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>

drivers/usb/host/xhci-mem.c

@@ -1685,6 +1685,8 @@ void xhci_free_command(struct xhci_hcd *xhci,
 void xhci_mem_cleanup(struct xhci_hcd *xhci)
 {
 	struct pci_dev	*pdev = to_pci_dev(xhci_to_hcd(xhci)->self.controller);
+	struct dev_info	*dev_info, *next;
+	unsigned long	flags;
 	int size;
 	int i;
 
@@ -1742,6 +1744,13 @@ void xhci_mem_cleanup(struct xhci_hcd *xhci)
 
 	scratchpad_free(xhci);
 
+	spin_lock_irqsave(&xhci->lock, flags);
+	list_for_each_entry_safe(dev_info, next, &xhci->lpm_failed_devs, list) {
+		list_del(&dev_info->list);
+		kfree(dev_info);
+	}
+	spin_unlock_irqrestore(&xhci->lock, flags);
+
 	xhci->num_usb2_ports = 0;
 	xhci->num_usb3_ports = 0;
 	kfree(xhci->usb2_ports);
@@ -2328,6 +2337,8 @@ int xhci_mem_init(struct xhci_hcd *xhci, gfp_t flags)
 	if (xhci_setup_port_arrays(xhci, flags))
 		goto fail;
 
+	INIT_LIST_HEAD(&xhci->lpm_failed_devs);
+
 	return 0;
 
 fail:

drivers/usb/host/xhci-pci.c

@@ -345,6 +345,10 @@ static const struct hc_driver xhci_pci_hc_driver = {
 	.hub_status_data =	xhci_hub_status_data,
 	.bus_suspend =		xhci_bus_suspend,
 	.bus_resume =		xhci_bus_resume,
+	/*
+	 * call back when device connected and addressed
+	 */
+	.update_device =        xhci_update_device,
 };
 
 /*-------------------------------------------------------------------------*/

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.
  */

drivers/usb/host/xhci.h

@@ -272,6 +272,7 @@ struct xhci_op_regs {
  */
 #define PORT_PLS_MASK	(0xf << 5)
 #define XDEV_U0		(0x0 << 5)
+#define XDEV_U2		(0x2 << 5)
 #define XDEV_U3		(0x3 << 5)
 #define XDEV_RESUME	(0xf << 5)
 /* true: port has power (see HCC_PPC) */
@@ -362,7 +363,11 @@ struct xhci_op_regs {
 /* Bits 24:31 for port testing */
 
 /* USB2 Protocol PORTSPMSC */
-#define PORT_RWE	(1 << 0x3)
+#define	PORT_L1S_MASK		7
+#define	PORT_L1S_SUCCESS	1
+#define	PORT_RWE		(1 << 3)
+#define	PORT_HIRD(p)		(((p) & 0xf) << 4)
+#define	PORT_L1DS(p)		(((p) & 0xff) << 8)
 
 /**
  * struct xhci_intr_reg - Interrupt Register Set
@@ -1324,6 +1329,12 @@ struct s3_save {
 	u64	erst_dequeue;
 };
 
+/* Use for lpm */
+struct dev_info {
+	u32			dev_id;
+	struct	list_head	list;
+};
+
 struct xhci_bus_state {
 	unsigned long		bus_suspended;
 	unsigned long		next_statechange;
@@ -1387,6 +1398,8 @@ struct xhci_hcd {
 	struct xhci_erst	erst;
 	/* Scratchpad */
 	struct xhci_scratchpad  *scratchpad;
+	/* Store LPM test failed devices' information */
+	struct list_head	lpm_failed_devs;
 
 	/* slot enabling and address device helpers */
 	struct completion	addr_dev;
@@ -1663,6 +1676,7 @@ int xhci_free_streams(struct usb_hcd *hcd, struct usb_device *udev,
 		struct usb_host_endpoint **eps, unsigned int num_eps,
 		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_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);