On 2017-04-29 23:29, Peter Rosin wrote:
> On 2017-04-28 16:13, Philipp Zabel wrote:
>> This driver can handle SoC internal and external video bus multiplexers,
>> controlled by mux controllers provided by the mux controller framework,
>> such as MMIO register bitfields or GPIOs. The subdevice passes through
>> the mbus configuration of the active input to the output side.
>>
>> Signed-off-by: Sascha Hauer <s.ha...@pengutronix.de>
>> Signed-off-by: Philipp Zabel <p.za...@pengutronix.de>
>> Signed-off-by: Steve Longerbeam <steve_longerb...@mentor.com>
>> ---
>> This has been last sent as part of the i.MX media series.
>>
>> Changes since https://patchwork.kernel.org/patch/9647869/:
>> - Split out the actual mux operation to be provided by the mux controller
>> framework [1]. GPIO and MMIO control can be provided by individual mux
>> controller drivers [2][3].
>> [1] https://patchwork.kernel.org/patch/9695837/
>> [2] https://patchwork.kernel.org/patch/9695839/
>> [3] https://patchwork.kernel.org/patch/9704509/
>> - Shortened 'video-multiplexer' to 'video-mux', replaced all instances of
>> vidsw with video_mux.
>> - Made the mux inactive by default, only activated by user interaction.
>> - Added CONFIG_OF and CONFIG_MULTIPLEXER dependencies.
>> - Reuse subdev.entity.num_pads instead of keeping our own count.
>> - Removed implicit link disabling. Instead, trying to enable a second
>> sink pad link yields -EBUSY.
>> - Merged _async_init into _probe.
>> - Removed superfluous pad index check from _set_format.
>> - Added is_source_pad helper to tell source and sink pads apart.
>> - Removed test for status property in endpoint nodes. Disable the remote
>> device or sever the endpoint link to disable a sink pad.
>> ---
>> drivers/media/platform/Kconfig | 6 +
>> drivers/media/platform/Makefile | 2 +
>> drivers/media/platform/video-mux.c | 341
>> +++++++++++++++++++++++++++++++++++++
>> 3 files changed, 349 insertions(+)
>> create mode 100644 drivers/media/platform/video-mux.c
>>
>> diff --git a/drivers/media/platform/Kconfig b/drivers/media/platform/Kconfig
>> index c9106e105baba..b046a6d39fee5 100644
>> --- a/drivers/media/platform/Kconfig
>> +++ b/drivers/media/platform/Kconfig
>> @@ -74,6 +74,12 @@ config VIDEO_M32R_AR_M64278
>> To compile this driver as a module, choose M here: the
>> module will be called arv.
>>
>> +config VIDEO_MUX
>> + tristate "Video Multiplexer"
>> + depends on OF && VIDEO_V4L2_SUBDEV_API && MEDIA_CONTROLLER &&
>> MULTIPLEXER
>> + help
>> + This driver provides support for N:1 video bus multiplexers.
>> +
>> config VIDEO_OMAP3
>> tristate "OMAP 3 Camera support"
>> depends on VIDEO_V4L2 && I2C && VIDEO_V4L2_SUBDEV_API && ARCH_OMAP3
>> diff --git a/drivers/media/platform/Makefile
>> b/drivers/media/platform/Makefile
>> index 349ddf6a69da2..fd2735ca3ff75 100644
>> --- a/drivers/media/platform/Makefile
>> +++ b/drivers/media/platform/Makefile
>> @@ -27,6 +27,8 @@ obj-$(CONFIG_VIDEO_SH_VEU) += sh_veu.o
>>
>> obj-$(CONFIG_VIDEO_MEM2MEM_DEINTERLACE) += m2m-deinterlace.o
>>
>> +obj-$(CONFIG_VIDEO_MUX) += video-mux.o
>> +
>> obj-$(CONFIG_VIDEO_S3C_CAMIF) += s3c-camif/
>> obj-$(CONFIG_VIDEO_SAMSUNG_EXYNOS4_IS) += exynos4-is/
>> obj-$(CONFIG_VIDEO_SAMSUNG_S5P_JPEG) += s5p-jpeg/
>> diff --git a/drivers/media/platform/video-mux.c
>> b/drivers/media/platform/video-mux.c
>> new file mode 100644
>> index 0000000000000..419541729f67e
>> --- /dev/null
>> +++ b/drivers/media/platform/video-mux.c
>> @@ -0,0 +1,341 @@
>> +/*
>> + * video stream multiplexer controlled via mux control
>> + *
>> + * Copyright (C) 2013 Pengutronix, Sascha Hauer <ker...@pengutronix.de>
>> + * Copyright (C) 2016 Pengutronix, Philipp Zabel <ker...@pengutronix.de>
>
> 2017?
