subdevice config into pointer (was Re: [PATCH 1/4] v4l2: device_register_subdev_nodes: allow calling multiple times)

  Hi!

> Making the sub-device bus configuration a pointer should be in a separate
> patch. It makes sense since the entire configuration is not valid for all
> sub-devices attached to the ISP anymore. I think it originally was a
> separate patch, but they probably have been merged at some point. I can't
> find it right now anyway.

Something like this?
									Pavel

commit df9141c66678b549fac9d143bd55ed0b242cf36e
Author: Pavel <pavel@ucw.cz>
Date:   Wed Mar 1 13:27:56 2017 +0100

    Turn bus in struct isp_async_subdev into pointer; some of our subdevs
    (flash, focus) will not need bus configuration.

Signed-off-by: Pavel Machek <pavel@ucw.cz>
  

Hi Pavel,

On Thu, Mar 02, 2017 at 10:07:27AM +0100, Pavel Machek wrote:
> Hi!
> 
> > Making the sub-device bus configuration a pointer should be in a separate
> > patch. It makes sense since the entire configuration is not valid for all
> > sub-devices attached to the ISP anymore. I think it originally was a
> > separate patch, but they probably have been merged at some point. I can't
> > find it right now anyway.
> 
> Something like this?
> 									Pavel
> 
> commit df9141c66678b549fac9d143bd55ed0b242cf36e
> Author: Pavel <pavel@ucw.cz>
> Date:   Wed Mar 1 13:27:56 2017 +0100
> 
>     Turn bus in struct isp_async_subdev into pointer; some of our subdevs
>     (flash, focus) will not need bus configuration.
> 
> Signed-off-by: Pavel Machek <pavel@ucw.cz>

I applied this to the ccp2 branch with an improved patch description.

> 
> diff --git a/drivers/media/platform/omap3isp/isp.c b/drivers/media/platform/omap3isp/isp.c
> index 8a456d4..36bd359 100644
> --- a/drivers/media/platform/omap3isp/isp.c
> +++ b/drivers/media/platform/omap3isp/isp.c
> @@ -2030,12 +2030,18 @@ enum isp_of_phy {
>  static int isp_fwnode_parse(struct device *dev, struct fwnode_handle *fwn,
>  			    struct isp_async_subdev *isd)
>  {
> -	struct isp_bus_cfg *buscfg = &isd->bus;
> +	struct isp_bus_cfg *buscfg;
>  	struct v4l2_fwnode_endpoint vfwn;
>  	unsigned int i;
>  	int ret;
>  	bool csi1 = false;
>  
> +	buscfg = devm_kzalloc(dev, sizeof(*isd->bus), GFP_KERNEL);
> +	if (!buscfg)
> +		return -ENOMEM;
> +
> +	isd->bus = buscfg;
> +
>  	ret = v4l2_fwnode_endpoint_parse(fwn, &vfwn);
>  	if (ret)
>  		return ret;
> @@ -2246,7 +2252,7 @@ static int isp_subdev_notifier_bound(struct v4l2_async_notifier *async,
>  		container_of(asd, struct isp_async_subdev, asd);
>  
>  	isd->sd = subdev;
> -	isd->sd->host_priv = &isd->bus;
> +	isd->sd->host_priv = isd->bus;
>  
>  	return 0;
>  }
> diff --git a/drivers/media/platform/omap3isp/isp.h b/drivers/media/platform/omap3isp/isp.h
> index 7e6f663..c0b9d1d 100644
> --- a/drivers/media/platform/omap3isp/isp.h
> +++ b/drivers/media/platform/omap3isp/isp.h
> @@ -228,7 +228,7 @@ struct isp_device {
>  
>  struct isp_async_subdev {
>  	struct v4l2_subdev *sd;
> -	struct isp_bus_cfg bus;
> +	struct isp_bus_cfg *bus;
>  	struct v4l2_async_subdev asd;
>  };
>  
> diff --git a/drivers/media/platform/omap3isp/ispcsiphy.c b/drivers/media/platform/omap3isp/ispcsiphy.c
> index f20abe8..be23408 100644
> --- a/drivers/media/platform/omap3isp/ispcsiphy.c
> +++ b/drivers/media/platform/omap3isp/ispcsiphy.c
> @@ -202,7 +202,7 @@ static int omap3isp_csiphy_config(struct isp_csiphy *phy)
>  		struct isp_async_subdev *isd =
>  			container_of(pipe->external->asd,
>  				     struct isp_async_subdev, asd);
> -		buscfg = &isd->bus;
> +		buscfg = isd->bus;
>  	}
>  
>  	if (buscfg->interface == ISP_INTERFACE_CCP2B_PHY1
> 
>
  

Hi!

