6.6-stable review patch. If anyone has any objections, please let me know.
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From: Sui Jingfeng suijingfeng@loongson.cn
[ 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@linux.dev Signed-off-by: Sui Jingfeng suijingfeng@loongson.cn [bhelgaas: reword commit log] Signed-off-by: Bjorn Helgaas bhelgaas@google.com Reviewed-by: Alex Deucher alexander.deucher@amd.com Stable-dep-of: c2bc958b2b03 ("fbdev: vesafb: Detect VGA compatibility from screen info's VESA attributes") Signed-off-by: Sasha Levin sashal@kernel.org --- 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; }