>
>> + *
>> + * This program is free software; you can redistribute it and/or
>> + * modify it under the terms of the GNU General Public License
>> + * as published by the Free Software Foundation; either version 2
>> + * of the License, or (at your option) any later version.
>> + * This program is distributed in the hope that it will be useful,
>> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
>> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
>> + * GNU General Public License for more details.
>> + */
>> +
>> +#include <linux/err.h>
>> +#include <linux/module.h>
>> +#include <linux/mux/consumer.h>
>> +#include <linux/of.h>
>> +#include <linux/of_graph.h>
>> +#include <linux/platform_device.h>
>> +#include <media/v4l2-async.h>
>> +#include <media/v4l2-device.h>
>> +#include <media/v4l2-subdev.h>
>> +#include <media/v4l2-of.h>
>> +
>> +struct video_mux {
>> + struct v4l2_subdev subdev;
>> + struct media_pad *pads;
>> + struct v4l2_mbus_framefmt *format_mbus;
>> + struct v4l2_of_endpoint *endpoint;
>> + struct mux_control *mux;
>> + int active;
>> +};
>> +
>> +static inline struct video_mux *v4l2_subdev_to_video_mux(struct v4l2_subdev
>> *sd)
>> +{
>> + return container_of(sd, struct video_mux, subdev);
>> +}
>> +
>> +static inline bool is_source_pad(struct video_mux *vmux, unsigned int pad)
>> +{
>> + return pad == vmux->subdev.entity.num_pads - 1;
>> +}
>> +
>> +static int video_mux_link_setup(struct media_entity *entity,
>> + const struct media_pad *local,
>> + const struct media_pad *remote, u32 flags)
>> +{
>> + struct v4l2_subdev *sd = media_entity_to_v4l2_subdev(entity);
>> + struct video_mux *vmux = v4l2_subdev_to_video_mux(sd);
>> + int ret;
>> +
>> + /*
>> + * The mux state is determined by the enabled sink pad link.
>> + * Enabling or disabling the source pad link has no effect.
>> + */
>> + if (is_source_pad(vmux, local->index))
>> + return 0;
>> +
>> + dev_dbg(sd->dev, "link setup '%s':%d->'%s':%d[%d]",
>> + remote->entity->name, remote->index, local->entity->name,
>> + local->index, flags & MEDIA_LNK_FL_ENABLED);
>> +
>> + if (flags & MEDIA_LNK_FL_ENABLED) {
>> + if (vmux->active == local->index)
>
> Here, you shortcut the mux_control_select_trylock test and return "OK"
> based on a driver-local variable that is intended to keep track of mux
> ownership.
>
>> + return 0;
>> +
>> + if (vmux->active >= 0)
>
> Here too (and this check is not needed, the situation will be covered by
> the mux_control_try_select call).
