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 JRottmann@LiPPERTEmbedded.de Acked-by: Marc Jones marc.jones@amd.com
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 */ }