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PCI: Add pci_get_base_class() helper

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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>
This commit is contained in:
Sui Jingfeng 2023-08-25 14:27:10 +08:00 committed by Bjorn Helgaas
parent 0bb80ecc33
commit d427da2323
2 changed files with 36 additions and 0 deletions
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31
drivers/pci/search.c
View File

@ -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

5
include/linux/pci.h
View File

@ -1181,6 +1181,8 @@ 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,
@ -1924,6 +1926,9 @@ 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; }