USB: xHCI: port power management implementation

Add software trigger USB device suspend resume function hook.
Do port suspend & resume in terms of xHCI spec.

Port Suspend:
Stop all endpoints via Stop Endpoint Command with Suspend (SP) flag set.
Place individual ports into suspend mode by writing '3' for Port Link State
(PLS) field into PORTSC register. This can only be done when the port is in
Enabled state. When writing, the Port Link State Write Strobe (LWS) bit shall
be set to '1'.
Allocate an xhci_command and stash it in xhci_virt_device to wait completion for
the last Stop Endpoint Command.  Use the Suspend bit in TRB to indicate the Stop
Endpoint Command is for port suspend. Based on Sarah's suggestion.

Port Resume:
Write '0' in PLS field, device will transition to running state.
Ring an endpoints' doorbell to restart it.

Ref: USB device remote wake need another patch to implement. For details of
how USB subsystem do power management, please see:
    Documentation/usb/power-management.txt

Signed-off-by: Crane Cai <crane.cai@amd.com>
Signed-off-by: Libin Yang <libin.yang@amd.com>
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-hub.c

@@ -129,6 +129,99 @@ static u32 xhci_port_state_to_neutral(u32 state)
 	return (state & XHCI_PORT_RO) | (state & XHCI_PORT_RWS);
 }
 
+/*
+ * find slot id based on port number.
+ */
+static int xhci_find_slot_id_by_port(struct xhci_hcd *xhci, u16 port)
+{
+	int slot_id;
+	int i;
+
+	slot_id = 0;
+	for (i = 0; i < MAX_HC_SLOTS; i++) {
+		if (!xhci->devs[i])
+			continue;
+		if (xhci->devs[i]->port == port) {
+			slot_id = i;
+			break;
+		}
+	}
+
+	return slot_id;
+}
+
+/*
+ * Stop device
+ * It issues stop endpoint command for EP 0 to 30. And wait the last command
+ * to complete.
+ * suspend will set to 1, if suspend bit need to set in command.
+ */
+static int xhci_stop_device(struct xhci_hcd *xhci, int slot_id, int suspend)
+{
+	struct xhci_virt_device *virt_dev;
+	struct xhci_command *cmd;
+	unsigned long flags;
+	int timeleft;
+	int ret;
+	int i;
+
+	ret = 0;
+	virt_dev = xhci->devs[slot_id];
+	cmd = xhci_alloc_command(xhci, false, true, GFP_NOIO);
+	if (!cmd) {
+		xhci_dbg(xhci, "Couldn't allocate command structure.\n");
+		return -ENOMEM;
+	}
+
+	spin_lock_irqsave(&xhci->lock, flags);
+	for (i = LAST_EP_INDEX; i > 0; i--) {
+		if (virt_dev->eps[i].ring && virt_dev->eps[i].ring->dequeue)
+			xhci_queue_stop_endpoint(xhci, slot_id, i, suspend);
+	}
+	cmd->command_trb = xhci->cmd_ring->enqueue;
+	list_add_tail(&cmd->cmd_list, &virt_dev->cmd_list);
+	xhci_queue_stop_endpoint(xhci, slot_id, 0, suspend);
+	xhci_ring_cmd_db(xhci);
+	spin_unlock_irqrestore(&xhci->lock, flags);
+
+	/* Wait for last stop endpoint command to finish */
+	timeleft = wait_for_completion_interruptible_timeout(
+			cmd->completion,
+			USB_CTRL_SET_TIMEOUT);
+	if (timeleft <= 0) {
+		xhci_warn(xhci, "%s while waiting for stop endpoint command\n",
+				timeleft == 0 ? "Timeout" : "Signal");
+		spin_lock_irqsave(&xhci->lock, flags);
+		/* The timeout might have raced with the event ring handler, so
+		 * only delete from the list if the item isn't poisoned.
+		 */
+		if (cmd->cmd_list.next != LIST_POISON1)
+			list_del(&cmd->cmd_list);
+		spin_unlock_irqrestore(&xhci->lock, flags);
+		ret = -ETIME;
+		goto command_cleanup;
+	}
+
+command_cleanup:
+	xhci_free_command(xhci, cmd);
+	return ret;
+}
+
+/*
+ * Ring device, it rings the all doorbells unconditionally.
+ */
+static void xhci_ring_device(struct xhci_hcd *xhci, int slot_id)
+{
+	int i;
+
+	for (i = 0; i < LAST_EP_INDEX + 1; i++)
+		if (xhci->devs[slot_id]->eps[i].ring &&
+		    xhci->devs[slot_id]->eps[i].ring->dequeue)
+			xhci_ring_ep_doorbell(xhci, slot_id, i, 0);
+
+	return;
+}
+
 static void xhci_disable_port(struct xhci_hcd *xhci, u16 wIndex,
 		u32 __iomem *addr, u32 port_status)
 {
@@ -162,6 +255,10 @@ static void xhci_clear_port_change_bit(struct xhci_hcd *xhci, u16 wValue,
 		status = PORT_PEC;
 		port_change_bit = "enable/disable";
 		break;
+	case USB_PORT_FEAT_C_SUSPEND:
+		status = PORT_PLC;
+		port_change_bit = "suspend/resume";
+		break;
 	default:
 		/* Should never happen */
 		return;
@@ -182,6 +279,7 @@ int xhci_hub_control(struct usb_hcd *hcd, u16 typeReq, u16 wValue,
 	u32 temp, status;
 	int retval = 0;
 	u32 __iomem *addr;
+	int slot_id;
 
