linux-kernel - Re: [PATCH 1/8] EDAC/amd64: Fix number of DIMMs and Chip Select bases/masks on Family17h

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Date:   Mon, 17 Jun 2019 15:37:35 +0200
From:   Borislav Petkov <bp@...en8.de>
To:     "Ghannam, Yazen" <Yazen.Ghannam@....com>
Cc:     "linux-edac@...r.kernel.org" <linux-edac@...r.kernel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH 1/8] EDAC/amd64: Fix number of DIMMs and Chip Select
 bases/masks on Family17h

On Thu, Jun 13, 2019 at 09:00:19PM +0000, Ghannam, Yazen wrote:
> Do you have any tips on how to handle it? I'm thinking it may be
> tricky because of the ranges and multiple variables.

It ain't pretty. It seems the if-else thing is still better, after all.

---
diff --git a/drivers/edac/amd64_edac.c b/drivers/edac/amd64_edac.c
index 873437be86d9..16235c0ef7e5 100644
--- a/drivers/edac/amd64_edac.c
+++ b/drivers/edac/amd64_edac.c
@@ -936,13 +936,25 @@ static void dump_misc_regs(struct amd64_pvt *pvt)
  */
 static void prep_chip_selects(struct amd64_pvt *pvt)
 {
-	if (pvt->fam == 0xf && pvt->ext_model < K8_REV_F) {
+	switch (pvt->fam) {
+	case 0xf:
+		if (pvt->ext_model >= K8_REV_F)
+			goto dflt;
+
 		pvt->csels[0].b_cnt = pvt->csels[1].b_cnt = 8;
 		pvt->csels[0].m_cnt = pvt->csels[1].m_cnt = 8;
-	} else if (pvt->fam == 0x15 && pvt->model == 0x30) {
+		break;
+
+	case 0x15:
+		if (pvt->model != 0x30)
+			goto dflt;
+
 		pvt->csels[0].b_cnt = pvt->csels[1].b_cnt = 4;
 		pvt->csels[0].m_cnt = pvt->csels[1].m_cnt = 2;
-	} else {
+		break;
+
+dflt:
+	default:
 		pvt->csels[0].b_cnt = pvt->csels[1].b_cnt = 8;
 		pvt->csels[0].m_cnt = pvt->csels[1].m_cnt = 4;
 	}

-- 
Regards/Gruss,
    Boris.

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