PCI: Add Precision Time Measurement (PTM) support

Add Precision Time Measurement (PTM) support (see PCIe r3.1, sec 6.22).

Enable PTM on PTM Root devices and switch ports.  This does not enable PTM
on endpoints.

There currently are no PTM-capable devices on the market, but it is
expected to be supported by the Intel Apollo Lake platform.

[bhelgaas: complete rework]
Signed-off-by: Jonathan Yong <jonathan.yong@intel.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>

1 files changed, 9 insertions, 1 deletions

diff --git a/include/uapi/linux/pci_regs.h b/include/uapi/linux/pci_regs.h
index 404095124ae2..926fff41b417 100644
--- a/include/uapi/linux/pci_regs.h
+++ b/include/uapi/linux/pci_regs.h
@@ -671,7 +671,8 @@
 #define PCI_EXT_CAP_ID_PMUX     0x1A    /* Protocol Multiplexing */
 #define PCI_EXT_CAP_ID_PASID    0x1B    /* Process Address Space ID */
 #define PCI_EXT_CAP_ID_DPC      0x1D    /* Downstream Port Containment */
-#define PCI_EXT_CAP_ID_MAX      PCI_EXT_CAP_ID_DPC
+#define PCI_EXT_CAP_ID_PTM      0x1F    /* Precision Time Measurement */
+#define PCI_EXT_CAP_ID_MAX      PCI_EXT_CAP_ID_PTM
 
 #define PCI_EXT_CAP_DSN_SIZEOF  12
 #define PCI_EXT_CAP_MCAST_ENDPOINT_SIZEOF 40
@@ -964,4 +965,11 @@
 
 #define PCI_EXP_DPC_SOURCE_ID           10      /* DPC Source Identifier */
 
+/* Precision Time Measurement */
+#define PCI_PTM_CAP                     0x04        /* PTM Capability */
+#define  PCI_PTM_CAP_ROOT               0x00000004  /* Root capable */
+#define PCI_PTM_CTRL                    0x08        /* PTM Control */
+#define  PCI_PTM_CTRL_ENABLE            0x00000001  /* PTM enable */
+#define  PCI_PTM_CTRL_ROOT              0x00000002  /* Root select */
+
 #endif /* LINUX_PCI_REGS_H */