// SPDX-License-Identifier: GPL-2.0
/*
* Copyright 2008-2016 Freescale Semiconductor, Inc.
* Copyright 2017-2018 NXP Semiconductor
*/
#include <common.h>
#include <soc/fsl/fsl_ddr_sdram.h>
#include <linux/log2.h>
#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;
}
