// SPDX-License-Identifier: GPL-2.0 /* * Copyright 2008-2016 Freescale Semiconductor, Inc. * Copyright 2017-2018 NXP Semiconductor */ #include #include #include #include "fsl_ddr.h" static unsigned int compute_cas_latency_ddr34(memctl_options_t *popts, struct fsl_ddr_controller *c, const struct dimm_params *dimm_params, struct common_timing_params *outpdimm, unsigned int number_of_dimms) { unsigned int i; unsigned int common_caslat; unsigned int caslat_actual; unsigned int retry = 16; unsigned int tmp = ~0; const unsigned int mclk_ps = get_memory_clk_period_ps(c); unsigned int taamax; if (is_ddr3(popts)) taamax = 20000; else taamax = 18000; /* compute the common CAS latency supported between slots */ for (i = 0; i < number_of_dimms; i++) { if (dimm_params[i].n_ranks) tmp &= dimm_params[i].caslat_x; } common_caslat = tmp; /* validate if the memory clk is in the range of dimms */ if (mclk_ps < outpdimm->tckmin_x_ps) { printf("DDR clock (MCLK cycle %u ps) is faster than " "the slowest DIMM(s) (tCKmin %u ps) can support.\n", mclk_ps, outpdimm->tckmin_x_ps); } if (is_ddr4(popts) && mclk_ps > outpdimm->tckmax_ps) { printf("DDR clock (MCLK cycle %u ps) is slower than DIMM(s) (tCKmax %u ps) can support.\n", mclk_ps, outpdimm->tckmax_ps); } /* determine the acutal cas latency */ caslat_actual = (outpdimm->taamin_ps + mclk_ps - 1) / mclk_ps; /* check if the dimms support the CAS latency */ while (!(common_caslat & (1 << caslat_actual)) && retry > 0) { caslat_actual++; retry--; } /* once the caculation of caslat_actual is completed * we must verify that this CAS latency value does not * exceed tAAmax, which is 20 ns for all DDR3 speed grades, * 18ns for all DDR4 speed grades. */ if (caslat_actual * mclk_ps > taamax) { printf("The chosen cas latency %d is too large\n", caslat_actual); } outpdimm->lowest_common_spd_caslat = caslat_actual; debug("lowest_common_spd_caslat is 0x%x\n", caslat_actual); return 0; } static unsigned int compute_cas_latency_ddr12(memctl_options_t *popts, struct fsl_ddr_controller *c, const struct dimm_params *dimm_params, struct common_timing_params *outpdimm, unsigned int number_of_dimms) { int i; const unsigned int mclk_ps = get_memory_clk_period_ps(c); unsigned int lowest_good_caslat; unsigned int not_ok; unsigned int temp1, temp2; debug("using mclk_ps = %u\n", mclk_ps); if (mclk_ps > outpdimm->tckmax_ps) { printf("Warning: DDR clock (%u ps) is slower than DIMM(s) (tCKmax %u ps)\n", mclk_ps, outpdimm->tckmax_ps); } /* * Compute a CAS latency suitable for all DIMMs * * Strategy for SPD-defined latencies: compute only * CAS latency defined by all DIMMs. */ /* * 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; /* * 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 glorious * __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); debug("checking common caslat = %u\n", temp2); /* Check if this CAS latency will work on all DIMMs at tCK. */ 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) { debug("CL = %u ok on DIMM %u at tCK=%u ps with tCKmin_X_ps of %u\n", temp2, i, mclk_ps, dimm_params[i].tckmin_x_ps); continue; } else { not_ok++; } } if (dimm_params[i].caslat_x_minus_1 == temp2) { unsigned int tckmin_x_minus_1_ps = dimm_params[i].tckmin_x_minus_1_ps; if (mclk_ps >= tckmin_x_minus_1_ps) { debug("CL = %u ok on DIMM %u at tCK=%u ps with tckmin_x_minus_1_ps of %u\n", temp2, i, mclk_ps, tckmin_x_minus_1_ps); continue; } else { not_ok++; } } if (dimm_params[i].caslat_x_minus_2 == temp2) { unsigned int tckmin_x_minus_2_ps = dimm_params[i].tckmin_x_minus_2_ps; if (mclk_ps >= tckmin_x_minus_2_ps) { debug("CL = %u ok on DIMM %u at tCK=%u ps with tckmin_x_minus_2_ps of %u\n", temp2, i, mclk_ps, tckmin_x_minus_2_ps); continue; } else { not_ok++; } } } if (!not_ok) lowest_good_caslat = temp2; temp1 &= ~(1 << temp2); } debug("lowest common SPD-defined CAS latency = %u\n", lowest_good_caslat); outpdimm->lowest_common_spd_caslat = lowest_good_caslat; /* * Compute a common 'de-rated' CAS latency. * * The strategy here is to find the *highest* dereated cas latency * with the assumption that all of the DIMMs will support a dereated * CAS latency higher than or equal to their lowest dereated value. */ temp1 = 0; for (i = 0; i < number_of_dimms; i++) temp1 = max(temp1, dimm_params[i].caslat_lowest_derated); outpdimm->highest_common_derated_caslat = temp1; debug("highest common dereated CAS latency = %u\n", temp1); return 0; } /* * 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(struct fsl_ddr_controller *c) { int number_of_dimms = c->dimm_slots_per_ctrl; memctl_options_t *popts = &c->memctl_opts; const struct dimm_params *dimm_params = c->dimm_params; struct common_timing_params *outpdimm = &c->common_timing_params; unsigned int i, j; unsigned int tckmin_x_ps = 0; unsigned int tckmax_ps = 0xFFFFFFFF; unsigned int trcd_ps = 0; unsigned int trp_ps = 0; unsigned int tras_ps = 0; unsigned int taamin_ps = 0; unsigned int twr_ps = 0; unsigned int trfc1_ps = 0; unsigned int trfc2_ps = 0; unsigned int trfc4_ps = 0; unsigned int trrds_ps = 0; unsigned int trrdl_ps = 0; unsigned int tccdl_ps = 0; unsigned int trfc_slr_ps = 0; unsigned int twtr_ps = 0; unsigned int trfc_ps = 0; unsigned int trrd_ps = 0; unsigned int trtp_ps = 0; unsigned int trc_ps = 0; unsigned int refresh_rate_ps = 0; unsigned int extended_op_srt = 1; unsigned int tis_ps = 0; unsigned int tih_ps = 0; unsigned int tds_ps = 0; unsigned int tdh_ps = 0; unsigned int tdqsq_max_ps = 0; unsigned int tqhs_ps = 0; unsigned int temp1, temp2; unsigned int additive_latency = 0; temp1 = 0; for (i = 0; i < number_of_dimms; i++) { /* * If there are no ranks on this DIMM, * it probably doesn't exist, so skip it. */ if (dimm_params[i].n_ranks == 0) { temp1++; continue; } if (dimm_params[i].n_ranks == 4 && i != 0) { printf("Found Quad-rank DIMM in wrong bank, ignored." " Software may not run as expected.\n"); temp1++; continue; } /* * check if quad-rank DIMM is plugged if * CONFIG_CHIP_SELECT_QUAD_CAPABLE is not defined * Only the board with proper design is capable */ if (dimm_params[i].n_ranks == 4 && \ c->chip_selects_per_ctrl / c->dimm_slots_per_ctrl < 4) { printf("Found Quad-rank DIMM, not able to support."); temp1++; continue; } /* * Find minimum tckmax_ps to find fastest slow speed, * i.e., this is the slowest the whole system can go. */ outpdimm->tckmax_ps = min(tckmax_ps, (unsigned int)dimm_params[i].tckmax_ps); if (is_ddr3_4(popts)) outpdimm->taamin_ps = max(taamin_ps, (unsigned int)dimm_params[i].taa_ps); outpdimm->tckmin_x_ps = max(tckmin_x_ps, (unsigned int)dimm_params[i].tckmin_x_ps); outpdimm->trcd_ps = max(trcd_ps, (unsigned int)dimm_params[i].trcd_ps); outpdimm->trp_ps = max(trp_ps, (unsigned int)dimm_params[i].trp_ps); outpdimm->tras_ps = max(tras_ps, (unsigned int)dimm_params[i].tras_ps); if (is_ddr4(popts)) { outpdimm->twr_ps = 15000; outpdimm->trfc1_ps = max(trfc1_ps, (unsigned int)dimm_params[i].trfc1_ps); outpdimm->trfc2_ps = max(trfc2_ps, (unsigned int)dimm_params[i].trfc2_ps); outpdimm->trfc4_ps = max(trfc4_ps, (unsigned int)dimm_params[i].trfc4_ps); outpdimm->trrds_ps = max(trrds_ps, (unsigned int)dimm_params[i].trrds_ps); outpdimm->trrdl_ps = max(trrdl_ps, (unsigned int)dimm_params[i].trrdl_ps); outpdimm->tccdl_ps = max(tccdl_ps, (unsigned int)dimm_params[i].tccdl_ps); outpdimm->trfc_slr_ps = max(trfc_slr_ps, (unsigned int)dimm_params[i].trfc_slr_ps); } else { twr_ps = max(twr_ps, (unsigned int)dimm_params[i].twr_ps); outpdimm->twtr_ps = max(twtr_ps, (unsigned int)dimm_params[i].twtr_ps); outpdimm->trfc_ps = max(trfc_ps, (unsigned int)dimm_params[i].trfc_ps); outpdimm->trrd_ps = max(trrd_ps, (unsigned int)dimm_params[i].trrd_ps); outpdimm->trtp_ps = max(trtp_ps, (unsigned int)dimm_params[i].trtp_ps); } outpdimm->trc_ps = max(trc_ps, (unsigned int)dimm_params[i].trc_ps); if (is_ddr1(popts) || is_ddr2(popts)) { outpdimm->tis_ps = max(tis_ps, (unsigned int)dimm_params[i].tis_ps); outpdimm->tih_ps = max(tih_ps, (unsigned int)dimm_params[i].tih_ps); outpdimm->tds_ps = max(tds_ps, (unsigned int)dimm_params[i].tds_ps); outpdimm->tdh_ps = max(tdh_ps, (unsigned int)dimm_params[i].tdh_ps); outpdimm->tqhs_ps = max(tqhs_ps, (unsigned int)dimm_params[i].tqhs_ps); /* * Find maximum tdqsq_max_ps to find slowest. * * FIXME: is finding the slowest value the correct * strategy for this parameter? */ outpdimm->tdqsq_max_ps = max(tdqsq_max_ps, (unsigned int)dimm_params[i].tdqsq_max_ps); } outpdimm->refresh_rate_ps = max(refresh_rate_ps, (unsigned int)dimm_params[i].refresh_rate_ps); /* extended_op_srt is either 0 or 1, 0 having priority */ outpdimm->extended_op_srt = min(extended_op_srt, (unsigned int)dimm_params[i].extended_op_srt); } outpdimm->ndimms_present = number_of_dimms - temp1; if (temp1 == number_of_dimms) { debug("no dimms this memory controller\n"); return 0; } /* Determine common burst length for all DIMMs. */ temp1 = 0xff; for (i = 0; i < number_of_dimms; i++) { if (dimm_params[i].n_ranks) { temp1 &= dimm_params[i].burst_lengths_bitmask; } } outpdimm->all_dimms_burst_lengths_bitmask = temp1; /* Determine if all DIMMs registered buffered. */ temp1 = temp2 = 0; for (i = 0; i < number_of_dimms; i++) { if (dimm_params[i].n_ranks) { if (dimm_params[i].registered_dimm) { temp1 = 1; printf("Detected RDIMM %s\n", dimm_params[i].mpart); } else { temp2 = 1; printf("Detected UDIMM %s\n", dimm_params[i].mpart); } } } outpdimm->all_dimms_registered = 0; outpdimm->all_dimms_unbuffered = 0; if (temp1 && !temp2) { outpdimm->all_dimms_registered = 1; } else if (!temp1 && temp2) { outpdimm->all_dimms_unbuffered = 1; } else { printf("ERROR: Mix of registered buffered and unbuffered " "DIMMs detected!\n"); } temp1 = 0; if (outpdimm->all_dimms_registered) for (j = 0; j < 16; j++) { outpdimm->rcw[j] = dimm_params[0].rcw[j]; for (i = 1; i < number_of_dimms; i++) { if (!dimm_params[i].n_ranks) continue; if (dimm_params[i].rcw[j] != dimm_params[0].rcw[j]) { temp1 = 1; break; } } } if (temp1 != 0) printf("ERROR: Mix different RDIMM detected!\n"); /* calculate cas latency for all DDR types */ if (is_ddr3_4(popts)) { if (compute_cas_latency_ddr34(popts, c, dimm_params, outpdimm, number_of_dimms)) return 1; } else { if (compute_cas_latency_ddr12(popts, c, dimm_params, outpdimm, number_of_dimms)) return 1; } /* Determine if all DIMMs ECC capable. */ temp1 = 1; for (i = 0; i < number_of_dimms; i++) { if (dimm_params[i].n_ranks && !