dm: pci: Add a way to iterate through all PCI devices

These functions allow iteration through all PCI devices including bridges.
The children of each PCI bus are returned in turn. This can be useful for
configuring, checking or enumerating all the devices.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>

2 files changed, 85 insertions, 0 deletions

diff --git a/drivers/pci/pci-uclass.c b/drivers/pci/pci-uclass.c
index b79927e..ad65427 100644
--- a/drivers/pci/pci-uclass.c
+++ b/drivers/pci/pci-uclass.c
@@ -775,6 +775,66 @@ static int pci_bridge_write_config(struct udevice *bus, pci_dev_t bdf,
 	return pci_bus_write_config(hose->ctlr, bdf, offset, value, size);
 }
 
+static int skip_to_next_device(struct udevice *bus, struct udevice **devp)
+{
+	struct udevice *dev;
+	int ret = 0;
+
+	/*
+	 * Scan through all the PCI controllers. On x86 there will only be one
+	 * but that is not necessarily true on other hardware.
+	 */
+	do {
+		device_find_first_child(bus, &dev);
+		if (dev) {
+			*devp = dev;
+			return 0;
+		}
+		ret = uclass_next_device(&bus);
+		if (ret)
+			return ret;
+	} while (bus);
+
+	return 0;
+}
+
+int pci_find_next_device(struct udevice **devp)
+{
+	struct udevice *child = *devp;
+	struct udevice *bus = child->parent;
+	int ret;
+
+	/* First try all the siblings */
+	*devp = NULL;
+	while (child) {
+		device_find_next_child(&child);
+		if (child) {
+			*devp = child;
+			return 0;
+		}
+	}
+
+	/* We ran out of siblings. Try the next bus */
+	ret = uclass_next_device(&bus);
+	if (ret)
+		return ret;
+
+	return bus ? skip_to_next_device(bus, devp) : 0;
+}
+
+int pci_find_first_device(struct udevice **devp)
+{
+	struct udevice *bus;
+	int ret;
+
+	*devp = NULL;
+	ret = uclass_first_device(UCLASS_PCI, &bus);
+	if (ret)
+		return ret;
+
+	return skip_to_next_device(bus, devp);
+}
+
 UCLASS_DRIVER(pci) = {
 	.id		= UCLASS_PCI,
 	.name		= "pci",
diff --git a/include/pci.h b/include/pci.h
index d1e2765..488ff44 100644
--- a/include/pci.h
+++ b/include/pci.h
@@ -910,6 +910,31 @@ int pci_bus_find_devfn(struct udevice *bus, pci_dev_t find_devfn,
 		       struct udevice **devp);
 
 /**
+ * pci_find_first_device() - return the first available PCI device
+ *
+ * This function and pci_find_first_device() allow iteration through all
+ * available PCI devices on all buses. Assuming there are any, this will
+ * return the first one.
+ *
+ * @devp:	Set to the first available device, or NULL if no more are left
+ *		or we got an error
+ * @return 0 if all is OK, -ve on error (e.g. a bus/bridge failed to probe)
+ */
+int pci_find_first_device(struct udevice **devp);
+
+/**
+ * pci_find_next_device() - return the next available PCI device
+ *
+ * Finds the next available PCI device after the one supplied, or sets @devp
+ * to NULL if there are no more.
+ *
+ * @devp:	On entry, the last device returned. Set to the next available
+ *		device, or NULL if no more are left or we got an error
+ * @return 0 if all is OK, -ve on error (e.g. a bus/bridge failed to probe)
+ */
+int pci_find_next_device(struct udevice **devp);
+
+/**
  * pci_get_ff() - Returns a mask for the given access size
  *
  * @size:	Access size