linux-kernel - [PATCH v3 7/8] EDAC/amd64: Support Asymmetric Dual-Rank DIMMs

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Date:   Thu, 22 Aug 2019 00:00:02 +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 v3 7/8] 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 where 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>
---
Link:
https://lkml.kernel.org/r/20190709215643.171078-8-Yazen.Ghannam@amd.com

v2->v3:
* Add check of csrow_nr before using secondary mask.

v1->v2:
* No change.

 drivers/edac/amd64_edac.c | 18 +++++++++++++++---
 1 file changed, 15 insertions(+), 3 deletions(-)

diff --git a/drivers/edac/amd64_edac.c b/drivers/edac/amd64_edac.c
index 26ce48fcaf00..4d1e6daa7ec4 100644
--- a/drivers/edac/amd64_edac.c
+++ b/drivers/edac/amd64_edac.c
@@ -790,9 +790,13 @@ 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_EVEN_SECONDARY	BIT(2)
+#define CS_ODD_SECONDARY	BIT(3)
 
-#define CS_EVEN			CS_EVEN_PRIMARY
-#define CS_ODD			CS_ODD_PRIMARY
+#define CS_EVEN			(CS_EVEN_PRIMARY | CS_EVEN_SECONDARY)
+#define CS_ODD			(CS_ODD_PRIMARY | CS_EVEN_SECONDARY)
+
+#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)
 {
@@ -804,6 +808,10 @@ 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;
 }
 
@@ -1600,7 +1608,11 @@ 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 ((csrow_nr & 1) && (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