On 2017-06-29 12:57:55 +0300, Sakari Ailus wrote:
> On Thu, Jun 29, 2017 at 11:02:03AM +0200, Niklas Söderlund wrote:
> > Hi Sakari,
> >
> > Thanks for your patch.
> >
> > On 2017-06-29 10:30:10 +0300, Sakari Ailus wrote:
> > > The current practice is that drivers iterate over their endpoints and
> > > parse each endpoint separately. This is very similar in a number of
> > > drivers, implement a generic function for the job. Driver specific matters
> > > can be taken into account in the driver specific callback.
> > >
> > > Convert the omap3isp as an example.
> > >
> > > Signed-off-by: Sakari Ailus <sakari.ailus@xxxxxxxxxxxxxxx>
> > > ---
> > > drivers/media/platform/omap3isp/isp.c | 91 ++++++++++-----------------------
> > > drivers/media/platform/omap3isp/isp.h | 3 --
> > > drivers/media/v4l2-core/v4l2-fwnode.c | 94 +++++++++++++++++++++++++++++++++++
> > > include/media/v4l2-async.h | 4 +-
> > > include/media/v4l2-fwnode.h | 9 ++++
> > > 5 files changed, 132 insertions(+), 69 deletions(-)
> > >
> > > diff --git a/drivers/media/platform/omap3isp/isp.c b/drivers/media/platform/omap3isp/isp.c
> > > index 9df64c1..9ccf883 100644
> > > --- a/drivers/media/platform/omap3isp/isp.c
> > > +++ b/drivers/media/platform/omap3isp/isp.c
> > > @@ -2008,43 +2008,42 @@ enum isp_of_phy {
> > > ISP_OF_PHY_CSIPHY2,
> > > };
> > >
> > > -static int isp_fwnode_parse(struct device *dev, struct fwnode_handle *fwnode,
> > > - struct isp_async_subdev *isd)
> > > +static int isp_fwnode_parse(struct device *dev,
> > > + struct v4l2_fwnode_endpoint *vep,
> > > + struct v4l2_async_subdev *asd)
> > > {
> > > + struct isp_async_subdev *isd =
> > > + container_of(asd, struct isp_async_subdev, asd);
> > > struct isp_bus_cfg *buscfg = &isd->bus;
> > > - struct v4l2_fwnode_endpoint vep;
> > > unsigned int i;
> > > - int ret;
> > > -
> > > - ret = v4l2_fwnode_endpoint_parse(fwnode, &vep);
> > > - if (ret)
> > > - return ret;
> > >
> > > dev_dbg(dev, "parsing endpoint %s, interface %u\n",
> > > - to_of_node(fwnode)->full_name, vep.base.port);
> > > + to_of_node(vep->base.local_fwnode)->full_name, vep->base.port);
> > >
> > > - switch (vep.base.port) {
> > > + switch (vep->base.port) {
> > > case ISP_OF_PHY_PARALLEL:
> > > buscfg->interface = ISP_INTERFACE_PARALLEL;
> > > buscfg->bus.parallel.data_lane_shift =
> > > - vep.bus.parallel.data_shift;
> > > + vep->bus.parallel.data_shift;
> > > buscfg->bus.parallel.clk_pol =
> > > - !!(vep.bus.parallel.flags
> > > + !!(vep->bus.parallel.flags
> > > & V4L2_MBUS_PCLK_SAMPLE_FALLING);
> > > buscfg->bus.parallel.hs_pol =
> > > - !!(vep.bus.parallel.flags & V4L2_MBUS_VSYNC_ACTIVE_LOW);
> > > + !!(vep->bus.parallel.flags &
> > > + V4L2_MBUS_VSYNC_ACTIVE_LOW);
> > > buscfg->bus.parallel.vs_pol =
> > > - !!(vep.bus.parallel.flags & V4L2_MBUS_HSYNC_ACTIVE_LOW);
> > > + !!(vep->bus.parallel.flags &
> > > + V4L2_MBUS_HSYNC_ACTIVE_LOW);
> > > buscfg->bus.parallel.fld_pol =
> > > - !!(vep.bus.parallel.flags & V4L2_MBUS_FIELD_EVEN_LOW);
> > > + !!(vep->bus.parallel.flags & V4L2_MBUS_FIELD_EVEN_LOW);
> > > buscfg->bus.parallel.data_pol =
> > > - !!(vep.bus.parallel.flags & V4L2_MBUS_DATA_ACTIVE_LOW);
> > > + !!(vep->bus.parallel.flags & V4L2_MBUS_DATA_ACTIVE_LOW);
> > > break;
> > >