>
>> + return -EBUSY;
>> +
>> + dev_dbg(sd->dev, "setting %d active\n", local->index);
>> + ret = mux_control_try_select(vmux->mux, local->index);
>> + if (ret < 0)
>> + return ret;
>> + vmux->active = local->index;
>> + } else {
>> + if (vmux->active != local->index)
>> + return 0;
>> +
>> + dev_dbg(sd->dev, "going inactive\n");
>> + mux_control_deselect(vmux->mux);
>
> But here you let go of the mux *before* you clear the driver-local
> ownership indicator. That looks suspicious. My guess is that this is
> "safe" because the upper layers has some serialization, but I don't
> know. Anyway, even if there is something saving you in the upper
> layers, it looks out of order and unneeded. I would have moved the
> below vmux->active = -1; statement up to before the above deselect.
>
> With that fixed, mux usage looks good to me, so you can add an Acked-
> by from me if you wish (goes for the bindings patch as well).
Ouch, that was a bit too soon. If there is *no* serialization in the
upper layers, this is *not* ok, even with my reordering. There must be
only one call to mux_control_deselect, and w/o serialization there
is a race where you might get multiple deselect calls when several
callers makes it through the active != index check before any of them
manages to set active = -1. That race must be taken care of!
Cheers,
peda
>> + vmux->active = -1;
>> + }
>> +
>> + return 0;
>> +}
>> +
>> +static struct media_entity_operations video_mux_ops = {
>> + .link_setup = video_mux_link_setup,
>> + .link_validate = v4l2_subdev_link_validate,
>> +};
>> +
>> +static bool video_mux_endpoint_disabled(struct device_node *ep)
>> +{
>> + struct device_node *rpp = of_graph_get_remote_port_parent(ep);
>> +
>> + return !of_device_is_available(rpp);
>> +}
>> +
>> +static int video_mux_g_mbus_config(struct v4l2_subdev *sd,
>> + struct v4l2_mbus_config *cfg)
>> +{
>> + struct video_mux *vmux = v4l2_subdev_to_video_mux(sd);
>> + struct v4l2_of_endpoint *endpoint;
>> + struct media_pad *pad;
>> + int ret;
>> +
>> + if (vmux->active == -1) {
>> + dev_err(sd->dev, "no configuration for inactive mux\n");
>> + return -EINVAL;
>> + }
>> +
>> + /*
>> + * Retrieve media bus configuration from the entity connected to the
>> + * active input
>> + */
>> + pad = media_entity_remote_pad(&vmux->pads[vmux->active]);
>> + if (pad) {
>> + sd = media_entity_to_v4l2_subdev(pad->entity);
>> + ret = v4l2_subdev_call(sd, video, g_mbus_config, cfg);
>> + if (ret == -ENOIOCTLCMD)
>> + pad = NULL;
>> + else if (ret < 0) {
>> + dev_err(sd->dev, "failed to get source
>> configuration\n");
>> + return ret;
>> + }
>> + }
>> + if (!pad) {
>> + endpoint = &vmux->endpoint[vmux->active];
>> +
>> + /* Mirror the input side on the output side */
>> + cfg->type = endpoint->bus_type;
>> + if (cfg->type == V4L2_MBUS_PARALLEL ||
>> + cfg->type == V4L2_MBUS_BT656)
>> + cfg->flags = endpoint->bus.parallel.flags;
>> + }
>> +
>> + return 0;
>> +}
>> +
>> +static int video_mux_s_stream(struct v4l2_subdev *sd, int enable)
>> +{
>> + struct video_mux *vmux = v4l2_subdev_to_video_mux(sd);
>> + struct v4l2_subdev *upstream_sd;
>> + struct media_pad *pad;
>> +
>> + if (vmux->active == -1) {
>> + dev_err(sd->dev, "Can not start streaming on inactive mux\n");
