Re: [PATCH v2 18/55] media: rkisp1: Fix sensor source pad retrieval at bound time

From: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
To: paul.elder@ideasonboard.com
Cc: linux-media@vger.kernel.org, linux-rockchip@lists.infradead.org,
	Dafna Hirschfeld <dafna@fastmail.com>,
	Heiko Stuebner <heiko@sntech.de>,
	Helen Koike <helen.koike@collabora.com>
Subject: Re: [PATCH v2 18/55] media: rkisp1: Fix sensor source pad retrieval at bound time
Date: Thu, 7 Jul 2022 17:47:51 +0300	[thread overview]
Message-ID: <YsbyFwtuhBChV+gn@pendragon.ideasonboard.com> (raw)
In-Reply-To: <20220707140123.GM3886060@pyrite.rasen.tech>

Hi Paul,

On Thu, Jul 07, 2022 at 11:01:23PM +0900, paul.elder@ideasonboard.com wrote:
> On Fri, Jul 01, 2022 at 02:06:36AM +0300, Laurent Pinchart wrote:
> > When a sensor is bound, its source pad is retrieved in the .bound()
> > operation with a call to media_entity_get_fwnode_pad(). The function
> > should be called with the source endpoint fwnode of the sensor, but is
> > instead called with the sensor's device fwnode.
> > 
> > Fix this, which involves storing a reference to the source endpoint
> > fwnode in the rkisp1_sensor_async structure, and thus implementing the
> > subdev notifier .destroy() operation to release the reference.
> > 
> > Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
> > ---
> >  .../platform/rockchip/rkisp1/rkisp1-common.h  |  2 ++
> >  .../platform/rockchip/rkisp1/rkisp1-dev.c     | 28 ++++++++++++++++---
> >  2 files changed, 26 insertions(+), 4 deletions(-)
> > 
> > diff --git a/drivers/media/platform/rockchip/rkisp1/rkisp1-common.h b/drivers/media/platform/rockchip/rkisp1/rkisp1-common.h
> > index b0896b508db3..f08b3dec1465 100644
> > --- a/drivers/media/platform/rockchip/rkisp1/rkisp1-common.h
> > +++ b/drivers/media/platform/rockchip/rkisp1/rkisp1-common.h
> > @@ -117,6 +117,7 @@ struct rkisp1_info {
> >   *
> >   * @asd:		async_subdev variable for the sensor
> >   * @index:		index of the sensor (counting sensor found in DT)
> > + * @source_ep:		fwnode for the sensor source endpoint
> >   * @lanes:		number of lanes
> >   * @mbus_type:		type of bus (currently only CSI2 is supported)
> >   * @mbus_flags:		media bus (V4L2_MBUS_*) flags
> > @@ -127,6 +128,7 @@ struct rkisp1_info {
> >  struct rkisp1_sensor_async {
> >  	struct v4l2_async_subdev asd;
> >  	unsigned int index;
> > +	struct fwnode_handle *source_ep;
> >  	unsigned int lanes;
> >  	enum v4l2_mbus_type mbus_type;
> >  	unsigned int mbus_flags;
> > diff --git a/drivers/media/platform/rockchip/rkisp1/rkisp1-dev.c b/drivers/media/platform/rockchip/rkisp1/rkisp1-dev.c
> > index 2e68f35e8ea5..813c013139ea 100644
> > --- a/drivers/media/platform/rockchip/rkisp1/rkisp1-dev.c
> > +++ b/drivers/media/platform/rockchip/rkisp1/rkisp1-dev.c
> > @@ -138,7 +138,7 @@ static int rkisp1_subdev_notifier_bound(struct v4l2_async_notifier *notifier,
> >  	phy_init(s_asd->dphy);
> >  
