xHCI: set USB2 hardware LPM

If the device pass the USB2 software LPM and the host supports hardware
LPM, enable hardware LPM for the device to let the host decide when to
put the link into lower power state.

If hardware LPM is enabled for a port and driver wants to put it into
suspend, it must first disable hardware LPM, resume the port into U0,
and then suspend the port.

Signed-off-by: Andiry Xu <[e-mail]>
Signed-off-by: Sarah Sharp <[e-mail]>
Signed-off-by: Greg Kroah-Hartman <[e-mail]>

drivers/usb/core/driver.c

···
 	return 0;
 }
 
+int usb_set_usb2_hardware_lpm(struct usb_device *udev, int enable)
+{
+	struct usb_hcd *hcd = bus_to_hcd(udev->bus);
+	int ret = -EPERM;
+
+	if (hcd->driver->set_usb2_hw_lpm) {
+		ret = hcd->driver->set_usb2_hw_lpm(hcd, udev, enable);
+		if (!ret)
+			udev->usb2_hw_lpm_enabled = enable;
+	}
+
+	return ret;
+}
+
 #endif /* CONFIG_USB_SUSPEND */
 
 struct bus_type usb_bus_type = {

drivers/usb/core/hub.c

···
 		}
 	}
 
+	/* disable USB2 hardware LPM */
+	if (udev->usb2_hw_lpm_enabled == 1)
+		usb_set_usb2_hardware_lpm(udev, 0);
+
 	/* see 7.1.7.6 */
 	if (hub_is_superspeed(hub->hdev))
 		status = set_port_feature(hub->hdev,
···
 	if (status < 0) {
 		dev_dbg(&udev->dev, "can't resume, status %d\n", status);
 		hub_port_logical_disconnect(hub, port1);
+	} else  {
+		/* Try to enable USB2 hardware LPM */
+		if (udev->usb2_hw_lpm_capable == 1)
+			usb_set_usb2_hardware_lpm(udev, 1);
 	}
+
 	return status;
 }
 

drivers/usb/core/usb.h

···
 extern int usb_runtime_suspend(struct device *dev);
 extern int usb_runtime_resume(struct device *dev);
 extern int usb_runtime_idle(struct device *dev);
+extern int usb_set_usb2_hardware_lpm(struct usb_device *udev, int enable);
 
 #else
 
···
 	return 0;
 }
 
+static inline int usb_set_usb2_hardware_lpm(struct usb_device *udev, int enable)
+{
+	return 0;
+}
 #endif
 
 extern struct bus_type usb_bus_type;

drivers/usb/host/xhci-hub.c

···
 		switch (wValue) {
 		case USB_PORT_FEAT_SUSPEND:
 			temp = xhci_readl(xhci, port_array[wIndex]);
+			if ((temp & PORT_PLS_MASK) != XDEV_U0) {
+				/* Resume the port to U0 first */
+				xhci_set_link_state(xhci, port_array, wIndex,
+							XDEV_U0);
+				spin_unlock_irqrestore(&xhci->lock, flags);
+				msleep(10);
+				spin_lock_irqsave(&xhci->lock, flags);
+			}
 			/* In spec software should not attempt to suspend
 			 * a port unless the port reports that it is in the
 			 * enabled (PED = ‘1’,PLS < ‘3’) state.
 			 */
+			temp = xhci_readl(xhci, port_array[wIndex]);
 			if ((temp & PORT_PE) == 0 || (temp & PORT_RESET)
 				|| (temp & PORT_PLS_MASK) >= XDEV_U3) {
 				xhci_warn(xhci, "USB core suspending device "

drivers/usb/host/xhci-pci.c

···
 	 * call back when device connected and addressed
 	 */
 	.update_device =        xhci_update_device,
+	.set_usb2_hw_lpm =	xhci_set_usb2_hardware_lpm,
 };
 
 /*-------------------------------------------------------------------------*/

drivers/usb/host/xhci.c

···
 		del_timer_sync(&virt_dev->eps[i].stop_cmd_timer);
 	}
 
+	if (udev->usb2_hw_lpm_enabled) {
+		xhci_set_usb2_hardware_lpm(hcd, udev, 0);
+		udev->usb2_hw_lpm_enabled = 0;
+	}
+
 	spin_lock_irqsave(&xhci->lock, flags);
 	/* Don't disable the slot if the host controller is dead. */
 	state = xhci_readl(xhci, &xhci->op_regs->status);
···
 	return ret;
 }
 
