diff options
| author | Ben Widawsky <ben.widawsky@intel.com> | 2021-10-09 19:44:39 +0300 |
|---|---|---|
| committer | Dan Williams <dan.j.williams@intel.com> | 2021-10-29 21:53:51 +0300 |
| commit | ee12203746e5cec678c7d126c9901548bfec1dd5 (patch) | |
| tree | c73255e3907f65cd1dd28ddaabda8765b27fc2fe /drivers/pci/pci.c | |
| parent | 85afc3175aeb100d72e59e3d0470ad75a0e26249 (diff) | |
| download | linux-ee12203746e5cec678c7d126c9901548bfec1dd5.tar.xz | |
PCI: Add pci_find_dvsec_capability to find designated VSEC
Add pci_find_dvsec_capability to locate a Designated Vendor-Specific
Extended Capability with the specified Vendor ID and Capability ID.
The Designated Vendor-Specific Extended Capability (DVSEC) allows one or
more "vendor" specific capabilities that are not tied to the Vendor ID
of the PCI component. Where the DVSEC Vendor may be a standards body
like CXL.
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: Andrew Donnellan <ajd@linux.ibm.com>
Cc: Lu Baolu <baolu.lu@linux.intel.com>
Reviewed-by: Frederic Barrat <fbarrat@linux.ibm.com>
Signed-off-by: Ben Widawsky <ben.widawsky@intel.com>
Reviewed-by: Andrew Donnellan <ajd@linux.ibm.com>
Acked-by: Bjorn Helgaas <bhelgaas@google.com>
Tested-by: Kan Liang <kan.liang@linux.intel.com>
Signed-off-by: Kan Liang <kan.liang@linux.intel.com>
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Link: https://lore.kernel.org/r/163379787943.692348.6814373487017444007.stgit@dwillia2-desk3.amr.corp.intel.com
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Diffstat (limited to 'drivers/pci/pci.c')
| -rw-r--r-- | drivers/pci/pci.c | 32 |
1 files changed, 32 insertions, 0 deletions
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 @@ -733,6 +733,38 @@ 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 * @dev: PCI device structure contains resources to be searched |