drivers/media/test-drivers/vimc/vimc-core.c - linux - Git at Google

 // SPDX-License-Identifier: GPL-2.0-or-later
 /*
  * vimc-core.c Virtual Media Controller Driver
  *
  * Copyright (C) 2015-2017 Helen Koike <helen.fornazier@gmail.com>
  */

 #include <linux/dma-mapping.h>
 #include <linux/font.h>
 #include <linux/init.h>
 #include <linux/module.h>
 #include <linux/platform_device.h>
 #include <media/media-device.h>
 #include <media/tpg/v4l2-tpg.h>
 #include <media/v4l2-device.h>

 #include "vimc-common.h"

 unsigned int vimc_allocator;
 module_param_named(allocator, vimc_allocator, uint, 0444);
 MODULE_PARM_DESC(allocator, " memory allocator selection, default is 0.\n"
 			     "\t\t    0 == vmalloc\n"
 			     "\t\t    1 == dma-contig");

 #define VIMC_MDEV_MODEL_NAME "VIMC MDEV"

 #define VIMC_DATA_LINK(src, srcpad, sink, sinkpad, link_flags) {	\
 	.src_ent = src,						\
 	.src_pad = srcpad,					\
 	.sink_ent = sink,					\
 	.sink_pad = sinkpad,					\
 	.flags = link_flags,					\
 }

 #define VIMC_ANCILLARY_LINK(primary, ancillary) {	\
 	.primary_ent = primary,			\
 	.ancillary_ent = ancillary		\
 }

 /* Structure which describes data links between entities */
 struct vimc_data_link {
 	unsigned int src_ent;
 	u16 src_pad;
 	unsigned int sink_ent;
 	u16 sink_pad;
 	u32 flags;
 };

 /* Enum to improve clarity when defining vimc_data_links */
 enum vimc_data_link_ents {
 	SENSOR_A,
 	SENSOR_B,
 	DEBAYER_A,
 	DEBAYER_B,
 	RAW_CAPTURE_0,
 	RAW_CAPTURE_1,
 	RGB_YUV_INPUT,
 	SCALER,
 	RGB_YUV_CAPTURE,
 	LENS_A,
 	LENS_B,
 };

 /* Structure which describes ancillary links between entities */
 struct vimc_ancillary_link {
 	unsigned int primary_ent;
 	unsigned int ancillary_ent;
 };

 /* Structure which describes the whole topology */
 struct vimc_pipeline_config {
 	const struct vimc_ent_config *ents;
 	size_t num_ents;
 	const struct vimc_data_link *data_links;
 	size_t num_data_links;
 	const struct vimc_ancillary_link *ancillary_links;
 	size_t num_ancillary_links;
 };

 /* --------------------------------------------------------------------------
  * Topology Configuration
  */

 static struct vimc_ent_config ent_config[] = {
 	[SENSOR_A] = {
 		.name = "Sensor A",
 		.type = &vimc_sensor_type
 	},
 	[SENSOR_B] = {
 		.name = "Sensor B",
 		.type = &vimc_sensor_type
 	},
 	[DEBAYER_A] = {
 		.name = "Debayer A",
 		.type = &vimc_debayer_type
 	},
 	[DEBAYER_B] = {
 		.name = "Debayer B",
 		.type = &vimc_debayer_type
 	},
 	[RAW_CAPTURE_0] = {
 		.name = "Raw Capture 0",
 		.type = &vimc_capture_type
 	},
 	[RAW_CAPTURE_1] = {
 		.name = "Raw Capture 1",
 		.type = &vimc_capture_type
 	},
 	[RGB_YUV_INPUT] = {
 		/* TODO: change this to vimc-input when it is implemented */
 		.name = "RGB/YUV Input",
 		.type = &vimc_sensor_type
 	},
 	[SCALER] = {
 		.name = "Scaler",
 		.type = &vimc_scaler_type
 	},
 	[RGB_YUV_CAPTURE] = {
 		.name = "RGB/YUV Capture",
 		.type = &vimc_capture_type
 	},
 	[LENS_A] = {
 		.name = "Lens A",
 		.type = &vimc_lens_type
 	},
 	[LENS_B] = {
 		.name = "Lens B",
 		.type = &vimc_lens_type
 	},
 };

