6.6-stable review patch. If anyone has any objections, please let me know.
------------------
From: Sui Jingfeng <suijingfeng@xxxxxxxxxxx>
[ Upstream commit d427da2323b093a65d8317783e76ab8fad2e2ef0 ]
There is no function to get all PCI devices in a system by matching
against the base class code only, ignoring the sub-class code and
the programming interface. Add pci_get_base_class() to suit the
need.
For example, if a driver wants to process all PCI display devices in
a system, it can do so like this:
pdev = NULL;
while ((pdev = pci_get_base_class(PCI_BASE_CLASS_DISPLAY, pdev))) {
do_something_for_pci_display_device(pdev);
}
Link: https://lore.kernel.org/r/20230825062714.6325-2-sui.jingfeng@xxxxxxxxx
Signed-off-by: Sui Jingfeng <suijingfeng@xxxxxxxxxxx>
[bhelgaas: reword commit log]
Signed-off-by: Bjorn Helgaas <bhelgaas@xxxxxxxxxx>
Reviewed-by: Alex Deucher <alexander.deucher@xxxxxxx>
Stable-dep-of: c2bc958b2b03 ("fbdev: vesafb: Detect VGA compatibility from screen info's VESA attributes")
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
drivers/pci/search.c | 31 +++++++++++++++++++++++++++++++
include/linux/pci.h | 5 +++++
2 files changed, 36 insertions(+)
diff --git a/drivers/pci/search.c b/drivers/pci/search.c
index b4c138a6ec025..53840634fbfc2 100644
--- a/drivers/pci/search.c
+++ b/drivers/pci/search.c
@@ -363,6 +363,37 @@ 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
diff --git a/include/linux/pci.h b/include/linux/pci.h
index f141300116219..7b18a4b3efb0e 100644
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -1182,6 +1182,8 @@ struct pci_dev *pci_get_slot(struct pci_bus *bus, unsigned int devfn);
struct pci_dev *pci_get_domain_bus_and_slot(int domain, unsigned int bus,
unsigned int devfn);
struct pci_dev *pci_get_class(unsigned int class, struct pci_dev *from);
+struct pci_dev *pci_get_base_class(unsigned int class, struct pci_dev *from);
+
int pci_dev_present(const struct pci_device_id *ids);
int pci_bus_read_config_byte(struct pci_bus *bus, unsigned int devfn,
@@ -1958,6 +1960,9 @@ static inline struct pci_dev *pci_get_class(unsigned int class,
struct pci_dev *from)
{ return NULL; }
+static inline struct pci_dev *pci_get_base_class(unsigned int class,
+ struct pci_dev *from)
+{ return NULL; }
static inline int pci_dev_present(const struct pci_device_id *ids)
{ return 0; }
--
2.43.0
