tjh.dev / kernel
Linux kernel mirror (for testing) git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel os linux
1
fork

Configure Feed

Select the types of activity you want to include in your feed.

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: 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>

authored by

Lorenzo Pieralisi and committed by
Rob Herring (Arm) 119aaeed 3a866087

+36 -3
+36 -3
drivers/of/irq.c
··· 671 671 } 672 672 } 673 673 674 + static int of_check_msi_parent(struct device_node *dev_node, struct device_node **msi_node) 675 + { 676 + struct of_phandle_args msi_spec; 677 + int ret; 678 + 679 + /* 680 + * An msi-parent phandle with a missing or == 0 #msi-cells 681 + * property identifies a 1:1 ID translation mapping. 682 + * 683 + * Set the msi controller node if the firmware matches this 684 + * condition. 685 + */ 686 + ret = of_parse_phandle_with_optional_args(dev_node, "msi-parent", "#msi-cells", 687 + 0, &msi_spec); 688 + if (ret) 689 + return ret; 690 + 691 + if ((*msi_node && *msi_node != msi_spec.np) || msi_spec.args_count != 0) 692 + ret = -EINVAL; 693 + 694 + if (!ret) { 695 + /* Return with a node reference held */ 696 + *msi_node = msi_spec.np; 697 + return 0; 698 + } 699 + of_node_put(msi_spec.np); 700 + 701 + return ret; 702 + } 703 + 674 704 /** 675 705 * of_msi_xlate - map a MSI ID and find relevant MSI controller node 676 706 * @dev: device for which the mapping is to be done. ··· 708 678 * @id_in: Device ID. 709 679 * 710 680 * Walk up the device hierarchy looking for devices with a "msi-map" 711 - * property. If found, apply the mapping to @id_in. 681 + * or "msi-parent" property. If found, apply the mapping to @id_in. 712 682 * If @msi_np points to a non-NULL device node pointer, only entries targeting 713 683 * that node will be matched; if it points to a NULL value, it will receive the 714 684 * device node of the first matching target phandle, with a reference held. ··· 722 692 723 693 /* 724 694 * Walk up the device parent links looking for one with a 725 - * "msi-map" property. 695 + * "msi-map" or an "msi-parent" property. 726 696 */ 727 - for (parent_dev = dev; parent_dev; parent_dev = parent_dev->parent) 697 + for (parent_dev = dev; parent_dev; parent_dev = parent_dev->parent) { 728 698 if (!of_map_id(parent_dev->of_node, id_in, "msi-map", 729 699 "msi-map-mask", msi_np, &id_out)) 730 700 break; 701 + if (!of_check_msi_parent(parent_dev->of_node, msi_np)) 702 + break; 703 + } 731 704 return id_out; 732 705 } 733 706