Change in ...coreboot[master]: [WIP] device/pci_device: Do not break tree topology

[Kyösti Mälkki (Code Review)]

Kyösti Mälkki has uploaded this change for review. ( https://review.coreboot.org/c/coreboot/+/30772

Change subject: [WIP] device/pci_device: Do not break tree topology
......................................................................

[WIP] device/pci_device: Do not break tree topology

Function pci_scan_bus() breaks bus->children link
in the devicetree topology while scanning a bus.
While the scan is in progress, accessing PCI
devices with number higher than what is being probed
was not possible.

Change-Id: I7bb497f7390628dd2f0310b380f199783a888c4c
Signed-off-by: Kyösti Mälkki 
---
M src/device/pci_device.c
1 file changed, 23 insertions(+), 27 deletions(-)

git pull ssh://review.coreboot.org:29418/coreboot refs/changes/72/30772/1

diff --git a/src/device/pci_device.c b/src/device/pci_device.c
index e35c22c..5aedeb6 100644
--- a/src/device/pci_device.c
+++ b/src/device/pci_device.c
@@ -998,24 +998,23 @@
  * @return Pointer to the device structure found or NULL if we have not
  *	   allocated a device for this devfn yet.
  */
-static struct device *pci_scan_get_dev(struct device **list, unsigned int devfn)
+static struct device *pci_scan_get_dev(struct bus *bus, unsigned int devfn)
 {
-	struct device *dev;
+	struct device *dev, **prev;

-	dev = 0;
-	for (; *list; list = &(*list)->sibling) {
-		if ((*list)->path.type != DEVICE_PATH_PCI) {
-			printk(BIOS_ERR, "child %s not a PCI device\n",
-			       dev_path(*list));
-			continue;
-		}
-		if ((*list)->path.pci.devfn == devfn) {
+	prev = &bus->children;
+	for (dev = bus->children; dev; dev = dev->sibling) {
+		if ((dev->path.type == DEVICE_PATH_PCI) &&
+		    (dev->path.pci.devfn == devfn)) {
    		/* Unlink from the list. */
-			dev = *list;
-			*list = (*list)->sibling;
+			*prev = dev->sibling;
    		dev->sibling = NULL;
    		break;
+		} else {
+			printk(BIOS_ERR, "child %s not a PCI device\n",
+			       dev_path(dev));
    	}
+		prev = &dev->sibling;
    }

/*
@@ -1027,15 +1026,15 @@
    if (dev) {
    	struct device *child;

-		/* Find the last child of our parent. */
-		for (child = dev->bus->children; child && child->sibling;)
+		/* Find the last child on the bus. */
+		for (child = bus->children; child && child->sibling;)
    		child = child->sibling;

-		/* Place the device on the list of children of its parent. */
+		/* Place the device as last on the bus. */
    	if (child)
    		child->sibling = dev;
    	else
-			dev->bus->children = dev;
+			bus->children = dev;
    }

return dev;
@@ -1180,7 +1179,7 @@
    		  unsigned max_devfn)
 {
    unsigned int devfn;
-	struct device *old_devices;
+	struct device *left;

printk(BIOS_DEBUG, "PCI: pci_scan_bus for bus %02x\n", bus->secondary);

@@ -1193,9 +1192,6 @@
    	max_devfn=0xff;
    }

-	old_devices = bus->children;
-	bus->children = NULL;
-
    post_code(0x24);

/*
@@ -1206,7 +1202,7 @@
    	struct device *dev;

/* First thing setup the device structure. */
-		dev = pci_scan_get_dev(&old_devices, devfn);
+		dev = pci_scan_get_dev(bus, devfn);

/* See if a device is present and setup the device structure. */
    	dev = pci_probe_dev(dev, bus, devfn);
@@ -1228,13 +1224,13 @@
     * Warn if any leftover static devices are are found.
     * There's probably a problem in devicetree.cb.
     */
-	if (old_devices) {
-		struct device *left;
-		printk(BIOS_WARNING, "PCI: Left over static devices:\n");
-		for (left = old_devices; left; left = left->sibling)
-			printk(BIOS_WARNING, "%s\n", dev_path(left));

-		printk(BIOS_WARNING, "PCI: Check your devicetree.cb.\n");
+	printk(BIOS_WARNING, "PCI: Left over static devices:\n");
+	for (left = bus->children; left; left = left->sibling) {
+		if (left->vendor == 0x0) {
+			printk(BIOS_WARNING, "%s\n", dev_path(left));
+			printk(BIOS_WARNING, "PCI: Check your devicetree.cb.\n");
+		}
    }

/*