usb: xhci: add USB2 Link power management BESL support

usb 2.0 devices with link power managment (LPM) can describe their idle link
timeouts either in BESL or HIRD format, so far xHCI has only supported HIRD but
later xHCI errata add BESL support as well

BESL timeouts need to inform exit latency changes with an evaluate
context command the same way USB 3.0 link PM code does.
The same xhci_change_max_exit_latency() function is used as with USB3
but code is pulled out from #ifdef CONFIG_PM as USB2.0 BESL LPM
funcionality does not depend on CONFIG_PM.

Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Signed-off-by: Sarah Sharp <sarah.a.sharp@linux.intel.com>

1 files changed, 140 insertions, 64 deletions

diff --git a/drivers/usb/host/xhci.c b/drivers/usb/host/xhci.c
index 31ce422af00a..3d34a0eed088 100644
--- a/drivers/usb/host/xhci.c
+++ b/drivers/usb/host/xhci.c
@@ -3815,6 +3815,56 @@ int xhci_find_raw_port_number(struct usb_hcd *hcd, int port1)
 	return raw_port;
 }
 
+/*
+ * Issue an Evaluate Context command to change the Maximum Exit Latency in the
+ * slot context.  If that succeeds, store the new MEL in the xhci_virt_device.
+ */
+static int xhci_change_max_exit_latency(struct xhci_hcd *xhci,
+			struct usb_device *udev, u16 max_exit_latency)
+{
+	struct xhci_virt_device *virt_dev;
+	struct xhci_command *command;
+	struct xhci_input_control_ctx *ctrl_ctx;
+	struct xhci_slot_ctx *slot_ctx;
+	unsigned long flags;
+	int ret;
+
+	spin_lock_irqsave(&xhci->lock, flags);
+	if (max_exit_latency == xhci->devs[udev->slot_id]->current_mel) {
+		spin_unlock_irqrestore(&xhci->lock, flags);
+		return 0;
+	}
+
+	/* Attempt to issue an Evaluate Context command to change the MEL. */
+	virt_dev = xhci->devs[udev->slot_id];
+	command = xhci->lpm_command;
+	xhci_slot_copy(xhci, command->in_ctx, virt_dev->out_ctx);
+	spin_unlock_irqrestore(&xhci->lock, flags);
+
+	ctrl_ctx = xhci_get_input_control_ctx(xhci, command->in_ctx);
+	ctrl_ctx->add_flags |= cpu_to_le32(SLOT_FLAG);
+	slot_ctx = xhci_get_slot_ctx(xhci, command->in_ctx);
+	slot_ctx->dev_info2 &= cpu_to_le32(~((u32) MAX_EXIT));
+	slot_ctx->dev_info2 |= cpu_to_le32(max_exit_latency);
+
+	xhci_dbg(xhci, "Set up evaluate context for LPM MEL change.\n");
+	xhci_dbg(xhci, "Slot %u Input Context:\n", udev->slot_id);
+	xhci_dbg_ctx(xhci, command->in_ctx, 0);
+
+	/* Issue and wait for the evaluate context command. */
+	ret = xhci_configure_endpoint(xhci, udev, command,
+			true, true);
+	xhci_dbg(xhci, "Slot %u Output Context:\n", udev->slot_id);
+	xhci_dbg_ctx(xhci, virt_dev->out_ctx, 0);
+
+	if (!ret) {
+		spin_lock_irqsave(&xhci->lock, flags);
+		virt_dev->current_mel = max_exit_latency;
+		spin_unlock_irqrestore(&xhci->lock, flags);
+	}
+	return ret;
+}
+
 #ifdef CONFIG_PM_RUNTIME
 
 /* BESL to HIRD Encoding array for USB2 LPM */
@@ -3856,6 +3906,28 @@ static int xhci_calculate_hird_besl(struct xhci_hcd *xhci,
 	return besl;
 }
 