> > > Making the sub-device bus configuration a pointer should be in a separate
> > > patch. It makes sense since the entire configuration is not valid for all
> > > sub-devices attached to the ISP anymore. I think it originally was a
> > > separate patch, but they probably have been merged at some point. I can't
> > > find it right now anyway.
> > 
> > Something like this?
> > 
> > commit df9141c66678b549fac9d143bd55ed0b242cf36e
> > Author: Pavel <pavel@ucw.cz>
> > Date:   Wed Mar 1 13:27:56 2017 +0100
> > 
> >     Turn bus in struct isp_async_subdev into pointer; some of our subdevs
> >     (flash, focus) will not need bus configuration.
> > 
> > Signed-off-by: Pavel Machek <pavel@ucw.cz>
> 
> I applied this to the ccp2 branch with an improved patch
> description.

Thanks!

[But the important part is to get subdevices to work on ccp2 based
branch, and it still fails to work at all if I attempt to enable
them. I'd like to understand why...]

									Pavel
  

Hi Pavel,

On Thu, Mar 02, 2017 at 03:58:08PM +0100, Pavel Machek wrote:
> Hi!
> 
> > > > Making the sub-device bus configuration a pointer should be in a separate
> > > > patch. It makes sense since the entire configuration is not valid for all
> > > > sub-devices attached to the ISP anymore. I think it originally was a
> > > > separate patch, but they probably have been merged at some point. I can't
> > > > find it right now anyway.
> > > 
> > > Something like this?
> > > 
> > > commit df9141c66678b549fac9d143bd55ed0b242cf36e
> > > Author: Pavel <pavel@ucw.cz>
> > > Date:   Wed Mar 1 13:27:56 2017 +0100
> > > 
> > >     Turn bus in struct isp_async_subdev into pointer; some of our subdevs
> > >     (flash, focus) will not need bus configuration.
> > > 
> > > Signed-off-by: Pavel Machek <pavel@ucw.cz>
> > 
> > I applied this to the ccp2 branch with an improved patch
> > description.
> 
> Thanks!
> 
> [But the important part is to get subdevices to work on ccp2 based
> branch, and it still fails to work at all if I attempt to enable
> them. I'd like to understand why...]

Did you add the flash / lens to the async list? The patches currently in the
ccp branch do not include that --- it should be in parsing the flash /
lens-focus properties in omap3isp device's node.
  

Hi Sakari,

On Thursday 02 Mar 2017 16:16:17 Sakari Ailus wrote:
> On Thu, Mar 02, 2017 at 10:07:27AM +0100, Pavel Machek wrote:
> > Hi!
> > 
> > > Making the sub-device bus configuration a pointer should be in a
> > > separate patch. It makes sense since the entire configuration is not
> > > valid for all sub-devices attached to the ISP anymore. I think it
> > > originally was a separate patch, but they probably have been merged at
> > > some point. I can'tfind it right now anyway.
> > 
> > Something like this?
> > 
> > 									Pavel
> > 
> > commit df9141c66678b549fac9d143bd55ed0b242cf36e
> > Author: Pavel <pavel@ucw.cz>
> > Date:   Wed Mar 1 13:27:56 2017 +0100
> > 
> >     Turn bus in struct isp_async_subdev into pointer; some of our subdevs
> >     (flash, focus) will not need bus configuration.
> > 
> > Signed-off-by: Pavel Machek <pavel@ucw.cz>
> 
> I applied this to the ccp2 branch with an improved patch description.
> 
> > diff --git a/drivers/media/platform/omap3isp/isp.c
> > b/drivers/media/platform/omap3isp/isp.c index 8a456d4..36bd359 100644
> > --- a/drivers/media/platform/omap3isp/isp.c
> > +++ b/drivers/media/platform/omap3isp/isp.c
> > @@ -2030,12 +2030,18 @@ enum isp_of_phy {
> > 
> >  static int isp_fwnode_parse(struct device *dev, struct fwnode_handle
> >  *fwn,
> >  
> >  			    struct isp_async_subdev *isd)
> >  
> >  {
> > 
> > -	struct isp_bus_cfg *buscfg = &isd->bus;
> > +	struct isp_bus_cfg *buscfg;
> > 
> >  	struct v4l2_fwnode_endpoint vfwn;
> >  	unsigned int i;
> >  	int ret;
> >  	bool csi1 = false;
> > 
> > +	buscfg = devm_kzalloc(dev, sizeof(*isd->bus), GFP_KERNEL);

Given that you recently get rid of devm_kzalloc() in the driver, let's not 
introduce a new one here.

