[coreboot-gerrit] Change in coreboot[master]: device/pci: Declare pci_root_bus()

[Kyösti Mälkki (Code Review)]

Kyösti Mälkki has submitted this change and it was merged. ( https://review.coreboot.org/c/coreboot/+/34004 )

Change subject: device/pci: Declare pci_root_bus()
......................................................................

device/pci: Declare pci_root_bus()

This is used a lot, cache the result so search
of domain from devicetree is only done once.

Improvement only applies when MAYBE_STATIC evaluates
to static.

Change-Id: If675abb632fe68acd59ba0bdfef854da3e0839a9
Signed-off-by: Kyösti Mälkki 
Reviewed-on: https://review.coreboot.org/c/coreboot/+/34004
Tested-by: build bot (Jenkins) 
Reviewed-by: Paul Menzel 
Reviewed-by: Nico Huber 
Reviewed-by: Angel Pons 
---
M src/device/device_const.c
M src/include/device/device.h
2 files changed, 17 insertions(+), 6 deletions(-)

Approvals:
  build bot (Jenkins): Verified
  Nico Huber: Looks good to me, approved
  Paul Menzel: Looks good to me, but someone else must approve
  Angel Pons: Looks good to me, approved

diff --git a/src/device/device_const.c b/src/device/device_const.c
index 6ce1d18..1853b4c 100644
--- a/src/device/device_const.c
+++ b/src/device/device_const.c
@@ -183,10 +183,24 @@
    return find_dev_path(parent, &path);
 }

-DEVTREE_CONST struct device *pcidev_path_on_root(pci_devfn_t devfn)
+DEVTREE_CONST struct bus *pci_root_bus(void)
 {
    DEVTREE_CONST struct device *pci_domain;
+	MAYBE_STATIC DEVTREE_CONST struct bus *pci_root = NULL;

+	if (pci_root)
+		return pci_root;
+
+	pci_domain = dev_find_path(NULL, DEVICE_PATH_DOMAIN);
+	if (!pci_domain)
+		return NULL;
+
+	pci_root = pci_domain->link_list;
+	return pci_root;
+}
+
+DEVTREE_CONST struct device *pcidev_path_on_root(pci_devfn_t devfn)
+{
    /* Work around pcidev_path_behind() below failing
     * due tue complicated devicetree with topology
     * being manipulated on-the-fly.
@@ -194,11 +208,7 @@
    if (CONFIG(NORTHBRIDGE_AMD_AMDFAM10))
    	return dev_find_slot(0, devfn);

-	pci_domain = dev_find_path(NULL, DEVICE_PATH_DOMAIN);
-	if (!pci_domain)
-		return NULL;
-
-	return pcidev_path_behind(pci_domain->link_list, devfn);
+	return pcidev_path_behind(pci_root_bus(), devfn);
 }

DEVTREE_CONST struct device *pcidev_on_root(uint8_t dev, uint8_t fn)
diff --git a/src/include/device/device.h b/src/include/device/device.h
index 8e9454c..a200de0 100644
--- a/src/include/device/device.h
+++ b/src/include/device/device.h
@@ -289,6 +289,7 @@
    	pci_devfn_t devfn);
 DEVTREE_CONST struct device *pcidev_path_on_root(pci_devfn_t devfn);
 DEVTREE_CONST struct device *pcidev_on_root(uint8_t dev, uint8_t fn);
+DEVTREE_CONST struct bus *pci_root_bus(void);

void scan_smbus(struct device *bus);
 void scan_generic_bus(struct device *bus);