diff options
| -rw-r--r-- | arch/arm/cpu/armv7/sunxi/dram.c | 17 |
1 files changed, 16 insertions, 1 deletions
diff --git a/arch/arm/cpu/armv7/sunxi/dram.c b/arch/arm/cpu/armv7/sunxi/dram.c index 0bbb10d..2ad685b 100644 --- a/arch/arm/cpu/armv7/sunxi/dram.c +++ b/arch/arm/cpu/armv7/sunxi/dram.c @@ -451,6 +451,21 @@ static void dramc_set_autorefresh_cycle(u32 clk, u32 density) writel(DRAM_DRR_TREFI(tREFI) | DRAM_DRR_TRFC(tRFC), &dram->drr); } +/* Calculate the value for A11, A10, A9 bits in MR0 (write recovery) */ +static u32 ddr3_write_recovery(u32 clk) +{ + u32 twr_ns = 15; /* DDR3 spec says that it is 15ns for all speed bins */ + u32 twr_ck = (twr_ns * clk + 999) / 1000; + if (twr_ck < 5) + return 1; + else if (twr_ck <= 8) + return twr_ck - 4; + else if (twr_ck <= 10) + return 5; + else + return 6; +} + /* * If the dram->ppwrsctl (SDR_DPCR) register has the lowest bit set to 1, this * means that DRAM is currently in self-refresh mode and retaining the old @@ -647,7 +662,7 @@ unsigned long dramc_init(struct dram_para *para) reg_val |= DRAM_MR_POWER_DOWN; #endif reg_val |= DRAM_MR_CAS_LAT(para->cas - 4); - reg_val |= DRAM_MR_WRITE_RECOVERY(0x5); + reg_val |= DRAM_MR_WRITE_RECOVERY(ddr3_write_recovery(para->clock)); writel(reg_val, &dram->mr); writel(para->emr1, &dram->emr); |