linux-kernel - [PATCH] EDAC, altera: Disable IRQ while injecting SDRAM errors

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Date:   Wed, 19 Oct 2016 14:53:47 -0500
From:   <tthayer@...nsource.altera.com>
To:     <bp@...en8.de>, <dougthompson@...ssion.com>, <mchehab@...nel.org>
CC:     <linux-edac@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
        <tthayer@...nsource.altera.com>
Subject: [PATCH] EDAC, altera: Disable IRQ while injecting SDRAM errors

From: Thor Thayer <tthayer@...nsource.altera.com>

Disable IRQs while injecting SDRAM errors. The RT patches exposed
a spinlock deadlock where the spinlock taken for the regmap write
deadlocked with the IRQ clear regmap write.
Error injection is not normally enabled for ECC but only for
testing.

Signed-off-by: Thor Thayer <tthayer@...nsource.altera.com>
---
 drivers/edac/altera_edac.c |    4 ++++
 1 file changed, 4 insertions(+)

diff --git a/drivers/edac/altera_edac.c b/drivers/edac/altera_edac.c
index 58d3e2b..6421cc3 100644
--- a/drivers/edac/altera_edac.c
+++ b/drivers/edac/altera_edac.c
@@ -153,13 +153,17 @@ static ssize_t altr_sdr_mc_err_inject_write(struct file *file,
 	if (count == 3) {
 		edac_printk(KERN_ALERT, EDAC_MC,
 			    "Inject Double bit error\n");
+		local_irq_disable();
 		regmap_write(drvdata->mc_vbase, priv->ce_ue_trgr_offset,
 			     (read_reg | priv->ue_set_mask));
+		local_irq_enable();
 	} else {
 		edac_printk(KERN_ALERT, EDAC_MC,
 			    "Inject Single bit error\n");
+		local_irq_disable();
 		regmap_write(drvdata->mc_vbase,	priv->ce_ue_trgr_offset,
 			     (read_reg | priv->ce_set_mask));
+		local_irq_enable();
 	}
 
 	ptemp[0] = 0x5A5A5A5A;
-- 
1.7.9.5