USB: xHCI: port remote wakeup implementation

This commit implements port remote wakeup.

When a port is in U3 state and resume signaling is detected from a device,
the port transitions to the Resume state, and the xHC generates a Port Status
Change Event.

For USB3 port, software write a '0' to the PLS field to complete the resume
signaling. For USB2 port, the resume should be signaling for at least 20ms,
irq handler set a timer for port remote wakeup, and then finishes process in
hub_control GetPortStatus.

Some codes are borrowed from EHCI code.

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

@@ -123,7 +123,7 @@ static unsigned int xhci_port_speed(unsigned int port_status)
  * writing a 0 clears the bit and writing a 1 sets the bit (RWS).
  * For all other types (RW1S, RW1CS, RW, and RZ), writing a '0' has no effect.
  */
-static u32 xhci_port_state_to_neutral(u32 state)
+u32 xhci_port_state_to_neutral(u32 state)
 {
 	/* Save read-only status and port state */
 	return (state & XHCI_PORT_RO) | (state & XHCI_PORT_RWS);
@@ -132,7 +132,7 @@ static u32 xhci_port_state_to_neutral(u32 state)
 /*
  * find slot id based on port number.
  */
-static int xhci_find_slot_id_by_port(struct xhci_hcd *xhci, u16 port)
+int xhci_find_slot_id_by_port(struct xhci_hcd *xhci, u16 port)
 {
 	int slot_id;
 	int i;
@@ -210,7 +210,7 @@ static int xhci_stop_device(struct xhci_hcd *xhci, int slot_id, int suspend)
 /*
  * Ring device, it rings the all doorbells unconditionally.
  */
-static void xhci_ring_device(struct xhci_hcd *xhci, int slot_id)
+void xhci_ring_device(struct xhci_hcd *xhci, int slot_id)
 {
 	int i;
 
@@ -276,7 +276,7 @@ int xhci_hub_control(struct usb_hcd *hcd, u16 typeReq, u16 wValue,
 	struct xhci_hcd	*xhci = hcd_to_xhci(hcd);
 	int ports;
 	unsigned long flags;
-	u32 temp, status;
+	u32 temp, temp1, status;
 	int retval = 0;
 	u32 __iomem *addr;
 	int slot_id;
@@ -315,6 +315,34 @@ int xhci_hub_control(struct usb_hcd *hcd, u16 typeReq, u16 wValue,
 		if ((temp & PORT_PLS_MASK) == XDEV_U3
 			&& (temp & PORT_POWER))
 			status |= 1 << USB_PORT_FEAT_SUSPEND;
+		if ((temp & PORT_PLS_MASK) == XDEV_RESUME) {
+			if ((temp & PORT_RESET) || !(temp & PORT_PE))
+				goto error;
+			if (!DEV_SUPERSPEED(temp) && time_after_eq(jiffies,
+						xhci->resume_done[wIndex])) {
+				xhci_dbg(xhci, "Resume USB2 port %d\n",
+					wIndex + 1);
+				xhci->resume_done[wIndex] = 0;
+				temp1 = xhci_port_state_to_neutral(temp);
+				temp1 &= ~PORT_PLS_MASK;
+				temp1 |= PORT_LINK_STROBE | XDEV_U0;
+				xhci_writel(xhci, temp1, addr);
+
+				xhci_dbg(xhci, "set port %d resume\n",
+					wIndex + 1);
+				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);
+				xhci->port_c_suspend[wIndex >> 5] |=
+						1 << (wIndex & 31);
+				xhci->suspended_ports[wIndex >> 5] &=
+						~(1 << (wIndex & 31));
+			}
+		}
 		if ((temp & PORT_PLS_MASK) == XDEV_U0
 			&& (temp & PORT_POWER)
 			&& (xhci->suspended_ports[wIndex >> 5] &
@@ -500,6 +528,7 @@ int xhci_hub_status_data(struct usb_hcd *hcd, char *buf)
 {
 	unsigned long flags;
 	u32 temp, status;
+	u32 mask;
 	int i, retval;
 	struct xhci_hcd	*xhci = hcd_to_xhci(hcd);
 	int ports;
@@ -512,13 +541,18 @@ int xhci_hub_status_data(struct usb_hcd *hcd, char *buf)
 	memset(buf, 0, retval);
 	status = 0;
 
+	mask = PORT_CSC | PORT_PEC | PORT_OCC;
+
 	spin_lock_irqsave(&xhci->lock, flags);
 	/* For each port, did anything change?  If so, set that bit in buf. */
 	for (i = 0; i < ports; i++) {
 		addr = &xhci->op_regs->port_status_base +
 			NUM_PORT_REGS*i;
 		temp = xhci_readl(xhci, addr);
-		if (temp & (PORT_CSC | PORT_PEC | PORT_OCC)) {
+		if ((temp & mask) != 0 ||
+			(xhci->port_c_suspend[i >> 5] &	1 << (i & 31)) ||
+			(xhci->resume_done[i] && time_after_eq(
+			    jiffies, xhci->resume_done[i]))) {
 			buf[(i + 1) / 8] |= 1 << (i + 1) % 8;
 			status = 1;
 		}

