There are a few bugs in the cpu/mpc83xx/spd_sdram.c the first bug is that the picos_to_clk routine introduces a huge rounding error in 83xx. the second bug is that the mode register write recovery field is tWR-1, not tWR >> 1.
--- This patch applies to the mpc83xx branch of the opensource.freescale.com u-boot-83xx.git tree
cpu/mpc83xx/spd_sdram.c | 6 +++--- 1 files changed, 3 insertions(+), 3 deletions(-)
diff --git a/cpu/mpc83xx/spd_sdram.c b/cpu/mpc83xx/spd_sdram.c index d9b8753..869dab4 100644 --- a/cpu/mpc83xx/spd_sdram.c +++ b/cpu/mpc83xx/spd_sdram.c @@ -58,8 +58,8 @@ picos_to_clk(int picos) int clks;
ddr_bus_clk = gd->ddr_clk >> 1; - clks = picos / ((1000000000 / ddr_bus_clk) * 1000); - if (picos % ((1000000000 / ddr_bus_clk) * 1000) != 0) + clks = picos / (1000000000 / (ddr_bus_clk / 1000)); + if (picos % (1000000000 / (ddr_bus_clk / 1000)) != 0) clks++;
return clks; @@ -624,7 +624,7 @@ long int spd_sdram() | (1 << (16 + 10)) /* DQS Differential disable */ | (add_lat << (16 + 3)) /* Additive Latency in EMRS1 */ | (mode_odt_enable << 16) /* ODT Enable in EMRS1 */ - | ((twr_clk >> 1) << 9) /* Write Recovery Autopre */ + | ((twr_clk - 1) << 9) /* Write Recovery Autopre */ | (caslat << 4) /* caslat */ | (burstlen << 0) /* Burst length */ );