Messages in this thread | | | Subject | Re: [PATCH v3 1/2] media: vimc: Collapse component structure into a single monolithic driver | From | Shuah Khan <> | Date | Tue, 27 Aug 2019 12:17:05 -0600 |
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On 8/27/19 10:55 AM, Laurent Pinchart wrote: > Hi Shuah, > > Thank you for the patch. > > On Tue, Aug 20, 2019 at 03:18:41PM -0600, Shuah Khan wrote: >> vimc uses Component API to split the driver into functional components. >> The real hardware resembles a monolith structure than component and >> component structure added a level of complexity making it hard to >> maintain without adding any real benefit. >> >> The sensor is one vimc component that would makes sense to be a separate >> module to closely align with the real hardware. It would be easier to >> collapse vimc into single monolithic driver first and then split the >> sensor off as a separate module. >> >> Collapse it into a single monolithic driver removing the Component API. >> This patch removes the component API and makes minimal changes to the >> code base preserving the functional division of the code structure. >> Preserving the functional structure allows us to split the sensor off >> as a separate module in the future. >> >> Major design elements in this change are: >> - Use existing struct vimc_ent_config and struct vimc_pipeline_config >> to drive the initialization of the functional components. >> - Make vimc_device and vimc_ent_config global by moving them to >> vimc-common.h >> - Add two new hooks add and rm to initialize and register, unregister >> and free subdevs. >> - All component API is now gone and bind and unbind hooks are modified >> to do "add" and "rm" with minimal changes to just add and rm subdevs. >> - vimc-core's bind and unbind are now register and unregister. >> - vimc-core invokes "add" hooks from its vimc_register_devices(). >> The "add" hooks remain the same and register subdevs. They don't >> create platform devices of their own and use vimc's pdev.dev as >> their reference device. The "add" hooks save their vimc_ent_device(s) >> in the corresponding vimc_ent_config. >> - vimc-core invokes "rm" hooks from its unregister to unregister subdevs >> and cleanup. >> - vimc-core invokes "add" and "rm" hooks with pointer to struct vimc_device >> and the corresponding struct vimc_ent_config pointer. >> >> The following configure and stream test works on all devices. >> >> media-ctl -d platform:vimc -V '"Sensor A":0[fmt:SBGGR8_1X8/640x480]' >> media-ctl -d platform:vimc -V '"Debayer A":0[fmt:SBGGR8_1X8/640x480]' >> media-ctl -d platform:vimc -V '"Sensor B":0[fmt:SBGGR8_1X8/640x480]' >> media-ctl -d platform:vimc -V '"Debayer B":0[fmt:SBGGR8_1X8/640x480]' >> >> v4l2-ctl -z platform:vimc -d "RGB/YUV Capture" -v width=1920,height=1440 >> v4l2-ctl -z platform:vimc -d "Raw Capture 0" -v pixelformat=BA81 >> v4l2-ctl -z platform:vimc -d "Raw Capture 1" -v pixelformat=BA81 >> >> v4l2-ctl --stream-mmap --stream-count=100 -d /dev/video1 >> v4l2-ctl --stream-mmap --stream-count=100 -d /dev/video2 >> v4l2-ctl --stream-mmap --stream-count=100 -d /dev/video3 >> >> Signed-off-by: Shuah Khan <skhan@linuxfoundation.org> >> --- >> drivers/media/platform/vimc/Makefile | 7 +- >> drivers/media/platform/vimc/vimc-capture.c | 79 ++------ >> drivers/media/platform/vimc/vimc-common.h | 48 +++++ >> drivers/media/platform/vimc/vimc-core.c | 199 ++++++++------------- >> drivers/media/platform/vimc/vimc-debayer.c | 67 ++----- >> drivers/media/platform/vimc/vimc-scaler.c | 71 ++------ >> drivers/media/platform/vimc/vimc-sensor.c | 71 ++------ >> 7 files changed, 176 insertions(+), 366 deletions(-) >> >> diff --git a/drivers/media/platform/vimc/Makefile b/drivers/media/platform/vimc/Makefile >> index 96d06f030c31..a53b2b532e9f 100644 >> --- a/drivers/media/platform/vimc/Makefile >> +++ b/drivers/media/platform/vimc/Makefile >> @@ -1,5 +1,6 @@ >> # SPDX-License-Identifier: GPL-2.0 >> -vimc-y := vimc-core.o vimc-common.o vimc-streamer.o >> +vimc-y := vimc-core.o vimc-common.o vimc-streamer.o