drivers/usb/host/xhci-mem.c

@@ -1803,6 +1803,8 @@ int xhci_mem_init(struct xhci_hcd *xhci, gfp_t flags)
 	init_completion(&xhci->addr_dev);
 	for (i = 0; i < MAX_HC_SLOTS; ++i)
 		xhci->devs[i] = NULL;
+	for (i = 0; i < MAX_HC_PORTS; ++i)
+		xhci->resume_done[i] = 0;
 
 	if (scratchpad_alloc(xhci, flags))
 		goto fail;

drivers/usb/host/xhci-ring.c

@@ -1165,17 +1165,72 @@ static void handle_vendor_event(struct xhci_hcd *xhci,
 static void handle_port_status(struct xhci_hcd *xhci,
 		union xhci_trb *event)
 {
+	struct usb_hcd *hcd = xhci_to_hcd(xhci);
 	u32 port_id;
+	u32 temp, temp1;
+	u32 __iomem *addr;
+	int ports;
+	int slot_id;
 
 	/* Port status change events always have a successful completion code */
 	if (GET_COMP_CODE(event->generic.field[2]) != COMP_SUCCESS) {
 		xhci_warn(xhci, "WARN: xHC returned failed port status event\n");
 		xhci->error_bitmask |= 1 << 8;
 	}
-	/* FIXME: core doesn't care about all port link state changes yet */
 	port_id = GET_PORT_ID(event->generic.field[0]);
 	xhci_dbg(xhci, "Port Status Change Event for port %d\n", port_id);
 
+	ports = HCS_MAX_PORTS(xhci->hcs_params1);
+	if ((port_id <= 0) || (port_id > ports)) {
+		xhci_warn(xhci, "Invalid port id %d\n", port_id);
+		goto cleanup;
+	}
+
+	addr = &xhci->op_regs->port_status_base + NUM_PORT_REGS * (port_id - 1);
+	temp = xhci_readl(xhci, addr);
+	if ((temp & PORT_CONNECT) && (hcd->state == HC_STATE_SUSPENDED)) {
+		xhci_dbg(xhci, "resume root hub\n");
+		usb_hcd_resume_root_hub(hcd);
+	}
+
+	if ((temp & PORT_PLC) && (temp & PORT_PLS_MASK) == XDEV_RESUME) {
+		xhci_dbg(xhci, "port resume event for port %d\n", port_id);
+
+		temp1 = xhci_readl(xhci, &xhci->op_regs->command);
+		if (!(temp1 & CMD_RUN)) {
+			xhci_warn(xhci, "xHC is not running.\n");
+			goto cleanup;
+		}
+
+		if (DEV_SUPERSPEED(temp)) {
+			xhci_dbg(xhci, "resume SS port %d\n", port_id);
+			temp = xhci_port_state_to_neutral(temp);
+			temp &= ~PORT_PLS_MASK;
+			temp |= PORT_LINK_STROBE | XDEV_U0;
+			xhci_writel(xhci, temp, addr);
+			slot_id = xhci_find_slot_id_by_port(xhci, port_id);
+			if (!slot_id) {
+				xhci_dbg(xhci, "slot_id is zero\n");
+				goto cleanup;
+			}
+			xhci_ring_device(xhci, slot_id);
+			xhci_dbg(xhci, "resume SS port %d finished\n", port_id);
+			/* Clear PORT_PLC */
+			temp = xhci_readl(xhci, addr);
+			temp = xhci_port_state_to_neutral(temp);
+			temp |= PORT_PLC;
+			xhci_writel(xhci, temp, addr);
+		} else {
+			xhci_dbg(xhci, "resume HS port %d\n", port_id);
+			xhci->resume_done[port_id - 1] = jiffies +
+				msecs_to_jiffies(20);
+			mod_timer(&hcd->rh_timer,
+				  xhci->resume_done[port_id - 1]);
+			/* Do the rest in GetPortStatus */
+		}
+	}
+
+cleanup:
 	/* Update event ring dequeue pointer before dropping the lock */
 	inc_deq(xhci, xhci->event_ring, true);
 

drivers/usb/host/xhci.h

@@ -1215,6 +1215,7 @@ struct xhci_hcd {
 	u32			port_c_suspend[8];	/* port suspend change*/
 	u32			suspended_ports[8];	/* which ports are
 							   suspended */
+	unsigned long		resume_done[MAX_HC_PORTS];
 };
 
 /* For testing purposes */
@@ -1459,6 +1460,9 @@ void xhci_ring_ep_doorbell(struct xhci_hcd *xhci, unsigned int slot_id,
 int xhci_hub_control(struct usb_hcd *hcd, u16 typeReq, u16 wValue, u16 wIndex,
 		char *buf, u16 wLength);
 int xhci_hub_status_data(struct usb_hcd *hcd, char *buf);
+u32 xhci_port_state_to_neutral(u32 state);
+int xhci_find_slot_id_by_port(struct xhci_hcd *xhci, u16 port);
+void xhci_ring_device(struct xhci_hcd *xhci, int slot_id);
 
 /* xHCI contexts */
 struct xhci_input_control_ctx *xhci_get_input_control_ctx(struct xhci_hcd *xhci, struct xhci_container_ctx *ctx);