 static const struct vimc_data_link data_links[] = {
 	/* Link: Sensor A (Pad 0)->(Pad 0) Debayer A */
 	VIMC_DATA_LINK(SENSOR_A, 0, DEBAYER_A, 0,
 		       MEDIA_LNK_FL_ENABLED | MEDIA_LNK_FL_IMMUTABLE),
 	/* Link: Sensor A (Pad 0)->(Pad 0) Raw Capture 0 */
 	VIMC_DATA_LINK(SENSOR_A, 0, RAW_CAPTURE_0, 0,
 		       MEDIA_LNK_FL_ENABLED | MEDIA_LNK_FL_IMMUTABLE),
 	/* Link: Sensor B (Pad 0)->(Pad 0) Debayer B */
 	VIMC_DATA_LINK(SENSOR_B, 0, DEBAYER_B, 0,
 		       MEDIA_LNK_FL_ENABLED | MEDIA_LNK_FL_IMMUTABLE),
 	/* Link: Sensor B (Pad 0)->(Pad 0) Raw Capture 1 */
 	VIMC_DATA_LINK(SENSOR_B, 0, RAW_CAPTURE_1, 0,
 		       MEDIA_LNK_FL_ENABLED | MEDIA_LNK_FL_IMMUTABLE),
 	/* Link: Debayer A (Pad 1)->(Pad 0) Scaler */
 	VIMC_DATA_LINK(DEBAYER_A, 1, SCALER, 0, MEDIA_LNK_FL_ENABLED),
 	/* Link: Debayer B (Pad 1)->(Pad 0) Scaler */
 	VIMC_DATA_LINK(DEBAYER_B, 1, SCALER, 0, 0),
 	/* Link: RGB/YUV Input (Pad 0)->(Pad 0) Scaler */
 	VIMC_DATA_LINK(RGB_YUV_INPUT, 0, SCALER, 0, 0),
 	/* Link: Scaler (Pad 1)->(Pad 0) RGB/YUV Capture */
 	VIMC_DATA_LINK(SCALER, 1, RGB_YUV_CAPTURE, 0,
 		       MEDIA_LNK_FL_ENABLED | MEDIA_LNK_FL_IMMUTABLE),
 };

 static const struct vimc_ancillary_link ancillary_links[] = {
 	/* Link: Sensor A -> Lens A */
 	VIMC_ANCILLARY_LINK(0, 9),
 	/* Link: Sensor B -> Lens B */
 	VIMC_ANCILLARY_LINK(1, 10),
 };

 static struct vimc_pipeline_config pipe_cfg = {
 	.ents		     = ent_config,
 	.num_ents	     = ARRAY_SIZE(ent_config),
 	.data_links	     = data_links,
 	.num_data_links	     = ARRAY_SIZE(data_links),
 	.ancillary_links     = ancillary_links,
 	.num_ancillary_links = ARRAY_SIZE(ancillary_links),
 };

 /* -------------------------------------------------------------------------- */

 static void vimc_rm_links(struct vimc_device *vimc)
 {
 	unsigned int i;

 	for (i = 0; i < vimc->pipe_cfg->num_ents; i++)
 		media_entity_remove_links(vimc->ent_devs[i]->ent);
 }

 static int vimc_create_links(struct vimc_device *vimc)
 {
 	unsigned int i;
 	int ret;

