On 10/30/20 3:42 PM, Dave Jiang wrote: > Add function that searches for DVSEC and returns the offset in PCI > configuration space for the interested DVSEC capability. > > Signed-off-by: Dave Jiang <dave.jiang@xxxxxxxxx> > Reviewed-by: Ashok Raj <ashok.raj@xxxxxxxxx> > --- > > The patch has dependency on David Box’s dvsec definition patch: > https://lore.kernel.org/linux-pci/bc5f059c5bae957daebde699945c80808286bf45.camel@xxxxxxxxxxxxxxx/T/#m1d0dc12e3b2c739e2c37106a45f325bb8f001774 > > drivers/pci/pci.c | 30 ++++++++++++++++++++++++++++++ > include/linux/pci.h | 3 +++ > 2 files changed, 33 insertions(+) > > diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c > index 6d4d5a2f923d..49e57b831509 100644 > --- a/drivers/pci/pci.c > +++ b/drivers/pci/pci.c > @@ -589,6 +589,36 @@ int pci_find_ext_capability(struct pci_dev *dev, int cap) > } > EXPORT_SYMBOL_GPL(pci_find_ext_capability); > > +/** > + * pci_find_dvsec - return position of DVSEC with provided vendor and DVSEC ID > + * @dev: the PCI device > + * @vendor: vendor for the DVSEC > + * @id: the DVSEC capibility ID capability > + * > + * Return the offset of DVSEC on success or -ENOTSUPP if not found * Return: the offset of DVSEC on success or -ENOTSUPP if not found > + */ > +int pci_find_dvsec(struct pci_dev *dev, u16 vendor, u16 id) > +{ > + u16 dev_vendor, dev_id; > + int pos; > + > + pos = pci_find_ext_capability(dev, PCI_EXT_CAP_ID_DVSEC); > + if (!pos) > + return -ENOTSUPP; > + > + while (pos) { > + pci_read_config_word(dev, pos + PCI_DVSEC_HEADER1, &dev_vendor); > + pci_read_config_word(dev, pos + PCI_DVSEC_HEADER2, &dev_id); > + if (dev_vendor == vendor && dev_id == id) > + return pos; > + > + pos = pci_find_next_ext_capability(dev, pos, PCI_EXT_CAP_ID_DVSEC); > + } > + > + return -ENOTSUPP; > +} > +EXPORT_SYMBOL_GPL(pci_find_dvsec); > + > /** > * pci_get_dsn - Read and return the 8-byte Device Serial Number > * @dev: PCI device to query > diff --git a/include/linux/pci.h b/include/linux/pci.h > index 22207a79762c..6c692d32c82a 100644 > --- a/include/linux/pci.h > +++ b/include/linux/pci.h > @@ -1069,6 +1069,7 @@ int pci_find_ext_capability(struct pci_dev *dev, int cap); > int pci_find_next_ext_capability(struct pci_dev *dev, int pos, int cap); > int pci_find_ht_capability(struct pci_dev *dev, int ht_cap); > int pci_find_next_ht_capability(struct pci_dev *dev, int pos, int ht_cap); > +int pci_find_dvsec(struct pci_dev *dev, u16 vendor, u16 id); > struct pci_bus *pci_find_next_bus(const struct pci_bus *from); > > u64 pci_get_dsn(struct pci_dev *dev); > @@ -1726,6 +1727,8 @@ static inline int pci_find_next_capability(struct pci_dev *dev, u8 post, > { return 0; } > static inline int pci_find_ext_capability(struct pci_dev *dev, int cap) > { return 0; } > +static inline int pci_find_dvsec(struct pci_dev *dev, u16 vendor, u16 id) > +{ return 0; } Why shouldn't this return -ENOTSUPP instead of 0? > > static inline u64 pci_get_dsn(struct pci_dev *dev) > { return 0; } > > -- ~Randy
