Each Chip-Select (CS) of a Unified Memory Controller (UMC) on AMD Zen-based SOCs has an Address Mask and a Secondary Address Mask register associated with it. The amd64_edac module logs DIMM sizes on a per-UMC per-CS granularity during init using these two registers.
Currently, the module primarily considers only the Address Mask register for computing DIMM sizes. The Secondary Address Mask register is only considered for odd CS. Additionally, if it has been considered, the Address Mask register is ignored altogether for that CS. For power-of-two DIMMs i.e. DIMMs whose total capacity is a power of two (32GB, 64GB, etc), this is not an issue since only the Address Mask register is used.
For non-power-of-two DIMMs i.e., DIMMs whose total capacity is not a power of two (48GB, 96GB, etc), however, the Secondary Address Mask register is used in conjunction with the Address Mask register. However, since the module only considers either of the two registers for a CS, the size computed by the module is incorrect. The Secondary Address Mask register is not considered for even CS, and the Address Mask register is not considered for odd CS.
Introduce a new helper function so that both Address Mask and Secondary Address Mask registers are considered, when valid, for computing DIMM sizes. Furthermore, also rename some variables for greater clarity.
Fixes: 81f5090db843 ("EDAC/amd64: Support asymmetric dual-rank DIMMs") Closes: https://lore.kernel.org/dbec22b6-00f2-498b-b70d-ab6f8a5ec87e@natrix.lt Reported-by: Žilvinas Žaltiena zilvinas@natrix.lt Signed-off-by: Avadhut Naik avadhut.naik@amd.com Signed-off-by: Borislav Petkov (AMD) bp@alien8.de Reviewed-by: Yazen Ghannam yazen.ghannam@amd.com Tested-by: Žilvinas Žaltiena zilvinas@natrix.lt Cc: stable@vger.kernel.org Link: https://lore.kernel.org/20250529205013.403450-1-avadhut.naik@amd.com (cherry picked from commit a3f3040657417aeadb9622c629d4a0c2693a0f93) Signed-off-by: Avadhut Naik avadhut.naik@amd.com --- drivers/edac/amd64_edac.c | 72 ++++++++++++++++++++++++--------------- 1 file changed, 44 insertions(+), 28 deletions(-)
diff --git a/drivers/edac/amd64_edac.c b/drivers/edac/amd64_edac.c index 2f854feeeb23..dd48e8a2d1cb 100644 --- a/drivers/edac/amd64_edac.c +++ b/drivers/edac/amd64_edac.c @@ -1371,7 +1371,9 @@ static int f17_get_cs_mode(int dimm, u8 ctrl, struct amd64_pvt *pvt) if (csrow_enabled(2 * dimm + 1, ctrl, pvt)) cs_mode |= CS_ODD_PRIMARY;
- /* Asymmetric dual-rank DIMM support. */ + if (csrow_sec_enabled(2 * dimm, ctrl, pvt)) + cs_mode |= CS_EVEN_SECONDARY; + if (csrow_sec_enabled(2 * dimm + 1, ctrl, pvt)) cs_mode |= CS_ODD_SECONDARY;
@@ -2191,11 +2193,41 @@ static int f16_dbam_to_chip_select(struct amd64_pvt *pvt, u8 dct, return ddr3_cs_size(cs_mode, false); }
+static int calculate_cs_size(u32 mask, unsigned int cs_mode) +{ + int msb, weight, num_zero_bits; + u32 deinterleaved_mask; + + if (!mask) + return 0; + + /* + * The number of zero bits in the mask is equal to the number of bits + * in a full mask minus the number of bits in the current mask. + * + * The MSB is the number of bits in the full mask because BIT[0] is + * always 0. + * + * In the special 3 Rank interleaving case, a single bit is flipped + * without swapping with the most significant bit. This can be handled + * by keeping the MSB where it is and ignoring the single zero bit. + */ + + msb = fls(mask) - 1; + weight = hweight_long(mask); + num_zero_bits = msb - weight - !!(cs_mode & CS_3R_INTERLEAVE); + + /* Take the number of zero bits off from the top of the mask. */ + deinterleaved_mask = GENMASK_ULL(msb - num_zero_bits, 1); + edac_dbg(1, " Deinterleaved AddrMask: 0x%x\n", deinterleaved_mask); + + return (deinterleaved_mask >> 2) + 1; +} + static int f17_addr_mask_to_cs_size(struct amd64_pvt *pvt, u8 umc, unsigned int cs_mode, int csrow_nr) { - u32 addr_mask_orig, addr_mask_deinterleaved; - u32 msb, weight, num_zero_bits; + u32 addr_mask = 0, addr_mask_sec = 0; int cs_mask_nr = csrow_nr; int dimm, size = 0;
@@ -2234,36 +2266,20 @@ static int f17_addr_mask_to_cs_size(struct amd64_pvt *pvt, u8 umc, if (!fam_type->flags.zn_regs_v2) cs_mask_nr >>= 1;
- /* Asymmetric dual-rank DIMM support. */ - if ((csrow_nr & 1) && (cs_mode & CS_ODD_SECONDARY)) - addr_mask_orig = pvt->csels[umc].csmasks_sec[cs_mask_nr]; - else - addr_mask_orig = pvt->csels[umc].csmasks[cs_mask_nr]; + if (cs_mode & (CS_EVEN_PRIMARY | CS_ODD_PRIMARY)) + addr_mask = pvt->csels[umc].csmasks[cs_mask_nr];
- /* - * The number of zero bits in the mask is equal to the number of bits - * in a full mask minus the number of bits in the current mask. - * - * The MSB is the number of bits in the full mask because BIT[0] is - * always 0. - * - * In the special 3 Rank interleaving case, a single bit is flipped - * without swapping with the most significant bit. This can be handled - * by keeping the MSB where it is and ignoring the single zero bit. - */ - msb = fls(addr_mask_orig) - 1; - weight = hweight_long(addr_mask_orig); - num_zero_bits = msb - weight - !!(cs_mode & CS_3R_INTERLEAVE); - - /* Take the number of zero bits off from the top of the mask. */ - addr_mask_deinterleaved = GENMASK_ULL(msb - num_zero_bits, 1); + if (cs_mode & (CS_EVEN_SECONDARY | CS_ODD_SECONDARY)) + addr_mask_sec = pvt->csels[umc].csmasks_sec[cs_mask_nr];
edac_dbg(1, "CS%d DIMM%d AddrMasks:\n", csrow_nr, dimm); - edac_dbg(1, " Original AddrMask: 0x%x\n", addr_mask_orig); - edac_dbg(1, " Deinterleaved AddrMask: 0x%x\n", addr_mask_deinterleaved); + edac_dbg(1, " Primary AddrMask: 0x%x\n", addr_mask);
/* Register [31:1] = Address [39:9]. Size is in kBs here. */ - size = (addr_mask_deinterleaved >> 2) + 1; + size = calculate_cs_size(addr_mask, cs_mode); + + edac_dbg(1, " Secondary AddrMask: 0x%x\n", addr_mask_sec); + size += calculate_cs_size(addr_mask_sec, cs_mode);
/* Return size in MBs. */ return size >> 10;