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usb: musb: fix setting JZ4740 gadget periphal mode on reset

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JZ4740 USB Device Controller is not OTG compatible and does not have
DEVCTL register in silicon.

During ethernet-over-usb transactions, on reset, musb driver tries to
read from DEVCTL and consequently sets device as host (A-Device)
instead of peripheral (B-Device), which makes it a composite device to
the USB gadget driver.
This induces a kernel panic during power down where the USB gadget
driver does a null pointer dereference when trying to access the
composite device configuration.

On reset, do not rely on DEVCTL value for setting gadget peripheral
mode. Use is_otg flag instead to set it to B-Device.

Signed-off-by: Apelete Seketeli <apelete@seketeli.net>
Signed-off-by: Felipe Balbi <balbi@ti.com>
This commit is contained in:
Apelete Seketeli 2013-12-19 21:42:27 +01:00 committed by Felipe Balbi
parent 10434d273c
commit 23db9fd238
1 changed files with 9 additions and 1 deletions
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10
drivers/usb/musb/musb_gadget.c
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@ -2119,7 +2119,15 @@ __acquires(musb->lock)
/* Normal reset, as B-Device;
* or else after HNP, as A-Device
*/
if (devctl & MUSB_DEVCTL_BDEVICE) {
if (!musb->g.is_otg) {
/* USB device controllers that are not OTG compatible
* may not have DEVCTL register in silicon.
* In that case, do not rely on devctl for setting
* peripheral mode.
*/
musb->xceiv->state = OTG_STATE_B_PERIPHERAL;
musb->g.is_a_peripheral = 0;
} else if (devctl & MUSB_DEVCTL_BDEVICE) {
musb->xceiv->state = OTG_STATE_B_PERIPHERAL;
musb->g.is_a_peripheral = 0;
} else {