 	/* Initialize the links between entities */
 	for (i = 0; i < vimc->pipe_cfg->num_data_links; i++) {
 		const struct vimc_data_link *link = &vimc->pipe_cfg->data_links[i];

 		struct vimc_ent_device *ved_src =
 			vimc->ent_devs[link->src_ent];
 		struct vimc_ent_device *ved_sink =
 			vimc->ent_devs[link->sink_ent];

 		ret = media_create_pad_link(ved_src->ent, link->src_pad,
 					    ved_sink->ent, link->sink_pad,
 					    link->flags);
 		if (ret)
 			goto err_rm_links;
 	}

 	for (i = 0; i < vimc->pipe_cfg->num_ancillary_links; i++) {
 		const struct vimc_ancillary_link *link = &vimc->pipe_cfg->ancillary_links[i];

 		struct vimc_ent_device *ved_primary =
 			vimc->ent_devs[link->primary_ent];
 		struct vimc_ent_device *ved_ancillary =
 			vimc->ent_devs[link->ancillary_ent];
 		struct media_link *ret_link =
 			media_create_ancillary_link(ved_primary->ent, ved_ancillary->ent);

 		if (IS_ERR(ret_link)) {
 			ret = PTR_ERR(link);
 			goto err_rm_links;
 		}
 	}

 	return 0;

 err_rm_links:
 	vimc_rm_links(vimc);
 	return ret;
 }

 static void vimc_release_subdevs(struct vimc_device *vimc)
 {
 	unsigned int i;

 	for (i = 0; i < vimc->pipe_cfg->num_ents; i++)
 		if (vimc->ent_devs[i])
 			vimc->pipe_cfg->ents[i].type->release(vimc->ent_devs[i]);
 }

 static void vimc_unregister_subdevs(struct vimc_device *vimc)
 {
 	unsigned int i;

 	for (i = 0; i < vimc->pipe_cfg->num_ents; i++)
 		if (vimc->ent_devs[i] && vimc->pipe_cfg->ents[i].type->unregister)
 			vimc->pipe_cfg->ents[i].type->unregister(vimc->ent_devs[i]);
 }

 static int vimc_add_subdevs(struct vimc_device *vimc)
 {
 	unsigned int i;

 	for (i = 0; i < vimc->pipe_cfg->num_ents; i++) {
 		dev_dbg(vimc->mdev.dev, "new entity for %s\n",
 			vimc->pipe_cfg->ents[i].name);
 		vimc->ent_devs[i] = vimc->pipe_cfg->ents[i].type->add(vimc,
 					vimc->pipe_cfg->ents[i].name);
 		if (IS_ERR(vimc->ent_devs[i])) {
 			int err = PTR_ERR(vimc->ent_devs[i]);

 			dev_err(vimc->mdev.dev, "adding entity %s failed (%d)\n",
 				vimc->pipe_cfg->ents[i].name, err);
 			vimc->ent_devs[i] = NULL;
 			vimc_unregister_subdevs(vimc);
 			vimc_release_subdevs(vimc);
 			return err;
 		}
 	}
 	return 0;
 }

 static void vimc_v4l2_dev_release(struct v4l2_device *v4l2_dev)
 {
 	struct vimc_device *vimc =
 		container_of(v4l2_dev, struct vimc_device, v4l2_dev);

 	vimc_release_subdevs(vimc);
 	media_device_cleanup(&vimc->mdev);
 	kfree(vimc->ent_devs);
 	kfree(vimc);
 }

 static int vimc_register_devices(struct vimc_device *vimc)
 {
 	int ret;

 	/* Register the v4l2 struct */
 	ret = v4l2_device_register(vimc->mdev.dev, &vimc->v4l2_dev);
 	if (ret) {
 		dev_err(vimc->mdev.dev,
 			"v4l2 device register failed (err=%d)\n", ret);
 		return ret;
 	}
 	/* allocate ent_devs */
 	vimc->ent_devs = kcalloc(vimc->pipe_cfg->num_ents,
 				 sizeof(*vimc->ent_devs), GFP_KERNEL);
 	if (!vimc->ent_devs) {
 		ret = -ENOMEM;
 		goto err_v4l2_unregister;
 	}

