Commit 119aaeed authored by Lorenzo Pieralisi's avatar Lorenzo Pieralisi Committed by Rob Herring (Arm)
Browse files

of/irq: Add msi-parent check to of_msi_xlate() 



In some legacy platforms the MSI controller for a PCI host bridge is
identified by an msi-parent property whose phandle points at an MSI
controller node with no #msi-cells property, that implicitly
means #msi-cells == 0.

For such platforms, mapping a device ID and retrieving the MSI controller
node becomes simply a matter of checking whether in the device hierarchy
there is an msi-parent property pointing at an MSI controller node with
such characteristics.

Add a helper function to of_msi_xlate() to check the msi-parent property in
addition to msi-map and retrieve the MSI controller node (with a 1:1 ID
deviceID-IN<->deviceID-OUT  mapping) to provide support for deviceID
mapping and MSI controller node retrieval for such platforms.

Fixes: 57d72196 ("irqchip/gic-v5: Add GICv5 ITS support")
Signed-off-by: default avatarLorenzo Pieralisi <lpieralisi@kernel.org>
Reviewed-by: default avatarFrank Li <Frank.Li@nxp.com>
Cc: Sascha Bischoff <sascha.bischoff@arm.com>
Cc: Rob Herring <robh@kernel.org>
Cc: Marc Zyngier <maz@kernel.org>
Link: https://patch.msgid.link/20251021124103.198419-2-lpieralisi@kernel.org


Signed-off-by: default avatarRob Herring (Arm) <robh@kernel.org>
parent 3a866087

drivers/of/irq.c

+36 −3
Original line number Diff line number Diff line
@@ -671,6 +671,36 @@ void __init of_irq_init(const struct of_device_id *matches) 
	}

}



static int of_check_msi_parent(struct device_node *dev_node, struct device_node **msi_node)

{

	struct of_phandle_args msi_spec;

	int ret;



	/*

	 * An msi-parent phandle with a missing or == 0 #msi-cells

	 * property identifies a 1:1 ID translation mapping.

	 *

	 * Set the msi controller node if the firmware matches this

	 * condition.

	 */

	ret = of_parse_phandle_with_optional_args(dev_node, "msi-parent", "#msi-cells",

						  0, &msi_spec);

	if (ret)

		return ret;



	if ((*msi_node && *msi_node != msi_spec.np) || msi_spec.args_count != 0)

		ret = -EINVAL;



	if (!ret) {

		/* Return with a node reference held */

		*msi_node = msi_spec.np;

		return 0;

	}

	of_node_put(msi_spec.np);



	return ret;

}



/**

 * of_msi_xlate - map a MSI ID and find relevant MSI controller node

 * @dev: device for which the mapping is to be done.
@@ -678,7 +708,7 @@ void __init of_irq_init(const struct of_device_id *matches) 
 * @id_in: Device ID.

 *

 * Walk up the device hierarchy looking for devices with a "msi-map"

 * property. If found, apply the mapping to @id_in.

 * or "msi-parent" property. If found, apply the mapping to @id_in.

 * If @msi_np points to a non-NULL device node pointer, only entries targeting

 * that node will be matched; if it points to a NULL value, it will receive the

 * device node of the first matching target phandle, with a reference held.
@@ -692,12 +722,15 @@ u32 of_msi_xlate(struct device *dev, struct device_node **msi_np, u32 id_in) 


	/*

	 * Walk up the device parent links looking for one with a

	 * "msi-map" property.

	 * "msi-map" or an "msi-parent" property.

	 */

	for (parent_dev = dev; parent_dev; parent_dev = parent_dev->parent)

	for (parent_dev = dev; parent_dev; parent_dev = parent_dev->parent) {

		if (!of_map_id(parent_dev->of_node, id_in, "msi-map",

				"msi-map-mask", msi_np, &id_out))

			break;

		if (!of_check_msi_parent(parent_dev->of_node, msi_np))

			break;

	}

	return id_out;

}