diff options
| -rw-r--r-- | drivers/edac/amd64_edac.c | 32 |
1 files changed, 28 insertions, 4 deletions
diff --git a/drivers/edac/amd64_edac.c b/drivers/edac/amd64_edac.c index b9424dcde90..03807283aca 100644 --- a/drivers/edac/amd64_edac.c +++ b/drivers/edac/amd64_edac.c @@ -1132,12 +1132,36 @@ static int k8_dbam_to_chip_select(struct amd64_pvt *pvt, u8 dct, return ddr2_cs_size(cs_mode, dclr & WIDTH_128); } else if (pvt->ext_model >= K8_REV_D) { + unsigned diff; WARN_ON(cs_mode > 10); - if (cs_mode == 3 || cs_mode == 8) - return 32 << (cs_mode - 1); - else - return 32 << cs_mode; + /* + * the below calculation, besides trying to win an obfuscated C + * contest, maps cs_mode values to DIMM chip select sizes. The + * mappings are: + * + * cs_mode CS size (mb) + * ======= ============ + * 0 32 + * 1 64 + * 2 128 + * 3 128 + * 4 256 + * 5 512 + * 6 256 + * 7 512 + * 8 1024 + * 9 1024 + * 10 2048 + * + * Basically, it calculates a value with which to shift the + * smallest CS size of 32MB. + * + * ddr[23]_cs_size have a similar purpose. + */ + diff = cs_mode/3 + (unsigned)(cs_mode > 5); + + return 32 << (cs_mode - diff); } else { WARN_ON(cs_mode > 6); |