linux-kernel - Re: [PATCH v1 2/3] usb: musb: core: added babble recovery func-ptr to musb->ops

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Date:	Wed, 26 Jun 2013 11:53:34 +0300
From:	Felipe Balbi <balbi@...com>
To:	"B, Ravi" <ravibabu@...com>
CC:	"Balbi, Felipe" <balbi@...com>,
	"linux-usb@...r.kernel.org" <linux-usb@...r.kernel.org>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v1 2/3] usb: musb: core: added babble recovery func-ptr
 to musb->ops

On Wed, Jun 26, 2013 at 10:37:39AM +0200, B, Ravi wrote:
> Felipe
> 
> > 
> > On Wed, May 29, 2013 at 06:37:03PM +0530, Ravi Babu wrote:
> > > Adding babble_recovery operation as part of musb->ops, used to recover
> > > from babble condition during babble interrupt.
> > >
> > > Signed-off-by: Ravi Babu <ravibabu@...com>
> > > ---
> > >  drivers/usb/musb/musb_core.c |    6 ++++++
> > >  drivers/usb/musb/musb_core.h |    7 +++++++
> > >  2 files changed, 13 insertions(+), 0 deletions(-)
> > >
> > > diff --git a/drivers/usb/musb/musb_core.c
> > > b/drivers/usb/musb/musb_core.c index ab6fa39..411c29d 100644
> > > --- a/drivers/usb/musb/musb_core.c
> > > +++ b/drivers/usb/musb/musb_core.c
> > > @@ -857,6 +857,12 @@ b_host:
> > >  		}
> > >  	}
> > >
> > > +	/* handle babble condition */
> > > +	if (int_usb & MUSB_INTR_BABBLE) {
> > > +		pr_info("babble: restarting the musb controller..");
> > > +		musb_babble_recovery(musb);
> > > +	}
> > > +
> > >  #if 0
> > >  /* REVISIT ... this would be for multiplexing periodic endpoints, or
> > >   * supporting transfer phasing to prevent exceeding ISO bandwidth
> > > diff --git a/drivers/usb/musb/musb_core.h
> > > b/drivers/usb/musb/musb_core.h index f96e899..bf37dc9 100644
> > > --- a/drivers/usb/musb/musb_core.h
> > > +++ b/drivers/usb/musb/musb_core.h
> > > @@ -213,6 +213,8 @@ struct musb_platform_ops {
> > >  	int	(*adjust_channel_params)(struct dma_channel *channel,
> > >  				u16 packet_sz, u8 *mode,
> > >  				dma_addr_t *dma_addr, u32 *len);
> > > +
> > > +	void	(*babble_recovery)(struct musb *musb);
> > 
> > I don't get why can't 'babble_recovery' be generic. Why do we need each glue
> > layer to implement it ?
> > 
> 
> Babble is generic, but recovery mechanism is nothing but "reset of
> usbss" which is SoC dependent and followed by generic restart of the
> musb controller. 

and that's what I don't get. Why do you need to reset usbss ?

-- 
balbi

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