6.17-stable review patch. If anyone has any objections, please let me know.
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From: Lorenzo Pieralisi lpieralisi@kernel.org
[ Upstream commit 119aaeed0b6729293f41ea33be05ecd27a947d48 ]
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: 57d72196dfc8 ("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 --- drivers/of/irq.c | 39 ++++++++++++++++++++++++++++++++++++--- 1 file changed, 36 insertions(+), 3 deletions(-)
diff --git a/drivers/of/irq.c b/drivers/of/irq.c index e7c12abd10ab7..3d4afeeb30ed7 100644 --- a/drivers/of/irq.c +++ b/drivers/of/irq.c @@ -670,6 +670,36 @@ 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. @@ -677,7 +707,7 @@ 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. @@ -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; }