 	/* Invoke entity config hooks to initialize and register subdevs */
 	ret = vimc_add_subdevs(vimc);
 	if (ret)
 		goto err_free_ent_devs;

 	/* Initialize links */
 	ret = vimc_create_links(vimc);
 	if (ret)
 		goto err_rm_subdevs;

 	/* Register the media device */
 	ret = media_device_register(&vimc->mdev);
 	if (ret) {
 		dev_err(vimc->mdev.dev,
 			"media device register failed (err=%d)\n", ret);
 		goto err_rm_subdevs;
 	}

 	/* Expose all subdev's nodes*/
 	ret = v4l2_device_register_subdev_nodes(&vimc->v4l2_dev);
 	if (ret) {
 		dev_err(vimc->mdev.dev,
 			"vimc subdev nodes registration failed (err=%d)\n",
 			ret);
 		goto err_mdev_unregister;
 	}

 	return 0;

 err_mdev_unregister:
 	media_device_unregister(&vimc->mdev);
 err_rm_subdevs:
 	vimc_unregister_subdevs(vimc);
 	vimc_release_subdevs(vimc);
 err_free_ent_devs:
 	kfree(vimc->ent_devs);
 err_v4l2_unregister:
 	v4l2_device_unregister(&vimc->v4l2_dev);

 	return ret;
 }

 static int vimc_probe(struct platform_device *pdev)
 {
 	const struct font_desc *font = find_font("VGA8x16");
 	struct vimc_device *vimc;
 	int ret;

 	dev_dbg(&pdev->dev, "probe");

 	if (!font) {
 		dev_err(&pdev->dev, "could not find font\n");
 		return -ENODEV;
 	}

 	tpg_set_font(font->data);

 	if (vimc_allocator == VIMC_ALLOCATOR_DMA_CONTIG)
 		dma_coerce_mask_and_coherent(&pdev->dev, DMA_BIT_MASK(32));

 	vimc = kzalloc(sizeof(*vimc), GFP_KERNEL);
 	if (!vimc)
 		return -ENOMEM;

 	vimc->pipe_cfg = &pipe_cfg;

 	/* Link the media device within the v4l2_device */
 	vimc->v4l2_dev.mdev = &vimc->mdev;

 	/* Initialize media device */
 	strscpy(vimc->mdev.model, VIMC_MDEV_MODEL_NAME,
 		sizeof(vimc->mdev.model));
 	snprintf(vimc->mdev.bus_info, sizeof(vimc->mdev.bus_info),
 		 "platform:%s", VIMC_PDEV_NAME);
 	vimc->mdev.dev = &pdev->dev;
 	media_device_init(&vimc->mdev);

 	ret = vimc_register_devices(vimc);
 	if (ret) {
 		media_device_cleanup(&vimc->mdev);
 		kfree(vimc);
 		return ret;
 	}
 	/*
 	 * the release cb is set only after successful registration.
 	 * if the registration fails, we release directly from probe
 	 */

 	vimc->v4l2_dev.release = vimc_v4l2_dev_release;
 	platform_set_drvdata(pdev, vimc);
 	return 0;
 }

 static int vimc_remove(struct platform_device *pdev)
 {
 	struct vimc_device *vimc = platform_get_drvdata(pdev);

 	dev_dbg(&pdev->dev, "remove");

 	vimc_unregister_subdevs(vimc);
 	media_device_unregister(&vimc->mdev);
 	v4l2_device_unregister(&vimc->v4l2_dev);
 	v4l2_device_put(&vimc->v4l2_dev);

 	return 0;
 }

 static void vimc_dev_release(struct device *dev)
 {
 }

 static struct platform_device vimc_pdev = {
 	.name = VIMC_PDEV_NAME,
 	.dev.release = vimc_dev_release,
 };

 static struct platform_driver vimc_pdrv = {
 	.probe		= vimc_probe,
 	.remove		= vimc_remove,
 	.driver		= {
 		.name	= VIMC_PDEV_NAME,
 	},
 };

