On 23.10.2008 01:38, ron minnich wrote:
> Jens, I am very happy to see these contributions from Lippert. I hope
> you or someone from this list can look at bringing them forward to v3
> as well.
This is the GeodeLX RAM speed calculation patch for v3.
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: Carl-Daniel Hailfinger <[EMAIL PROTECTED]>
Index: corebootv3-geodelx_speedcalc/northbridge/amd/geodelx/raminit.c
===================================================================
--- corebootv3-geodelx_speedcalc/northbridge/amd/geodelx/raminit.c
(Revision 946)
+++ corebootv3-geodelx_speedcalc/northbridge/amd/geodelx/raminit.c
(Arbeitskopie)
@@ -261,7 +261,7 @@
spd_byte0 = spd_byte1;
/* 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));
printk(BIOS_DEBUG, "ddr max speed is %d\n", speed);
/* Current speed > max speed? */
@@ -353,15 +353,14 @@
/* 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) {
/* If -1 timing is supported, check -1 timing >
GeodeLink. */
/* EEPROM byte usage: (25) SDRAM Minimum Clock
Cycle Time @ CLX -1 */
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) {
/* Set we can use -.5 timing
but not -1. */
spd_byte = 31 -
__builtin_clz((u32) casmap0);
@@ -388,14 +387,14 @@
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) {
/* If -1 timing is supported, check -1 timing >
GeodeLink. */
/* EEPROM byte usage: (25) SDRAM Minimum Clock
Cycle Time @ CLX -1 */
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) {
/* Set we can use -.5 timing
but not -1. */
spd_byte = 31 -
__builtin_clz((u32) casmap1);
--
http://www.hailfinger.org/
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