xHCI: test USB2 software LPM

This patch tests USB2 software LPM for a USB2 LPM-capable device.

When a lpm-capable device is addressed, if the host also supports software
LPM, apply a test by putting the device into L1 state and resume it to see
if the device can do L1 suspend/resume successfully.

If the device fails to enter L1 or resume from L1 state, it may not
function normally and usbcore may disconnect and re-enumerate it. In this
case, store the device's Vid and Pid information, make sure the host will
not test LPM for it twice.

The test result is per device/host. Some devices claim to be lpm-capable,
but fail to enter L1 or resume. So the test is necessary.

The xHCI 1.0 errata has modified the USB2.0 LPM implementation. It redefines
the HIRD field to BESL, and adds another register Port Hardware LPM Control
(PORTHLPMC). However, this should not affect the LPM behavior on xHC which
does not implement 1.0 errata.

USB2.0 LPM errata defines a new bit BESL in the device's USB 2.0 extension
descriptor. If the device reports it uses BESL, driver should use BESL
instead of HIRD for it.

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>

1 files changed, 181 insertions, 0 deletions

diff --git a/drivers/usb/host/xhci.c b/drivers/usb/host/xhci.c
index 54cb762..b0649a4 100644
--- a/drivers/usb/host/xhci.c
+++ b/drivers/usb/host/xhci.c
@@ -3539,6 +3539,187 @@ int xhci_address_device(struct usb_hcd *hcd, struct usb_device *udev)
 	return 0;
 }
 