 static int __init vimc_init(void)
 {
 	int ret;

 	ret = platform_device_register(&vimc_pdev);
 	if (ret) {
 		dev_err(&vimc_pdev.dev,
 			"platform device registration failed (err=%d)\n", ret);
 		return ret;
 	}

 	ret = platform_driver_register(&vimc_pdrv);
 	if (ret) {
 		dev_err(&vimc_pdev.dev,
 			"platform driver registration failed (err=%d)\n", ret);
 		platform_driver_unregister(&vimc_pdrv);
 		return ret;
 	}

 	return 0;
 }

 static void __exit vimc_exit(void)
 {
 	platform_driver_unregister(&vimc_pdrv);

 	platform_device_unregister(&vimc_pdev);
 }

 module_init(vimc_init);
 module_exit(vimc_exit);

 MODULE_DESCRIPTION("Virtual Media Controller Driver (VIMC)");
 MODULE_AUTHOR("Helen Fornazier <helen.fornazier@gmail.com>");
 MODULE_LICENSE("GPL");
	// SPDX-License-Identifier: GPL-2.0-or-later
	/*
	* vimc-core.c Virtual Media Controller Driver
	*
	* Copyright (C) 2015-2017 Helen Koike <helen.fornazier@gmail.com>
	*/

	#include <linux/dma-mapping.h>
	#include <linux/font.h>
	#include <linux/init.h>
	#include <linux/module.h>
	#include <linux/platform_device.h>
	#include <media/media-device.h>
	#include <media/tpg/v4l2-tpg.h>
	#include <media/v4l2-device.h>

	#include "vimc-common.h"

	unsigned int vimc_allocator;
	module_param_named(allocator, vimc_allocator, uint, 0444);
	MODULE_PARM_DESC(allocator, " memory allocator selection, default is 0.\n"
	"\t\t 0 == vmalloc\n"
	"\t\t 1 == dma-contig");

	#define VIMC_MDEV_MODEL_NAME "VIMC MDEV"

	#define VIMC_DATA_LINK(src, srcpad, sink, sinkpad, link_flags) { \
	.src_ent = src, \
	.src_pad = srcpad, \
	.sink_ent = sink, \
	.sink_pad = sinkpad, \
	.flags = link_flags, \
	}

	#define VIMC_ANCILLARY_LINK(primary, ancillary) { \
	.primary_ent = primary, \
	.ancillary_ent = ancillary \
	}

	/* Structure which describes data links between entities */
	struct vimc_data_link {
	unsigned int src_ent;
	u16 src_pad;
	unsigned int sink_ent;
	u16 sink_pad;
	u32 flags;
	};

	/* Enum to improve clarity when defining vimc_data_links */
	enum vimc_data_link_ents {
	SENSOR_A,
	SENSOR_B,
	DEBAYER_A,
	DEBAYER_B,
	RAW_CAPTURE_0,
	RAW_CAPTURE_1,
	RGB_YUV_INPUT,
	SCALER,
	RGB_YUV_CAPTURE,
	LENS_A,
	LENS_B,
	};

	/* Structure which describes ancillary links between entities */
	struct vimc_ancillary_link {
	unsigned int primary_ent;
	unsigned int ancillary_ent;
	};

	/* Structure which describes the whole topology */
	struct vimc_pipeline_config {
	const struct vimc_ent_config *ents;
	size_t num_ents;
	const struct vimc_data_link *data_links;
	size_t num_data_links;
	const struct vimc_ancillary_link *ancillary_links;
	size_t num_ancillary_links;
	};

