1 files changed, 85 insertions, 8 deletions

diff --git a/drivers/pci/search.c b/drivers/pci/search.c
index b4c138a6ec02..e6e84dc62e82 100644
--- a/drivers/pci/search.c
+++ b/drivers/pci/search.c
@@ -282,6 +282,45 @@ static struct pci_dev *pci_get_dev_by_id(const struct pci_device_id *id,
 	return pdev;
 }
 
+static struct pci_dev *pci_get_dev_by_id_reverse(const struct pci_device_id *id,
+						 struct pci_dev *from)
+{
+	struct device *dev;
+	struct device *dev_start = NULL;
+	struct pci_dev *pdev = NULL;
+
+	if (from)
+		dev_start = &from->dev;
+	dev = bus_find_device_reverse(&pci_bus_type, dev_start, (void *)id,
+				      match_pci_dev_by_id);
+	if (dev)
+		pdev = to_pci_dev(dev);
+	pci_dev_put(from);
+	return pdev;
+}
+
+enum pci_search_direction {
+	PCI_SEARCH_FORWARD,
+	PCI_SEARCH_REVERSE,
+};
+
+static struct pci_dev *__pci_get_subsys(unsigned int vendor, unsigned int device,
+				 unsigned int ss_vendor, unsigned int ss_device,
+				 struct pci_dev *from, enum pci_search_direction dir)
+{
+	struct pci_device_id id = {
+		.vendor = vendor,
+		.device = device,
+		.subvendor = ss_vendor,
+		.subdevice = ss_device,
+	};
+
+	if (dir == PCI_SEARCH_FORWARD)
+		return pci_get_dev_by_id(&id, from);
+	else
+		return pci_get_dev_by_id_reverse(&id, from);
+}
+
 /**
  * pci_get_subsys - begin or continue searching for a PCI device by vendor/subvendor/device/subdevice id
  * @vendor: PCI vendor id to match, or %PCI_ANY_ID to match all vendor ids
@@ -302,14 +341,8 @@ struct pci_dev *pci_get_subsys(unsigned int vendor, unsigned int device,
 			       unsigned int ss_vendor, unsigned int ss_device,
 			       struct pci_dev *from)
 {
-	struct pci_device_id id = {
-		.vendor = vendor,
-		.device = device,
-		.subvendor = ss_vendor,
-		.subdevice = ss_device,
-	};
-
-	return pci_get_dev_by_id(&id, from);
+	return __pci_get_subsys(vendor, device, ss_vendor, ss_device, from,
+				PCI_SEARCH_FORWARD);
 }
 EXPORT_SYMBOL(pci_get_subsys);
 
@@ -334,6 +367,19 @@ struct pci_dev *pci_get_device(unsigned int vendor, unsigned int device,
 }
 EXPORT_SYMBOL(pci_get_device);
 
+/*
+ * Same semantics as pci_get_device(), except walks the PCI device list
+ * in reverse discovery order.
+ */
+struct pci_dev *pci_get_device_reverse(unsigned int vendor,
+				       unsigned int device,
+				       struct pci_dev *from)
+{
+	return __pci_get_subsys(vendor, device, PCI_ANY_ID, PCI_ANY_ID, from,
+				PCI_SEARCH_REVERSE);
+}
+EXPORT_SYMBOL(pci_get_device_reverse);
+
 /**
  * pci_get_class - begin or continue searching for a PCI device by class
  * @class: search for a PCI device with this class designation
@@ -364,6 +410,37 @@ struct pci_dev *pci_get_class(unsigned int class, struct pci_dev *from)
 EXPORT_SYMBOL(pci_get_class);
 
 /**
+ * pci_get_base_class - searching for a PCI device by matching against the base class code only
+ * @class: search for a PCI device with this base class code
+ * @from: Previous PCI device found in search, or %NULL for new search.
+ *
+ * Iterates through the list of known PCI devices. If a PCI device is found
+ * with a matching base class code, the reference count to the device is
+ * incremented. See pci_match_one_device() to figure out how does this works.
+ * A new search is initiated by passing %NULL as the @from argument.
+ * Otherwise if @from is not %NULL, searches continue from next device on the
+ * global list. The reference count for @from is always decremented if it is
+ * not %NULL.
+ *
+ * Returns:
+ * A pointer to a matched PCI device, %NULL Otherwise.
+ */
+struct pci_dev *pci_get_base_class(unsigned int class, struct pci_dev *from)
+{
+	struct pci_device_id id = {
+		.vendor = PCI_ANY_ID,
+		.device = PCI_ANY_ID,
+		.subvendor = PCI_ANY_ID,
+		.subdevice = PCI_ANY_ID,
+		.class_mask = 0xFF0000,
+		.class = class << 16,
+	};
+
+	return pci_get_dev_by_id(&id, from);
+}
+EXPORT_SYMBOL(pci_get_base_class);
+
+/**
  * pci_dev_present - Returns 1 if device matching the device list is present, 0 if not.
  * @ids: A pointer to a null terminated list of struct pci_device_id structures
  * that describe the type of PCI device the caller is trying to find.