+int xhci_set_usb2_hardware_lpm(struct usb_hcd *hcd,
+			struct usb_device *udev, int enable)
+{
+	struct xhci_hcd	*xhci = hcd_to_xhci(hcd);
+	__le32 __iomem	**port_array;
+	__le32 __iomem	*pm_addr;
+	u32		temp;
+	unsigned int	port_num;
+	unsigned long	flags;
+	int		u2del, hird;
+
+	if (hcd->speed == HCD_USB3 || !xhci->hw_lpm_support ||
+			!udev->lpm_capable)
+		return -EPERM;
+
+	if (!udev->parent || udev->parent->parent ||
+			udev->descriptor.bDeviceClass == USB_CLASS_HUB)
+		return -EPERM;
+
+	if (udev->usb2_hw_lpm_capable != 1)
+		return -EPERM;
+
+	spin_lock_irqsave(&xhci->lock, flags);
+
+	port_array = xhci->usb2_ports;
+	port_num = udev->portnum - 1;
+	pm_addr = port_array[port_num] + 1;
+	temp = xhci_readl(xhci, pm_addr);
+
+	xhci_dbg(xhci, "%s port %d USB2 hardware LPM\n",
+			enable ? "enable" : "disable", port_num);
+
+	u2del = HCS_U2_LATENCY(xhci->hcs_params3);
+	if (le32_to_cpu(udev->bos->ext_cap->bmAttributes) & (1 << 2))
+		hird = xhci_calculate_hird_besl(u2del, 1);
+	else
+		hird = xhci_calculate_hird_besl(u2del, 0);
+
+	if (enable) {
+		temp &= ~PORT_HIRD_MASK;
+		temp |= PORT_HIRD(hird) | PORT_RWE;
+		xhci_writel(xhci, temp, pm_addr);
+		temp = xhci_readl(xhci, pm_addr);
+		temp |= PORT_HLE;
+		xhci_writel(xhci, temp, pm_addr);
+	} else {
+		temp &= ~(PORT_HLE | PORT_RWE | PORT_HIRD_MASK);
+		xhci_writel(xhci, temp, pm_addr);
+	}
+
+	spin_unlock_irqrestore(&xhci->lock, flags);
+	return 0;
+}
+
 int xhci_update_device(struct usb_hcd *hcd, struct usb_device *udev)
 {
 	struct xhci_hcd	*xhci = hcd_to_xhci(hcd);
 	int		ret;
 
 	ret = xhci_usb2_software_lpm_test(hcd, udev);
-	if (!ret)
+	if (!ret) {
 		xhci_dbg(xhci, "software LPM test succeed\n");
+		if (xhci->hw_lpm_support == 1) {
+			udev->usb2_hw_lpm_capable = 1;
+			ret = xhci_set_usb2_hardware_lpm(hcd, udev, 1);
+			if (!ret)
+				udev->usb2_hw_lpm_enabled = 1;
+		}
+	}
 
 	return 0;
 }
 
 #else
+
+int xhci_set_usb2_hardware_lpm(struct usb_hcd *hcd,
+				struct usb_device *udev, int enable)
+{
+	return 0;
+}
 
 int xhci_update_device(struct usb_hcd *hcd, struct usb_device *udev)
 {

drivers/usb/host/xhci.h

···
 #define	PORT_L1S_SUCCESS	1
 #define	PORT_RWE		(1 << 3)
 #define	PORT_HIRD(p)		(((p) & 0xf) << 4)
+#define	PORT_HIRD_MASK		(0xf << 4)
 #define	PORT_L1DS(p)		(((p) & 0xff) << 8)
+#define	PORT_HLE		(1 << 16)
 
 /**
  * struct xhci_intr_reg - Interrupt Register Set
···
 		gfp_t mem_flags);
 int xhci_address_device(struct usb_hcd *hcd, struct usb_device *udev);
 int xhci_update_device(struct usb_hcd *hcd, struct usb_device *udev);
+int xhci_set_usb2_hardware_lpm(struct usb_hcd *hcd,
+				struct usb_device *udev, int enable);
 int xhci_update_hub_device(struct usb_hcd *hcd, struct usb_device *hdev,
 			struct usb_tt *tt, gfp_t mem_flags);
 int xhci_urb_enqueue(struct usb_hcd *hcd, struct urb *urb, gfp_t mem_flags);

include/linux/usb.h

···
  * @authenticated: Crypto authentication passed
  * @wusb: device is Wireless USB
  * @lpm_capable: device supports LPM
+ * @usb2_hw_lpm_capable: device can perform USB2 hardware LPM
+ * @usb2_hw_lpm_enabled: USB2 hardware LPM enabled
  * @string_langid: language ID for strings
  * @product: iProduct string, if present (static)
  * @manufacturer: iManufacturer string, if present (static)
···
 	unsigned authenticated:1;
 	unsigned wusb:1;
 	unsigned lpm_capable:1;
+	unsigned usb2_hw_lpm_capable:1;
+	unsigned usb2_hw_lpm_enabled:1;
 	int string_langid;
 
 	/* static strings from the device */

include/linux/usb/hcd.h

···
 		 * address is set
 		 */
 	int	(*update_device)(struct usb_hcd *, struct usb_device *);
+	int	(*set_usb2_hw_lpm)(struct usb_hcd *, struct usb_device *, int);
 };
 
 extern int usb_hcd_link_urb_to_ep(struct usb_hcd *hcd, struct urb *urb);