Re: [PATCH 1/2] bus: mhi: core: Fix parsing of mhi_flags

[Manivannan Sadhasivam]

On Thu, Apr 16, 2020 at 12:01:30PM -0700, Hemant Kumar wrote:
> Hi Mani,
> 
> On 4/13/20 5:07 AM, Manivannan Sadhasivam wrote:
> > With the current parsing of mhi_flags, the following statement always
> > return false:
> > 
> > eob = !!(flags & MHI_EOB);
> > 
> > This is due to the fact that 'enum mhi_flags' starts with index 0 and we
> > are using direct AND operation to extract each bit. Fix this by using
> > BIT() macro to extract each bit and make the mhi_flags index start from 1.
> > 
> > Fixes: 189ff97cca53 ("bus: mhi: core: Add support for data transfer")
> > Reported-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx>
> > Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@xxxxxxxxxx>
> > ---
> >   drivers/bus/mhi/core/main.c | 6 +++---
> >   include/linux/mhi.h         | 2 +-
> >   2 files changed, 4 insertions(+), 4 deletions(-)
> > 
> > diff --git a/drivers/bus/mhi/core/main.c b/drivers/bus/mhi/core/main.c
> > index eb4256b81406..4165a853c189 100644
> > --- a/drivers/bus/mhi/core/main.c
> > +++ b/drivers/bus/mhi/core/main.c
> > @@ -1090,9 +1090,9 @@ int mhi_gen_tre(struct mhi_controller *mhi_cntrl, struct mhi_chan *mhi_chan,
> >   	if (ret)
> >   		return ret;
> > -	eob = !!(flags & MHI_EOB);
> > -	eot = !!(flags & MHI_EOT);
> > -	chain = !!(flags & MHI_CHAIN);
> > +	eob = !!(flags & BIT(0));
> > +	eot = !!(flags & BIT(1));
> > +	chain = !!(flags & BIT(2));
> 
> How about setting enums  with BIT macro and still use same enums above. If
> flags is having MHI _CHAIN (enum value 3) but comparing with BIT(2) (value
> 4) will not work.
> 

Doh, you are right. Will fix it!

Thanks,
Mani

> >   	bei = !!(mhi_chan->intmod);
> >   	mhi_tre = tre_ring->wp;
> > diff --git a/include/linux/mhi.h b/include/linux/mhi.h
> > index ad1996001965..22185fecbbf2 100644
> > --- a/include/linux/mhi.h
> > +++ b/include/linux/mhi.h
> > @@ -53,7 +53,7 @@ enum mhi_callback {
> >    * @MHI_CHAIN: Linked transfer
> >    */
> >   enum mhi_flags {
> > -	MHI_EOB,
> > +	MHI_EOB = 1,
> >   	MHI_EOT,
> >   	MHI_CHAIN,
> >   };
> 
> enum mhi_flags {
> 
>     MHI_EOB = BIT(0),
> 
>     MHI_EOT = BIT(1),
> 
>     MHI_CHAIN = BIT(2),
> 
> }
> 
> -- 
> The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
> a Linux Foundation Collaborative Project