EDAC/altera: Handle OCRAM ECC enable after warm reset

The OCRAM ECC is always enabled either by the BootROM or by the Secure Device
Manager (SDM) during a power-on reset on SoCFPGA.

However, during a warm reset, the OCRAM content is retained to preserve data,
while the control and status registers are reset to their default values. As
a result, ECC must be explicitly re-enabled after a warm reset.

Fixes: 17e47dc ("EDAC/altera: Add Stratix10 OCRAM ECC support")
Signed-off-by: Niravkumar L Rabara <[email protected]>
Signed-off-by: Borislav Petkov (AMD) <[email protected]>
Acked-by: Dinh Nguyen <[email protected]>
Cc: [email protected]
Link: https://patch.msgid.link/[email protected]

Author: rabara

drivers/edac/altera_edac.c

@@ -1184,10 +1184,22 @@ altr_check_ocram_deps_init(struct altr_edac_device_dev *device)
 	if (ret)
 		return ret;
 
-	/* Verify OCRAM has been initialized */
+	/*
+	 * Verify that OCRAM has been initialized.
+	 * During a warm reset, OCRAM contents are retained, but the control
+	 * and status registers are reset to their default values. Therefore,
+	 * ECC must be explicitly re-enabled in the control register.
+	 * Error condition: if INITCOMPLETEA is clear and ECC_EN is already set.
+	 */
 	if (!ecc_test_bits(ALTR_A10_ECC_INITCOMPLETEA,
-			   (base + ALTR_A10_ECC_INITSTAT_OFST)))
-		return -ENODEV;
+			   (base + ALTR_A10_ECC_INITSTAT_OFST))) {
+		if (!ecc_test_bits(ALTR_A10_ECC_EN,
+				   (base + ALTR_A10_ECC_CTRL_OFST)))
+			ecc_set_bits(ALTR_A10_ECC_EN,
+				     (base + ALTR_A10_ECC_CTRL_OFST));
+		else
+			return -ENODEV;
+	}
 
 	/* Enable IRQ on Single Bit Error */
 	writel(ALTR_A10_ECC_SERRINTEN, (base + ALTR_A10_ECC_ERRINTENS_OFST));