> > > case ISP_OF_PHY_CSIPHY1:
> > > case ISP_OF_PHY_CSIPHY2:
> > > /* FIXME: always assume CSI-2 for now. */
> > > - switch (vep.base.port) {
> > > + switch (vep->base.port) {
> > > case ISP_OF_PHY_CSIPHY1:
> > > buscfg->interface = ISP_INTERFACE_CSI2C_PHY1;
> > > break;
> > > @@ -2052,18 +2051,19 @@ static int isp_fwnode_parse(struct device *dev, struct fwnode_handle *fwnode,
> > > buscfg->interface = ISP_INTERFACE_CSI2A_PHY2;
> > > break;
> > > }
> > > - buscfg->bus.csi2.lanecfg.clk.pos = vep.bus.mipi_csi2.clock_lane;
> > > + buscfg->bus.csi2.lanecfg.clk.pos =
> > > + vep->bus.mipi_csi2.clock_lane;
> > > buscfg->bus.csi2.lanecfg.clk.pol =
> > > - vep.bus.mipi_csi2.lane_polarities[0];
> > > + vep->bus.mipi_csi2.lane_polarities[0];
> > > dev_dbg(dev, "clock lane polarity %u, pos %u\n",
> > > buscfg->bus.csi2.lanecfg.clk.pol,
> > > buscfg->bus.csi2.lanecfg.clk.pos);
> > >
> > > for (i = 0; i < ISP_CSIPHY2_NUM_DATA_LANES; i++) {
> > > buscfg->bus.csi2.lanecfg.data[i].pos =
> > > - vep.bus.mipi_csi2.data_lanes[i];
> > > + vep->bus.mipi_csi2.data_lanes[i];
> > > buscfg->bus.csi2.lanecfg.data[i].pol =
> > > - vep.bus.mipi_csi2.lane_polarities[i + 1];
> > > + vep->bus.mipi_csi2.lane_polarities[i + 1];
> > > dev_dbg(dev, "data lane %u polarity %u, pos %u\n", i,
> > > buscfg->bus.csi2.lanecfg.data[i].pol,
> > > buscfg->bus.csi2.lanecfg.data[i].pos);
> > > @@ -2079,55 +2079,14 @@ static int isp_fwnode_parse(struct device *dev, struct fwnode_handle *fwnode,
> > >
> > > default:
> > > dev_warn(dev, "%s: invalid interface %u\n",
> > > - to_of_node(fwnode)->full_name, vep.base.port);
> > > + to_of_node(vep->base.local_fwnode)->full_name,
> > > + vep->base.port);
> > > break;
> > > }
> > >
> > > return 0;
> > > }
> > >
> > > -static int isp_fwnodes_parse(struct device *dev,
> > > - struct v4l2_async_notifier *notifier)
> > > -{
> > > - struct fwnode_handle *fwnode = NULL;
> > > -
> > > - notifier->subdevs = devm_kcalloc(
> > > - dev, ISP_MAX_SUBDEVS, sizeof(*notifier->subdevs), GFP_KERNEL);
> > > - if (!notifier->subdevs)
> > > - return -ENOMEM;
> > > -
> > > - while (notifier->num_subdevs < ISP_MAX_SUBDEVS &&
> > > - (fwnode = fwnode_graph_get_next_endpoint(
> > > - of_fwnode_handle(dev->of_node), fwnode))) {
> > > - struct isp_async_subdev *isd;
> > > -
> > > - isd = devm_kzalloc(dev, sizeof(*isd), GFP_KERNEL);
> > > - if (!isd)
> > > - goto error;
> > > -
> > > - notifier->subdevs[notifier->num_subdevs] = &isd->asd;
> > > -
> > > - if (isp_fwnode_parse(dev, fwnode, isd))
> > > - goto error;
> > > -
> > > - isd->asd.match.fwnode.fwnode =
> > > - fwnode_graph_get_remote_port_parent(fwnode);
> > > - if (!isd->asd.match.fwnode.fwnode) {
> > > - dev_warn(dev, "bad remote port parent\n");
> > > - goto error;
> > > - }
> > > -
> > > - isd->asd.match_type = V4L2_ASYNC_MATCH_FWNODE;
> > > - notifier->num_subdevs++;
> > > - }
> > > -
> > > - return notifier->num_subdevs;
> > > -
> > > -error:
> > > - fwnode_handle_put(fwnode);
> > > - return -EINVAL;
> > > -}
> > > -
> > > static int isp_subdev_notifier_bound(struct v4l2_async_notifier *async,
> > > struct v4l2_subdev *subdev,
> > > struct v4l2_async_subdev *asd)
> > > @@ -2210,7 +2169,9 @@ static int isp_probe(struct platform_device *pdev)
> > > if (ret)