 	ports = HCS_MAX_PORTS(xhci->hcs_params1);
 
@@ -211,9 +309,21 @@ int xhci_hub_control(struct usb_hcd *hcd, u16 typeReq, u16 wValue,
 		if ((temp & PORT_OCC))
 			status |= USB_PORT_STAT_C_OVERCURRENT << 16;
 		/*
-		 * FIXME ignoring suspend, reset, and USB 2.1/3.0 specific
+		 * FIXME ignoring reset and USB 2.1/3.0 specific
 		 * changes
 		 */
+		if ((temp & PORT_PLS_MASK) == XDEV_U3
+			&& (temp & PORT_POWER))
+			status |= 1 << USB_PORT_FEAT_SUSPEND;
+		if ((temp & PORT_PLS_MASK) == XDEV_U0
+			&& (temp & PORT_POWER)
+			&& (xhci->suspended_ports[wIndex >> 5] &
+			    (1 << (wIndex & 31)))) {
+			xhci->suspended_ports[wIndex >> 5] &=
+					~(1 << (wIndex & 31));
+			xhci->port_c_suspend[wIndex >> 5] |=
+					1 << (wIndex & 31);
+		}
 		if (temp & PORT_CONNECT) {
 			status |= USB_PORT_STAT_CONNECTION;
 			status |= xhci_port_speed(temp);
@@ -226,6 +336,8 @@ int xhci_hub_control(struct usb_hcd *hcd, u16 typeReq, u16 wValue,
 			status |= USB_PORT_STAT_RESET;
 		if (temp & PORT_POWER)
 			status |= USB_PORT_STAT_POWER;
+		if (xhci->port_c_suspend[wIndex >> 5] & (1 << (wIndex & 31)))
+			status |= 1 << USB_PORT_FEAT_C_SUSPEND;
 		xhci_dbg(xhci, "Get port status returned 0x%x\n", status);
 		put_unaligned(cpu_to_le32(status), (__le32 *) buf);
 		break;
@@ -238,6 +350,42 @@ int xhci_hub_control(struct usb_hcd *hcd, u16 typeReq, u16 wValue,
 		temp = xhci_readl(xhci, addr);
 		temp = xhci_port_state_to_neutral(temp);
 		switch (wValue) {
+		case USB_PORT_FEAT_SUSPEND:
+			temp = xhci_readl(xhci, addr);
+			/* 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.
+			 */
+			if ((temp & PORT_PE) == 0 || (temp & PORT_RESET)
+				|| (temp & PORT_PLS_MASK) >= XDEV_U3) {
+				xhci_warn(xhci, "USB core suspending device "
+					  "not in U0/U1/U2.\n");
+				goto error;
+			}
+
+			slot_id = xhci_find_slot_id_by_port(xhci, wIndex + 1);
+			if (!slot_id) {
+				xhci_warn(xhci, "slot_id is zero\n");
+				goto error;
+			}
+			/* unlock to execute stop endpoint commands */
+			spin_unlock_irqrestore(&xhci->lock, flags);
+			xhci_stop_device(xhci, slot_id, 1);
+			spin_lock_irqsave(&xhci->lock, flags);
+
+			temp = xhci_port_state_to_neutral(temp);
+			temp &= ~PORT_PLS_MASK;
+			temp |= PORT_LINK_STROBE | XDEV_U3;
+			xhci_writel(xhci, temp, addr);
+
+			spin_unlock_irqrestore(&xhci->lock, flags);
+			msleep(10); /* wait device to enter */
+			spin_lock_irqsave(&xhci->lock, flags);
+
+			temp = xhci_readl(xhci, addr);
+			xhci->suspended_ports[wIndex >> 5] |=
+					1 << (wIndex & (31));
+			break;
 		case USB_PORT_FEAT_POWER:
 			/*
 			 * Turn on ports, even if there isn't per-port switching.
@@ -271,6 +419,52 @@ int xhci_hub_control(struct usb_hcd *hcd, u16 typeReq, u16 wValue,
 		temp = xhci_readl(xhci, addr);
 		temp = xhci_port_state_to_neutral(temp);
 		switch (wValue) {
+		case USB_PORT_FEAT_SUSPEND:
+			temp = xhci_readl(xhci, addr);
+			xhci_dbg(xhci, "clear USB_PORT_FEAT_SUSPEND\n");
+			xhci_dbg(xhci, "PORTSC %04x\n", temp);
+			if (temp & PORT_RESET)
+				goto error;
+			if (temp & XDEV_U3) {
+				if ((temp & PORT_PE) == 0)
+					goto error;
+				if (DEV_SUPERSPEED(temp)) {
+					temp = xhci_port_state_to_neutral(temp);
+					temp &= ~PORT_PLS_MASK;
+					temp |= PORT_LINK_STROBE | XDEV_U0;
+					xhci_writel(xhci, temp, addr);
+					xhci_readl(xhci, addr);
+				} else {
+					temp = xhci_port_state_to_neutral(temp);
+					temp &= ~PORT_PLS_MASK;
+					temp |= PORT_LINK_STROBE | XDEV_RESUME;
+					xhci_writel(xhci, temp, addr);
+
+					spin_unlock_irqrestore(&xhci->lock,
+							       flags);
+					msleep(20);
+					spin_lock_irqsave(&xhci->lock, flags);
+
+					temp = xhci_readl(xhci, addr);
+					temp = xhci_port_state_to_neutral(temp);
+					temp &= ~PORT_PLS_MASK;
+					temp |= PORT_LINK_STROBE | XDEV_U0;
+					xhci_writel(xhci, temp, addr);
+				}
+				xhci->port_c_suspend[wIndex >> 5] |=
+						1 << (wIndex & 31);
+			}
+
+			slot_id = xhci_find_slot_id_by_port(xhci, wIndex + 1);
+			if (!slot_id) {
+				xhci_dbg(xhci, "slot_id is zero\n");
+				goto error;
+			}
+			xhci_ring_device(xhci, slot_id);
+			break;
+		case USB_PORT_FEAT_C_SUSPEND:
+			xhci->port_c_suspend[wIndex >> 5] &=
+					~(1 << (wIndex & 31));
 		case USB_PORT_FEAT_C_RESET:
 		case USB_PORT_FEAT_C_CONNECTION:
 		case USB_PORT_FEAT_C_OVER_CURRENT:

