bus: fsl-mc: pause the MC firmware when unloading

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@nxp.com>
Link: https://lore.kernel.org/r/20210715140718.8513-6-laurentiu.tudor@nxp.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

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;
 }