From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: stable@vger.kernel.org
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	patches@lists.linux.dev,
	Niklas Neronin <niklas.neronin@linux.intel.com>,
	Mathias Nyman <mathias.nyman@linux.intel.com>,
	Sasha Levin <sashal@kernel.org>
Subject: [PATCH 6.12 0956/1102] usb: xhci: add USB Port Register Set struct
Date: Thu, 17 Sep 2026 16:14:59 +0100
Message-ID: <20260917151604.660872578@linuxfoundation.org>
In-Reply-To: <20260917151539.408551884@linuxfoundation.org>
References: <20260917151539.408551884@linuxfoundation.org>
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6.12-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Niklas Neronin <niklas.neronin@linux.intel.com>

[ Upstream commit 377a91594e008848363641d07f51d2e48f4bdde5 ]

Introduce a new struct for the Host Controller USB Port Register Set to
enhance readability and maintainability.

The Host Controller Operational Registers (struct 'xhci_op_regs') span from
offset 0x0 to 0x3FF and consist of fixed fields. Following these fixed
fields are the Host Controller USB Port Register Sets, which are dynamic
and repeat from 1 to MaxPorts, as defined by HCSPARAMS1.

Currently, the struct 'xhci_op_regs' includes:
 __le32 port_status_base;		The first PORTSC
 __le32 port_power_base;		The first PORTPMSC
 __le32 port_link_base;			The first PORTLI
 __le32 reserved5;			The first PORTHLPMC, not reserved
 __le32 reserved6[NUM_PORT_REGS*254];	Port registers 2 to MaxPorts

Replace this with the simpler:
 struct xhci_port_regs port_regs[];	Port registers 1 to MaxPorts

Host Controller USB Port Register Set:
| Offset	| Mnemonic	| Register Name
--------------------------------------------------------------------------
| 0x0		| PORTSC	| Port Status and Control
| 0x4		| PORTPMSC	| Port Power Management Status and Control
| 0x8		| PORTLI	| Port Link Info
| 0xC		| PORTHLPMC	| Port Hardware LPM Control

Signed-off-by: Niklas Neronin <niklas.neronin@linux.intel.com>
Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Link: https://patch.msgid.link/20251119142417.2820519-8-mathias.nyman@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Stable-dep-of: 78203d5b54a4 ("usb: xhci: bail out of setup if the controller is inaccessible")
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 drivers/usb/host/xhci-mem.c |    3 +--
 drivers/usb/host/xhci.h     |   36 ++++++++++++++++--------------------
 2 files changed, 17 insertions(+), 22 deletions(-)

--- a/drivers/usb/host/xhci-mem.c
+++ b/drivers/usb/host/xhci-mem.c
@@ -2161,8 +2161,7 @@ static int xhci_setup_port_arrays(struct
 		return -ENOMEM;
 
 	for (i = 0; i < num_ports; i++) {
-		xhci->hw_ports[i].addr = &xhci->op_regs->port_status_base +
-			NUM_PORT_REGS * i;
+		xhci->hw_ports[i].addr = &xhci->op_regs->port_regs[i].portsc;
 		xhci->hw_ports[i].hw_portnum = i;
 
 		init_completion(&xhci->hw_ports[i].rexit_done);
--- a/drivers/usb/host/xhci.h
+++ b/drivers/usb/host/xhci.h
@@ -66,14 +66,25 @@ struct xhci_cap_regs {
 	/* Reserved up to (CAPLENGTH - 0x1C) */
 };
 
-/* Number of registers per port */
-#define	NUM_PORT_REGS	4
-
 #define PORTSC		0
 #define PORTPMSC	1
 #define PORTLI		2
 #define PORTHLPMC	3
 
+/*
+ * struct xhci_port_regs - Host Controller USB Port Register Set. xHCI spec 5.4.8
+ * @portsc:	Port Status and Control
+ * @portpmsc:	Port Power Management Status and Control
+ * @portli:	Port Link Info
+ * @porthlmpc:	Port Hardware LPM Control
+ */
+struct xhci_port_regs {
+	__le32	portsc;
+	__le32	portpmsc;
+	__le32	portli;
+	__le32	porthlmpc;
+};
+
 /**
  * struct xhci_op_regs - xHCI Host Controller Operational Registers.
  * @command:		USBCMD - xHC command register
@@ -85,16 +96,7 @@ struct xhci_cap_regs {
  * @cmd_ring:		CRP - 64-bit Command Ring Pointer
  * @dcbaa_ptr:		DCBAAP - 64-bit Device Context Base Address Array Pointer
  * @config_reg:		CONFIG - Configure Register
- * @port_status_base:	PORTSCn - base address for Port Status and Control
- * 			Each port has a Port Status and Control register,
- * 			followed by a Port Power Management Status and Control
- * 			register, a Port Link Info register, and a reserved
- * 			register.
- * @port_power_base:	PORTPMSCn - base address for
- * 			Port Power Management Status and Control
- * @port_link_base:	PORTLIn - base address for Port Link Info (current
- * 			Link PM state and control) for USB 2.1 and USB 3.0
- * 			devices.
+ * @port_regs:		Port Register Sets, from 1 to MaxPorts (defined by HCSPARAMS1).
  */
 struct xhci_op_regs {
 	__le32	command;
@@ -110,13 +112,7 @@ struct xhci_op_regs {
 	__le32	config_reg;
 	/* rsvd: offset 0x3C-3FF */
 	__le32	reserved4[241];
-	/* port 1 registers, which serve as a base address for other ports */
-	__le32	port_status_base;
-	__le32	port_power_base;
-	__le32	port_link_base;
-	__le32	reserved5;
-	/* registers for ports 2-255 */
-	__le32	reserved6[NUM_PORT_REGS*254];
+	struct xhci_port_regs port_regs[];
 };
 
 /* USBCMD - USB command - command bitmasks */