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authorJens Rottmann <JRottmann@LiPPERTEmbedded.de>2008-10-22 22:26:09 +0000
committerMarc Jones <marc.jones@amd.com>2008-10-22 22:26:09 +0000
commitf6fa12d89e8b260bae9652406b8a4ce519c783e0 (patch)
tree4bd7dbe69258a5f9b5104f8dab1f4001d7bbfe16
parent5e5bef5fbdc9ed15884f659ee6d822824a1080f1 (diff)
Changed RAM speed calculation to fix RAM modules getting rejected only
due to integer rounding errors. Previously, the formula was: speed = 2 * (10000/spd_value) For spd_value=60 this means speed = 2 * 166 = 332, which is less than 333 and coreboot died saying RAM was incompatible. The new formula is: speed = 20000 / spd_value For spd_value=60, speed=333, which is fine. Signed-off-by: Jens Rottmann <JRottmann@LiPPERTEmbedded.de> Acked-by: Marc Jones <marc.jones@amd.com> git-svn-id: svn://svn.coreboot.org/coreboot/trunk@3689 2b7e53f0-3cfb-0310-b3e9-8179ed1497e1
-rw-r--r--src/northbridge/amd/lx/raminit.c11
1 files changed, 5 insertions, 6 deletions
diff --git a/src/northbridge/amd/lx/raminit.c b/src/northbridge/amd/lx/raminit.c
index 0c8fd801ee..54618c314b 100644
--- a/src/northbridge/amd/lx/raminit.c
+++ b/src/northbridge/amd/lx/raminit.c
@@ -194,7 +194,7 @@ static void checkDDRMax(void)
}
/* Turn SPD ns time into MHZ. Check what the asm does to this math. */
- speed = 2 * ((10000 / (((spd_byte0 >> 4) * 10) + (spd_byte0 & 0x0F))));
+ speed = 20000 / (((spd_byte0 >> 4) * 10) + (spd_byte0 & 0x0F));
/* current speed > max speed? */
if (GeodeLinkSpeed() > speed) {
@@ -274,15 +274,14 @@ static void setCAS(void)
spd_byte = spd_read_byte(DIMM0, SPD_SDRAM_CYCLE_TIME_2ND);
if (spd_byte != 0) {
/* Turn SPD ns time into MHZ. Check what the asm does to this math. */
- dimm_speed = 2 * (10000 / (((spd_byte >> 4) * 10) +
- (spd_byte & 0x0F)));
+ dimm_speed = 20000 / (((spd_byte >> 4) * 10) + (spd_byte & 0x0F));
if (dimm_speed >= glspeed) {
casmap_shift = 1; /* -.5 is a shift of 1 */
/* IF -1 timing is supported, check -1 timing > GeodeLink */
spd_byte = spd_read_byte(DIMM0, SPD_SDRAM_CYCLE_TIME_3RD);
if (spd_byte != 0) {
/* Turn SPD ns time into MHZ. Check what the asm does to this math. */
- dimm_speed = 2 * (10000 / (((spd_byte >> 4) * 10) + (spd_byte & 0x0F)));
+ dimm_speed = 20000 / (((spd_byte >> 4) * 10) + (spd_byte & 0x0F));
if (dimm_speed >= glspeed) {
casmap_shift = 2; /* -1 is a shift of 2 */
}
@@ -306,14 +305,14 @@ static void setCAS(void)
spd_byte = spd_read_byte(DIMM1, SPD_SDRAM_CYCLE_TIME_2ND);
if (spd_byte != 0) {
/* Turn SPD ns time into MHZ. Check what the asm does to this math. */
- dimm_speed = 2 * (10000 / (((spd_byte >> 4) * 10) + (spd_byte & 0x0F)));
+ dimm_speed = 20000 / (((spd_byte >> 4) * 10) + (spd_byte & 0x0F));
if (dimm_speed >= glspeed) {
casmap_shift = 1; /* -.5 is a shift of 1 */
/* IF -1 timing is supported, check -1 timing > GeodeLink */
spd_byte = spd_read_byte(DIMM1, SPD_SDRAM_CYCLE_TIME_3RD);
if (spd_byte != 0) {
/* Turn SPD ns time into MHZ. Check what the asm does to this math. */
- dimm_speed = 2 * (10000 / (((spd_byte >> 4) * 10) + (spd_byte & 0x0F)));
+ dimm_speed = 20000 / (((spd_byte >> 4) * 10) + (spd_byte & 0x0F));
if (dimm_speed >= glspeed) {
casmap_shift = 2; /* -1 is a shift of 2 */
}