linux-kernel - [PATCH 8/8] EDAC/amd64: Support Asymmetric Dual-Rank DIMMs

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Date:   Fri, 31 May 2019 23:45:15 +0000
From:   "Ghannam, Yazen" <Yazen.Ghannam@....com>
To:     "linux-edac@...r.kernel.org" <linux-edac@...r.kernel.org>
CC:     "Ghannam, Yazen" <Yazen.Ghannam@....com>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "bp@...en8.de" <bp@...en8.de>
Subject: [PATCH 8/8] EDAC/amd64: Support Asymmetric Dual-Rank DIMMs

From: Yazen Ghannam <yazen.ghannam@....com>

Future AMD systems will support "Asymmetric" Dual-Rank DIMMs. These are
DIMMs were the ranks are of different sizes.

The even rank will use the Primary Even Chip Select registers and the
odd rank will use the Secondary Odd Chip Select registers.

Recognize if a Secondary Odd Chip Select is being used. Use the
Secondary Odd Address Mask when calculating the chip select size.

Signed-off-by: Yazen Ghannam <yazen.ghannam@....com>
---
 drivers/edac/amd64_edac.c | 13 ++++++++++++-
 1 file changed, 12 insertions(+), 1 deletion(-)

diff --git a/drivers/edac/amd64_edac.c b/drivers/edac/amd64_edac.c
index 006417cb79dc..6c284a4f980c 100644
--- a/drivers/edac/amd64_edac.c
+++ b/drivers/edac/amd64_edac.c
@@ -790,6 +790,9 @@ static void debug_dump_dramcfg_low(struct amd64_pvt *pvt, u32 dclr, int chan)
 
 #define CS_EVEN_PRIMARY		BIT(0)
 #define CS_ODD_PRIMARY		BIT(1)
+#define CS_ODD_SECONDARY	BIT(2)
+
+#define csrow_sec_enabled(i, dct, pvt)	((pvt)->csels[(dct)].csbases_sec[(i)] & DCSB_CS_ENABLE)
 
 static int f17_get_cs_mode(int dimm, u8 ctrl, struct amd64_pvt *pvt)
 {
@@ -801,6 +804,10 @@ 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 + 1, ctrl, pvt))
+		cs_mode |= CS_ODD_SECONDARY;
+
 	return cs_mode;
 }
 
@@ -1590,7 +1597,11 @@ static int f17_addr_mask_to_cs_size(struct amd64_pvt *pvt, u8 umc,
 	 */
 	dimm = csrow_nr >> 1;
 
-	addr_mask_orig = pvt->csels[umc].csmasks[dimm];
+	/* Asymmetric Dual-Rank DIMM support. */
+	if (cs_mode & CS_ODD_SECONDARY)
+		addr_mask_orig = pvt->csels[umc].csmasks_sec[dimm];
+	else
+		addr_mask_orig = pvt->csels[umc].csmasks[dimm];
 
 	/*
 	 * The number of zero bits in the mask is equal to the number of bits
-- 
2.17.1