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

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[ Upstream commit 119aaeed0b ]

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: 57d72196df ("irqchip/gic-v5: Add GICv5 ITS support")
Signed-off-by: Lorenzo Pieralisi <lpieralisi@kernel.org>
Reviewed-by: Frank 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: Rob Herring (Arm) <robh@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
Lorenzo Pieralisi
2025-10-21 14:40:59 +02:00
committed by Greg Kroah-Hartman
parent e4fd1e731f
commit eff5761b05
1 changed files with 36 additions and 3 deletions
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39
drivers/of/irq.c
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@@ -670,6 +670,36 @@ err:
}
}
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.
@@ -677,7 +707,7 @@ err:
* @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.
@@ -691,12 +721,15 @@ 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;
}