dm: pci: Add support for PCI driver matching

At present all PCI devices must be present in the device tree in order to
be used. Many or most PCI devices don't require any configuration other than
that which is done automatically by U-Boot. It is inefficent to add a node
with nothing but a compatible string in order to get a device working.

Add a mechanism whereby PCI drivers can be declared along with the device
parameters they support (vendor/device/class). When no suitable driver is
found in the device tree the list of such devices is consulted to determine
the correct driver. If this also fails, then a generic driver is used as
before.

The mechanism used is very similar to that provided by Linux and the header
file defintions are copied from Linux 4.1.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Joe Hershberger <joe.hershberger@ni.com>

1 files changed, 116 insertions, 13 deletions

diff --git a/drivers/pci/pci-uclass.c b/drivers/pci/pci-uclass.c
index 5b91fe3dce..41daa0d6eb 100644
--- a/drivers/pci/pci-uclass.c
+++ b/drivers/pci/pci-uclass.c
@@ -353,6 +353,101 @@ int dm_pci_hose_probe_bus(struct pci_controller *hose, pci_dev_t bdf)
 	return sub_bus;
 }
 
+/**
+ * pci_match_one_device - Tell if a PCI device structure has a matching
+ *                        PCI device id structure
+ * @id: single PCI device id structure to match
+ * @dev: the PCI device structure to match against
+ *
+ * Returns the matching pci_device_id structure or %NULL if there is no match.
+ */
+static bool pci_match_one_id(const struct pci_device_id *id,
+			     const struct pci_device_id *find)
+{
+	if ((id->vendor == PCI_ANY_ID || id->vendor == find->vendor) &&
+	    (id->device == PCI_ANY_ID || id->device == find->device) &&
+	    (id->subvendor == PCI_ANY_ID || id->subvendor == find->subvendor) &&
+	    (id->subdevice == PCI_ANY_ID || id->subdevice == find->subdevice) &&
+	    !((id->class ^ find->class) & id->class_mask))
+		return true;
+
+	return false;
+}
+
+/**
+ * pci_find_and_bind_driver() - Find and bind the right PCI driver
+ *
+ * This only looks at certain fields in the descriptor.
+ */
+static int pci_find_and_bind_driver(struct udevice *parent,
+				    struct pci_device_id *find_id, int devfn,
+				    struct udevice **devp)
+{
+	struct pci_driver_entry *start, *entry;
+	const char *drv;
+	int n_ents;
+	int ret;
+	char name[30], *str;
+
+	*devp = NULL;
+
+	debug("%s: Searching for driver: vendor=%x, device=%x\n", __func__,
+	      find_id->vendor, find_id->device);
+	start = ll_entry_start(struct pci_driver_entry, pci_driver_entry);
+	n_ents = ll_entry_count(struct pci_driver_entry, pci_driver_entry);
+	for (entry = start; entry != start + n_ents; entry++) {
+		const struct pci_device_id *id;
+		struct udevice *dev;
+		const struct driver *drv;
+
+		for (id = entry->match;
+		     id->vendor || id->subvendor || id->class_mask;
+		     id++) {
+			if (!pci_match_one_id(id, find_id))
+				continue;
+
+			drv = entry->driver;
+			/*
+			 * We could pass the descriptor to the driver as
+			 * platdata (instead of NULL) and allow its bind()
+			 * method to return -ENOENT if it doesn't support this
+			 * device. That way we could continue the search to
+			 * find another driver. For now this doesn't seem
+			 * necesssary, so just bind the first match.
+			 */
+			ret = device_bind(parent, drv, drv->name, NULL, -1,
+					  &dev);
+			if (ret)
+				goto error;
+			debug("%s: Match found: %s\n", __func__, drv->name);
+			dev->driver_data = find_id->driver_data;
+			*devp = dev;
+			return 0;
+		}
+	}
+
+	/* Bind a generic driver so that the device can be used */
+	sprintf(name, "pci_%x:%x.%x", parent->seq, PCI_DEV(devfn),
+		PCI_FUNC(devfn));
+	str = strdup(name);
+	if (!str)
+		return -ENOMEM;
+	drv = (find_id->class >> 8) == PCI_CLASS_BRIDGE_PCI ? "pci_bridge_drv" :
+			"pci_generic_drv";
+	ret = device_bind_driver(parent, drv, str, devp);
+	if (ret) {
+		debug("%s: Failed to bind generic driver: %d", __func__, ret);
+		return ret;
+	}
+	debug("%s: No match found: bound generic driver instead\n", __func__);
+
+	return 0;
+
+error:
+	debug("%s: No match found: error %d\n", __func__, ret);
+	return ret;
+}
+
 int pci_bind_bus_devices(struct udevice *bus)
 {
 	ulong vendor, device;
@@ -387,25 +482,33 @@ int pci_bind_bus_devices(struct udevice *bus)
 		      bus->seq, bus->name, PCI_DEV(devfn), PCI_FUNC(devfn));
 		pci_bus_read_config(bus, devfn, PCI_DEVICE_ID, &device,
 				    PCI_SIZE_16);
-		pci_bus_read_config(bus, devfn, PCI_CLASS_DEVICE, &class,
-				    PCI_SIZE_16);
+		pci_bus_read_config(bus, devfn, PCI_CLASS_REVISION, &class,
+				    PCI_SIZE_32);
+		class >>= 8;
 
 		/* Find this device in the device tree */
 		ret = pci_bus_find_devfn(bus, devfn, &dev);
 
+		/* Search for a driver */
+
 		/* If nothing in the device tree, bind a generic device */
 		if (ret == -ENODEV) {
-			char name[30], *str;
-			const char *drv;
-
-			sprintf(name, "pci_%x:%x.%x", bus->seq,
-				PCI_DEV(devfn), PCI_FUNC(devfn));
-			str = strdup(name);
-			if (!str)
-				return -ENOMEM;
-			drv = class == PCI_CLASS_BRIDGE_PCI ?
-				"pci_bridge_drv" : "pci_generic_drv";
-			ret = device_bind_driver(bus, drv, str, &dev);
+			struct pci_device_id find_id;
+			ulong val;
+
+			memset(&find_id, '\0', sizeof(find_id));
+			find_id.vendor = vendor;
+			find_id.device = device;
+			find_id.class = class;
+			if ((header_type & 0x7f) == PCI_HEADER_TYPE_NORMAL) {
+				pci_bus_read_config(bus, devfn,
+						    PCI_SUBSYSTEM_VENDOR_ID,
+						    &val, PCI_SIZE_32);
+				find_id.subvendor = val & 0xffff;
+				find_id.subdevice = val >> 16;
+			}
+			ret = pci_find_and_bind_driver(bus, &find_id, devfn,
+						       &dev);
 		}
 		if (ret)
 			return ret;