usb: add usb2 Link PM variables to sysfs and usb_device

Adds abitilty to tune L1 timeout (inactivity timer for usb2 link sleep)
and BESL (best effort service latency)via sysfs.

This also adds a new usb2_lpm_parameters structure with those variables to
struct usb_device.

Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Signed-off-by: Sarah Sharp <sarah.a.sharp@linux.intel.com>
diff --git a/drivers/usb/core/sysfs.c b/drivers/usb/core/sysfs.c
index aa38db4..d9284b9 100644
--- a/drivers/usb/core/sysfs.c
+++ b/drivers/usb/core/sysfs.c
@@ -497,8 +497,62 @@
 static DEVICE_ATTR(usb2_hardware_lpm, S_IRUGO | S_IWUSR, show_usb2_hardware_lpm,
 			set_usb2_hardware_lpm);
 
+static ssize_t
+show_usb2_lpm_l1_timeout(struct device *dev, struct device_attribute *attr,
+			 char *buf)
+{
+	struct usb_device *udev = to_usb_device(dev);
+	return sprintf(buf, "%d\n", udev->l1_params.timeout);
+}
+
+static ssize_t
+set_usb2_lpm_l1_timeout(struct device *dev, struct device_attribute *attr,
+			const char *buf, size_t count)
+{
+	struct usb_device *udev = to_usb_device(dev);
+	u16 timeout;
+
+	if (kstrtou16(buf, 0, &timeout))
+		return -EINVAL;
+
+	udev->l1_params.timeout = timeout;
+
+	return count;
+}
+
+static DEVICE_ATTR(usb2_lpm_l1_timeout, S_IRUGO | S_IWUSR,
+		   show_usb2_lpm_l1_timeout, set_usb2_lpm_l1_timeout);
+
+static ssize_t
+show_usb2_lpm_besl(struct device *dev, struct device_attribute *attr,
+		   char *buf)
+{
+	struct usb_device *udev = to_usb_device(dev);
+	return sprintf(buf, "%d\n", udev->l1_params.besl);
+}
+
+static ssize_t
+set_usb2_lpm_besl(struct device *dev, struct device_attribute *attr,
+		const char *buf, size_t count)
+{
+	struct usb_device *udev = to_usb_device(dev);
+	u8 besl;
+
+	if (kstrtou8(buf, 0, &besl) || besl > 15)
+		return -EINVAL;
+
+	udev->l1_params.besl = besl;
+
+	return count;
+}
+
+static DEVICE_ATTR(usb2_lpm_besl, S_IRUGO | S_IWUSR,
+		   show_usb2_lpm_besl, set_usb2_lpm_besl);
+
 static struct attribute *usb2_hardware_lpm_attr[] = {
 	&dev_attr_usb2_hardware_lpm.attr,
+	&dev_attr_usb2_lpm_l1_timeout.attr,
+	&dev_attr_usb2_lpm_besl.attr,
 	NULL,
 };
 static struct attribute_group usb2_hardware_lpm_attr_group = {
diff --git a/drivers/usb/host/xhci.c b/drivers/usb/host/xhci.c
index 3d34a0e..8be34f8 100644
--- a/drivers/usb/host/xhci.c
+++ b/drivers/usb/host/xhci.c
@@ -3917,7 +3917,7 @@
 	field = le32_to_cpu(udev->bos->ext_cap->bmAttributes);
 
 	/* xHCI l1 is set in steps of 256us, xHCI 1.0 section 5.4.11.2 */
-	l1 = XHCI_L1_TIMEOUT / 256;
+	l1 = udev->l1_params.timeout / 256;
 
 	/* device has preferred BESLD */
 	if (field & USB_BESL_DEEP_VALID) {
@@ -4101,7 +4101,7 @@
 			    (field & USB_BESL_BASELINE_VALID))
 				hird = USB_GET_BESL_BASELINE(field);
 			else
-				hird = XHCI_DEFAULT_BESL;
+				hird = udev->l1_params.besl;
 
 			exit_latency = xhci_besl_encoding[hird];
 			spin_unlock_irqrestore(&xhci->lock, flags);
@@ -4191,6 +4191,8 @@
 		if (xhci->hw_lpm_support == 1 &&
 		    xhci_check_usb2_port_capability(xhci, portnum, XHCI_HLC)) {
 			udev->usb2_hw_lpm_capable = 1;
+			udev->l1_params.timeout = XHCI_L1_TIMEOUT;
+			udev->l1_params.besl = XHCI_DEFAULT_BESL;
 			if (xhci_check_usb2_port_capability(xhci, portnum,
 							    XHCI_BLC))
 				udev->usb2_hw_lpm_besl_capable = 1;