>> + return -EINVAL;
>> + }
>> +
>> + pad = media_entity_remote_pad(&sd->entity.pads[vmux->active]);
>> + if (!pad) {
>> + dev_err(sd->dev, "Failed to find remote source pad\n");
>> + return -ENOLINK;
>> + }
>> +
>> + if (!is_media_entity_v4l2_subdev(pad->entity)) {
>> + dev_err(sd->dev, "Upstream entity is not a v4l2 subdev\n");
>> + return -ENODEV;
>> + }
>> +
>> + upstream_sd = media_entity_to_v4l2_subdev(pad->entity);
>> +
>> + return v4l2_subdev_call(upstream_sd, video, s_stream, enable);
>> +}
>> +
>> +static const struct v4l2_subdev_video_ops video_mux_subdev_video_ops = {
>> + .g_mbus_config = video_mux_g_mbus_config,
>> + .s_stream = video_mux_s_stream,
>> +};
>> +
>> +static struct v4l2_mbus_framefmt *
>> +__video_mux_get_pad_format(struct v4l2_subdev *sd,
>> + struct v4l2_subdev_pad_config *cfg,
>> + unsigned int pad, u32 which)
>> +{
>> + struct video_mux *vmux = v4l2_subdev_to_video_mux(sd);
>> +
>> + switch (which) {
>> + case V4L2_SUBDEV_FORMAT_TRY:
>> + return v4l2_subdev_get_try_format(sd, cfg, pad);
>> + case V4L2_SUBDEV_FORMAT_ACTIVE:
>> + return &vmux->format_mbus[pad];
>> + default:
>> + return NULL;
>> + }
>> +}
>> +
>> +static int video_mux_get_format(struct v4l2_subdev *sd,
>> + struct v4l2_subdev_pad_config *cfg,
>> + struct v4l2_subdev_format *sdformat)
>> +{
>> + sdformat->format = *__video_mux_get_pad_format(sd, cfg, sdformat->pad,
>> + sdformat->which);
>> + return 0;
>> +}
>> +
>> +static int video_mux_set_format(struct v4l2_subdev *sd,
>> + struct v4l2_subdev_pad_config *cfg,
>> + struct v4l2_subdev_format *sdformat)
>> +{
>> + struct video_mux *vmux = v4l2_subdev_to_video_mux(sd);
>> + struct v4l2_mbus_framefmt *mbusformat;
>> +
>> + mbusformat = __video_mux_get_pad_format(sd, cfg, sdformat->pad,
>> + sdformat->which);
>> + if (!mbusformat)
>> + return -EINVAL;
>> +
>> + /* Source pad mirrors active sink pad, no limitations on sink pads */
>> + if (is_source_pad(vmux, sdformat->pad) && vmux->active >= 0)
>> + sdformat->format = vmux->format_mbus[vmux->active];
>> +
>> + *mbusformat = sdformat->format;
>> +
>> + return 0;
>> +}
>> +
>> +static struct v4l2_subdev_pad_ops video_mux_pad_ops = {
>> + .get_fmt = video_mux_get_format,
>> + .set_fmt = video_mux_set_format,
>> +};
>> +
>> +static struct v4l2_subdev_ops video_mux_subdev_ops = {
>> + .pad = &video_mux_pad_ops,
>> + .video = &video_mux_subdev_video_ops,
>> +};
>> +
>> +static int video_mux_probe(struct platform_device *pdev)
>> +{
>> + struct device_node *np = pdev->dev.of_node;
>> + struct device *dev = &pdev->dev;
>> + struct v4l2_of_endpoint endpoint;
>> + struct device_node *ep;
>> + struct video_mux *vmux;
>> + unsigned int num_pads = 0;
>> + int ret;
>> + int i;
>> +
>> + vmux = devm_kzalloc(dev, sizeof(*vmux), GFP_KERNEL);
>> + if (!vmux)
>> + return -ENOMEM;
>> +
>> + platform_set_drvdata(pdev, vmux);
>> +
>> + v4l2_subdev_init(&vmux->subdev, &video_mux_subdev_ops);
>> + snprintf(vmux->subdev.name, sizeof(vmux->subdev.name), "%s", np->name);
>> + vmux->subdev.flags |= V4L2_SUBDEV_FL_HAS_DEVNODE;
>> + vmux->subdev.dev = dev;
>> +
>> + /*
>> + * The largest numbered port is the output port. It determines
>> + * total number of pads.
