Commit 6f4a36f0 authored Oct 09, 2017 by Jonathan Liu Committed by Greg Kroah-Hartman Oct 27, 2017

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



commit 445ef61543da3db5b699f87fb0aa4f227165f6ed upstream.

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.

Signed-off-by: Jonathan Liu <net147@gmail.com>
Signed-off-by: Bin Liu <b-liu@ti.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

parent b4ecc15d

drivers/usb/musb/musb_core.c

+2 −4

Original line number	Diff line number	Diff line
		@@ -890,7 +890,7 @@ 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
		@@ -900,8 +900,6 @@ 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);
		} else {
		musb_dbg(musb, "BUS RESET as %s",