12[5:3]
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* SPD byte4 - sdram density and banks
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* bit[3:0] size(bit) size(byte)
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* SPD byte13 - module memory bus width
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* bit[2:0] primary bus width
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* SPD byte12 - module organization
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* bit[2:0] sdram device width
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* SPD byte12 - module organization
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* bit[5:3] number of package ranks per DIMM
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* SPD byte6 - SDRAM package type
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* SPD byte6 - SRAM package type
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* bit[1:0] Signal loading
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* 10 Sigle load stack (3DS)
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static unsigned long long
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compute_ranksize(const struct ddr4_spd_eeprom_s *spd)
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unsigned long long bsize;
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int nbit_sdram_cap_bsize = 0;
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int nbit_primary_bus_width = 0;
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int nbit_sdram_width = 0;
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if ((spd->density_banks & 0xf) <= 7)
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nbit_sdram_cap_bsize = (spd->density_banks & 0xf) + 28;
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if ((spd->bus_width & 0x7) < 4)
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nbit_primary_bus_width = (spd->bus_width & 0x7) + 3;
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if ((spd->organization & 0x7) < 4)
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nbit_sdram_width = (spd->organization & 0x7) + 2;
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package_3ds = (spd->package_type & 0x3) == 0x2;
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die_count = (spd->package_type >> 4) & 0x7;
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bsize = 1ULL << (nbit_sdram_cap_bsize - 3 +
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nbit_primary_bus_width - nbit_sdram_width +
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debug("DDR: DDR III rank density = 0x%16llx\n", bsize);
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#define spd_to_ps(mtb, ftb) \
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(mtb * pdimm->mtb_ps + (ftb * pdimm->ftb_10th_ps) / 10)
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* ddr_compute_dimm_parameters for DDR3 SPD
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* Compute DIMM parameters based upon the SPD information in spd.
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* Writes the results to the dimm_params_t structure pointed by pdimm.
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ddr_compute_dimm_parameters(const generic_spd_eeprom_t *spd,
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dimm_params_t *pdimm,
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unsigned int dimm_number)
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if (spd->mem_type != SPD_MEMTYPE_DDR4) {
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printf("DIMM %u: is not a DDR4 SPD.\n", dimm_number);
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memset(pdimm, 0, sizeof(dimm_params_t));
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retval = ddr4_spd_check(spd);
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printf("DIMM %u: failed checksum\n", dimm_number);
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* The part name in ASCII in the SPD EEPROM is not null terminated.
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* Guarantee null termination here by presetting all bytes to 0
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* and copying the part name in ASCII from the SPD onto it
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memset(pdimm->mpart, 0, sizeof(pdimm->mpart));
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if ((spd->info_size_crc & 0xF) > 2)
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memcpy(pdimm->mpart, spd->mpart, sizeof(pdimm->mpart) - 1);
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/* DIMM organization parameters */
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pdimm->n_ranks = ((spd->organization >> 3) & 0x7) + 1;
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pdimm->rank_density = compute_ranksize(spd);
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pdimm->capacity = pdimm->n_ranks * pdimm->rank_density;
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pdimm->primary_sdram_width = 1 << (3 + (spd->bus_width & 0x7));
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if ((spd->bus_width >> 3) & 0x3)
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pdimm->ec_sdram_width = 8;
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pdimm->ec_sdram_width = 0;
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pdimm->data_width = pdimm->primary_sdram_width
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+ pdimm->ec_sdram_width;
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pdimm->device_width = 1 << ((spd->organization & 0x7) + 2);
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/* These are the types defined by the JEDEC DDR3 SPD spec */
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pdimm->mirrored_dimm = 0;
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pdimm->registered_dimm = 0;
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switch (spd->module_type & DDR3_SPD_MODULETYPE_MASK) {
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case DDR3_SPD_MODULETYPE_RDIMM:
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/* Registered/buffered DIMMs */
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pdimm->registered_dimm = 1;
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case DDR3_SPD_MODULETYPE_UDIMM:
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case DDR3_SPD_MODULETYPE_SO_DIMM:
