PCI: Add decoding for 16 GT/s link speed

PCIe 4.0 defines the 16.0 GT/s link speed.  Links can run at that speed
without any Linux changes, but previously their sysfs "max_link_speed" and
"current_link_speed" files contained "Unknown speed", not the expected
"16.0 GT/s".

Add decoding for the new 16 GT/s link speed.

Signed-off-by: Jay Fang <f.fangjian@huawei.com>
[bhelgaas: add PCI_EXP_LNKCAP2_SLS_16_0GB]
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Dongdong Liu <liudongdong3@huawei.com>
diff --git a/include/linux/pci.h b/include/linux/pci.h
index 024a1be..8043a59 100644
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -256,6 +256,7 @@ enum pci_bus_speed {
 	PCIE_SPEED_2_5GT		= 0x14,
 	PCIE_SPEED_5_0GT		= 0x15,
 	PCIE_SPEED_8_0GT		= 0x16,
+	PCIE_SPEED_16_0GT		= 0x17,
 	PCI_SPEED_UNKNOWN		= 0xff,
 };
 
diff --git a/include/uapi/linux/pci_regs.h b/include/uapi/linux/pci_regs.h
index 0c79eac..103ba79 100644
--- a/include/uapi/linux/pci_regs.h
+++ b/include/uapi/linux/pci_regs.h
@@ -520,6 +520,7 @@
 #define  PCI_EXP_LNKCAP_SLS_2_5GB 0x00000001 /* LNKCAP2 SLS Vector bit 0 */
 #define  PCI_EXP_LNKCAP_SLS_5_0GB 0x00000002 /* LNKCAP2 SLS Vector bit 1 */
 #define  PCI_EXP_LNKCAP_SLS_8_0GB 0x00000003 /* LNKCAP2 SLS Vector bit 2 */
+#define  PCI_EXP_LNKCAP_SLS_16_0GB 0x00000004 /* LNKCAP2 SLS Vector bit 3 */
 #define  PCI_EXP_LNKCAP_MLW	0x000003f0 /* Maximum Link Width */
 #define  PCI_EXP_LNKCAP_ASPMS	0x00000c00 /* ASPM Support */
 #define  PCI_EXP_LNKCAP_L0SEL	0x00007000 /* L0s Exit Latency */
@@ -547,6 +548,7 @@
 #define  PCI_EXP_LNKSTA_CLS_2_5GB 0x0001 /* Current Link Speed 2.5GT/s */
 #define  PCI_EXP_LNKSTA_CLS_5_0GB 0x0002 /* Current Link Speed 5.0GT/s */
 #define  PCI_EXP_LNKSTA_CLS_8_0GB 0x0003 /* Current Link Speed 8.0GT/s */
+#define  PCI_EXP_LNKSTA_CLS_16_0GB 0x0004 /* Current Link Speed 16.0GT/s */
 #define  PCI_EXP_LNKSTA_NLW	0x03f0	/* Negotiated Link Width */
 #define  PCI_EXP_LNKSTA_NLW_X1	0x0010	/* Current Link Width x1 */
 #define  PCI_EXP_LNKSTA_NLW_X2	0x0020	/* Current Link Width x2 */
@@ -648,8 +650,9 @@
 #define PCI_CAP_EXP_RC_ENDPOINT_SIZEOF_V2	44	/* v2 endpoints without link end here */
 #define PCI_EXP_LNKCAP2		44	/* Link Capabilities 2 */
 #define  PCI_EXP_LNKCAP2_SLS_2_5GB	0x00000002 /* Supported Speed 2.5GT/s */
-#define  PCI_EXP_LNKCAP2_SLS_5_0GB	0x00000004 /* Supported Speed 5.0GT/s */
-#define  PCI_EXP_LNKCAP2_SLS_8_0GB	0x00000008 /* Supported Speed 8.0GT/s */
+#define  PCI_EXP_LNKCAP2_SLS_5_0GB	0x00000004 /* Supported Speed 5GT/s */
+#define  PCI_EXP_LNKCAP2_SLS_8_0GB	0x00000008 /* Supported Speed 8GT/s */
+#define  PCI_EXP_LNKCAP2_SLS_16_0GB	0x00000010 /* Supported Speed 16GT/s */
 #define  PCI_EXP_LNKCAP2_CROSSLINK	0x00000100 /* Crosslink supported */
 #define PCI_EXP_LNKCTL2		48	/* Link Control 2 */
 #define PCI_EXP_LNKSTA2		50	/* Link Status 2 */