diff options
| -rw-r--r-- | drivers/pci/pcie/ptm.c | 45 | ||||
| -rw-r--r-- | include/linux/pci.h | 7 | ||||
| -rw-r--r-- | include/uapi/linux/pci_regs.h | 1 |
3 files changed, 53 insertions, 0 deletions
diff --git a/drivers/pci/pcie/ptm.c b/drivers/pci/pcie/ptm.c index 48eea4e..a14ac94 100644 --- a/drivers/pci/pcie/ptm.c +++ b/drivers/pci/pcie/ptm.c @@ -68,3 +68,48 @@ void pci_ptm_init(struct pci_dev *dev) pci_ptm_info(dev); } + +int pci_enable_ptm(struct pci_dev *dev, u8 *granularity) +{ + int pos; + u32 cap, ctrl; + struct pci_dev *ups; + + if (!pci_is_pcie(dev)) + return -EINVAL; + + pos = pci_find_ext_capability(dev, PCI_EXT_CAP_ID_PTM); + if (!pos) + return -EINVAL; + + pci_read_config_dword(dev, pos + PCI_PTM_CAP, &cap); + if (!(cap & PCI_PTM_CAP_REQ)) + return -EINVAL; + + /* + * For a PCIe Endpoint, PTM is only useful if the endpoint can + * issue PTM requests to upstream devices that have PTM enabled. + * + * For Root Complex Integrated Endpoints, there is no upstream + * device, so there must be some implementation-specific way to + * associate the endpoint with a time source. + */ + if (pci_pcie_type(dev) == PCI_EXP_TYPE_ENDPOINT) { + ups = pci_upstream_bridge(dev); + if (!ups || !ups->ptm_enabled) + return -EINVAL; + } else if (pci_pcie_type(dev) == PCI_EXP_TYPE_RC_END) { + } else + return -EINVAL; + + ctrl = PCI_PTM_CTRL_ENABLE; + pci_write_config_dword(dev, pos + PCI_PTM_CTRL, ctrl); + dev->ptm_enabled = 1; + + pci_ptm_info(dev); + + if (granularity) + *granularity = 0; + return 0; +} +EXPORT_SYMBOL(pci_enable_ptm); diff --git a/include/linux/pci.h b/include/linux/pci.h index 96c509f..9e4b6d6 100644 --- a/include/linux/pci.h +++ b/include/linux/pci.h @@ -1407,6 +1407,13 @@ static inline void pci_disable_ats(struct pci_dev *d) { } static inline int pci_ats_queue_depth(struct pci_dev *d) { return -ENODEV; } #endif +#ifdef CONFIG_PCIE_PTM +int pci_enable_ptm(struct pci_dev *dev, u8 *granularity); +#else +static inline int pci_enable_ptm(struct pci_dev *dev, u8 *granularity) +{ return -EINVAL; } +#endif + void pci_cfg_access_lock(struct pci_dev *dev); bool pci_cfg_access_trylock(struct pci_dev *dev); void pci_cfg_access_unlock(struct pci_dev *dev); diff --git a/include/uapi/linux/pci_regs.h b/include/uapi/linux/pci_regs.h index 926fff4..72bbe14 100644 --- a/include/uapi/linux/pci_regs.h +++ b/include/uapi/linux/pci_regs.h @@ -967,6 +967,7 @@ /* Precision Time Measurement */ #define PCI_PTM_CAP 0x04 /* PTM Capability */ +#define PCI_PTM_CAP_REQ 0x00000001 /* Requester capable */ #define PCI_PTM_CAP_ROOT 0x00000004 /* Root capable */ #define PCI_PTM_CTRL 0x08 /* PTM Control */ #define PCI_PTM_CTRL_ENABLE 0x00000001 /* PTM enable */ |
