[PATCH AUTOSEL 4.9 02/13] usb: gadget: composite: Support more than 500mA MaxPower

[PATCH AUTOSEL 4.9 02/13] usb: gadget: composite: Support more than 500mA MaxPower

[Sasha Levin]

From: Jack Pham <jackp@codeaurora.org>

[ Upstream commit a2035411fa1d1206cea7d5dfe833e78481844a76 ]

USB 3.x SuperSpeed peripherals can draw up to 900mA of VBUS power
when in configured state. However, if a configuration wanting to
take advantage of this is added with MaxPower greater than 500
(currently possible if using a ConfigFS gadget) the composite
driver fails to accommodate this for a couple reasons:

 - usb_gadget_vbus_draw() when called from set_config() and
   composite_resume() will be passed the MaxPower value without
   regard for the current connection speed, resulting in a
   violation for USB 2.0 since the max is 500mA.

 - the bMaxPower of the configuration descriptor would be
   incorrectly encoded, again if the connection speed is only
   at USB 2.0 or below, likely wrapping around U8_MAX since
   the 2mA multiplier corresponds to a maximum of 510mA.

Fix these by adding checks against the current gadget->speed
when the c->MaxPower value is used (set_config() and
composite_resume()) and appropriately limit based on whether
it is currently at a low-/full-/high- or super-speed connection.

Because 900 is not divisible by 8, with the round-up division
currently used in encode_bMaxPower() a MaxPower of 900mA will
result in an encoded value of 0x71. When a host stack (including
Linux and Windows) enumerates this on a single port root hub, it
reads this value back and decodes (multiplies by 8) to get 904mA
which is strictly greater than 900mA that is typically budgeted
for that port, causing it to reject the configuration. Instead,
we should be using the round-down behavior of normal integral
division so that 900 / 8 -> 0x70 or 896mA to stay within range.
And we might as well change it for the high/full/low case as well
for consistency.

N.B. USB 3.2 Gen N x 2 allows for up to 1500mA but there doesn't
seem to be any any peripheral controller supported by Linux that
does two lane operation, so for now keeping the clamp at 900
should be fine.

Signed-off-by: Jack Pham <jackp@codeaurora.org>
Signed-off-by: Felipe Balbi <balbi@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/usb/gadget/composite.c | 24 ++++++++++++++++++------
 1 file changed, 18 insertions(+), 6 deletions(-)

diff --git a/drivers/usb/gadget/composite.c b/drivers/usb/gadget/composite.c
index 4d7df2f6caf5b..3a0452ff1a565 100644
--- a/drivers/usb/gadget/composite.c
+++ b/drivers/usb/gadget/composite.c
@@ -438,9 +438,13 @@ static u8 encode_bMaxPower(enum usb_device_speed speed,
 	if (!val)
 		return 0;
 	if (speed < USB_SPEED_SUPER)
-		return DIV_ROUND_UP(val, 2);
+		return min(val, 500U) / 2;
 	else
-		return DIV_ROUND_UP(val, 8);
+		/*
+		 * USB 3.x supports up to 900mA, but since 900 isn't divisible
+		 * by 8 the integral division will effectively cap to 896mA.
+		 */
+		return min(val, 900U) / 8;
 }
 
 static int config_buf(struct usb_configuration *config,
@@ -833,6 +837,10 @@ static int set_config(struct usb_composite_dev *cdev,
 
 	/* when we return, be sure our power usage is valid */
 	power = c->MaxPower ? c->MaxPower : CONFIG_USB_GADGET_VBUS_DRAW;
+	if (gadget->speed < USB_SPEED_SUPER)
+		power = min(power, 500U);
+	else
+		power = min(power, 900U);
 done:
 	usb_gadget_vbus_draw(gadget, power);
 	if (result >= 0 && cdev->delayed_status)
@@ -2272,7 +2280,7 @@ void composite_resume(struct usb_gadget *gadget)
 {
 	struct usb_composite_dev	*cdev = get_gadget_data(gadget);
 	struct usb_function		*f;
-	u16				maxpower;
+	unsigned			maxpower;
 
 	/* REVISIT:  should we have config level
 	 * suspend/resume callbacks?
@@ -2286,10 +2294,14 @@ void composite_resume(struct usb_gadget *gadget)
 				f->resume(f);
 		}
 
-		maxpower = cdev->config->MaxPower;
+		maxpower = cdev->config->MaxPower ?
+			cdev->config->MaxPower : CONFIG_USB_GADGET_VBUS_DRAW;
+		if (gadget->speed < USB_SPEED_SUPER)
+			maxpower = min(maxpower, 500U);
+		else
+			maxpower = min(maxpower, 900U);
 
-		usb_gadget_vbus_draw(gadget, maxpower ?
-			maxpower : CONFIG_USB_GADGET_VBUS_DRAW);
+		usb_gadget_vbus_draw(gadget, maxpower);
 	}
 
 	cdev->suspended = 0;
-- 
2.20.1

[PATCH AUTOSEL 4.9 03/13] usb: gadget: ffs: ffs_aio_cancel(): Save/restore IRQ flags

[Sasha Levin]

From: Lars-Peter Clausen <lars@metafoo.de>

[ Upstream commit 43d565727a3a6fd24e37c7c2116475106af71806 ]

ffs_aio_cancel() can be called from both interrupt and thread context. Make
sure that the current IRQ state is saved and restored by using
spin_{un,}lock_irq{save,restore}().

Otherwise undefined behavior might occur.

Acked-by: Michal Nazarewicz <mina86@mina86.com>
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Alexandru Ardelean <alexandru.ardelean@analog.com>
Signed-off-by: Felipe Balbi <balbi@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/usb/gadget/function/f_fs.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/drivers/usb/gadget/function/f_fs.c b/drivers/usb/gadget/function/f_fs.c
index d1278d2d544b4..b5747f1270a6d 100644
--- a/drivers/usb/gadget/function/f_fs.c
+++ b/drivers/usb/gadget/function/f_fs.c
@@ -1077,18 +1077,19 @@ static int ffs_aio_cancel(struct kiocb *kiocb)
 {
 	struct ffs_io_data *io_data = kiocb->private;
 	struct ffs_epfile *epfile = kiocb->ki_filp->private_data;
+	unsigned long flags;
 	int value;
 
 	ENTER();
 
-	spin_lock_irq(&epfile->ffs->eps_lock);
+	spin_lock_irqsave(&epfile->ffs->eps_lock, flags);
 
 	if (likely(io_data && io_data->ep && io_data->req))
 		value = usb_ep_dequeue(io_data->ep, io_data->req);
 	else
 		value = -EINVAL;
 
-	spin_unlock_irq(&epfile->ffs->eps_lock);
+	spin_unlock_irqrestore(&epfile->ffs->eps_lock, flags);
 
 	return value;
 }
-- 
2.20.1

[PATCH AUTOSEL 4.9 04/13] usb: gadget: serial: fix Tx stall after buffer overflow

[Sasha Levin]

From: Sergey Organov <sorganov@gmail.com>

[ Upstream commit e4bfded56cf39b8d02733c1e6ef546b97961e18a ]

Symptom: application opens /dev/ttyGS0 and starts sending (writing) to
it while either USB cable is not connected, or nobody listens on the
other side of the cable. If driver circular buffer overflows before
connection is established, no data will be written to the USB layer
until/unless /dev/ttyGS0 is closed and re-opened again by the
application (the latter besides having no means of being notified about
the event of establishing of the connection.)

Fix: on open and/or connect, kick Tx to flush circular buffer data to
USB layer.

Signed-off-by: Sergey Organov <sorganov@gmail.com>
Reviewed-by: Michał Mirosław <mirq-linux@rere.qmqm.pl>
Signed-off-by: Felipe Balbi <balbi@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/usb/gadget/function/u_serial.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/usb/gadget/function/u_serial.c b/drivers/usb/gadget/function/u_serial.c
index 510a54f889635..5d7d0f2e80a5e 100644
--- a/drivers/usb/gadget/function/u_serial.c
+++ b/drivers/usb/gadget/function/u_serial.c
@@ -715,8 +715,10 @@ static int gs_start_io(struct gs_port *port)
 	port->n_read = 0;
 	started = gs_start_rx(port);
 
-	/* unblock any pending writes into our circular buffer */
 	if (started) {
+		gs_start_tx(port);
+		/* Unblock any pending writes into our circular buffer, in case
+		 * we didn't in gs_start_tx() */
 		tty_wakeup(port->port.tty);
 	} else {
 		gs_free_requests(ep, head, &port->read_allocated);
-- 
2.20.1