Hi Laurent,
On Fri, Sep 15, 2023 at 12:48:50PM +0300, Laurent Pinchart wrote:
> Hi Sakari,
>
> Thank you for the patch.
>
> On Fri, Sep 15, 2023 at 10:28:08AM +0300, Sakari Ailus wrote:
> > Use sub-device active state. Rely on control handler lock to serialise
> > access to the active state. Also clean up locking on s_stream handler.
> >
> > Signed-off-by: Sakari Ailus <sakari.ailus@xxxxxxxxxxxxxxx>
> > ---
> > drivers/media/i2c/ov2740.c | 121 +++++++++++++++----------------------
> > 1 file changed, 49 insertions(+), 72 deletions(-)
> >
> > diff --git a/drivers/media/i2c/ov2740.c b/drivers/media/i2c/ov2740.c
> > index 319dc00e47b4..de39a66b1b81 100644
> > --- a/drivers/media/i2c/ov2740.c
> > +++ b/drivers/media/i2c/ov2740.c
> > @@ -336,9 +336,6 @@ struct ov2740 {
> > /* Current mode */
> > const struct ov2740_mode *cur_mode;
> >
> > - /* To serialize asynchronus callbacks */
> > - struct mutex mutex;
> > -
> > /* Streaming on/off */
> > bool streaming;
> >
> > @@ -582,7 +579,6 @@ static int ov2740_init_controls(struct ov2740 *ov2740)
> > if (ret)
> > return ret;
> >
> > - ctrl_hdlr->lock = &ov2740->mutex;
> > cur_mode = ov2740->cur_mode;
> > size = ARRAY_SIZE(link_freq_menu_items);
> >
> > @@ -792,18 +788,18 @@ static int ov2740_set_stream(struct v4l2_subdev *sd, int enable)
> > {
> > struct ov2740 *ov2740 = to_ov2740(sd);
> > struct i2c_client *client = v4l2_get_subdevdata(sd);
> > + struct v4l2_subdev_state *sd_state;
> > int ret = 0;
> >
> > + sd_state = v4l2_subdev_lock_and_get_active_state(&ov2740->sd);
> > +
> > if (ov2740->streaming == enable)
> > - return 0;
> > + goto out_unlock;
> >
> > - mutex_lock(&ov2740->mutex);
> > if (enable) {
> > ret = pm_runtime_resume_and_get(&client->dev);
> > - if (ret < 0) {
> > - mutex_unlock(&ov2740->mutex);
> > - return ret;
> > - }
> > + if (ret < 0)
> > + goto out_unlock;
> >
> > ret = ov2740_start_streaming(ov2740);
> > if (ret) {
> > @@ -817,7 +813,9 @@ static int ov2740_set_stream(struct v4l2_subdev *sd, int enable)
> > }
> >
> > ov2740->streaming = enable;
> > - mutex_unlock(&ov2740->mutex);
> > +
> > +out_unlock:
> > + v4l2_subdev_unlock_state(sd_state);
> >
> > return ret;
> > }
> > @@ -826,12 +824,13 @@ static int ov2740_suspend(struct device *dev)
> > {
> > struct v4l2_subdev *sd = dev_get_drvdata(dev);
> > struct ov2740 *ov2740 = to_ov2740(sd);
> > + struct v4l2_subdev_state *sd_state;
> >
> > - mutex_lock(&ov2740->mutex);
> > + sd_state = v4l2_subdev_lock_and_get_active_state(&ov2740->sd);
> > if (ov2740->streaming)
> > ov2740_stop_streaming(ov2740);
> >
> > - mutex_unlock(&ov2740->mutex);
> > + v4l2_subdev_unlock_state(sd_state);
> >
> > return 0;
> > }
>
> This conflicts with a series I've just sent. As my series contains 57
> patches, I would appreciate not to have to rebase it :-) You could pick
> up the ov2740 patches and include them in this series, before this one.