+/* Calculate BESLD, L1 timeout and HIRDM for USB2 PORTHLPMC */
+static int xhci_calculate_usb2_hw_lpm_params(struct usb_device *udev)
+{
+	u32 field;
+	int l1;
+	int besld = 0;
+	int hirdm = 0;
+
+	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;
+
+	/* device has preferred BESLD */
+	if (field & USB_BESL_DEEP_VALID) {
+		besld = USB_GET_BESL_DEEP(field);
+		hirdm = 1;
+	}
+
+	return PORT_BESLD(besld) | PORT_L1_TIMEOUT(l1) | PORT_HIRDM(hirdm);
+}
+
 static int xhci_usb2_software_lpm_test(struct usb_hcd *hcd,
 					struct usb_device *udev)
 {
@@ -3988,11 +4060,12 @@ int xhci_set_usb2_hardware_lpm(struct usb_hcd *hcd,
 {
 	struct xhci_hcd	*xhci = hcd_to_xhci(hcd);
 	__le32 __iomem	**port_array;
-	__le32 __iomem	*pm_addr;
-	u32		temp;
+	__le32 __iomem	*pm_addr, *hlpm_addr;
+	u32		pm_val, hlpm_val, field;
 	unsigned int	port_num;
 	unsigned long	flags;
-	int		hird;
+	int		hird, exit_latency;
+	int		ret;
 
 	if (hcd->speed == HCD_USB3 || !xhci->hw_lpm_support ||
 			!udev->lpm_capable)
@@ -4010,23 +4083,73 @@ int xhci_set_usb2_hardware_lpm(struct usb_hcd *hcd,
 	port_array = xhci->usb2_ports;
 	port_num = udev->portnum - 1;
 	pm_addr = port_array[port_num] + PORTPMSC;
-	temp = xhci_readl(xhci, pm_addr);
+	pm_val = xhci_readl(xhci, pm_addr);
+	hlpm_addr = port_array[port_num] + PORTHLPMC;
+	field = le32_to_cpu(udev->bos->ext_cap->bmAttributes);
 
 	xhci_dbg(xhci, "%s port %d USB2 hardware LPM\n",
 			enable ? "enable" : "disable", port_num);
 
-	hird = xhci_calculate_hird_besl(xhci, udev);
-
 	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);
+		/* Host supports BESL timeout instead of HIRD */
+		if (udev->usb2_hw_lpm_besl_capable) {
+			/* if device doesn't have a preferred BESL value use a
+			 * default one which works with mixed HIRD and BESL
+			 * systems. See XHCI_DEFAULT_BESL definition in xhci.h
+			 */
+			if ((field & USB_BESL_SUPPORT) &&
+			    (field & USB_BESL_BASELINE_VALID))
+				hird = USB_GET_BESL_BASELINE(field);
+			else
+				hird = XHCI_DEFAULT_BESL;
+
+			exit_latency = xhci_besl_encoding[hird];
+			spin_unlock_irqrestore(&xhci->lock, flags);
+
+			/* USB 3.0 code dedicate one xhci->lpm_command->in_ctx
+			 * input context for link powermanagement evaluate
+			 * context commands. It is protected by hcd->bandwidth
+			 * mutex and is shared by all devices. We need to set
+			 * the max ext latency in USB 2 BESL LPM as well, so
+			 * use the same mutex and xhci_change_max_exit_latency()
+			 */
+			mutex_lock(hcd->bandwidth_mutex);
+			ret = xhci_change_max_exit_latency(xhci, udev,
+							   exit_latency);
+			mutex_unlock(hcd->bandwidth_mutex);
+
+			if (ret < 0)
+				return ret;
+			spin_lock_irqsave(&xhci->lock, flags);
+
+			hlpm_val = xhci_calculate_usb2_hw_lpm_params(udev);
+			xhci_writel(xhci, hlpm_val, hlpm_addr);
+			/* flush write */
+			xhci_readl(xhci, hlpm_addr);
+		} else {
+			hird = xhci_calculate_hird_besl(xhci, udev);
+		}
+
+		pm_val &= ~PORT_HIRD_MASK;
+		pm_val |= PORT_HIRD(hird) | PORT_RWE;
+		xhci_writel(xhci, pm_val, pm_addr);
+		pm_val = xhci_readl(xhci, pm_addr);
+		pm_val |= PORT_HLE;
+		xhci_writel(xhci, pm_val, pm_addr);
+		/* flush write */
+		xhci_readl(xhci, pm_addr);
 	} else {
-		temp &= ~(PORT_HLE | PORT_RWE | PORT_HIRD_MASK);
-		xhci_writel(xhci, temp, pm_addr);
+		pm_val &= ~(PORT_HLE | PORT_RWE | PORT_HIRD_MASK);
+		xhci_writel(xhci, pm_val, pm_addr);
+		/* flush write */
+		xhci_readl(xhci, pm_addr);
+		if (udev->usb2_hw_lpm_besl_capable) {
+			spin_unlock_irqrestore(&xhci->lock, flags);
+			mutex_lock(hcd->bandwidth_mutex);
+			xhci_change_max_exit_latency(xhci, udev, 0);
+			mutex_unlock(hcd->bandwidth_mutex);
+			return 0;
+		}
 	}
 
