EDAC/bluefield: Don't use bluefield_edac_readl() result on error

The bluefield_edac_readl() routine returns an uninitialized result on error
paths. In those cases the calling routine should not use the uninitialized
result. The driver should simply log the error, and then return early.

Fixes: e419675 ("EDAC/bluefield: Use Arm SMC for EMI access on BlueField-2")
Signed-off-by: David Thompson <davthompson@nvidia.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Shravan Kumar Ramani <shravankr@nvidia.com>
Link: https://lore.kernel.org/20250318214747.12271-1-davthompson@nvidia.com

Author: dthompso

drivers/edac/bluefield_edac.c

@@ -199,8 +199,10 @@ static void bluefield_gather_report_ecc(struct mem_ctl_info *mci,
 	 * error without the detailed information.
 	 */
 	err = bluefield_edac_readl(priv, MLXBF_SYNDROM, &dram_syndrom);
-	if (err)
+	if (err) {
 		dev_err(priv->dev, "DRAM syndrom read failed.\n");
+		return;
+	}
 
 	serr = FIELD_GET(MLXBF_SYNDROM__SERR, dram_syndrom);
 	derr = FIELD_GET(MLXBF_SYNDROM__DERR, dram_syndrom);
@@ -213,20 +215,26 @@ static void bluefield_gather_report_ecc(struct mem_ctl_info *mci,
 	}
 
 	err = bluefield_edac_readl(priv, MLXBF_ADD_INFO, &dram_additional_info);
-	if (err)
+	if (err) {
 		dev_err(priv->dev, "DRAM additional info read failed.\n");
+		return;
+	}
 
 	err_prank = FIELD_GET(MLXBF_ADD_INFO__ERR_PRANK, dram_additional_info);
 
 	ecc_dimm = (err_prank >= 2 && priv->dimm_ranks[0] <= 2) ? 1 : 0;
 
 	err = bluefield_edac_readl(priv, MLXBF_ERR_ADDR_0, &edea0);
-	if (err)
+	if (err) {
 		dev_err(priv->dev, "Error addr 0 read failed.\n");
+		return;
+	}
 
 	err = bluefield_edac_readl(priv, MLXBF_ERR_ADDR_1, &edea1);
-	if (err)
+	if (err) {
 		dev_err(priv->dev, "Error addr 1 read failed.\n");
+		return;
+	}
 
 	ecc_dimm_addr = ((u64)edea1 << 32) | edea0;
 
@@ -250,8 +258,10 @@ static void bluefield_edac_check(struct mem_ctl_info *mci)
 		return;
 
 	err = bluefield_edac_readl(priv, MLXBF_ECC_CNT, &ecc_count);
-	if (err)
+	if (err) {
 		dev_err(priv->dev, "ECC count read failed.\n");
+		return;
+	}
 
 	single_error_count = FIELD_GET(MLXBF_ECC_CNT__SERR_CNT, ecc_count);
 	double_error_count = FIELD_GET(MLXBF_ECC_CNT__DERR_CNT, ecc_count);