>
> > @@ -840,9 +839,10 @@ static int ov2740_resume(struct device *dev)
> > {
> > struct v4l2_subdev *sd = dev_get_drvdata(dev);
> > struct ov2740 *ov2740 = to_ov2740(sd);
> > + struct v4l2_subdev_state *sd_state;
> > int ret = 0;
> >
> > - mutex_lock(&ov2740->mutex);
> > + sd_state = v4l2_subdev_lock_and_get_active_state(&ov2740->sd);
> > if (!ov2740->streaming)
> > goto exit;
> >
> > @@ -853,7 +853,7 @@ static int ov2740_resume(struct device *dev)
> > }
> >
> > exit:
> > - mutex_unlock(&ov2740->mutex);
> > + v4l2_subdev_unlock_state(sd_state);
> > return ret;
> > }
> >
> > @@ -870,48 +870,26 @@ static int ov2740_set_format(struct v4l2_subdev *sd,
> > height, fmt->format.width,
> > fmt->format.height);
> >
> > - mutex_lock(&ov2740->mutex);
> > ov2740_update_pad_format(mode, &fmt->format);
> > - if (fmt->which == V4L2_SUBDEV_FORMAT_TRY) {
> > - *v4l2_subdev_get_try_format(sd, sd_state, fmt->pad) = fmt->format;
> > - } else {
> > - ov2740->cur_mode = mode;
> > - __v4l2_ctrl_s_ctrl(ov2740->link_freq, mode->link_freq_index);
> > - __v4l2_ctrl_s_ctrl_int64(ov2740->pixel_rate,
> > - to_pixel_rate(mode->link_freq_index));
> > -
> > - /* Update limits and set FPS to default */
> > - vblank_def = mode->vts_def - mode->height;
> > - __v4l2_ctrl_modify_range(ov2740->vblank,
> > - mode->vts_min - mode->height,
> > - OV2740_VTS_MAX - mode->height, 1,
> > - vblank_def);
> > - __v4l2_ctrl_s_ctrl(ov2740->vblank, vblank_def);
> > - h_blank = to_pixels_per_line(mode->hts, mode->link_freq_index) -
> > - mode->width;
> > - __v4l2_ctrl_modify_range(ov2740->hblank, h_blank, h_blank, 1,
> > - h_blank);
> > - }
> > - mutex_unlock(&ov2740->mutex);
> > -
> > - return 0;
> > -}
> > + *v4l2_subdev_get_pad_format(sd, sd_state, fmt->pad) = fmt->format;
> >
> > -static int ov2740_get_format(struct v4l2_subdev *sd,
> > - struct v4l2_subdev_state *sd_state,
> > - struct v4l2_subdev_format *fmt)
> > -{
> > - struct ov2740 *ov2740 = to_ov2740(sd);
> > -
> > - mutex_lock(&ov2740->mutex);
> > if (fmt->which == V4L2_SUBDEV_FORMAT_TRY)
> > - fmt->format = *v4l2_subdev_get_try_format(&ov2740->sd,
> > - sd_state,
> > - fmt->pad);
> > - else
> > - ov2740_update_pad_format(ov2740->cur_mode, &fmt->format);
> > + return 0;
> >
> > - mutex_unlock(&ov2740->mutex);
> > + ov2740->cur_mode = mode;
> > + __v4l2_ctrl_s_ctrl(ov2740->link_freq, mode->link_freq_index);
> > + __v4l2_ctrl_s_ctrl_int64(ov2740->pixel_rate,
> > + to_pixel_rate(mode->link_freq_index));
> > +
> > + /* Update limits and set FPS to default */
> > + vblank_def = mode->vts_def - mode->height;
> > + __v4l2_ctrl_modify_range(ov2740->vblank,
> > + mode->vts_min - mode->height,
> > + OV2740_VTS_MAX - mode->height, 1, vblank_def);
> > + __v4l2_ctrl_s_ctrl(ov2740->vblank, vblank_def);
> > + h_blank = to_pixels_per_line(mode->hts, mode->link_freq_index) -
> > + mode->width;
> > + __v4l2_ctrl_modify_range(ov2740->hblank, h_blank, h_blank, 1, h_blank);
> >
> > return 0;
> > }
> > @@ -946,14 +924,11 @@ static int ov2740_enum_frame_size(struct v4l2_subdev *sd,
> > return 0;
> > }
> >
> > -static int ov2740_open(struct v4l2_subdev *sd, struct v4l2_subdev_fh *fh)
> > +static int ov2740_init_cfg(struct v4l2_subdev *sd,
> > + struct v4l2_subdev_state *sd_state)
> > {
> > - struct ov2740 *ov2740 = to_ov2740(sd);
> > -
> > - mutex_lock(&ov2740->mutex);
> > ov2740_update_pad_format(&supported_modes[0],
> > - v4l2_subdev_get_try_format(sd, fh->state, 0));
> > - mutex_unlock(&ov2740->mutex);
> > + v4l2_subdev_get_pad_format(sd, sd_state, 0));
> >
> > return 0;
> > }
> > @@ -963,10 +938,11 @@ static const struct v4l2_subdev_video_ops ov2740_video_ops = {
> > };
> >
> > static const struct v4l2_subdev_pad_ops ov2740_pad_ops = {
> > + .get_fmt = v4l2_subdev_get_fmt,
> > .set_fmt = ov2740_set_format,
> > - .get_fmt = ov2740_get_format,
> > .enum_mbus_code = ov2740_enum_mbus_code,
> > .enum_frame_size = ov2740_enum_frame_size,
> > + .init_cfg = ov2740_init_cfg,
> > };
> >