> >  	/* Create the link to the sensor. */
> > -	source_pad = media_entity_get_fwnode_pad(&sd->entity, sd->fwnode,
> > +	source_pad = media_entity_get_fwnode_pad(&sd->entity, s_asd->source_ep,
> >  						 MEDIA_PAD_FL_SOURCE);
> >  	if (source_pad < 0) {
> >  		dev_err(rkisp1->dev, "failed to find source pad for %s\n",
> > @@ -170,10 +170,19 @@ static int rkisp1_subdev_notifier_complete(struct v4l2_async_notifier *notifier)
> >  	return v4l2_device_register_subdev_nodes(&rkisp1->v4l2_dev);
> >  }
> >  
> > +static void rkisp1_subdev_notifier_destroy(struct v4l2_async_subdev *asd)
> > +{
> > +	struct rkisp1_sensor_async *rk_asd =
> > +		container_of(asd, struct rkisp1_sensor_async, asd);
> > +
> > +	fwnode_handle_put(rk_asd->source_ep);
> > +}
> > +
> >  static const struct v4l2_async_notifier_operations rkisp1_subdev_notifier_ops = {
> >  	.bound = rkisp1_subdev_notifier_bound,
> >  	.unbind = rkisp1_subdev_notifier_unbind,
> >  	.complete = rkisp1_subdev_notifier_complete,
> > +	.destroy = rkisp1_subdev_notifier_destroy,
> >  };
> >  
> >  static int rkisp1_subdev_notifier_register(struct rkisp1_device *rkisp1)
> > @@ -190,6 +199,7 @@ static int rkisp1_subdev_notifier_register(struct rkisp1_device *rkisp1)
> >  			.bus_type = V4L2_MBUS_CSI2_DPHY
> >  		};
> >  		struct rkisp1_sensor_async *rk_asd;
> > +		struct fwnode_handle *source = NULL;
> >  		struct fwnode_handle *ep;
> >  
> >  		ep = fwnode_graph_get_endpoint_by_id(dev_fwnode(rkisp1->dev),
> > @@ -202,15 +212,24 @@ static int rkisp1_subdev_notifier_register(struct rkisp1_device *rkisp1)
> >  		if (ret)
> >  			goto err_parse;
> >  
> > -		rk_asd = v4l2_async_nf_add_fwnode_remote(ntf, ep,
> > -							 struct
> > -							 rkisp1_sensor_async);
> > +		source = fwnode_graph_get_remote_endpoint(ep);
> > +		if (!source) {
> > +			dev_err(rkisp1->dev,
> > +				"endpoint %pfw has no remote endpoint\n",
> > +				ep);
> > +			ret = -ENODEV;
> > +			goto err_parse;
> 
> source is error here so you don't need to fwnode_handle_put() it later I
> think.

That's right, but I still need the fwnode_handle_put(ep) and
v4l2_async_nf_cleanup(ntf). As fwnode_handle_put(NULL) is a no-op, I
didn't add a NULL check before calling it.

> > +		}
> > +
> > +		rk_asd = v4l2_async_nf_add_fwnode(ntf, source,
> > +						  struct rkisp1_sensor_async);
> >  		if (IS_ERR(rk_asd)) {
> >  			ret = PTR_ERR(rk_asd);
> >  			goto err_parse;
> >  		}
> >  
> >  		rk_asd->index = index++;
> > +		rk_asd->source_ep = source;
> >  		rk_asd->mbus_type = vep.bus_type;
> >  		rk_asd->mbus_flags = vep.bus.mipi_csi2.flags;
> >  		rk_asd->lanes = vep.bus.mipi_csi2.num_data_lanes;
> > @@ -225,6 +244,7 @@ static int rkisp1_subdev_notifier_register(struct rkisp1_device *rkisp1)
> >  		continue;
> >  err_parse:
> >  		fwnode_handle_put(ep);
> > +		fwnode_handle_put(source);
> >  		v4l2_async_nf_cleanup(ntf);
> >  		return ret;
> >  	}

-- 
Regards,

Laurent Pinchart