Messages in this thread | | | Date | Thu, 10 Aug 2023 21:05:44 +0800 | Subject | Re: [PATCH v2 02/11] PCI: Add the pci_get_class_masked() helper | From | suijingfeng <> |
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Hi,
On 2023/8/9 22:01, Ilpo Järvinen wrote: > On Wed, 9 Aug 2023, Sui Jingfeng wrote: > >> From: Sui Jingfeng <suijingfeng@loongson.cn> >> >> 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@loongson.cn> >> --- >> 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; } >>
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