PCI: Add defines for Designated Vendor-Specific Extended Capability

Add PCIe Designated Vendor-Specific Extended Capability (DVSEC) and defines
for the header offsets. Defined in PCIe r5.0, sec 7.9.6.

Signed-off-by: David E. Box <[e-mail]>
Acked-by: Bjorn Helgaas <[e-mail]>
Reviewed-by: Andy Shevchenko <[e-mail]>
Signed-off-by: Lee Jones <[e-mail]>

include/uapi/linux/pci_regs.h

···
 #define PCI_EXT_CAP_ID_DPC	0x1D	/* Downstream Port Containment */
 #define PCI_EXT_CAP_ID_L1SS	0x1E	/* L1 PM Substates */
 #define PCI_EXT_CAP_ID_PTM	0x1F	/* Precision Time Measurement */
+#define PCI_EXT_CAP_ID_DVSEC	0x23	/* Designated Vendor-Specific */
 #define PCI_EXT_CAP_ID_DLF	0x25	/* Data Link Feature */
 #define PCI_EXT_CAP_ID_PL_16GT	0x26	/* Physical Layer 16.0 GT/s */
 #define PCI_EXT_CAP_ID_MAX	PCI_EXT_CAP_ID_PL_16GT
···
 #define  PCI_L1SS_CTL1_LTR_L12_TH_VALUE	0x03ff0000  /* LTR_L1.2_THRESHOLD_Value */
 #define  PCI_L1SS_CTL1_LTR_L12_TH_SCALE	0xe0000000  /* LTR_L1.2_THRESHOLD_Scale */
 #define PCI_L1SS_CTL2		0x0c	/* Control 2 Register */
+
+/* Designated Vendor-Specific (DVSEC, PCI_EXT_CAP_ID_DVSEC) */
+#define PCI_DVSEC_HEADER1		0x4 /* Designated Vendor-Specific Header1 */
+#define PCI_DVSEC_HEADER2		0x8 /* Designated Vendor-Specific Header2 */
 
 /* Data Link Feature */
 #define PCI_DLF_CAP		0x04	/* Capabilities Register */