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/* Unbuffered DIMMs */
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if (spd->mod_section.unbuffered.addr_mapping & 0x1)
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pdimm->mirrored_dimm = 1;
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printf("unknown module_type 0x%02X\n", spd->module_type);
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/* SDRAM device parameters */
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pdimm->n_row_addr = ((spd->addressing >> 3) & 0x7) + 12;
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pdimm->n_col_addr = (spd->addressing & 0x7) + 9;
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pdimm->bank_addr_bits = (spd->density_banks >> 4) & 0x3;
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pdimm->bank_group_bits = (spd->density_banks >> 6) & 0x3;
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* The SPD spec has not the ECC bit,
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* We consider the DIMM as ECC capability
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* when the extension bus exist
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if (pdimm->ec_sdram_width)
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pdimm->edc_config = 0x02;
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pdimm->edc_config = 0x00;
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* The SPD spec has not the burst length byte
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* but DDR4 spec has nature BL8 and BC4,
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* BL8 -bit3, BC4 -bit2
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pdimm->burst_lengths_bitmask = 0x0c;
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pdimm->row_density = __ilog2(pdimm->rank_density);
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/* MTB - medium timebase
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* The MTB in the SPD spec is 125ps,
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* FTB - fine timebase
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* use 1/10th of ps as our unit to avoid floating point
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* eg, 10 for 1ps, 25 for 2.5ps, 50 for 5ps
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if ((spd->timebases & 0xf) == 0x0) {
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pdimm->ftb_10th_ps = 10;
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printf("Unknown Timebases\n");
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/* sdram minimum cycle time */
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pdimm->tckmin_x_ps = spd_to_ps(spd->tck_min, spd->fine_tck_min);
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/* sdram max cycle time */
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pdimm->tckmax_ps = spd_to_ps(spd->tck_max, spd->fine_tck_max);
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* CAS latency supported
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pdimm->caslat_x = (spd->caslat_b1 << 7) |
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(spd->caslat_b2 << 15) |
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(spd->caslat_b3 << 23);
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BUG_ON(spd->caslat_b4 != 0);
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* min CAS latency time
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pdimm->taa_ps = spd_to_ps(spd->taa_min, spd->fine_taa_min);
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* min RAS to CAS delay time
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pdimm->trcd_ps = spd_to_ps(spd->trcd_min, spd->fine_trcd_min);
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* Min Row Precharge Delay Time
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pdimm->trp_ps = spd_to_ps(spd->trp_min, spd->fine_trp_min);
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/* min active to precharge delay time */
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pdimm->tras_ps = (((spd->tras_trc_ext & 0xf) << 8) +
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spd->tras_min_lsb) * pdimm->mtb_ps;
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/* min active to actice/refresh delay time */
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pdimm->trc_ps = spd_to_ps((((spd->tras_trc_ext & 0xf0) << 4) +
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spd->trc_min_lsb), spd->fine_trc_min);
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/* Min Refresh Recovery Delay Time */
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pdimm->trfc1_ps = ((spd->trfc1_min_msb << 8) | (spd->trfc1_min_lsb)) *
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pdimm->trfc2_ps = ((spd->trfc2_min_msb << 8) | (spd->trfc2_min_lsb)) *
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pdimm->trfc4_ps = ((spd->trfc4_min_msb << 8) | (spd->trfc4_min_lsb)) *
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/* min four active window delay time */
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pdimm->tfaw_ps = (((spd->tfaw_msb & 0xf) << 8) | spd->tfaw_min) *
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/* min row active to row active delay time, different bank group */
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pdimm->trrds_ps = spd_to_ps(spd->trrds_min, spd->fine_trrds_min);
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/* min row active to row active delay time, same bank group */
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pdimm->trrdl_ps = spd_to_ps(spd->trrdl_min, spd->fine_trrdl_min);
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/* min CAS to CAS Delay Time (tCCD_Lmin), same bank group */
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pdimm->tccdl_ps = spd_to_ps(spd->tccdl_min, spd->fine_tccdl_min);
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* Average periodic refresh interval
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* tREFI = 7.8 us at normal temperature range
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pdimm->refresh_rate_ps = 7800000;
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for (i = 0; i < 18; i++)
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pdimm->dq_mapping[i] = spd->mapping[i];
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pdimm->dq_mapping_ors = ((spd->mapping[0] >> 6) & 0x3) == 0 ? 1 : 0;