vimc-capture.o \ >> + vimc-debayer.o vimc-scaler.o vimc-sensor.o >> + >> +obj-$(CONFIG_VIDEO_VIMC) += vimc.o >> >> -obj-$(CONFIG_VIDEO_VIMC) += vimc.o vimc-capture.o vimc-debayer.o \ >> - vimc-scaler.o vimc-sensor.o >> diff --git a/drivers/media/platform/vimc/vimc-capture.c b/drivers/media/platform/vimc/vimc-capture.c >> index 1d56b91830ba..e04b60ec0738 100644 >> --- a/drivers/media/platform/vimc/vimc-capture.c >> +++ b/drivers/media/platform/vimc/vimc-capture.c >> @@ -5,10 +5,6 @@ >> * Copyright (C) 2015-2017 Helen Koike <helen.fornazier@gmail.com> >> */ >> >> -#include <linux/component.h> >> -#include <linux/module.h> >> -#include <linux/mod_devicetable.h> >> -#include <linux/platform_device.h> >> #include <media/v4l2-ioctl.h> >> #include <media/videobuf2-core.h> >> #include <media/videobuf2-vmalloc.h> >> @@ -16,8 +12,6 @@ >> #include "vimc-common.h" >> #include "vimc-streamer.h" >> >> -#define VIMC_CAP_DRV_NAME "vimc-capture" >> - >> struct vimc_cap_device { >> struct vimc_ent_device ved; >> struct video_device vdev; >> @@ -340,13 +334,15 @@ static void vimc_cap_release(struct video_device *vdev) >> kfree(vcap); >> } >> >> -static void vimc_cap_comp_unbind(struct device *comp, struct device *master, >> - void *master_data) >> +void vimc_cap_rm(struct vimc_device *vimc, struct vimc_ent_config *vcfg) >> { >> - struct vimc_ent_device *ved = dev_get_drvdata(comp); >> - struct vimc_cap_device *vcap = container_of(ved, struct vimc_cap_device, >> - ved); >> + struct vimc_ent_device *ved = vcfg->ved; >> + struct vimc_cap_device *vcap; >> + >> + if (!ved) >> + return; >> >> + vcap = container_of(ved, struct vimc_cap_device, ved); >> vb2_queue_release(&vcap->queue); >> media_entity_cleanup(ved->ent); >> video_unregister_device(&vcap->vdev); >> @@ -391,11 +387,9 @@ static void *vimc_cap_process_frame(struct vimc_ent_device *ved, >> return NULL; >> } >> >> -static int vimc_cap_comp_bind(struct device *comp, struct device *master, >> - void *master_data) >> +int vimc_cap_add(struct vimc_device *vimc, struct vimc_ent_config *vcfg) >> { >> - struct v4l2_device *v4l2_dev = master_data; >> - struct vimc_platform_data *pdata = comp->platform_data; >> + struct v4l2_device *v4l2_dev = &vimc->v4l2_dev; >> const struct vimc_pix_map *vpix; >> struct vimc_cap_device *vcap; >> struct video_device *vdev; >> @@ -416,7 +410,7 @@ static int vimc_cap_comp_bind(struct device *comp, struct device *master, >> } >> >> /* Initialize the media entity */ >> - vcap->vdev.entity.name = pdata->entity_name; >> + vcap->vdev.entity.name = vcfg->name; >> vcap->vdev.entity.function = MEDIA_ENT_F_IO_V4L; >> ret = media_entity_pads_init(&vcap->vdev.entity, >> 1, vcap->ved.pads); >> @@ -440,8 +434,8 @@ static int vimc_cap_comp_bind(struct device *comp, struct device *master, >> >> ret = vb2_queue_init(q); >> if (ret) { >> - dev_err(comp, "%s: vb2 queue init failed (err=%d)\n", >> - pdata->entity_name, ret); >> + dev_err(&vimc->pdev.dev, "%s: vb2 queue init failed (err=%d)\n", >> + vcfg->name, ret); >> goto err_clean_m_ent; >> } >> >> @@ -460,8 +454,7 @@ static int vimc_cap_comp_bind(struct device *comp, struct device *master, >> vcap->ved.ent = &vcap->vdev.entity; >> vcap->ved.process_frame = vimc_cap_process_frame; >> vcap->ved.vdev_get_format = vimc_cap_get_format; >> - dev_set_drvdata(comp, &vcap->ved); >> - vcap->dev = comp; >> + vcap->dev = &vimc->pdev.dev; >> >> /* Initialize the video_device struct */ >> vdev = &vcap->vdev; >> @@ -474,17 +467,18 @@ static int vimc_cap_comp_bind(struct device *comp, struct device *master, >> vdev->queue = q; >> vdev->v4l2_dev = v4l2_dev; >> vdev->vfl_dir = VFL_DIR_RX; >> - strscpy(vdev->name, pdata->entity_name, sizeof(vdev->name)); >> + strscpy(vdev->name, vcfg->name, sizeof(vdev->name)); >> video_set_drvdata(vdev, &vcap->ved); >> >> /* Register the video_device with the v4l2 and the media framework */ >> ret = video_register_device(vdev, VFL_TYPE_GRABBER, -1); >> if (ret) { >> - dev_err(comp, "%s: video register failed (err=%d)\n", >> + dev_err(&vimc->pdev.dev, "%s: video register failed (err=%d)\n", >> vcap->vdev.name, ret); >> goto err_release_queue; >> } >> >> + vcfg->ved = &vcap->ved; >> return 0; >> >> err_release_queue: >> @@ -498,44 +492,3 @@ static int vimc_cap_comp_bind(struct device *comp, struct device *master, >> >> return ret; >> } >> - >> -static const struct component_ops vimc_cap_comp_ops = { >> - .bind = vimc_cap_comp_bind, >> - .unbind = vimc_cap_comp_unbind, >> -}; >> - >> -static int vimc_cap_probe(struct platform_device *pdev) >> -{ >> - return component_add(&pdev->dev, &vimc_cap_comp_ops); >> -} >> - >> -static int vimc_cap_remove(struct platform_device *pdev) >> -{ >> - component_del(&pdev->dev, &vimc_cap_comp_ops); >> - >> - return 0; >> -} >> - >> -static const struct platform_device_id vimc_cap_driver_ids[] = { >> - { >> - .name = VIMC_CAP_DRV_NAME, >> - }, >> - { } >> -}; >> - >> -static struct platform_driver vimc_cap_pdrv = { >> - .probe = vimc_cap_probe, >> - .remove = vimc_cap_remove, >> - .id_table = vimc_cap_driver_ids, >> - .driver = { >> - .name = VIMC_CAP_DRV_NAME, >> - }, >> -}; >> - >> -module_platform_driver(vimc_cap_pdrv); >> - >> -MODULE_DEVICE_TABLE(platform, vimc_cap_driver_ids); >> - >> -MODULE_DESCRIPTION("Virtual Media Controller Driver (VIMC) Capture"); >> -MODULE_AUTHOR("Helen Mae Koike Fornazier <helen.fornazier@gmail.com>"); >> -MODULE_LICENSE("GPL"); >> diff --git a/drivers/media/platform/vimc/vimc-common.h b/drivers/media/platform/vimc/vimc-common.h >> index 9c2e0e216c6b..5b2282de395c 100644 >> --- a/drivers/media/platform/vimc/vimc-common.h >> +++ b/drivers/media/platform/vimc/vimc-common.h >> @@ -9,6 +9,7 @@ >> #define _VIMC_COMMON_H_ >> >> #include <linux/slab.h> >> +#include <linux/platform_device.h> >> #include <media/media-device.h> >> #include <media/v4l2-device.h> >> >> @@ -84,6 +85,21 @@ struct vimc_pix_map { >> bool bayer; >> }; >> >> +/** >> + * struct vimc_device - main device for vimc driver >> + * >> + * @pdev pointer to the platform device >> + * @pipe_cfg pointer to the vimc pipeline configuration structure >> + * @mdev the associated media_device parent >> + * @v4l2_dev Internal v4l2 parent device >> + */ >> +struct vimc_device { >> + struct platform_device pdev; >> + const struct vimc_pipeline_config *pipe_cfg; >> + struct media_device mdev; >> + struct v4l2_device v4l2_dev; >> +}; >> + >> /** >> * struct vimc_ent_device - core struct that represents a node in the topology >> * >> @@ -111,6 +127,38 @@ struct vimc_ent_device { >> struct v4l2_pix_format *fmt); >> }; >> >> +/** >> + * struct vimc_ent_config Structure which describes individual >> + * configuration for each entity >> + * >> + * @name entity name >> + * @ved pointer to vimc_ent_device (a node in the >> + * topology) >> + * @add subdev add hook - initializes and registers >> + * subdev called from vimc-core >> + * @rm subdev rm hook - unregisters and frees >> + * subdev called from vimc-core >> + */ >> +struct vimc_ent_config { >> + const char *name; >> + struct vimc_ent_device *ved; >> + int (*add)(struct vimc_device *vimc, struct vimc_ent_config *vcfg); >> + void (*rm)(struct vimc_device *vimc, struct vimc_ent_config *vcfg); >> +}; > > Mixing data and function pointers in a read-write structure is a > security issue, as it helps an attacker who could overwrite the > structure to run arbitrary code :-/ I think you should split this in > two, with the read-only name and function pointers stored as a const > array, and the vimc_ent_device pointers stored separately (possibly in a > linked list, or worst case an array that mirrors ent_config, as I > suppose the configfs support will remove the ent_config array). >
Array that mirrors might be sufficient. We do all or nothing adds for these entities anyway. If we can't add one entity, we delete all and fail the probe.
> This is I think the only blocker for this patch series, and fortunately > it shouldn't be difficult to fix. >
Yeah. I should have thought about that in the first place. :( Will fix it and send updated patch.
thanks, -- Shuah
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