diff mbox

usb: musb: Check for host-mode using is_host_active() on reset interrupt

Message ID 20170927103522.30202-1-net147@gmail.com (mailing list archive)
State New, archived
Headers show

Commit Message

Jonathan Liu Sept. 27, 2017, 10:35 a.m. UTC
The sunxi musb has a bug where sometimes it will generate a babble
error on device disconnect instead of a disconnect IRQ. When this
happens the musb controller switches from host mode to device mode
(it clears MUSB_DEVCTL_HM/MUSB_DEVCTL_SESSION and sets
MUSB_DEVCTL_BDEVICE) and gets stuck in this state.

The babble error is misdetected as a bus reset because MUSB_DEVCTL_HM
was cleared.

To fix this, use is_host_active() rather than (devctl & MUSB_DEVCTL_HM)
to detect babble error so that sunxi musb babble recovery can handle it
by restoring the mode. This information is provided by the driver logic
and does not rely on register contents.

Cc: stable@vger.kernel.org # v4.1+
Signed-off-by: Jonathan Liu <net147@gmail.com>
---
 drivers/usb/musb/musb_core.c | 6 ++----
 1 file changed, 2 insertions(+), 4 deletions(-)

Comments

Bin Liu Oct. 9, 2017, 4:03 p.m. UTC | #1
Hi,

On Wed, Sep 27, 2017 at 08:35:22PM +1000, Jonathan Liu wrote:
> The sunxi musb has a bug where sometimes it will generate a babble
> error on device disconnect instead of a disconnect IRQ. When this
> happens the musb controller switches from host mode to device mode
> (it clears MUSB_DEVCTL_HM/MUSB_DEVCTL_SESSION and sets
> MUSB_DEVCTL_BDEVICE) and gets stuck in this state.
> 
> The babble error is misdetected as a bus reset because MUSB_DEVCTL_HM
> was cleared.
> 
> To fix this, use is_host_active() rather than (devctl & MUSB_DEVCTL_HM)
> to detect babble error so that sunxi musb babble recovery can handle it
> by restoring the mode. This information is provided by the driver logic
> and does not rely on register contents.
> 
> Cc: stable@vger.kernel.org # v4.1+
> Signed-off-by: Jonathan Liu <net147@gmail.com>

Applied. Thanks.
-Bin.
diff mbox

Patch

diff --git a/drivers/usb/musb/musb_core.c b/drivers/usb/musb/musb_core.c
index 029692053dd3..1bce7df3e110 100644
--- a/drivers/usb/musb/musb_core.c
+++ b/drivers/usb/musb/musb_core.c
@@ -906,7 +906,7 @@  static irqreturn_t musb_stage0_irq(struct musb *musb, u8 int_usb,
 	 */
 	if (int_usb & MUSB_INTR_RESET) {
 		handled = IRQ_HANDLED;
-		if (devctl & MUSB_DEVCTL_HM) {
+		if (is_host_active(musb)) {
 			/*
 			 * When BABBLE happens what we can depends on which
 			 * platform MUSB is running, because some platforms
@@ -916,9 +916,7 @@  static irqreturn_t musb_stage0_irq(struct musb *musb, u8 int_usb,
 			 * drop the session.
 			 */
 			dev_err(musb->controller, "Babble\n");
-
-			if (is_host_active(musb))
-				musb_recover_from_babble(musb);
+			musb_recover_from_babble(musb);
 		} else {
 			musb_dbg(musb, "BUS RESET as %s",
 				usb_otg_state_string(musb->xceiv->otg->state));