linux-kernel - [PATCH 2/4] EDAC/amd64: Remove NUM

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Message-ID: <20251013173632.1449366-3-avadhut.naik@amd.com>
Date: Mon, 13 Oct 2025 17:30:41 +0000
From: Avadhut Naik <avadhut.naik@....com>
To: <linux-edac@...r.kernel.org>
CC: <bp@...en8.de>, <yazen.ghannam@....com>, <linux-kernel@...r.kernel.org>,
	<avadhut.naik@....com>
Subject: [PATCH 2/4] EDAC/amd64: Remove NUM_CONTROLLERS macro

Currently, the NUM_CONTROLLERS macro is only used to statically allocate
the csels array of struct chip_select in struct amd64_pvt.

The size of this array, however, will never exceed the number of UMCs on
the SOC. Since, max_mcs variable in struct amd64_pvt already stores the
number of UMCs on the SOC, the macro can be removed and the static array
can be dynamically allocated instead.

The max_mcs variable and the csels array are used for legacy systems too.
These systems have a max of 2 controllers (DCTs). Since the default value
of max_mcs, set in per_family_init(), is 2, these legacy system are also
covered by this change.

Signed-off-by: Avadhut Naik <avadhut.naik@....com>
---
 drivers/edac/amd64_edac.c | 5 +++++
 drivers/edac/amd64_edac.h | 5 ++---
 2 files changed, 7 insertions(+), 3 deletions(-)

diff --git a/drivers/edac/amd64_edac.c b/drivers/edac/amd64_edac.c
index 886ad075d222..2391f3469961 100644
--- a/drivers/edac/amd64_edac.c
+++ b/drivers/edac/amd64_edac.c
@@ -3732,6 +3732,7 @@ static void hw_info_put(struct amd64_pvt *pvt)
 	pci_dev_put(pvt->F1);
 	pci_dev_put(pvt->F2);
 	kfree(pvt->umc);
+	kfree(pvt->csels);
 }
 
 static struct low_ops umc_ops = {
@@ -3915,6 +3916,10 @@ static int per_family_init(struct amd64_pvt *pvt)
 		scnprintf(pvt->ctl_name, sizeof(pvt->ctl_name), "F%02Xh_M%02Xh",
 			  pvt->fam, pvt->model);
 
+	pvt->csels = kcalloc(pvt->max_mcs, sizeof(*pvt->csels), GFP_KERNEL);
+	if (!pvt->csels)
+		return -ENOMEM;
+
 	return 0;
 }
 
diff --git a/drivers/edac/amd64_edac.h b/drivers/edac/amd64_edac.h
index bb6cf4b1ab77..5f61631c8a7d 100644
--- a/drivers/edac/amd64_edac.h
+++ b/drivers/edac/amd64_edac.h
@@ -96,7 +96,6 @@
 /* Hardware limit on ChipSelect rows per MC and processors per system */
 #define NUM_CHIPSELECTS			8
 #define DRAM_RANGES			8
-#define NUM_CONTROLLERS			16
 
 #define ON true
 #define OFF false
@@ -347,8 +346,8 @@ struct amd64_pvt {
 	u32 dbam0;		/* DRAM Base Address Mapping reg for DCT0 */
 	u32 dbam1;		/* DRAM Base Address Mapping reg for DCT1 */
 
-	/* one for each DCT/UMC */
-	struct chip_select csels[NUM_CONTROLLERS];
+	/* Allocate one for each DCT/UMC */
+	struct chip_select *csels;
 
 	/* DRAM base and limit pairs F1x[78,70,68,60,58,50,48,40] */
 	struct dram_range ranges[DRAM_RANGES];
-- 
2.43.0