diff options
| author | Jens Rottmann <JRottmann@LiPPERTEmbedded.de> | 2008-10-22 22:26:09 +0000 |
|---|---|---|
| committer | Marc Jones <marc.jones@amd.com> | 2008-10-22 22:26:09 +0000 |
| commit | f6fa12d89e8b260bae9652406b8a4ce519c783e0 (patch) | |
| tree | 4bd7dbe69258a5f9b5104f8dab1f4001d7bbfe16 /src/northbridge | |
| parent | 5e5bef5fbdc9ed15884f659ee6d822824a1080f1 (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
Diffstat (limited to 'src/northbridge')
| -rw-r--r-- | src/northbridge/amd/lx/raminit.c | 11 |
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 */ } |