xHCI: Check host USB2 LPM capability

Check the host's USB2 LPM capability.

USB2 software LPM support is optional for xHCI 0.96 hosts. xHCI 1.0 hosts
should support software LPM, and may support hardware LPM.
Signed-off-by: Andiry Xu <andiry.xu@amd.com>
Signed-off-by: Sarah Sharp <sarah.a.sharp@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

drivers/usb/host/xhci-ext-caps.h

@@ -65,6 +65,12 @@
 /* bits 1:2, 5:12, and 17:19 need to be preserved; bits 21:28 should be zero */
 #define	XHCI_LEGACY_DISABLE_SMI		((0x3 << 1) + (0xff << 5) + (0x7 << 17))
 
+/* USB 2.0 xHCI 0.96 L1C capability - section 7.2.2.1.3.2 */
+#define XHCI_L1C               (1 << 16)
+
+/* USB 2.0 xHCI 1.0 hardware LMP capability - section 7.2.2.1.3.2 */
+#define XHCI_HLC               (1 << 19)
+
 /* command register values to disable interrupts and halt the HC */
 /* start/stop HC execution - do not write unless HC is halted*/
 #define XHCI_CMD_RUN		(1 << 0)

drivers/usb/host/xhci-mem.c

@@ -1959,6 +1959,23 @@ static void xhci_add_in_port(struct xhci_hcd *xhci, unsigned int num_ports,
 	if (port_offset == 0 || (port_offset + port_count - 1) > num_ports)
 		/* WTF? "Valid values are ‘1’ to MaxPorts" */
 		return;
+
+	/* Check the host's USB2 LPM capability */
+	if ((xhci->hci_version == 0x96) && (major_revision != 0x03) &&
+			(temp & XHCI_L1C)) {
+		xhci_dbg(xhci, "xHCI 0.96: support USB2 software lpm\n");
+		xhci->sw_lpm_support = 1;
+	}
+
+	if ((xhci->hci_version >= 0x100) && (major_revision != 0x03)) {
+		xhci_dbg(xhci, "xHCI 1.0: support USB2 software lpm\n");
+		xhci->sw_lpm_support = 1;
+		if (temp & XHCI_HLC) {
+			xhci_dbg(xhci, "xHCI 1.0: support USB2 hardware lpm\n");
+			xhci->hw_lpm_support = 1;
+		}
+	}
+
 	port_offset--;
 	for (i = port_offset; i < (port_offset + port_count); i++) {
 		/* Duplicate entry.  Ignore the port if the revisions differ. */

drivers/usb/host/xhci.h

@@ -1459,6 +1459,10 @@ struct xhci_hcd {
 	/* Array of pointers to USB 2.0 PORTSC registers */
 	__le32 __iomem		**usb2_ports;
 	unsigned int		num_usb2_ports;
+	/* support xHCI 0.96 spec USB2 software LPM */
+	unsigned		sw_lpm_support:1;
+	/* support xHCI 1.0 spec USB2 hardware LPM */
+	unsigned		hw_lpm_support:1;
 };
 
 /* convert between an HCD pointer and the corresponding EHCI_HCD */