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| author | Jacob Keller <jacob.e.keller@intel.com> | 2020-03-02 18:25:00 -0800 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2020-03-05 17:36:24 -0800 |
| commit | 70c0923b0ef10b1c8d8f78fb50fcaef8eaae619d (patch) | |
| tree | 13fa85fb4022d726761d0e49f3c01ffc014d8d03 | |
| parent | 367ab29e3d88be42504aca0af13f8ebb9451a1ed (diff) | |
| download | linux-70c0923b0ef10b1c8d8f78fb50fcaef8eaae619d.tar.gz | |
PCI: Introduce pci_get_dsn
Several device drivers read their Device Serial Number from the PCIe extended config space. Introduce a new helper function, pci_get_dsn(). This function reads the eight bytes of the DSN and returns them as a u64. If the capability does not exist for the device, the function returns 0. Signed-off-by: Jacob Keller <jacob.e.keller@intel.com> Cc: Bjorn Helgaas <bhelgaas@google.com> Cc: Jeff Kirsher <jeffrey.t.kirsher@intel.com> Cc: Michael Chan <michael.chan@broadcom.com> Acked-by: Bjorn Helgaas <bhelgaas@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
| -rw-r--r-- | drivers/pci/pci.c | 34 | ||||
| -rw-r--r-- | include/linux/pci.h | 5 |
2 files changed, 39 insertions, 0 deletions
diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c index c16b0ba2a895..86821313c007 100644 --- a/drivers/pci/pci.c +++ b/drivers/pci/pci.c @@ -580,6 +580,40 @@ int pci_find_ext_capability(struct pci_dev *dev, int cap) } EXPORT_SYMBOL_GPL(pci_find_ext_capability); +/** + * pci_get_dsn - Read and return the 8-byte Device Serial Number + * @dev: PCI device to query + * + * Looks up the PCI_EXT_CAP_ID_DSN and reads the 8 bytes of the Device Serial + * Number. + * + * Returns the DSN, or zero if the capability does not exist. + */ +u64 pci_get_dsn(struct pci_dev *dev) +{ + u32 dword; + u64 dsn; + int pos; + + pos = pci_find_ext_capability(dev, PCI_EXT_CAP_ID_DSN); + if (!pos) + return 0; + + /* + * The Device Serial Number is two dwords offset 4 bytes from the + * capability position. The specification says that the first dword is + * the lower half, and the second dword is the upper half. + */ + pos += 4; + pci_read_config_dword(dev, pos, &dword); + dsn = (u64)dword; + pci_read_config_dword(dev, pos + 4, &dword); + dsn |= ((u64)dword) << 32; + + return dsn; +} +EXPORT_SYMBOL_GPL(pci_get_dsn); + static int __pci_find_next_ht_cap(struct pci_dev *dev, int pos, int ht_cap) { int rc, ttl = PCI_FIND_CAP_TTL; diff --git a/include/linux/pci.h b/include/linux/pci.h index 7beaf51e98ec..fc54b8922e66 100644 --- a/include/linux/pci.h +++ b/include/linux/pci.h @@ -1052,6 +1052,8 @@ 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); struct pci_bus *pci_find_next_bus(const struct pci_bus *from); +u64 pci_get_dsn(struct pci_dev *dev); + struct pci_dev *pci_get_device(unsigned int vendor, unsigned int device, struct pci_dev *from); struct pci_dev *pci_get_subsys(unsigned int vendor, unsigned int device, @@ -1707,6 +1709,9 @@ static inline int pci_find_next_capability(struct pci_dev *dev, u8 post, static inline int pci_find_ext_capability(struct pci_dev *dev, int cap) { return 0; } +static inline u64 pci_get_dsn(struct pci_dev *dev) +{ return 0; } + /* Power management related routines */ static inline int pci_save_state(struct pci_dev *dev) { return 0; } static inline void pci_restore_state(struct pci_dev *dev) { } |