RE: [PATCH 3/6] mei: vsc: Enhance SPI transfer of IVSC rom

[Wu, Wentong]

> From: Sakari Ailus <sakari.ailus@xxxxxxxxxxxxxxx>
> 
> Hi Wentong,
> 
> On Sun, Jun 23, 2024 at 05:30:53PM +0800, Wentong Wu wrote:
> > Constructing the SPI transfer command as per the specific request.
> >
> > Fixes: 566f5ca97680 ("mei: Add transport driver for IVSC device")
> > Cc: stable@xxxxxxxxxxxxxxx # for 6.8+
> > Signed-off-by: Wentong Wu <wentong.wu@xxxxxxxxx>
> > Tested-by: Jason Chen <jason.z.chen@xxxxxxxxx>
> > ---
> >  drivers/misc/mei/vsc-tp.c | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/drivers/misc/mei/vsc-tp.c b/drivers/misc/mei/vsc-tp.c
> > index 4595b1a25536..7a89e4e5d553 100644
> > --- a/drivers/misc/mei/vsc-tp.c
> > +++ b/drivers/misc/mei/vsc-tp.c
> > @@ -331,7 +331,7 @@ int vsc_tp_rom_xfer(struct vsc_tp *tp, const void
> *obuf, void *ibuf, size_t len)
> >  		return ret;
> >  	}
> >
> > -	ret = vsc_tp_dev_xfer(tp, tp->tx_buf, tp->rx_buf, len);
> > +	ret = vsc_tp_dev_xfer(tp, tp->tx_buf, ibuf ? tp->rx_buf : ibuf,
> > +len);
> 
> Is this correct? I.e. use ibuf when it's NULL, otherwise use tp->rx_buf?

Yes, the SPI framework will adjust this. If ibuf is NULL, but we give tp->rx_buf,
the actual transfer will tx more data than needed.

BR,
Wentong
> 
> >  	if (ret)
> >  		return ret;
> >
> 
> --
> Kind regards,
> 
> Sakari Ailus