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driver/ddr/fsl: Fix MRC_CYC calculation for DDR3

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For DDR controller version 4.7 or newer, MRC_CYC (mode register set
cycle time) is max(tMRD, tMOD). tMRD is 4nCK, or 8nCK (RDIMM). tMOD
is max(12nCK, 15ns) according to JEDEC spec.

DDR4 is not affected by this change.

Signed-off-by: York Sun <yorksun@freescale.com>
This commit is contained in:
York Sun 2014-12-02 11:18:09 -08:00
parent 84d13c5810
commit 938bbb6013
1 changed files with 20 additions and 1 deletions
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21
drivers/ddr/fsl/ctrl_regs.c
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@ -324,6 +324,7 @@ static void set_timing_cfg_0(fsl_ddr_cfg_regs_t *ddr,
#elif defined(CONFIG_SYS_FSL_DDR3)
unsigned int data_rate = get_ddr_freq(0);
int txp;
unsigned int ip_rev;
int odt_overlap;
/*
* (tXARD and tXARDS). Empirical?
@ -336,7 +337,25 @@ static void set_timing_cfg_0(fsl_ddr_cfg_regs_t *ddr,
*/
txp = max((int)mclk_ps * 3, (mclk_ps > 1540 ? 7500 : 6000));
tmrd_mclk = 4;
ip_rev = fsl_ddr_get_version();
if (ip_rev >= 0x40700) {
/*
* MRS_CYC = max(tMRD, tMOD)
* tMRD = 4nCK (8nCK for RDIMM)
* tMOD = max(12nCK, 15ns)
*/
tmrd_mclk = max((unsigned int)12, picos_to_mclk(15000));
} else {
/*
* MRS_CYC = tMRD
* tMRD = 4nCK (8nCK for RDIMM)
*/
if (popts->registered_dimm_en)
tmrd_mclk = 8;
else
tmrd_mclk = 4;
}
/* set the turnaround time */
/*