Author: mjones
Date: 2008-10-23 00:26:09 +0200 (Thu, 23 Oct 2008)
New Revision: 3689
Modified:
trunk/coreboot-v2/src/northbridge/amd/lx/raminit.c
Log:
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 <[EMAIL PROTECTED]>
Acked-by: Marc Jones <[EMAIL PROTECTED]>
Modified: trunk/coreboot-v2/src/northbridge/amd/lx/raminit.c
===================================================================
--- trunk/coreboot-v2/src/northbridge/amd/lx/raminit.c 2008-10-22 22:24:47 UTC
(rev 3688)
+++ trunk/coreboot-v2/src/northbridge/amd/lx/raminit.c 2008-10-22 22:26:09 UTC
(rev 3689)
@@ -194,7 +194,7 @@
}
/* 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 @@
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 @@
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 */
}
--
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