> > > return ret;
> > >
> > > - ret = isp_fwnodes_parse(&pdev->dev, &isp->notifier);
> > > + ret = v4l2_fwnode_endpoints_parse(
> > > + &pdev->dev, &isp->notifier, sizeof(struct isp_async_subdev),
> > > + isp_fwnode_parse);
> > > if (ret < 0)
> > > return ret;
> > >
> > > diff --git a/drivers/media/platform/omap3isp/isp.h b/drivers/media/platform/omap3isp/isp.h
> > > index 2f2ae60..a852c11 100644
> > > --- a/drivers/media/platform/omap3isp/isp.h
> > > +++ b/drivers/media/platform/omap3isp/isp.h
> > > @@ -220,9 +220,6 @@ struct isp_device {
> > >
> > > unsigned int sbl_resources;
> > > unsigned int subclk_resources;
> > > -
> > > -#define ISP_MAX_SUBDEVS 8
> > > - struct v4l2_subdev *subdevs[ISP_MAX_SUBDEVS];
> > > };
> > >
> > > struct isp_async_subdev {
> > > diff --git a/drivers/media/v4l2-core/v4l2-fwnode.c b/drivers/media/v4l2-core/v4l2-fwnode.c
> > > index 0ec6c14..b35d525 100644
> > > --- a/drivers/media/v4l2-core/v4l2-fwnode.c
> > > +++ b/drivers/media/v4l2-core/v4l2-fwnode.c
> > > @@ -26,6 +26,7 @@
> > > #include <linux/string.h>
> > > #include <linux/types.h>
> > >
> > > +#include <media/v4l2-async.h>
> > > #include <media/v4l2-fwnode.h>
> > >
> > > static int v4l2_fwnode_endpoint_parse_csi_bus(struct fwnode_handle *fwnode,
> > > @@ -339,6 +340,99 @@ void v4l2_fwnode_put_link(struct v4l2_fwnode_link *link)
> > > }
> > > EXPORT_SYMBOL_GPL(v4l2_fwnode_put_link);
> > >
> > > +static int notifier_realloc(struct device *dev,
> > > + struct v4l2_async_notifier *notifier,
> > > + unsigned int max_subdevs)
> > > +{
> > > + struct v4l2_async_subdev **subdevs;
> > > + unsigned int i;
> > > +
> > > + if (max_subdevs <= notifier->max_subdevs)
> > > + return 0;
> > > +
> > > + subdevs = devm_kcalloc(
> > > + dev, max_subdevs, sizeof(*notifier->subdevs), GFP_KERNEL);
> > > + if (!subdevs)
> > > + return -ENOMEM;
> > > +
> > > + if (notifier->subdevs) {
> > > + for (i = 0; i < notifier->num_subdevs; i++)
> > > + subdevs[i] = notifier->subdevs[i];
> > > +
> > > + devm_kfree(dev, notifier->subdevs);
> > > + }
> > > +
> > > + notifier->subdevs = subdevs;
> > > + notifier->max_subdevs = max_subdevs;
> > > +
> > > + return 0;
> > > +}
> > > +
> > > +int v4l2_fwnode_endpoints_parse(
> > > + struct device *dev, struct v4l2_async_notifier *notifier,
> > > + size_t asd_struct_size,
> > > + int (*parse_single)(struct device *dev,
> > > + struct v4l2_fwnode_endpoint *vep,
> > > + struct v4l2_async_subdev *asd))
> > > +{
> > > + struct fwnode_handle *fwnode = NULL;
> > > + unsigned int max_subdevs = notifier->max_subdevs;
> > > + int ret;
> > > +
> > > + if (asd_struct_size < sizeof(struct v4l2_async_subdev))
> > > + return -EINVAL;
> > > +
> > > + while ((fwnode = fwnode_graph_get_next_endpoint(dev_fwnode(dev),
> > > + fwnode)))
> > > + max_subdevs++;
> > > +
> > > + ret = notifier_realloc(dev, notifier, max_subdevs);
> > > + if (ret)
> > > + return ret;
> > > +
> > > + for (fwnode = NULL; (fwnode = fwnode_graph_get_next_endpoint(
> > > + dev_fwnode(dev), fwnode)) &&
> > > + !WARN_ON(notifier->num_subdevs >= notifier->max_subdevs);
> > > + ) {
> > > + struct v4l2_fwnode_endpoint *vep;
> > > + struct v4l2_async_subdev *asd;
> > > +
> > > + asd = devm_kzalloc(dev, asd_struct_size, GFP_KERNEL);
