[U-Boot] [PATCH] mpc83xx: Improve the performance of DDR memory

[Dave Liu]

From: Howard Gregory <Greg.Howard at freescale.com>

modify the CAS timings. my understanding is that these
settings decrease various wait times in the DDR interface.
Because these wait times are in clock cycles, and the DDR
clock on the 8315 RDB runs slower than on some other 83xx
platforms, we can dial down these values without a problem,
thereby decreasing the latency of memory a little.

Signed-off-by: Howard Gregory <Greg.Howard at freescale.com>
Signed-off-by: Dave Liu <daveliu at freescale.com>
---
 include/configs/MPC8315ERDB.h |   12 ++++++------
 1 files changed, 6 insertions(+), 6 deletions(-)

diff --git a/include/configs/MPC8315ERDB.h b/include/configs/MPC8315ERDB.h
index 64bb62a..48043c4 100644
--- a/include/configs/MPC8315ERDB.h
+++ b/include/configs/MPC8315ERDB.h
@@ -118,23 +118,23 @@
 				| ( 8 << TIMING_CFG0_ODT_PD_EXIT_SHIFT ) \
 				| ( 2 << TIMING_CFG0_MRS_CYC_SHIFT ) )
 				/* 0x00220802 */
-#define CONFIG_SYS_DDR_TIMING_1	( ( 3 << TIMING_CFG1_PRETOACT_SHIFT ) \
-				| ( 9 << TIMING_CFG1_ACTTOPRE_SHIFT ) \
-				| ( 3 << TIMING_CFG1_ACTTORW_SHIFT ) \
+#define CONFIG_SYS_DDR_TIMING_1	( ( 2 << TIMING_CFG1_PRETOACT_SHIFT ) \
+				| ( 7 << TIMING_CFG1_ACTTOPRE_SHIFT ) \
+				| ( 2 << TIMING_CFG1_ACTTORW_SHIFT ) \
 				| ( 5 << TIMING_CFG1_CASLAT_SHIFT ) \
 				| ( 6 << TIMING_CFG1_REFREC_SHIFT ) \
 				| ( 2 << TIMING_CFG1_WRREC_SHIFT ) \
 				| ( 2 << TIMING_CFG1_ACTTOACT_SHIFT ) \
 				| ( 2 << TIMING_CFG1_WRTORD_SHIFT ) )
-				/* 0x39356222 */
+				/* 0x27256222 */
 #define CONFIG_SYS_DDR_TIMING_2	( ( 1 << TIMING_CFG2_ADD_LAT_SHIFT ) \
 				| ( 4 << TIMING_CFG2_CPO_SHIFT ) \
 				| ( 2 << TIMING_CFG2_WR_LAT_DELAY_SHIFT ) \
 				| ( 2 << TIMING_CFG2_RD_TO_PRE_SHIFT ) \
 				| ( 2 << TIMING_CFG2_WR_DATA_DELAY_SHIFT ) \
 				| ( 3 << TIMING_CFG2_CKE_PLS_SHIFT ) \
-				| ( 7 << TIMING_CFG2_FOUR_ACT_SHIFT) )
-				/* 0x121048c7 */
+				| ( 5 << TIMING_CFG2_FOUR_ACT_SHIFT) )
+				/* 0x121048c5 */
 #define CONFIG_SYS_DDR_INTERVAL	( ( 0x0360 << SDRAM_INTERVAL_REFINT_SHIFT ) \
 				| ( 0x0100 << SDRAM_INTERVAL_BSTOPRE_SHIFT ) )
 				/* 0x03600100 */
-- 
1.5.5.1.248.g4b17