>> + */
>> + for_each_endpoint_of_node(np, ep) {
>> + of_graph_parse_endpoint(ep, &endpoint.base);
>> + num_pads = max(num_pads, endpoint.base.port + 1);
>> + }
>> +
>> + if (num_pads < 2) {
>> + dev_err(dev, "Not enough ports %d\n", num_pads);
>> + return -EINVAL;
>> + }
>> +
>> + vmux->mux = devm_mux_control_get(dev, NULL);
>> + if (IS_ERR(vmux->mux)) {
>> + ret = PTR_ERR(vmux->mux);
>> + if (ret != -EPROBE_DEFER)
>> + dev_err(dev, "Failed to get mux: %d\n", ret);
>> + return ret;
>> + }
>> +
>> + vmux->active = -1;
>> + vmux->pads = devm_kzalloc(dev, sizeof(*vmux->pads) * num_pads,
>> + GFP_KERNEL);
>> + vmux->format_mbus = devm_kzalloc(dev, sizeof(*vmux->format_mbus) *
>> + num_pads, GFP_KERNEL);
>> + vmux->endpoint = devm_kzalloc(dev, sizeof(*vmux->endpoint) *
>> + (num_pads - 1), GFP_KERNEL);
>> +
>> + for (i = 0; i < num_pads - 1; i++)
>> + vmux->pads[i].flags = MEDIA_PAD_FL_SINK;
>> + vmux->pads[num_pads - 1].flags = MEDIA_PAD_FL_SOURCE;
>> +
>> + vmux->subdev.entity.function = MEDIA_ENT_F_VID_MUX;
>> + ret = media_entity_pads_init(&vmux->subdev.entity, num_pads,
>> + vmux->pads);
>> + if (ret < 0)
>> + return ret;
>> +
>> + vmux->subdev.entity.ops = &video_mux_ops;
>> +
>> + for_each_endpoint_of_node(np, ep) {
>> + v4l2_of_parse_endpoint(ep, &endpoint);
>> +
>> + if (video_mux_endpoint_disabled(ep)) {
>> + dev_dbg(dev, "port %d disabled\n", endpoint.base.port);
>> + continue;
>> + }
>> +
>> + vmux->endpoint[endpoint.base.port] = endpoint;
>> + }
>> +
>> + return v4l2_async_register_subdev(&vmux->subdev);
>> +}
>> +
>> +static int video_mux_remove(struct platform_device *pdev)
>> +{
>> + struct video_mux *vmux = platform_get_drvdata(pdev);
>> + struct v4l2_subdev *sd = &vmux->subdev;
>> +
>> + v4l2_async_unregister_subdev(sd);
>> + media_entity_cleanup(&sd->entity);
>> +
>> + return 0;
>> +}
>> +
>> +static const struct of_device_id video_mux_dt_ids[] = {
>> + { .compatible = "video-mux", },
>> + { /* sentinel */ }
>> +};
>> +MODULE_DEVICE_TABLE(of, video_mux_dt_ids);
>> +
>> +static struct platform_driver video_mux_driver = {
>> + .probe = video_mux_probe,
>> + .remove = video_mux_remove,
>> + .driver = {
>> + .of_match_table = video_mux_dt_ids,
>> + .name = "video-mux",
>> + },
>> +};
>> +
>> +module_platform_driver(video_mux_driver);
>> +
>> +MODULE_DESCRIPTION("video stream multiplexer");
>> +MODULE_AUTHOR("Sascha Hauer, Pengutronix");
>> +MODULE_AUTHOR("Philipp Zabel, Pengutronix");
>> +MODULE_LICENSE("GPL");
>>
>