> > > + if (!asd) {
> > > + ret = -ENOMEM;
> > > + goto error;
> > > + }
> > > +
> > > + notifier->subdevs[notifier->num_subdevs] = asd;
> > > +
> > > + /* Ignore endpoints the parsing of which failed. */
> > > + vep = v4l2_fwnode_endpoint_alloc_parse(fwnode);
> > > + if (IS_ERR(vep))
> > > + continue;
> > > +
> > > + ret = parse_single(dev, vep, asd);
> > > + v4l2_fwnode_endpoint_free(vep);
> > > + if (ret)
> > > + goto error;
> >
> > First off I think this is a good step in the right direction to create
> > core functions for this task.
> >
> > However while reading this I got to think about a use-case I have with
> > the Renesas R-Car VIN and CSI-2 drivers where I would not be able to use
> > this helper. I have previously posted a patch-set to introduce
> > incremental async, see [1]. If that gets picked-up not only the video
> > device driver can have use of this helper but subdevices drivers. As
> > the subdevice driver would also need to pars its DT node to search for
> > subdevices to add to it's own subnotifier. In this case this helper wont
> > suffice, I think.
> >
> > Since the subdevice DT node will contain endpoints pointing to both the
> > subdevice which the incremental async notifier would like to find and
> > endpoints pointing back to the root video device node it self.
> >
> > In my use-case for Renesas R-Car Gen3 VIN and CSI-2 DT (not yet accepted
> > upstream) I have solved this by having the CSI-2 DT node having two port
> > nodes, port0 and port1. In port0 endpoints describing the 'upstream'
> > video source from the CSI-2 point of view are defined (these should be
> > added to the subnotifier). In port1 endpoints describing connections
> > back to the VIN video devices are described. Currently the CSI-2 driver
> > simply only looks for endpoints in the port0 node to add to its
> > subnotifier, and I don't think this would be possible with this helper?
>
> What we could also do is to add a variant of this that parses the endpoints
> by the port / endpoint IDs. Then you don't need to have a cumbersome way to
> skip parsing of some ports --- you would have allocated the memory and
> parsed the port for nothing by the time you call the callback anyway.
>
> That would seem to be a better approach in general. I remember Rob was
> pushing this for DRM as it greatly simplified driver code there. But then
> the DT bindings have to be written accordingly: in current bindings the
> endpoint IDs are mostly undefined.
>
> We may still need to take extra measures to support cases where there are
> multiple links between two sub-devices.
>
> What do you think?
A variant of this that as you suggest parses by port I think make sens.
I'm not sure how one would go about creating a simple interface which
would support parsing by port+endpoint IDs, but if it's possible that
would be also be nice.
Another option is to instead of passing a struct device pass a struct
fwnode_handle which would act as the root search path. That way one
could pass a fwnode_handle to a specific port node and just iterate over
all endpoints in that port. But that way the driver side implementation
becomes more complex since it needs to lookup the fwnode_handle so I'm
not sure I think that is the best solution.