	/* --------------------------------------------------------------------------
	* Topology Configuration
	*/

	static struct vimc_ent_config ent_config[] = {
	[SENSOR_A] = {
	.name = "Sensor A",
	.type = &vimc_sensor_type
	},
	[SENSOR_B] = {
	.name = "Sensor B",
	.type = &vimc_sensor_type
	},
	[DEBAYER_A] = {
	.name = "Debayer A",
	.type = &vimc_debayer_type
	},
	[DEBAYER_B] = {
	.name = "Debayer B",
	.type = &vimc_debayer_type
	},
	[RAW_CAPTURE_0] = {
	.name = "Raw Capture 0",
	.type = &vimc_capture_type
	},
	[RAW_CAPTURE_1] = {
	.name = "Raw Capture 1",
	.type = &vimc_capture_type
	},
	[RGB_YUV_INPUT] = {
	/* TODO: change this to vimc-input when it is implemented */
	.name = "RGB/YUV Input",
	.type = &vimc_sensor_type
	},
	[SCALER] = {
	.name = "Scaler",
	.type = &vimc_scaler_type
	},
	[RGB_YUV_CAPTURE] = {
	.name = "RGB/YUV Capture",
	.type = &vimc_capture_type
	},
	[LENS_A] = {
	.name = "Lens A",
	.type = &vimc_lens_type
	},
	[LENS_B] = {
	.name = "Lens B",
	.type = &vimc_lens_type
	},
	};

	static const struct vimc_data_link data_links[] = {
	/* Link: Sensor A (Pad 0)->(Pad 0) Debayer A */
	VIMC_DATA_LINK(SENSOR_A, 0, DEBAYER_A, 0,
	MEDIA_LNK_FL_ENABLED \| MEDIA_LNK_FL_IMMUTABLE),
	/* Link: Sensor A (Pad 0)->(Pad 0) Raw Capture 0 */
	VIMC_DATA_LINK(SENSOR_A, 0, RAW_CAPTURE_0, 0,
	MEDIA_LNK_FL_ENABLED \| MEDIA_LNK_FL_IMMUTABLE),
	/* Link: Sensor B (Pad 0)->(Pad 0) Debayer B */
	VIMC_DATA_LINK(SENSOR_B, 0, DEBAYER_B, 0,
	MEDIA_LNK_FL_ENABLED \| MEDIA_LNK_FL_IMMUTABLE),
	/* Link: Sensor B (Pad 0)->(Pad 0) Raw Capture 1 */
	VIMC_DATA_LINK(SENSOR_B, 0, RAW_CAPTURE_1, 0,
	MEDIA_LNK_FL_ENABLED \| MEDIA_LNK_FL_IMMUTABLE),
	/* Link: Debayer A (Pad 1)->(Pad 0) Scaler */
	VIMC_DATA_LINK(DEBAYER_A, 1, SCALER, 0, MEDIA_LNK_FL_ENABLED),
	/* Link: Debayer B (Pad 1)->(Pad 0) Scaler */
	VIMC_DATA_LINK(DEBAYER_B, 1, SCALER, 0, 0),
	/* Link: RGB/YUV Input (Pad 0)->(Pad 0) Scaler */
	VIMC_DATA_LINK(RGB_YUV_INPUT, 0, SCALER, 0, 0),
	/* Link: Scaler (Pad 1)->(Pad 0) RGB/YUV Capture */
	VIMC_DATA_LINK(SCALER, 1, RGB_YUV_CAPTURE, 0,
	MEDIA_LNK_FL_ENABLED \| MEDIA_LNK_FL_IMMUTABLE),
	};

	static const struct vimc_ancillary_link ancillary_links[] = {
	/* Link: Sensor A -> Lens A */
	VIMC_ANCILLARY_LINK(0, 9),
	/* Link: Sensor B -> Lens B */
	VIMC_ANCILLARY_LINK(1, 10),
	};

	static struct vimc_pipeline_config pipe_cfg = {
	.ents = ent_config,
	.num_ents = ARRAY_SIZE(ent_config),
	.data_links = data_links,
	.num_data_links = ARRAY_SIZE(data_links),
	.ancillary_links = ancillary_links,
	.num_ancillary_links = ARRAY_SIZE(ancillary_links),
	};

