[PATCH V2] staging: vchiq_2835_arm: Make cache-line-size a required DT property

[Stefan Wahren]

[add Eric]

> Michael Zoran <mzoran at crowfest.net> hat am 18. Februar 2017 um 12:59 geschrieben:
> 
> 
> On Sat, 2017-02-18 at 03:22 -0800, Michael Zoran wrote:
> > The original github source allowed for the cache-line-size property
> > to be missing.  Since recent firmwares also require this property,
> > it makes sense to always require it in the driver as well.
> > 
> > If the cache-line-size property is missing, then the driver probe
> > should fail as no dev since the kernel and dt may be out of sync.
> > The fix is to add a check for the return value of
> > of_property_read_u32.
> > 
> > Changes V2:
> > 	1. Add error message if cache-line-size is missing.
> > 	2. Simple check for non-zero return value from 
> > 	   of_property_read_u32.
> > 
> > Signed-off-by: Michael Zoran <mzoran at crowfest.net>
> > ---
> >  .../staging/vc04_services/interface/vchiq_arm/vchiq_2835_arm.c    |
> > 8 +++++++-
> >  1 file changed, 7 insertions(+), 1 deletion(-)
> > 
> > diff --git
> > a/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_2835_arm.c
> > b/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_2835_arm.c
> > index e6241fb5cfa6..3aeffcb9c87e 100644
> > ---
> > a/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_2835_arm.c
> > +++
> > b/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_2835_arm.c
> > @@ -121,8 +121,14 @@ int vchiq_platform_init(struct platform_device
> > *pdev, VCHIQ_STATE_T *state)
> >  	if (err < 0)
> >  		return err;
> >  
> > -	(void)of_property_read_u32(dev->of_node, "cache-line-size",
> > +	err = of_property_read_u32(dev->of_node, "cache-line-size",
> >  				   &g_cache_line_size);
> > +
> > +	if (err) {
> > +		dev_err(dev, "Missing cache-line-size property\n");
> > +		return -ENODEV;
> > +	}
> > +
> >  	g_fragments_size = 2 * g_cache_line_size;
> >  
> >  	/* Allocate space for the channels in coherent memory */
> 
> If anybody is willing to add an Reviewed-by, Acked, or even tested-by
> to this it would be great.  I know gregk is a busy guy so it might make
> sense to make a note that someone else looked at this and that I'm not
> out in left field.
> 
> It would be really great if this made it into 4.11.  I'm a bit
> concerned about someone accidently trying to mix this driver with an
> ancient DT. Things would probably sort of work if that was done, but it
> would result in difficult to debug errors.

I think Greg is waiting for Eric's Ack, but it seems you didn't send him a copy.

@Eric: Are you okay with this patch?