Empirically set cpo and clk_adjust for mpc85xx DDR2 support
This patch is against u-boot-mpc85xx.git of www.denx.com
Setting cpo to 0x9 for frequencies higher than 333MHz is verified on
both MPC8548CDS board and MPC8568MDS board, especially for supporting
533MHz DDR2.
Setting clk_adjust to 0x6(3/4 late cycle) for MPC8568MDS board is for
DDR2 on all current board versions especially ver 1.92 or later to bring
up.
Signed-off-by: Haiying Wang <Haiying.Wang@freescale.com>
diff --git a/cpu/mpc85xx/spd_sdram.c b/cpu/mpc85xx/spd_sdram.c
index 679f360..5dc223a 100644
--- a/cpu/mpc85xx/spd_sdram.c
+++ b/cpu/mpc85xx/spd_sdram.c
@@ -692,13 +692,10 @@
*/
cpo = 0;
if (spd.mem_type == SPD_MEMTYPE_DDR2) {
- if (effective_data_rate == 266 || effective_data_rate == 333) {
+ if (effective_data_rate <= 333) {
cpo = 0x7; /* READ_LAT + 5/4 */
- } else if (effective_data_rate == 400) {
- cpo = 0x9; /* READ_LAT + 7/4 */
} else {
- /* Pure speculation */
- cpo = 0xb;
+ cpo = 0x9; /* READ_LAT + 7/4 */
}
}
@@ -905,7 +902,12 @@
if (spd.mem_type == SPD_MEMTYPE_DDR)
clk_adjust = 0x6;
else
+#ifdef CONFIG_MPC8568
+ /* Empirally setting clk_adjust */
+ clk_adjust = 0x6;
+#else
clk_adjust = 0x7;
+#endif
ddr->sdram_clk_cntl = (0
| 0x80000000