[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...@renesas.com>

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...@renesas.com>
Signed-off-by: Felipe Balbi <felipe.ba...@linux.intel.com>
Signed-off-by: Ben Hutchings <b...@decadent.org.uk>
---
 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;
 }