Commit 8c97a4fc authored by Laurentiu Tudor's avatar Laurentiu Tudor Committed by Greg Kroah-Hartman
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bus: fsl-mc: pause the MC firmware before IOMMU setup 



Add a bus notifier to pause the MC firmware as soon as its device
gets discovered. This is needed as the firmware is live thus, as soon
as the SMMU gets probed and enabled, it will crash the firmware due to
SMMU context faults. The firmware will be resumed at probe time, after
the required IOMMU setup was completed.

Signed-off-by: default avatarLaurentiu Tudor <laurentiu.tudor@nxp.com>
Link: https://lore.kernel.org/r/20210715140718.8513-5-laurentiu.tudor@nxp.com


Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 3ab520cf

drivers/bus/fsl-mc/fsl-mc-bus.c

+43 −1
Original line number Diff line number Diff line
@@ -896,6 +896,8 @@ int fsl_mc_device_add(struct fsl_mc_obj_desc *obj_desc, 
}

EXPORT_SYMBOL_GPL(fsl_mc_device_add);



static struct notifier_block fsl_mc_nb;



/**

 * fsl_mc_device_remove - Remove an fsl-mc device from being visible to

 * Linux
@@ -1203,6 +1205,8 @@ static int fsl_mc_bus_remove(struct platform_device *pdev) 
	fsl_destroy_mc_io(mc->root_mc_bus_dev->mc_io);

	mc->root_mc_bus_dev->mc_io = NULL;



	bus_unregister_notifier(&fsl_mc_bus_type, &fsl_mc_nb);



	return 0;

}
@@ -1236,6 +1240,44 @@ static struct platform_driver fsl_mc_bus_driver = { 
	.shutdown = fsl_mc_bus_shutdown,

};



static int fsl_mc_bus_notifier(struct notifier_block *nb,

			       unsigned long action, void *data)

{

	struct device *dev = data;

	struct resource *res;

	void __iomem *fsl_mc_regs;



	if (action != BUS_NOTIFY_ADD_DEVICE)

		return 0;



	if (!of_match_device(fsl_mc_bus_match_table, dev) &&

	    !acpi_match_device(fsl_mc_bus_acpi_match_table, dev))

		return 0;



	res = platform_get_resource(to_platform_device(dev), IORESOURCE_MEM, 1);

	if (!res)

		return 0;



	fsl_mc_regs = ioremap(res->start, resource_size(res));

	if (!fsl_mc_regs)

		return 0;



	/*

	 * Make sure that the MC firmware is paused before the IOMMU setup for

	 * it is done or otherwise the firmware will crash right after the SMMU

	 * gets probed and enabled.

	 */

	writel(readl(fsl_mc_regs + FSL_MC_GCR1) | (GCR1_P1_STOP | GCR1_P2_STOP),

	       fsl_mc_regs + FSL_MC_GCR1);

	iounmap(fsl_mc_regs);



	return 0;

}



static struct notifier_block fsl_mc_nb = {

	.notifier_call = fsl_mc_bus_notifier,

};



static int __init fsl_mc_bus_driver_init(void)

{

	int error;
@@ -1260,7 +1302,7 @@ static int __init fsl_mc_bus_driver_init(void) 
	if (error < 0)

		goto error_cleanup_dprc_driver;



	return 0;

	return bus_register_notifier(&platform_bus_type, &fsl_mc_nb);



error_cleanup_dprc_driver:

	dprc_driver_exit();