+#ifdef CONFIG_USB_SUSPEND
+
+/* BESL to HIRD Encoding array for USB2 LPM */
+static int xhci_besl_encoding[16] = {125, 150, 200, 300, 400, 500, 1000, 2000,
+	3000, 4000, 5000, 6000, 7000, 8000, 9000, 10000};
+
+/* Calculate HIRD/BESL for USB2 PORTPMSC*/
+static int xhci_calculate_hird_besl(int u2del, bool use_besl)
+{
+	int hird;
+
+	if (use_besl) {
+		for (hird = 0; hird < 16; hird++) {
+			if (xhci_besl_encoding[hird] >= u2del)
+				break;
+		}
+	} else {
+		if (u2del <= 50)
+			hird = 0;
+		else
+			hird = (u2del - 51) / 75 + 1;
+
+		if (hird > 15)
+			hird = 15;
+	}
+
+	return hird;
+}
+
+static int xhci_usb2_software_lpm_test(struct usb_hcd *hcd,
+					struct usb_device *udev)
+{
+	struct xhci_hcd	*xhci = hcd_to_xhci(hcd);
+	struct dev_info	*dev_info;
+	__le32 __iomem	**port_array;
+	__le32 __iomem	*addr, *pm_addr;
+	u32		temp, dev_id;
+	unsigned int	port_num;
+	unsigned long	flags;
+	int		u2del, hird;
+	int		ret;
+
+	if (hcd->speed == HCD_USB3 || !xhci->sw_lpm_support ||
+			!udev->lpm_capable)
+		return -EINVAL;
+
+	/* we only support lpm for non-hub device connected to root hub yet */
+	if (!udev->parent || udev->parent->parent ||
+			udev->descriptor.bDeviceClass == USB_CLASS_HUB)
+		return -EINVAL;
+
+	spin_lock_irqsave(&xhci->lock, flags);
+
+	/* Look for devices in lpm_failed_devs list */
+	dev_id = le16_to_cpu(udev->descriptor.idVendor) << 16 |
+			le16_to_cpu(udev->descriptor.idProduct);
+	list_for_each_entry(dev_info, &xhci->lpm_failed_devs, list) {
+		if (dev_info->dev_id == dev_id) {
+			ret = -EINVAL;
+			goto finish;
+		}
+	}
+
+	port_array = xhci->usb2_ports;
+	port_num = udev->portnum - 1;
+
+	if (port_num > HCS_MAX_PORTS(xhci->hcs_params1)) {
+		xhci_dbg(xhci, "invalid port number %d\n", udev->portnum);
+		ret = -EINVAL;
+		goto finish;
+	}
+
+	/*
+	 * Test USB 2.0 software LPM.
+	 * FIXME: some xHCI 1.0 hosts may implement a new register to set up
+	 * hardware-controlled USB 2.0 LPM. See section 5.4.11 and 4.23.5.1.1.1
+	 * in the June 2011 errata release.
+	 */
+	xhci_dbg(xhci, "test port %d software LPM\n", port_num);
+	/*
+	 * Set L1 Device Slot and HIRD/BESL.
+	 * Check device's USB 2.0 extension descriptor to determine whether
+	 * HIRD or BESL shoule be used. See USB2.0 LPM errata.
+	 */
+	pm_addr = port_array[port_num] + 1;
+	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);
+
+	temp = PORT_L1DS(udev->slot_id) | PORT_HIRD(hird);
+	xhci_writel(xhci, temp, pm_addr);
+
+	/* Set port link state to U2(L1) */
+	addr = port_array[port_num];
+	xhci_set_link_state(xhci, port_array, port_num, XDEV_U2);
+
+	/* wait for ACK */
+	spin_unlock_irqrestore(&xhci->lock, flags);
+	msleep(10);
+	spin_lock_irqsave(&xhci->lock, flags);
+
+	/* Check L1 Status */
+	ret = handshake(xhci, pm_addr, PORT_L1S_MASK, PORT_L1S_SUCCESS, 125);
+	if (ret != -ETIMEDOUT) {
+		/* enter L1 successfully */
+		temp = xhci_readl(xhci, addr);
+		xhci_dbg(xhci, "port %d entered L1 state, port status 0x%x\n",
+				port_num, temp);
+		ret = 0;
+	} else {
+		temp = xhci_readl(xhci, pm_addr);
+		xhci_dbg(xhci, "port %d software lpm failed, L1 status %d\n",
+				port_num, temp & PORT_L1S_MASK);
+		ret = -EINVAL;
+	}
+
+	/* Resume the port */
+	xhci_set_link_state(xhci, port_array, port_num, XDEV_U0);
+
+	spin_unlock_irqrestore(&xhci->lock, flags);
+	msleep(10);
+	spin_lock_irqsave(&xhci->lock, flags);
+
+	/* Clear PLC */
+	xhci_test_and_clear_bit(xhci, port_array, port_num, PORT_PLC);
+
+	/* Check PORTSC to make sure the device is in the right state */
+	if (!ret) {
+		temp = xhci_readl(xhci, addr);
+		xhci_dbg(xhci, "resumed port %d status 0x%x\n",	port_num, temp);
+		if (!(temp & PORT_CONNECT) || !(temp & PORT_PE) ||
+				(temp & PORT_PLS_MASK) != XDEV_U0) {
+			xhci_dbg(xhci, "port L1 resume fail\n");
+			ret = -EINVAL;
+		}
+	}
+
+	if (ret) {
+		/* Insert dev to lpm_failed_devs list */
+		xhci_warn(xhci, "device LPM test failed, may disconnect and "
+				"re-enumerate\n");
+		dev_info = kzalloc(sizeof(struct dev_info), GFP_ATOMIC);
+		if (!dev_info) {
+			ret = -ENOMEM;
+			goto finish;
+		}
+		dev_info->dev_id = dev_id;
+		INIT_LIST_HEAD(&dev_info->list);
+		list_add(&dev_info->list, &xhci->lpm_failed_devs);
+	} else {
+		xhci_ring_device(xhci, udev->slot_id);
+	}
+
+finish:
+	spin_unlock_irqrestore(&xhci->lock, flags);
+	return ret;
+}
+
+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)
+		xhci_dbg(xhci, "software LPM test succeed\n");
+
+	return 0;
+}
+
+#else
+
+int xhci_update_device(struct usb_hcd *hcd, struct usb_device *udev)
+{
+	return 0;
+}
+
+#endif /* CONFIG_USB_SUSPEND */
+
 /* Once a hub descriptor is fetched for a device, we need to update the xHC's
  * internal data structures for the device.
  */