So yes I think your suggestion of adding a variant which takes port
and/or port+endpoint IDs into account to be the best solution.
>
> Cc Rob + devicetree list as well.
>
> >
> > Perhaps this patch can be modified so that en error code from the
> > callback parse_single() could be taken in to account when making the
> > decision if the parsed endpoint should be added to the notifiers
> > list of subdevices?
> >
> > > +
> > > + asd->match.fwnode.fwnode =
> > > + fwnode_graph_get_remote_port_parent(fwnode);
> > > + if (!asd->match.fwnode.fwnode) {
> > > + dev_warn(dev, "bad remote port parent\n");
> > > + ret = -EINVAL;
> > > + goto error;
> > > + }
> > > +
> > > + asd->match_type = V4L2_ASYNC_MATCH_FWNODE;
> > > + notifier->num_subdevs++;
> > > + }
> > > +
> > > +error:
> > > + fwnode_handle_put(fwnode);
> > > + return ret;
> > > +}
> > > +EXPORT_SYMBOL_GPL(v4l2_fwnode_endpoints_parse);
> > > +
> > > MODULE_LICENSE("GPL");
> > > MODULE_AUTHOR("Sakari Ailus <sakari.ailus@xxxxxxxxxxxxxxx>");
> > > MODULE_AUTHOR("Sylwester Nawrocki <s.nawrocki@xxxxxxxxxxx>");
> > > diff --git a/include/media/v4l2-async.h b/include/media/v4l2-async.h
> > > index c69d8c8..067f368 100644
> > > --- a/include/media/v4l2-async.h
> > > +++ b/include/media/v4l2-async.h
> > > @@ -78,7 +78,8 @@ struct v4l2_async_subdev {
> > > /**
> > > * struct v4l2_async_notifier - v4l2_device notifier data
> > > *
> > > - * @num_subdevs: number of subdevices
> > > + * @num_subdevs: number of subdevices used in subdevs array
> > > + * @max_subdevs: number of subdevices allocated in subdevs array
> > > * @subdevs: array of pointers to subdevice descriptors
> > > * @v4l2_dev: pointer to struct v4l2_device
> > > * @waiting: list of struct v4l2_async_subdev, waiting for their drivers
> > > @@ -90,6 +91,7 @@ struct v4l2_async_subdev {
> > > */
> > > struct v4l2_async_notifier {
> > > unsigned int num_subdevs;
> > > + unsigned int max_subdevs;
> > > struct v4l2_async_subdev **subdevs;
> > > struct v4l2_device *v4l2_dev;
> > > struct list_head waiting;
> > > diff --git a/include/media/v4l2-fwnode.h b/include/media/v4l2-fwnode.h
> > > index ecc1233..ff489f7 100644
> > > --- a/include/media/v4l2-fwnode.h
> > > +++ b/include/media/v4l2-fwnode.h
> > > @@ -25,6 +25,8 @@
> > > #include <media/v4l2-mediabus.h>
> > >
> > > struct fwnode_handle;
> > > +struct v4l2_async_notifier;
> > > +struct v4l2_async_subdev;
> > >
> > > /**
> > > * struct v4l2_fwnode_bus_mipi_csi2 - MIPI CSI-2 bus data structure
> > > @@ -101,4 +103,11 @@ int v4l2_fwnode_parse_link(struct fwnode_handle *fwnode,
> > > struct v4l2_fwnode_link *link);
> > > void v4l2_fwnode_put_link(struct v4l2_fwnode_link *link);
> > >
> > > +int v4l2_fwnode_endpoints_parse(
> > > + struct device *dev, struct v4l2_async_notifier *notifier,
> > > + size_t asd_struct_size,
> > > + int (*parse_single)(struct device *dev,
> > > + struct v4l2_fwnode_endpoint *vep,
> > > + struct v4l2_async_subdev *asd));
> > > +
> > > #endif /* _V4L2_FWNODE_H */
> > > --
> > > 2.1.4
> > >
> > >
> >
> > --
> > Regards,
> > Niklas Söderlund
>
> --
> Sakari Ailus
> e-mail: sakari.ailus@xxxxxx XMPP: sailus@xxxxxxxxxxxxxx
--
Regards,
Niklas Söderlund
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