Hi,
On 2023/8/9 22:01, Ilpo Järvinen wrote:
On Wed, 9 Aug 2023, Sui Jingfeng wrote:
From: Sui Jingfeng <suijingfeng@xxxxxxxxxxx>
Because there is no good way to get the mask member used to searching for
devices that conform to a specific PCI class code, an application needs to
process all PCI display devices can achieve its goal as follows:
This is mixing old and new way in a single sentence (which is confusing)?
Thanks for reviewing, but I can't understand this sentence.
Are you telling me that my description have grammar problem or something else?
I means that before apply this patch, we don't have a function can be used
to get all PCI(e) devices in a system by matching against its the PCI base class code only,
while keep the Sub-Class code and the Programming Interface ignored.
By supply a mask as argument, such thing become possible.
If an application want to process all PCI display devices in the system,
then it can achieve its goal by calling pci_get_class_masked() function.
pdev = NULL;
do {
pdev = pci_get_class_masked(PCI_BASE_CLASS_DISPLAY << 16, 0xFF0000, pdev);
if (pdev)
do_something_for_pci_display_device(pdev);
} while (pdev);
While previously, we just can not ignore Sub-Class code and the Programming
cannot
Interface byte when do the searching.
doing the search.
OK, will be fixed at the next version.
Signed-off-by: Sui Jingfeng <suijingfeng@xxxxxxxxxxx>
---
drivers/pci/search.c | 30 ++++++++++++++++++++++++++++++
include/linux/pci.h | 7 +++++++
2 files changed, 37 insertions(+)
diff --git a/drivers/pci/search.c b/drivers/pci/search.c
index b4c138a6ec02..f1c15aea868b 100644
--- a/drivers/pci/search.c
+++ b/drivers/pci/search.c
@@ -334,6 +334,36 @@ struct pci_dev *pci_get_device(unsigned int vendor, unsigned int device,
}
EXPORT_SYMBOL(pci_get_device);
+/**
+ * pci_get_class_masked - begin or continue searching for a PCI device by class and mask
+ * @class: search for a PCI device with this class designation
+ * @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
No double spaces in kernel comments. Perhaps your editor might be adding
them on reflow (might be configurable to not do that).
+ * found with a matching @class, the reference count to the device is
+ * incremented and a pointer to its device structure is returned.
+ * Otherwise, %NULL is returned.
+ * 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.
Use kerneldoc's Return: section for describing return value.
+ */
+struct pci_dev *pci_get_class_masked(unsigned int class, unsigned int mask,
+ 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 = mask,
+ .class = class,
+ };
+
+ return pci_get_dev_by_id(&id, from);
+}
+EXPORT_SYMBOL(pci_get_class_masked);
+
/**
* pci_get_class - begin or continue searching for a PCI device by class
* @class: search for a PCI device with this class designation
diff --git a/include/linux/pci.h b/include/linux/pci.h
index 0ff7500772e6..b20e7ba844bf 100644
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -1180,6 +1180,9 @@ 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_class_masked(unsigned int class, unsigned int mask,
+ 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,
@@ -1895,6 +1898,10 @@ static inline struct pci_dev *pci_get_class(unsigned int class,
struct pci_dev *from)
{ return NULL; }
+static inline struct pci_dev *pci_get_class_masked(unsigned int class,
+ unsigned int mask,
+ struct pci_dev *from)
+{ return NULL; }
static inline int pci_dev_present(const struct pci_device_id *ids)
{ return 0; }