	/* -------------------------------------------------------------------------- */

	static void vimc_rm_links(struct vimc_device *vimc)
	{
	unsigned int i;

	for (i = 0; i < vimc->pipe_cfg->num_ents; i++)
	media_entity_remove_links(vimc->ent_devs[i]->ent);
	}

	static int vimc_create_links(struct vimc_device *vimc)
	{
	unsigned int i;
	int ret;

	/* Initialize the links between entities */
	for (i = 0; i < vimc->pipe_cfg->num_data_links; i++) {
	const struct vimc_data_link *link = &vimc->pipe_cfg->data_links[i];

	struct vimc_ent_device *ved_src =
	vimc->ent_devs[link->src_ent];
	struct vimc_ent_device *ved_sink =
	vimc->ent_devs[link->sink_ent];

	ret = media_create_pad_link(ved_src->ent, link->src_pad,
	ved_sink->ent, link->sink_pad,
	link->flags);
	if (ret)
	goto err_rm_links;
	}

	for (i = 0; i < vimc->pipe_cfg->num_ancillary_links; i++) {
	const struct vimc_ancillary_link *link = &vimc->pipe_cfg->ancillary_links[i];

	struct vimc_ent_device *ved_primary =
	vimc->ent_devs[link->primary_ent];
	struct vimc_ent_device *ved_ancillary =
	vimc->ent_devs[link->ancillary_ent];
	struct media_link *ret_link =
	media_create_ancillary_link(ved_primary->ent, ved_ancillary->ent);

	if (IS_ERR(ret_link)) {
	ret = PTR_ERR(link);
	goto err_rm_links;
	}
	}

	return 0;

	err_rm_links:
	vimc_rm_links(vimc);
	return ret;
	}

	static void vimc_release_subdevs(struct vimc_device *vimc)
	{
	unsigned int i;

	for (i = 0; i < vimc->pipe_cfg->num_ents; i++)
	if (vimc->ent_devs[i])
	vimc->pipe_cfg->ents[i].type->release(vimc->ent_devs[i]);
	}

	static void vimc_unregister_subdevs(struct vimc_device *vimc)
	{
	unsigned int i;

	for (i = 0; i < vimc->pipe_cfg->num_ents; i++)
	if (vimc->ent_devs[i] && vimc->pipe_cfg->ents[i].type->unregister)
	vimc->pipe_cfg->ents[i].type->unregister(vimc->ent_devs[i]);
	}

	static int vimc_add_subdevs(struct vimc_device *vimc)
	{
	unsigned int i;

	for (i = 0; i < vimc->pipe_cfg->num_ents; i++) {
	dev_dbg(vimc->mdev.dev, "new entity for %s\n",
	vimc->pipe_cfg->ents[i].name);
	vimc->ent_devs[i] = vimc->pipe_cfg->ents[i].type->add(vimc,
	vimc->pipe_cfg->ents[i].name);
	if (IS_ERR(vimc->ent_devs[i])) {
	int err = PTR_ERR(vimc->ent_devs[i]);

	dev_err(vimc->mdev.dev, "adding entity %s failed (%d)\n",
	vimc->pipe_cfg->ents[i].name, err);
	vimc->ent_devs[i] = NULL;
	vimc_unregister_subdevs(vimc);
	vimc_release_subdevs(vimc);
	return err;
	}
	}
	return 0;
	}

	static void vimc_v4l2_dev_release(struct v4l2_device *v4l2_dev)
	{
	struct vimc_device *vimc =
	container_of(v4l2_dev, struct vimc_device, v4l2_dev);

	vimc_release_subdevs(vimc);
	media_device_cleanup(&vimc->mdev);
	kfree(vimc->ent_devs);
	kfree(vimc);
	}

	static int vimc_register_devices(struct vimc_device *vimc)
	{
	int ret;

