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>

3 files changed, 27 insertions, 0 deletions

diff --git a/drivers/usb/host/xhci-ext-caps.h b/drivers/usb/host/xhci-ext-caps.h
index ce5c9e51748e..c7f33123d4c0 100644
--- a/drivers/usb/host/xhci-ext-caps.h
+++ b/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)
diff --git a/drivers/usb/host/xhci-mem.c b/drivers/usb/host/xhci-mem.c
index bc6ec0cb3c61..9c7ddf0f3a43 100644
--- a/drivers/usb/host/xhci-mem.c
+++ b/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. */
diff --git a/drivers/usb/host/xhci.h b/drivers/usb/host/xhci.h
index fa921cbbe872..8673f985046e 100644
--- a/drivers/usb/host/xhci.h
+++ b/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 */