 	spin_unlock_irqrestore(&xhci->lock, flags);
@@ -4068,6 +4191,9 @@ int xhci_update_device(struct usb_hcd *hcd, struct usb_device *udev)
 		if (xhci->hw_lpm_support == 1 &&
 		    xhci_check_usb2_port_capability(xhci, portnum, XHCI_HLC)) {
 			udev->usb2_hw_lpm_capable = 1;
+			if (xhci_check_usb2_port_capability(xhci, portnum,
+							    XHCI_BLC))
+				udev->usb2_hw_lpm_besl_capable = 1;
 			ret = xhci_set_usb2_hardware_lpm(hcd, udev, 1);
 			if (!ret)
 				udev->usb2_hw_lpm_enabled = 1;
@@ -4398,56 +4524,6 @@ static u16 xhci_calculate_lpm_timeout(struct usb_hcd *hcd,
 	return timeout;
 }
 
-/*
- * Issue an Evaluate Context command to change the Maximum Exit Latency in the
- * slot context.  If that succeeds, store the new MEL in the xhci_virt_device.
- */
-static int xhci_change_max_exit_latency(struct xhci_hcd *xhci,
-			struct usb_device *udev, u16 max_exit_latency)
-{
-	struct xhci_virt_device *virt_dev;
-	struct xhci_command *command;
-	struct xhci_input_control_ctx *ctrl_ctx;
-	struct xhci_slot_ctx *slot_ctx;
-	unsigned long flags;
-	int ret;
-
-	spin_lock_irqsave(&xhci->lock, flags);
-	if (max_exit_latency == xhci->devs[udev->slot_id]->current_mel) {
-		spin_unlock_irqrestore(&xhci->lock, flags);
-		return 0;
-	}
-
-	/* Attempt to issue an Evaluate Context command to change the MEL. */
-	virt_dev = xhci->devs[udev->slot_id];
-	command = xhci->lpm_command;
-	xhci_slot_copy(xhci, command->in_ctx, virt_dev->out_ctx);
-	spin_unlock_irqrestore(&xhci->lock, flags);
-
-	ctrl_ctx = xhci_get_input_control_ctx(xhci, command->in_ctx);
-	ctrl_ctx->add_flags |= cpu_to_le32(SLOT_FLAG);
-	slot_ctx = xhci_get_slot_ctx(xhci, command->in_ctx);
-	slot_ctx->dev_info2 &= cpu_to_le32(~((u32) MAX_EXIT));
-	slot_ctx->dev_info2 |= cpu_to_le32(max_exit_latency);
-
-	xhci_dbg(xhci, "Set up evaluate context for LPM MEL change.\n");
-	xhci_dbg(xhci, "Slot %u Input Context:\n", udev->slot_id);
-	xhci_dbg_ctx(xhci, command->in_ctx, 0);
-
-	/* Issue and wait for the evaluate context command. */
-	ret = xhci_configure_endpoint(xhci, udev, command,
-			true, true);
-	xhci_dbg(xhci, "Slot %u Output Context:\n", udev->slot_id);
-	xhci_dbg_ctx(xhci, virt_dev->out_ctx, 0);
-
-	if (!ret) {
-		spin_lock_irqsave(&xhci->lock, flags);
-		virt_dev->current_mel = max_exit_latency;
-		spin_unlock_irqrestore(&xhci->lock, flags);
-	}
-	return ret;
-}
-
 static int calculate_max_exit_latency(struct usb_device *udev,
 		enum usb3_link_state state_changed,
 		u16 hub_encoded_timeout)