From d427da2323b093a65d8317783e76ab8fad2e2ef0 Mon Sep 17 00:00:00 2001 From: Sui Jingfeng Date: Fri, 25 Aug 2023 14:27:10 +0800 Subject: PCI: Add pci_get_base_class() helper 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 [bhelgaas: reword commit log] Signed-off-by: Bjorn Helgaas Reviewed-by: Alex Deucher --- drivers/pci/search.c | 31 +++++++++++++++++++++++++++++++ 1 file changed, 31 insertions(+) (limited to 'drivers/pci/search.c') diff --git a/drivers/pci/search.c b/drivers/pci/search.c index b4c138a6ec02..53840634fbfc 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 -- cgit v1.2.3