[RFC PATCH 1/3] PCI: Add PCIe Gen 7 (128 GT/s) register and speed definitions

["Ionut Nechita (Sunlight Linux)" <sunlightlinux@gmail.com>]

From: Ionut Nechita <ionut_n2001@yahoo.com>

Add register definitions for PCIe Gen 7 128 GT/s link speed:

  - PCI_EXP_LNKCAP_SLS_128_0GB (encoding 0x7)
  - PCI_EXP_LNKCAP2_SLS_128_0GB (bit 6 in Supported Link Speeds Vector)
  - PCI_EXP_LNKCTL2_TLS_128_0GT (Target Link Speed 0x7)
  - PCIE_SPEED_128_0GT enum value (0x1a)

Widen pci_dev.supported_speeds from u8 to u16 to accommodate the
expanded Supported Link Speeds Vector which now uses bits 1-7.

PCIe Gen 7 doubles the data rate to 128 GT/s using PAM4 signaling
with mandatory Flit mode encoding (1:1, no overhead), providing
up to 256 GB/s unidirectional (512 GB/s bi-directional) bandwidth
on an x16 link.

Note: Based on the PCIe 7.0 specification announced by PCI-SIG in
2022, targeted for member release in 2025. No hardware exists yet
to validate these definitions.

Signed-off-by: Ionut Nechita <ionut_n2001@yahoo.com>
---
 include/linux/pci.h           | 3 ++-
 include/uapi/linux/pci_regs.h | 3 +++
 2 files changed, 5 insertions(+), 1 deletion(-)

diff --git a/include/linux/pci.h b/include/linux/pci.h
index b5cc0c2b99065..21dd6ea5beb6d 100644
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -303,6 +303,7 @@ enum pci_bus_speed {
 	PCIE_SPEED_16_0GT		= 0x17,
 	PCIE_SPEED_32_0GT		= 0x18,
 	PCIE_SPEED_64_0GT		= 0x19,
+	PCIE_SPEED_128_0GT		= 0x1a,
 	PCI_SPEED_UNKNOWN		= 0xff,
 };
 
@@ -558,7 +559,7 @@ struct pci_dev {
 	struct pci_tsm *tsm;		/* TSM operation state */
 #endif
 	u16		acs_cap;	/* ACS Capability offset */
-	u8		supported_speeds; /* Supported Link Speeds Vector */
+	u16		supported_speeds; /* Supported Link Speeds Vector */
 	phys_addr_t	rom;		/* Physical address if not from BAR */
 	size_t		romlen;		/* Length if not from BAR */
 	/*
diff --git a/include/uapi/linux/pci_regs.h b/include/uapi/linux/pci_regs.h
index 3add74ae25948..fa00c6ca9f382 100644
--- a/include/uapi/linux/pci_regs.h
+++ b/include/uapi/linux/pci_regs.h
@@ -545,6 +545,7 @@
 #define  PCI_EXP_LNKCAP_SLS_16_0GB 0x00000004 /* LNKCAP2 SLS Vector bit 3 */
 #define  PCI_EXP_LNKCAP_SLS_32_0GB 0x00000005 /* LNKCAP2 SLS Vector bit 4 */
 #define  PCI_EXP_LNKCAP_SLS_64_0GB 0x00000006 /* LNKCAP2 SLS Vector bit 5 */
+#define  PCI_EXP_LNKCAP_SLS_128_0GB 0x00000007 /* LNKCAP2 SLS Vector bit 6 */
 #define  PCI_EXP_LNKCAP_MLW	0x000003f0 /* Maximum Link Width */
 #define  PCI_EXP_LNKCAP_ASPMS	0x00000c00 /* ASPM Support */
 #define  PCI_EXP_LNKCAP_ASPM_L0S 0x00000400 /* ASPM L0s Support */
@@ -693,6 +694,7 @@
 #define  PCI_EXP_LNKCAP2_SLS_16_0GB	0x00000010 /* Supported Speed 16GT/s */
 #define  PCI_EXP_LNKCAP2_SLS_32_0GB	0x00000020 /* Supported Speed 32GT/s */
 #define  PCI_EXP_LNKCAP2_SLS_64_0GB	0x00000040 /* Supported Speed 64GT/s */
+#define  PCI_EXP_LNKCAP2_SLS_128_0GB	0x00000080 /* Supported Speed 128GT/s */
 #define  PCI_EXP_LNKCAP2_CROSSLINK	0x00000100 /* Crosslink supported */
 #define PCI_EXP_LNKCTL2		0x30	/* Link Control 2 */
 #define  PCI_EXP_LNKCTL2_TLS		0x000f
@@ -702,6 +704,7 @@
 #define  PCI_EXP_LNKCTL2_TLS_16_0GT	0x0004 /* Supported Speed 16GT/s */
 #define  PCI_EXP_LNKCTL2_TLS_32_0GT	0x0005 /* Supported Speed 32GT/s */
 #define  PCI_EXP_LNKCTL2_TLS_64_0GT	0x0006 /* Supported Speed 64GT/s */
+#define  PCI_EXP_LNKCTL2_TLS_128_0GT	0x0007 /* Supported Speed 128GT/s */
 #define  PCI_EXP_LNKCTL2_ENTER_COMP	0x0010 /* Enter Compliance */
 #define  PCI_EXP_LNKCTL2_TX_MARGIN	0x0380 /* Transmit Margin */
 #define  PCI_EXP_LNKCTL2_HASD		0x0020 /* HW Autonomous Speed Disable */
-- 
2.53.0