| Message ID | 20210921220459.2437386-6-ben.widawsky@intel.com |
|---|---|
| State | New |
| Headers | show |
| Series | cxl_pci refactor for reusability | expand |
On 22/09/2021 00:04, Ben Widawsky wrote: > Add pci_find_dvsec_capability to locate a Designated Vendor-Specific > Extended Capability with the specified DVSEC ID. > > The Designated Vendor-Specific Extended Capability (DVSEC) allows one or > more vendor specific capabilities that aren't tied to the vendor ID of > the PCI component. > > DVSEC is critical for both the Compute Express Link (CXL) driver as well > as the driver for OpenCAPI coherent accelerator (OCXL). > > Cc: David E. Box <david.e.box@linux.intel.com> > Cc: Jonathan Cameron <Jonathan.Cameron@huawei.com> > Cc: Bjorn Helgaas <bhelgaas@google.com> > Cc: Dan Williams <dan.j.williams@intel.com> > Cc: linux-pci@vger.kernel.org > Cc: linuxppc-dev@lists.ozlabs.org > Cc: Frederic Barrat <fbarrat@linux.ibm.com> > Cc: Andrew Donnellan <ajd@linux.ibm.com> > Signed-off-by: Ben Widawsky <ben.widawsky@intel.com> > --- LGTM Reviewed-by: Frederic Barrat <fbarrat@linux.ibm.com> > drivers/pci/pci.c | 32 ++++++++++++++++++++++++++++++++ > include/linux/pci.h | 1 + > 2 files changed, 33 insertions(+) > > diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c > index ce2ab62b64cf..94ac86ff28b0 100644 > --- a/drivers/pci/pci.c > +++ b/drivers/pci/pci.c > @@ -732,6 +732,38 @@ u16 pci_find_vsec_capability(struct pci_dev *dev, u16 vendor, int cap) > } > EXPORT_SYMBOL_GPL(pci_find_vsec_capability); > > +/** > + * pci_find_dvsec_capability - Find DVSEC for vendor > + * @dev: PCI device to query > + * @vendor: Vendor ID to match for the DVSEC > + * @dvsec: Designated Vendor-specific capability ID > + * > + * If DVSEC has Vendor ID @vendor and DVSEC ID @dvsec return the capability > + * offset in config space; otherwise return 0. > + */ > +u16 pci_find_dvsec_capability(struct pci_dev *dev, u16 vendor, u16 dvsec) > +{ > + int pos; > + > + pos = pci_find_ext_capability(dev, PCI_EXT_CAP_ID_DVSEC); > + if (!pos) > + return 0; > + > + while (pos) { > + u16 v, id; > + > + pci_read_config_word(dev, pos + PCI_DVSEC_HEADER1, &v); > + pci_read_config_word(dev, pos + PCI_DVSEC_HEADER2, &id); > + if (vendor == v && dvsec == id) > + return pos; > + > + pos = pci_find_next_ext_capability(dev, pos, PCI_EXT_CAP_ID_DVSEC); > + } > + > + return 0; > +} > +EXPORT_SYMBOL_GPL(pci_find_dvsec_capability); > + > /** > * pci_find_parent_resource - return resource region of parent bus of given > * region > diff --git a/include/linux/pci.h b/include/linux/pci.h > index cd8aa6fce204..c93ccfa4571b 100644 > --- a/include/linux/pci.h > +++ b/include/linux/pci.h > @@ -1130,6 +1130,7 @@ u16 pci_find_ext_capability(struct pci_dev *dev, int cap); > u16 pci_find_next_ext_capability(struct pci_dev *dev, u16 pos, int cap); > struct pci_bus *pci_find_next_bus(const struct pci_bus *from); > u16 pci_find_vsec_capability(struct pci_dev *dev, u16 vendor, int cap); > +u16 pci_find_dvsec_capability(struct pci_dev *dev, u16 vendor, u16 dvsec); > > u64 pci_get_dsn(struct pci_dev *dev); > >
diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c index ce2ab62b64cf..94ac86ff28b0 100644 --- a/drivers/pci/pci.c +++ b/drivers/pci/pci.c @@ -732,6 +732,38 @@ u16 pci_find_vsec_capability(struct pci_dev *dev, u16 vendor, int cap) } EXPORT_SYMBOL_GPL(pci_find_vsec_capability); +/** + * pci_find_dvsec_capability - Find DVSEC for vendor + * @dev: PCI device to query + * @vendor: Vendor ID to match for the DVSEC + * @dvsec: Designated Vendor-specific capability ID + * + * If DVSEC has Vendor ID @vendor and DVSEC ID @dvsec return the capability + * offset in config space; otherwise return 0. + */ +u16 pci_find_dvsec_capability(struct pci_dev *dev, u16 vendor, u16 dvsec) +{ + int pos; + + pos = pci_find_ext_capability(dev, PCI_EXT_CAP_ID_DVSEC); + if (!pos) + return 0; + + while (pos) { + u16 v, id; + + pci_read_config_word(dev, pos + PCI_DVSEC_HEADER1, &v); + pci_read_config_word(dev, pos + PCI_DVSEC_HEADER2, &id); + if (vendor == v && dvsec == id) + return pos; + + pos = pci_find_next_ext_capability(dev, pos, PCI_EXT_CAP_ID_DVSEC); + } + + return 0; +} +EXPORT_SYMBOL_GPL(pci_find_dvsec_capability); + /** * pci_find_parent_resource - return resource region of parent bus of given * region diff --git a/include/linux/pci.h b/include/linux/pci.h index cd8aa6fce204..c93ccfa4571b 100644 --- a/include/linux/pci.h +++ b/include/linux/pci.h @@ -1130,6 +1130,7 @@ u16 pci_find_ext_capability(struct pci_dev *dev, int cap); u16 pci_find_next_ext_capability(struct pci_dev *dev, u16 pos, int cap); struct pci_bus *pci_find_next_bus(const struct pci_bus *from); u16 pci_find_vsec_capability(struct pci_dev *dev, u16 vendor, int cap); +u16 pci_find_dvsec_capability(struct pci_dev *dev, u16 vendor, u16 dvsec); u64 pci_get_dsn(struct pci_dev *dev);
Add pci_find_dvsec_capability to locate a Designated Vendor-Specific Extended Capability with the specified DVSEC ID. The Designated Vendor-Specific Extended Capability (DVSEC) allows one or more vendor specific capabilities that aren't tied to the vendor ID of the PCI component. DVSEC is critical for both the Compute Express Link (CXL) driver as well as the driver for OpenCAPI coherent accelerator (OCXL). Cc: David E. Box <david.e.box@linux.intel.com> Cc: Jonathan Cameron <Jonathan.Cameron@huawei.com> Cc: Bjorn Helgaas <bhelgaas@google.com> Cc: Dan Williams <dan.j.williams@intel.com> Cc: linux-pci@vger.kernel.org Cc: linuxppc-dev@lists.ozlabs.org Cc: Frederic Barrat <fbarrat@linux.ibm.com> Cc: Andrew Donnellan <ajd@linux.ibm.com> Signed-off-by: Ben Widawsky <ben.widawsky@intel.com> --- drivers/pci/pci.c | 32 ++++++++++++++++++++++++++++++++ include/linux/pci.h | 1 + 2 files changed, 33 insertions(+)