[PATCH v3 3/3] musb: sunxi: Force session end on babble errors in host-mode

[Bin Liu]

On Fri, Sep 23, 2016 at 04:40:58PM +0300, 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 adds a sunxi_musb_recover() callback which makes
> sunxi_musb_work call phy_set_mode with the current mode, which
> will force end the current session.
> 
> This fixes the musb controller getting 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 <hdegoede at redhat.com>

Applied. Thanks.
-Bin.

> ---
> Changes in v2:
> -Use musb_platform_recover callback instead of using DYI code in the
>  interrupt handler
> -Call phy_set_mode with the current mode instead of adding a new custom
>  sunxi phy callback
> ---
>  drivers/usb/musb/sunxi.c | 15 +++++++++++++++
>  1 file changed, 15 insertions(+)
> 
> diff --git a/drivers/usb/musb/sunxi.c b/drivers/usb/musb/sunxi.c
> index 82eba92..d0be0ea 100644
> --- a/drivers/usb/musb/sunxi.c
> +++ b/drivers/usb/musb/sunxi.c
> @@ -380,6 +380,20 @@ static int sunxi_musb_set_mode(struct musb *musb, u8 mode)
>  	return 0;
>  }
>  
> +static int sunxi_musb_recover(struct musb *musb)
> +{
> +	struct sunxi_glue *glue = dev_get_drvdata(musb->controller->parent);
> +
> +	/*
> +	 * Schedule a phy_set_mode with the current glue->phy_mode value,
> +	 * this will force end the current session.
> +	 */
> +	set_bit(SUNXI_MUSB_FL_PHY_MODE_PEND, &glue->flags);
> +	schedule_work(&glue->work);
> +
> +	return 0;
> +}
> +
>  /*
>   * sunxi musb register layout
>   * 0x00 - 0x17	fifo regs, 1 long per fifo
> @@ -608,6 +622,7 @@ static const struct musb_platform_ops sunxi_musb_ops = {
>  	.dma_init	= sunxi_musb_dma_controller_create,
>  	.dma_exit	= sunxi_musb_dma_controller_destroy,
>  	.set_mode	= sunxi_musb_set_mode,
> +	.recover	= sunxi_musb_recover,
>  	.set_vbus	= sunxi_musb_set_vbus,
>  	.pre_root_reset_end = sunxi_musb_pre_root_reset_end,
>  	.post_root_reset_end = sunxi_musb_post_root_reset_end,
> -- 
> 2.9.3
>