> > +	if (!buscfg)
> > +		return -ENOMEM;
> > +
> > +	isd->bus = buscfg;
> > +
> >  	ret = v4l2_fwnode_endpoint_parse(fwn, &vfwn);
> >  	if (ret)
> >  	
> >  		return ret;
> > 

[snip]
  

Hi!

> > >  static int isp_fwnode_parse(struct device *dev, struct fwnode_handle
> > >  *fwn,
> > >  
> > >  			    struct isp_async_subdev *isd)
> > >  
> > >  {
> > > 
> > > -	struct isp_bus_cfg *buscfg = &isd->bus;
> > > +	struct isp_bus_cfg *buscfg;
> > > 
> > >  	struct v4l2_fwnode_endpoint vfwn;
> > >  	unsigned int i;
> > >  	int ret;
> > >  	bool csi1 = false;
> > > 
> > > +	buscfg = devm_kzalloc(dev, sizeof(*isd->bus), GFP_KERNEL);
> 
> Given that you recently get rid of devm_kzalloc() in the driver, let's not 
> introduce a new one here.

What is wrong with devm_kzalloc()?
									Pavel
  

Hi Laurent,

On Thu, Mar 02, 2017 at 08:39:51PM +0200, Laurent Pinchart wrote:
> Hi Sakari,
> 
> On Thursday 02 Mar 2017 16:16:17 Sakari Ailus wrote:
> > On Thu, Mar 02, 2017 at 10:07:27AM +0100, Pavel Machek wrote:
> > > Hi!
> > > 
> > > > Making the sub-device bus configuration a pointer should be in a
> > > > separate patch. It makes sense since the entire configuration is not
> > > > valid for all sub-devices attached to the ISP anymore. I think it
> > > > originally was a separate patch, but they probably have been merged at
> > > > some point. I can'tfind it right now anyway.
> > > 
> > > Something like this?
> > > 
> > > 									Pavel
> > > 
> > > commit df9141c66678b549fac9d143bd55ed0b242cf36e
> > > Author: Pavel <pavel@ucw.cz>
> > > Date:   Wed Mar 1 13:27:56 2017 +0100
> > > 
> > >     Turn bus in struct isp_async_subdev into pointer; some of our subdevs
> > >     (flash, focus) will not need bus configuration.
> > > 
> > > Signed-off-by: Pavel Machek <pavel@ucw.cz>
> > 
> > I applied this to the ccp2 branch with an improved patch description.
> > 
> > > diff --git a/drivers/media/platform/omap3isp/isp.c
> > > b/drivers/media/platform/omap3isp/isp.c index 8a456d4..36bd359 100644
> > > --- a/drivers/media/platform/omap3isp/isp.c
> > > +++ b/drivers/media/platform/omap3isp/isp.c
> > > @@ -2030,12 +2030,18 @@ enum isp_of_phy {
> > > 
> > >  static int isp_fwnode_parse(struct device *dev, struct fwnode_handle
> > >  *fwn,
> > >  
> > >  			    struct isp_async_subdev *isd)
> > >  
> > >  {
> > > 
> > > -	struct isp_bus_cfg *buscfg = &isd->bus;
> > > +	struct isp_bus_cfg *buscfg;
> > > 
> > >  	struct v4l2_fwnode_endpoint vfwn;
> > >  	unsigned int i;
> > >  	int ret;
> > >  	bool csi1 = false;
> > > 
> > > +	buscfg = devm_kzalloc(dev, sizeof(*isd->bus), GFP_KERNEL);
> 
> Given that you recently get rid of devm_kzalloc() in the driver, let's not 
> introduce a new one here.

That's certainly a valid point.

Still, the entire async sub-devices array is allocated with devm_()
allocation functions still; that part wasn't addressed by the patchset
mostly removing devm_() memory allocation, so this patch does actually not
change how the memory is allocated.

Beyond that, I'm not entirely sure whether this is a problem to begin with:
devm resources are released after remove() callback and access to this data
structure should only happen as a direct result of user IOCTL. IOCTLs may
only be in progress as long as there are open file handles on a device ---
and such file handles must be closed until the remove() callback may finish.
(Referring to the Oslo meeting notes.)

Some of the above must be still verified; either way, but the options are
clear: either devm must be removed here as well (with the rest) or that it's
fine to use it here: from this point of view this patch makes no difference.

> 
> > > +	if (!buscfg)
> > > +		return -ENOMEM;
> > > +
> > > +	isd->bus = buscfg;
> > > +
> > >  	ret = v4l2_fwnode_endpoint_parse(fwn, &vfwn);
> > >  	if (ret)
> > >  	
> > >  		return ret;
> > > 
> 
> [snip]
>