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mpc83xx: Improve the performance of DDR memory

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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@freescale.com>
Signed-off-by: Dave Liu <daveliu@freescale.com>
Signed-off-by: Kim Phillips <kim.phillips@freescale.com>
This commit is contained in:
Howard Gregory 2008-11-04 14:55:33 +08:00 committed by Kim Phillips
parent 9b827cf172
commit 2f2a5c3714
1 changed files with 6 additions and 6 deletions
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12
include/configs/MPC8315ERDB.h
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@ -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 */