drivers/usb/host/xhci-mem.c

@@ -867,6 +867,7 @@ int xhci_setup_addressable_virt_dev(struct xhci_hcd *xhci, struct usb_device *ud
 			top_dev = top_dev->parent)
 		/* Found device below root hub */;
 	slot_ctx->dev_info2 |= (u32) ROOT_HUB_PORT(top_dev->portnum);
+	dev->port = top_dev->portnum;
 	xhci_dbg(xhci, "Set root hub portnum to %d\n", top_dev->portnum);
 
 	/* Is this a LS/FS device under a HS hub? */

drivers/usb/host/xhci-ring.c

@@ -68,6 +68,10 @@
 #include <linux/slab.h>
 #include "xhci.h"
 
+static int handle_cmd_in_cmd_wait_list(struct xhci_hcd *xhci,
+		struct xhci_virt_device *virt_dev,
+		struct xhci_event_cmd *event);
+
 /*
  * Returns zero if the TRB isn't in this segment, otherwise it returns the DMA
  * address of the TRB.
@@ -313,7 +317,7 @@ void xhci_ring_cmd_db(struct xhci_hcd *xhci)
 	xhci_readl(xhci, &xhci->dba->doorbell[0]);
 }
 
-static void ring_ep_doorbell(struct xhci_hcd *xhci,
+void xhci_ring_ep_doorbell(struct xhci_hcd *xhci,
 		unsigned int slot_id,
 		unsigned int ep_index,
 		unsigned int stream_id)
@@ -353,15 +357,16 @@ static void ring_doorbell_for_active_rings(struct xhci_hcd *xhci,
 	/* A ring has pending URBs if its TD list is not empty */
 	if (!(ep->ep_state & EP_HAS_STREAMS)) {
 		if (!(list_empty(&ep->ring->td_list)))
-			ring_ep_doorbell(xhci, slot_id, ep_index, 0);
+			xhci_ring_ep_doorbell(xhci, slot_id, ep_index, 0);
 		return;
 	}
 
 	for (stream_id = 1; stream_id < ep->stream_info->num_streams;
 			stream_id++) {
 		struct xhci_stream_info *stream_info = ep->stream_info;
 		if (!list_empty(&stream_info->stream_rings[stream_id]->td_list))
-			ring_ep_doorbell(xhci, slot_id, ep_index, stream_id);
+			xhci_ring_ep_doorbell(xhci, slot_id, ep_index,
+						stream_id);
 	}
 }
 
