libpayload: usb: Remove generic roothub reset port function

The generic roothub reset port function is overly broad and does some
things which may be undesirable, such as issuing multiple resets to a
port if the reset is deemed to have finished too quickly. Remove the
generic function and replace it with a controller-specific function,
currently only implemented for xhci.

Change-Id: Id46f73ea3341d4d01d2b517c6bf687402022d272
Signed-off-by: Shawn Nematbakhsh <shawnn@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/189495
Reviewed-by: Julius Werner <jwerner@chromium.org>
(cherry picked from commit 54e1da075b0106b0a1f736641fa52c39401d349d)
Signed-off-by: Isaac Christensen <isaac.christensen@se-eng.com>
Reviewed-on: http://review.coreboot.org/7001
Tested-by: build bot (Jenkins)
Reviewed-by: Ronald G. Minnich <rminnich@gmail.com>

3 files changed, 18 insertions, 37 deletions

diff --git a/payloads/libpayload/drivers/usb/generic_hub.c b/payloads/libpayload/drivers/usb/generic_hub.c
index fa95969f2a..9f8670597e 100644
--- a/payloads/libpayload/drivers/usb/generic_hub.c
+++ b/payloads/libpayload/drivers/usb/generic_hub.c
@@ -93,7 +93,7 @@ generic_hub_debounce(usbdev_t *const dev, const int port)
 	return 0; /* ignore timeouts, try to always go on */
 }
 
-static int
+int
 generic_hub_wait_for_port(usbdev_t *const dev, const int port,
 			  const int wait_for,
 			  int (*const port_op)(usbdev_t *, int),
@@ -135,38 +135,6 @@ generic_hub_resetport(usbdev_t *const dev, const int port)
 	return 0; /* ignore timeouts, try to always go on */
 }
 
-int
-generic_hub_rh_resetport(usbdev_t *const dev, const int port)
-{
-	generic_hub_t *const hub = GEN_HUB(dev);
-
-	/*
-	 * Resetting a root hub port should hold 50ms with pulses of at
-	 * least 10ms and gaps of at most 3ms (usb20 spec 7.1.7.5).
-	 * After reset, the port will be enabled automatically.
-	 */
-	int total = 500; /* 500 * 100us = 50ms */
-	while (total > 0) {
-		if (hub->ops->start_port_reset(dev, port) < 0)
-			return -1;
-
-		/* wait 100ms for the hub to finish the reset pulse */
-		const int timeout = generic_hub_wait_for_port(
-				/* time out after 1000 * 100us = 100ms */
-				dev, port, 0, hub->ops->port_in_reset, 1000, 100);
-		const int reset_time = 1000 - timeout;
-		if (timeout < 0)
-			return -1;
-		else if (!timeout)
-			usb_debug("generic_hub: Reset timed out at port %d\n",
-				  port);
-		else if (reset_time < 100) /* i.e. < 100 * 100us */
-			usb_debug("generic_hub: Port reset too short\n");
-		total -= reset_time;
-	}
-	return 0; /* ignore timeouts, try to always go on */
-}
-
 static int
 generic_hub_detach_dev(usbdev_t *const dev, const int port)
 {
diff --git a/payloads/libpayload/drivers/usb/generic_hub.h b/payloads/libpayload/drivers/usb/generic_hub.h
index cd4ebb6616..21536c0ecf 100644
--- a/payloads/libpayload/drivers/usb/generic_hub.h
+++ b/payloads/libpayload/drivers/usb/generic_hub.h
@@ -72,8 +72,11 @@ typedef struct generic_hub {
 } generic_hub_t;
 
 void generic_hub_destroy(usbdev_t *);
+int generic_hub_wait_for_port(usbdev_t *const dev, const int port,
+			      const int wait_for,
+			      int (*const port_op)(usbdev_t *, int),
+			      int timeout_steps, const int step_us);
 int  generic_hub_resetport(usbdev_t *, int port);
-int  generic_hub_rh_resetport(usbdev_t *, int port); /* root hubs have different timing requirements */
 int  generic_hub_scanport(usbdev_t *, int port);
 /* the provided generic_hub_ops struct has to be static */
 int generic_hub_init(usbdev_t *, int num_ports, const generic_hub_ops_t *);
diff --git a/payloads/libpayload/drivers/usb/xhci_rh.c b/payloads/libpayload/drivers/usb/xhci_rh.c
index c4cbeeaab8..26bb4f9c02 100644
--- a/payloads/libpayload/drivers/usb/xhci_rh.c
+++ b/payloads/libpayload/drivers/usb/xhci_rh.c
@@ -100,12 +100,22 @@ xhci_rh_port_speed(usbdev_t *const dev, const int port)
 }
 
 static int
-xhci_rh_start_port_reset(usbdev_t *const dev, const int port)
+xhci_rh_reset_port(usbdev_t *const dev, const int port)
 {
 	xhci_t *const xhci = XHCI_INST(dev->controller);
 	volatile u32 *const portsc = &xhci->opreg->prs[port - 1].portsc;
 
+	/* Trigger port reset. */
 	*portsc = (*portsc & PORTSC_RW_MASK) | PORTSC_PR;
+
+	/* Wait for port_in_reset == 0, up to 150 * 1000us = 150ms */
+	if (generic_hub_wait_for_port(dev, port, 0, xhci_rh_port_in_reset,
+				      150, 1000) == 0)
+		usb_debug("xhci_rh: Reset timed out at port %d\n", port);
+	else
+		/* Clear reset status bits, since port is out of reset. */
+		*portsc = (*portsc & PORTSC_RW_MASK) | PORTSC_PRC | PORTSC_WRC;
+
 	return 0;
 }
 
@@ -118,8 +128,8 @@ static const generic_hub_ops_t xhci_rh_ops = {
 	.port_speed		= xhci_rh_port_speed,
 	.enable_port		= NULL,
 	.disable_port		= NULL,
-	.start_port_reset	= xhci_rh_start_port_reset,
-	.reset_port		= generic_hub_rh_resetport,
+	.start_port_reset	= NULL,
+	.reset_port		= xhci_rh_reset_port,
 };
 
 void