EDAC, altera: Add panic flag check to A10 IRQ

In preparation for additional memory module ECCs, the IRQ function will
check a panic flag before doing a kernel panic on double bit errors.

OCRAM uncorrectable errors cause a panic because sleep/resume functions
and FPGA contents during sleep are stored in OCRAM.

ECCs on peripheral FIFO buffers will not cause a kernel panic on DBERRs
because the packet can be retried and therefore recovered.

Signed-off-by: Thor Thayer <tthayer@opensource.altera.com>
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-edac <linux-edac@vger.kernel.org>
Link: http://lkml.kernel.org/r/1466603939-7526-3-git-send-email-tthayer@opensource.altera.com
Signed-off-by: Borislav Petkov <bp@suse.de>

drivers/edac/altera_edac.c

@@ -897,7 +897,8 @@ static irqreturn_t altr_edac_a10_ecc_irq(int irq, void *dev_id)
 		writel(ALTR_A10_ECC_DERRPENA,
 		       base + ALTR_A10_ECC_INTSTAT_OFST);
 		edac_device_handle_ue(dci->edac_dev, 0, 0, dci->edac_dev_name);
-		panic("\nEDAC:ECC_DEVICE[Uncorrectable errors]\n");
+		if (dci->data->panic)
+			panic("\nEDAC:ECC_DEVICE[Uncorrectable errors]\n");
 
 		return IRQ_HANDLED;
 	}
@@ -936,6 +937,12 @@ static const struct edac_device_prv_data a10_ocramecc_data = {
 	.set_err_ofst = ALTR_A10_ECC_INTTEST_OFST,
 	.ecc_irq_handler = altr_edac_a10_ecc_irq,
 	.inject_fops = &altr_edac_a10_device_inject_fops,
+	/*
+	 * OCRAM panic on uncorrectable error because sleep/resume
+	 * functions and FPGA contents are stored in OCRAM. Prefer
+	 * a kernel panic over executing/loading corrupted data.
+	 */
+	.panic = true,
 };
 
 #endif	/* CONFIG_EDAC_ALTERA_OCRAM */

drivers/edac/altera_edac.h

@@ -298,6 +298,7 @@ struct edac_device_prv_data {
 	irqreturn_t (*ecc_irq_handler)(int irq, void *dev_id);
 	int trig_alloc_sz;
 	const struct file_operations *inject_fops;
+	bool panic;
 };
 
 struct altr_edac_device_dev {