(dimm_params[i].edc_config & EDC_ECC)) { temp1 = 0; break; } } if (temp1) { debug("all DIMMs ECC capable\n"); } else { debug("Warning: not all DIMMs ECC capable, cant enable ECC\n"); } outpdimm->all_dimms_ecc_capable = temp1; /* * Compute additive latency. * * For DDR1, additive latency should be 0. * * For DDR2, with ODT enabled, use "a value" less than ACTTORW, * which comes from Trcd, and also note that: * add_lat + caslat must be >= 4 * * For DDR3, we use the AL=0 * * When to use additive latency for DDR2: * * I. Because you are using CL=3 and need to do ODT on writes and * want functionality. * 1. Are you going to use ODT? (Does your board not have * additional termination circuitry for DQ, DQS, DQS_, * DM, RDQS, RDQS_ for x4/x8 configs?) * 2. If so, is your lowest supported CL going to be 3? * 3. If so, then you must set AL=1 because * * WL >= 3 for ODT on writes * RL = AL + CL * WL = RL - 1 * -> * WL = AL + CL - 1 * AL + CL - 1 >= 3 * AL + CL >= 4 * QED * * RL >= 3 for ODT on reads * RL = AL + CL * * Since CL aren't usually less than 2, AL=0 is a minimum, * so the WL-derived AL should be the -- FIXME? * * II. Because you are using auto-precharge globally and want to * use additive latency (posted CAS) to get more bandwidth. * 1. Are you going to use auto-precharge mode globally? * * Use addtivie latency and compute AL to be 1 cycle less than * tRCD, i.e. the READ or WRITE command is in the cycle * immediately following the ACTIVATE command.. * * III. Because you feel like it or want to do some sort of * degraded-performance experiment. * 1. Do you just want to use additive latency because you feel * like it? * * Validation: AL is less than tRCD, and within the other * read-to-precharge constraints. */ additive_latency = 0; if (is_ddr2(popts) && outpdimm->lowest_common_spd_caslat < 4 && picos_to_mclk(c, trcd_ps > outpdimm->lowest_common_spd_caslat)) { additive_latency = picos_to_mclk(c, trcd_ps) - outpdimm->lowest_common_spd_caslat; if (mclk_to_picos(c, additive_latency) > trcd_ps) { additive_latency = picos_to_mclk(c, trcd_ps); debug("setting additive_latency to %u because it was " " greater than tRCD_ps\n", additive_latency); } } /* * Validate additive latency * * AL <= tRCD(min) */ if (mclk_to_picos(c, additive_latency) > trcd_ps) { printf("Error: invalid additive latency exceeds tRCD(min).\n"); return 1; } /* * RL = CL + AL; RL >= 3 for ODT_RD_CFG to be enabled * WL = RL - 1; WL >= 3 for ODT_WL_CFG to be enabled * ADD_LAT (the register) must be set to a value less * than ACTTORW if WL = 1, then AL must be set to 1 * RD_TO_PRE (the register) must be set to a minimum * tRTP + AL if AL is nonzero */ /* * Additive latency will be applied only if the memctl option to * use it. */ outpdimm->additive_latency = additive_latency; debug("tCKmin_ps = %u\n", outpdimm->tckmin_x_ps); debug("trcd_ps = %u\n", outpdimm->trcd_ps); debug("trp_ps = %u\n", outpdimm->trp_ps); debug("tras_ps = %u\n", outpdimm->tras_ps); if (is_ddr4(popts)) { debug("trfc1_ps = %u\n", trfc1_ps); debug("trfc2_ps = %u\n", trfc2_ps); debug("trfc4_ps = %u\n", trfc4_ps); debug("trrds_ps = %u\n", trrds_ps); debug("trrdl_ps = %u\n", trrdl_ps); debug("tccdl_ps = %u\n", tccdl_ps); debug("trfc_slr_ps = %u\n", trfc_slr_ps); } else { debug("twtr_ps = %u\n", outpdimm->twtr_ps); debug("trfc_ps = %u\n", outpdimm->trfc_ps); debug("trrd_ps = %u\n", outpdimm->trrd_ps); } debug("twr_ps = %u\n", outpdimm->twr_ps); debug("trc_ps = %u\n", outpdimm->trc_ps); return 0; }