Hi,

On 09/22/2016 05:33 AM, Bin Liu wrote:
Hi,

On Sun, Sep 18, 2016 at 06:50:18PM +0200, Hans de Goede 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_SESSION and sets MUSB_DEVCTL_BDEVICE) and
gets stuck in this state.

Clearing this requires reporting Vbus low for 200 or more ms, but
on some devices Vbus is simply always high (host-only mode, no Vbus
control).

This commit calls sun4i_usb_phy_force_session_end() on babble errors
in host-mode, fixing the musb controller being stuck in this state
on systems without Vbus control; and also fixes the need to unplug
the usb-b -> usb-a cable to get out of this state on systems with
Vbus control.

Signed-off-by: Hans de Goede <hdego...@redhat.com>
---
 drivers/usb/musb/sunxi.c | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/drivers/usb/musb/sunxi.c b/drivers/usb/musb/sunxi.c
index 1408245..5079d90 100644
--- a/drivers/usb/musb/sunxi.c
+++ b/drivers/usb/musb/sunxi.c
@@ -192,8 +192,18 @@ static irqreturn_t sunxi_musb_interrupt(int irq, void 
*__hci)
         * normally babble never happens treat it as disconnect.
         */
        if ((musb->int_usb & MUSB_INTR_BABBLE) && is_host_active(musb)) {

musb_interrupt() handle BABBLE in host mode, and has a glue hook
musb_platform_recover() in musb_recover_from_babble().

Maybe you can use it?

Ah yes, I looked at this at the past, but that was before the babble
recover rework by Felipe Balbi which got commited on 2015-03-10.

With this rework the sunxi code should indeed be able to use the core
recovery, and we can use the musb_platform_recover() to force a
session end.

And thinking more about you're other remark, I do think I can
actually modify the sun4i phy_set_mode callback so that it can
be used for this.

I'll post a v2 with these changes soon-ish.

Regards,

Hans


+               struct sunxi_glue *glue =
+                               dev_get_drvdata(musb->controller->parent);
+
+               dev_warn(musb->controller->parent, "babble, treating as 
disconnect\n");
+
                musb->int_usb &= ~MUSB_INTR_BABBLE;
                musb->int_usb |= MUSB_INTR_DISCONNECT;
+               /*
+                * Fix the musb controller sometimes getting stuck in
+                * bdevice state after a babble error.
+                */
+               sun4i_usb_phy_force_session_end(glue->phy);

As I commented in PATCH 1/2, can you somehow reuse
sun4i_usb_phy_set_mode() instead?

        }

        if ((musb->int_usb & MUSB_INTR_RESET) && !is_host_active(musb)) {
--
2.9.3

Regards,
-Bin.

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