[PATCH 5/5] EDAC/amd64: Adjust printed Chip Select sizes when interleaved

From: Ghannam, Yazen
Date: Tue Feb 19 2019 - 15:26:29 EST


From: Yazen Ghannam <yazen.ghannam@xxxxxxx>

AMD systems may support Chip Select interleaving. However, on Fam17h+
this was not taken into account when printing the Chip Select sizes.

Add support to detect if Chip Selects are interleaved on Fam17h+, and
adjust the sizes accordingly.

Signed-off-by: Yazen Ghannam <yazen.ghannam@xxxxxxx>
---
drivers/edac/amd64_edac.c | 31 +++++++++++++++++++++++++++++--
1 file changed, 29 insertions(+), 2 deletions(-)

diff --git a/drivers/edac/amd64_edac.c b/drivers/edac/amd64_edac.c
index 656788699c64..073bfd112c44 100644
--- a/drivers/edac/amd64_edac.c
+++ b/drivers/edac/amd64_edac.c
@@ -784,6 +784,22 @@ static void debug_dump_dramcfg_low(struct amd64_pvt *pvt, u32 dclr, int chan)
(dclr & BIT(15)) ? "yes" : "no");
}

+/*
+ * The Address Mask should be a contiguous set of bits in the non-interleaved
+ * case. So to check for CS interleaving, find the most- and least-significant
+ * bits of the mask, generate a contiguous bitmask, and compare the two.
+ */
+static bool f17_cs_interleaved(struct amd64_pvt *pvt, u8 ctrl, int cs)
+{
+ u32 mask = pvt->csels[ctrl].csmasks[cs >> 1];
+ u32 msb = fls(mask) - 1, lsb = ffs(mask) - 1;
+ u32 test_mask = GENMASK(msb, lsb);
+
+ edac_dbg(1, "mask=0x%08x test_mask=0x%08x\n", mask, test_mask);
+
+ return mask ^ test_mask;
+}
+
static void debug_display_dimm_sizes_df(struct amd64_pvt *pvt, u8 ctrl)
{
int dimm, size0, size1, cs0, cs1;
@@ -800,8 +816,19 @@ static void debug_display_dimm_sizes_df(struct amd64_pvt *pvt, u8 ctrl)
size1 = 0;
cs1 = dimm * 2 + 1;

- if (csrow_enabled(cs1, ctrl, pvt))
- size1 = pvt->ops->dbam_to_cs(pvt, ctrl, 0, cs1);
+ if (csrow_enabled(cs1, ctrl, pvt)) {
+ /*
+ * CS interleaving is only supported if both CSes have
+ * the same amount of memory. Because they are
+ * interleaved, it will look like both CSes have the
+ * full amount of memory. Save the size for both as
+ * half the amount we found on CS0, if interleaved.
+ */
+ if (f17_cs_interleaved(pvt, ctrl, cs1))
+ size1 = size0 = (size0 >> 1);
+ else
+ size1 = pvt->ops->dbam_to_cs(pvt, ctrl, 0, cs1);
+ }

amd64_info(EDAC_MC ": %d: %5dMB %d: %5dMB\n",
cs0, size0,
--
2.17.1