@@ -626,10 +631,11 @@ static void xhci_giveback_urb_in_irq(struct xhci_hcd *xhci,
  *     bit cleared) so that the HW will skip over them.
  */
 static void handle_stopped_endpoint(struct xhci_hcd *xhci,
-		union xhci_trb *trb)
+		union xhci_trb *trb, struct xhci_event_cmd *event)
 {
 	unsigned int slot_id;
 	unsigned int ep_index;
+	struct xhci_virt_device *virt_dev;
 	struct xhci_ring *ep_ring;
 	struct xhci_virt_ep *ep;
 	struct list_head *entry;
@@ -638,6 +644,21 @@ static void handle_stopped_endpoint(struct xhci_hcd *xhci,
 
 	struct xhci_dequeue_state deq_state;
 
+	if (unlikely(TRB_TO_SUSPEND_PORT(
+			xhci->cmd_ring->dequeue->generic.field[3]))) {
+		slot_id = TRB_TO_SLOT_ID(
+			xhci->cmd_ring->dequeue->generic.field[3]);
+		virt_dev = xhci->devs[slot_id];
+		if (virt_dev)
+			handle_cmd_in_cmd_wait_list(xhci, virt_dev,
+				event);
+		else
+			xhci_warn(xhci, "Stop endpoint command "
+				"completion for disabled slot %u\n",
+				slot_id);
+		return;
+	}
+
 	memset(&deq_state, 0, sizeof(deq_state));
 	slot_id = TRB_TO_SLOT_ID(trb->generic.field[3]);
 	ep_index = TRB_TO_EP_INDEX(trb->generic.field[3]);
@@ -1091,7 +1112,7 @@ static void handle_cmd_completion(struct xhci_hcd *xhci,
 		complete(&xhci->addr_dev);
 		break;
 	case TRB_TYPE(TRB_STOP_RING):
-		handle_stopped_endpoint(xhci, xhci->cmd_ring->dequeue);
+		handle_stopped_endpoint(xhci, xhci->cmd_ring->dequeue, event);
 		break;
 	case TRB_TYPE(TRB_SET_DEQ):
 		handle_set_deq_completion(xhci, event, xhci->cmd_ring->dequeue);
@@ -2347,7 +2368,7 @@ static void giveback_first_trb(struct xhci_hcd *xhci, int slot_id,
 	 */
 	wmb();
 	start_trb->field[3] |= start_cycle;
-	ring_ep_doorbell(xhci, slot_id, ep_index, stream_id);
+	xhci_ring_ep_doorbell(xhci, slot_id, ep_index, stream_id);
 }
 
 /*
@@ -2931,7 +2952,7 @@ static int xhci_queue_isoc_tx(struct xhci_hcd *xhci, gfp_t mem_flags,
 	wmb();
 	start_trb->field[3] |= start_cycle;
 
-	ring_ep_doorbell(xhci, slot_id, ep_index, urb->stream_id);
+	xhci_ring_ep_doorbell(xhci, slot_id, ep_index, urb->stream_id);
 	return 0;
 }
 
@@ -3108,15 +3129,20 @@ int xhci_queue_evaluate_context(struct xhci_hcd *xhci, dma_addr_t in_ctx_ptr,
 			false);
 }
 
+/*
+ * Suspend is set to indicate "Stop Endpoint Command" is being issued to stop
+ * activity on an endpoint that is about to be suspended.
+ */
 int xhci_queue_stop_endpoint(struct xhci_hcd *xhci, int slot_id,
-		unsigned int ep_index)
+		unsigned int ep_index, int suspend)
 {
 	u32 trb_slot_id = SLOT_ID_FOR_TRB(slot_id);
 	u32 trb_ep_index = EP_ID_FOR_TRB(ep_index);
 	u32 type = TRB_TYPE(TRB_STOP_RING);
+	u32 trb_suspend = SUSPEND_PORT_FOR_TRB(suspend);
 
 	return queue_command(xhci, 0, 0, 0,
-			trb_slot_id | trb_ep_index | type, false);
+			trb_slot_id | trb_ep_index | type | trb_suspend, false);
 }
 
 /* Set Transfer Ring Dequeue Pointer command.

drivers/usb/host/xhci.c

@@ -968,7 +968,7 @@ int xhci_urb_dequeue(struct usb_hcd *hcd, struct urb *urb, int status)
 		ep->stop_cmd_timer.expires = jiffies +
 			XHCI_STOP_EP_CMD_TIMEOUT * HZ;
 		add_timer(&ep->stop_cmd_timer);
-		xhci_queue_stop_endpoint(xhci, urb->dev->slot_id, ep_index);
+		xhci_queue_stop_endpoint(xhci, urb->dev->slot_id, ep_index, 0);
 		xhci_ring_cmd_db(xhci);
 	}
 done: