[PATCH 3.2 007/152] usb: renesas_usbhs: protect the CFIFOSEL setting in usbhsg_ep_enable()

[Ben Hutchings]

3.2.84-rc1 review patch.  If anyone has any objections, please let me know.

------------------

From: Yoshihiro Shimoda <yoshihiro.shimoda.uh@xxxxxxxxxxx>

commit 15e4292a2d21e9997fdb2b8c014cc461b3f268f0 upstream.

This patch fixes an issue that the CFIFOSEL register value is possible
to be changed by usbhsg_ep_enable() wrongly. And then, a data transfer
using CFIFO may not work correctly.

For example:
 # modprobe g_multi file=usb-storage.bin
 # ifconfig usb0 192.168.1.1 up
 (During the USB host is sending file to the mass storage)
 # ifconfig usb0 down

In this case, since the u_ether.c may call usb_ep_enable() in
eth_stop(), if the renesas_usbhs driver is also using CFIFO for
mass storage, the mass storage may not work correctly.

So, this patch adds usbhs_lock() and usbhs_unlock() calling in
usbhsg_ep_enable() to protect CFIFOSEL register. This is because:
 - CFIFOSEL.CURPIPE = 0 is also needed for the pipe configuration
 - The CFIFOSEL (fifo->sel) is already protected by usbhs_lock()

Fixes: 97664a207bc2 ("usb: renesas_usbhs: shrink spin lock area")
Signed-off-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@xxxxxxxxxxx>
Signed-off-by: Felipe Balbi <felipe.balbi@xxxxxxxxxxxxxxx>
Signed-off-by: Ben Hutchings <ben@xxxxxxxxxxxxxxx>
---
 drivers/usb/renesas_usbhs/mod_gadget.c | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

--- a/drivers/usb/renesas_usbhs/mod_gadget.c
+++ b/drivers/usb/renesas_usbhs/mod_gadget.c
@@ -472,6 +472,9 @@ static int usbhsg_ep_enable(struct usb_e
 	struct usbhs_priv *priv = usbhsg_gpriv_to_priv(gpriv);
 	struct usbhs_pipe *pipe;
 	int ret = -EIO;
+	unsigned long flags;
+
+	usbhs_lock(priv, flags);
 
 	/*
 	 * if it already have pipe,
@@ -480,7 +483,8 @@ static int usbhsg_ep_enable(struct usb_e
 	if (uep->pipe) {
 		usbhs_pipe_clear(uep->pipe);
 		usbhs_pipe_sequence_data0(uep->pipe);
-		return 0;
+		ret = 0;
+		goto usbhsg_ep_enable_end;
 	}
 
 	pipe = usbhs_pipe_malloc(priv,
@@ -508,6 +512,9 @@ static int usbhsg_ep_enable(struct usb_e
 		ret = 0;
 	}
 
+usbhsg_ep_enable_end:
+	usbhs_unlock(priv, flags);
+
 	return ret;
 }