device/pci: Declare pcidev_path_on_bus()

It is recommended to never reference PCI busses
using a static number. There is exception with
OPROM execution, where we want to translate the
bus number captured from the actual IO operation
into a matching device node in the devicetree.

Change-Id: I733c645ac5581c000b4cd6cdc05829cd039324d5
Signed-off-by: Kyösti Mälkki <kyosti.malkki@gmail.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/34077
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Patrick Georgi <pgeorgi@google.com>

1 files changed, 18 insertions, 0 deletions

diff --git a/src/device/device_const.c b/src/device/device_const.c
index 1853b4c4d2..c1b0b063ff 100644
--- a/src/device/device_const.c
+++ b/src/device/device_const.c
@@ -183,6 +183,24 @@ DEVTREE_CONST struct device *pcidev_path_behind(
 	return find_dev_path(parent, &path);
 }
 
+DEVTREE_CONST struct device *pcidev_path_on_bus(unsigned int bus, pci_devfn_t devfn)
+{
+	DEVTREE_CONST struct bus *parent = pci_root_bus();
+	DEVTREE_CONST struct device *dev = parent->children;
+
+	/* FIXME: Write the loop with topology links. */
+	while (dev) {
+		if (dev->path.type != DEVICE_PATH_PCI) {
+			dev = dev->next;
+			continue;
+		}
+		if (dev->bus->secondary == bus)
+			return pcidev_path_behind(dev->bus, devfn);
+		dev = dev->next;
+	}
+	return NULL;
+}
+
 DEVTREE_CONST struct bus *pci_root_bus(void)
 {
 	DEVTREE_CONST struct device *pci_domain;