linux-kernel - [PATCH 6/8] bus: fsl-mc: pause the MC firmware when unloading

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Message-Id: <20210715140718.8513-6-laurentiu.tudor@nxp.com>
Date:   Thu, 15 Jul 2021 17:07:16 +0300
From:   laurentiu.tudor@....com
To:     gregkh@...uxfoundation.org, linux-kernel@...r.kernel.org
Cc:     diana.craciun@....com, ioana.ciornei@....com, jon@...id-run.com,
        leoyang.li@....com, Laurentiu Tudor <laurentiu.tudor@....com>
Subject: [PATCH 6/8] bus: fsl-mc: pause the MC firmware when unloading

From: Laurentiu Tudor <laurentiu.tudor@....com>

Pause the MC firmware when unloading the driver so that it doesn't
crash in certain scenarios, such as kexec.

Signed-off-by: Laurentiu Tudor <laurentiu.tudor@....com>
---
 drivers/bus/fsl-mc/fsl-mc-bus.c | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/drivers/bus/fsl-mc/fsl-mc-bus.c b/drivers/bus/fsl-mc/fsl-mc-bus.c
index 41861ca5c8f1..e5b4830cf3c5 100644
--- a/drivers/bus/fsl-mc/fsl-mc-bus.c
+++ b/drivers/bus/fsl-mc/fsl-mc-bus.c
@@ -1207,6 +1207,16 @@ static int fsl_mc_bus_remove(struct platform_device *pdev)
 
 	bus_unregister_notifier(&fsl_mc_bus_type, &fsl_mc_nb);
 
+	if (mc->fsl_mc_regs) {
+		/*
+		 * Pause the MC firmware so that it doesn't crash in certain
+		 * scenarios, such as kexec.
+		 */
+		writel(readl(mc->fsl_mc_regs + FSL_MC_GCR1) |
+		       (GCR1_P1_STOP | GCR1_P2_STOP),
+		       mc->fsl_mc_regs + FSL_MC_GCR1);
+	}
+
 	return 0;
 }
 
-- 
2.17.1