> > static const struct v4l2_subdev_ops ov2740_subdev_ops = {
> > @@ -978,10 +954,6 @@ static const struct media_entity_operations ov2740_subdev_entity_ops = {
> > .link_validate = v4l2_subdev_link_validate,
> > };
> >
> > -static const struct v4l2_subdev_internal_ops ov2740_internal_ops = {
> > - .open = ov2740_open,
> > -};
> > -
> > static int ov2740_check_hwcfg(struct device *dev)
> > {
> > struct fwnode_handle *ep;
> > @@ -1047,13 +1019,12 @@ static int ov2740_check_hwcfg(struct device *dev)
> > static void ov2740_remove(struct i2c_client *client)
> > {
> > struct v4l2_subdev *sd = i2c_get_clientdata(client);
> > - struct ov2740 *ov2740 = to_ov2740(sd);
> >
> > v4l2_async_unregister_subdev(sd);
> > media_entity_cleanup(&sd->entity);
> > + v4l2_subdev_cleanup(sd);
> > v4l2_ctrl_handler_free(sd->ctrl_handler);
> > pm_runtime_disable(&client->dev);
> > - mutex_destroy(&ov2740->mutex);
> > }
> >
> > static int ov2740_nvmem_read(void *priv, unsigned int off, void *val,
> > @@ -1062,9 +1033,10 @@ static int ov2740_nvmem_read(void *priv, unsigned int off, void *val,
> > struct nvm_data *nvm = priv;
> > struct device *dev = regmap_get_device(nvm->regmap);
> > struct ov2740 *ov2740 = to_ov2740(dev_get_drvdata(dev));
> > + struct v4l2_subdev_state *sd_state;
> > int ret = 0;
> >
> > - mutex_lock(&ov2740->mutex);
> > + sd_state = v4l2_subdev_lock_and_get_active_state(&ov2740->sd);
>
> This function seems unrelated to the state. What was the lock protecting
> against ?
It is. I guess I could acquire the lock directly from the control handler
but I think this is cleaner.
Acquiring the lock is needed to serialise access to the sensor by other
users.
>
> >
> > if (nvm->nvm_buffer) {
> > memcpy(val, nvm->nvm_buffer + off, count);
> > @@ -1082,7 +1054,7 @@ static int ov2740_nvmem_read(void *priv, unsigned int off, void *val,
> >
> > pm_runtime_put(dev);
> > exit:
> > - mutex_unlock(&ov2740->mutex);
> > + v4l2_subdev_unlock_state(sd_state);
> > return ret;
> > }
> >
> > @@ -1153,7 +1125,6 @@ static int ov2740_probe(struct i2c_client *client)
> > return dev_err_probe(dev, ret, "failed to find sensor\n");
> > }
> >
> > - mutex_init(&ov2740->mutex);
> > ov2740->cur_mode = &supported_modes[0];
> > ret = ov2740_init_controls(ov2740);
> > if (ret) {
> > @@ -1161,7 +1132,7 @@ static int ov2740_probe(struct i2c_client *client)
> > goto probe_error_v4l2_ctrl_handler_free;
> > }
> >
> > - ov2740->sd.internal_ops = &ov2740_internal_ops;
> > + ov2740->sd.state_lock = ov2740->ctrl_handler.lock;
> > ov2740->sd.flags |= V4L2_SUBDEV_FL_HAS_DEVNODE;
> > ov2740->sd.entity.ops = &ov2740_subdev_entity_ops;
> > ov2740->sd.entity.function = MEDIA_ENT_F_CAM_SENSOR;
> > @@ -1172,6 +1143,10 @@ static int ov2740_probe(struct i2c_client *client)
> > goto probe_error_v4l2_ctrl_handler_free;
> > }
> >
> > + ret = v4l2_subdev_init_finalize(&ov2740->sd);
> > + if (ret)
> > + goto probe_error_media_entity_cleanup;
> > +
> > /* Set the device's state to active if it's in D0 state. */
> > if (full_power)
> > pm_runtime_set_active(&client->dev);
> > @@ -1181,7 +1156,7 @@ static int ov2740_probe(struct i2c_client *client)
> > ret = v4l2_async_register_subdev_sensor(&ov2740->sd);
> > if (ret < 0) {
> > dev_err_probe(dev, ret, "failed to register V4L2 subdev\n");
> > - goto probe_error_media_entity_cleanup;
> > + goto probe_error_v4l2_subdev_cleanup;
> > }
> >
> > ret = ov2740_register_nvmem(client, ov2740);
> > @@ -1190,6 +1165,9 @@ static int ov2740_probe(struct i2c_client *client)
> >
> > return 0;
> >
> > +probe_error_v4l2_subdev_cleanup:
> > + v4l2_subdev_cleanup(&ov2740->sd);
> > +
> > probe_error_media_entity_cleanup:
> > media_entity_cleanup(&ov2740->sd.entity);
> > pm_runtime_disable(&client->dev);
> > @@ -1197,7 +1175,6 @@ static int ov2740_probe(struct i2c_client *client)
> >
> > probe_error_v4l2_ctrl_handler_free:
> > v4l2_ctrl_handler_free(ov2740->sd.ctrl_handler);
> > - mutex_destroy(&ov2740->mutex);
> >
> > return ret;
> > }
>
--
Regards,
Sakari Ailus