	/* Register the v4l2 struct */
	ret = v4l2_device_register(vimc->mdev.dev, &vimc->v4l2_dev);
	if (ret) {
	dev_err(vimc->mdev.dev,
	"v4l2 device register failed (err=%d)\n", ret);
	return ret;
	}
	/* allocate ent_devs */
	vimc->ent_devs = kcalloc(vimc->pipe_cfg->num_ents,
	sizeof(*vimc->ent_devs), GFP_KERNEL);
	if (!vimc->ent_devs) {
	ret = -ENOMEM;
	goto err_v4l2_unregister;
	}

	/* Invoke entity config hooks to initialize and register subdevs */
	ret = vimc_add_subdevs(vimc);
	if (ret)
	goto err_free_ent_devs;

	/* Initialize links */
	ret = vimc_create_links(vimc);
	if (ret)
	goto err_rm_subdevs;

	/* Register the media device */
	ret = media_device_register(&vimc->mdev);
	if (ret) {
	dev_err(vimc->mdev.dev,
	"media device register failed (err=%d)\n", ret);
	goto err_rm_subdevs;
	}

	/* Expose all subdev's nodes*/
	ret = v4l2_device_register_subdev_nodes(&vimc->v4l2_dev);
	if (ret) {
	dev_err(vimc->mdev.dev,
	"vimc subdev nodes registration failed (err=%d)\n",
	ret);
	goto err_mdev_unregister;
	}

	return 0;

	err_mdev_unregister:
	media_device_unregister(&vimc->mdev);
	err_rm_subdevs:
	vimc_unregister_subdevs(vimc);
	vimc_release_subdevs(vimc);
	err_free_ent_devs:
	kfree(vimc->ent_devs);
	err_v4l2_unregister:
	v4l2_device_unregister(&vimc->v4l2_dev);

	return ret;
	}

	static int vimc_probe(struct platform_device *pdev)
	{
	const struct font_desc *font = find_font("VGA8x16");
	struct vimc_device *vimc;
	int ret;

	dev_dbg(&pdev->dev, "probe");

	if (!font) {
	dev_err(&pdev->dev, "could not find font\n");
	return -ENODEV;
	}

	tpg_set_font(font->data);

	if (vimc_allocator == VIMC_ALLOCATOR_DMA_CONTIG)
	dma_coerce_mask_and_coherent(&pdev->dev, DMA_BIT_MASK(32));

	vimc = kzalloc(sizeof(*vimc), GFP_KERNEL);
	if (!vimc)
	return -ENOMEM;

	vimc->pipe_cfg = &pipe_cfg;

	/* Link the media device within the v4l2_device */
	vimc->v4l2_dev.mdev = &vimc->mdev;

	/* Initialize media device */
	strscpy(vimc->mdev.model, VIMC_MDEV_MODEL_NAME,
	sizeof(vimc->mdev.model));
	snprintf(vimc->mdev.bus_info, sizeof(vimc->mdev.bus_info),
	"platform:%s", VIMC_PDEV_NAME);
	vimc->mdev.dev = &pdev->dev;
	media_device_init(&vimc->mdev);

	ret = vimc_register_devices(vimc);
	if (ret) {
	media_device_cleanup(&vimc->mdev);
	kfree(vimc);
	return ret;
	}
	/*
	* the release cb is set only after successful registration.
	* if the registration fails, we release directly from probe
	*/

	vimc->v4l2_dev.release = vimc_v4l2_dev_release;
	platform_set_drvdata(pdev, vimc);
	return 0;
	}

	static int vimc_remove(struct platform_device *pdev)
	{
	struct vimc_device *vimc = platform_get_drvdata(pdev);

	dev_dbg(&pdev->dev, "remove");

	vimc_unregister_subdevs(vimc);
	media_device_unregister(&vimc->mdev);
	v4l2_device_unregister(&vimc->v4l2_dev);
	v4l2_device_put(&vimc->v4l2_dev);

	return 0;
	}

	static void vimc_dev_release(struct device *dev)
	{
	}

	static struct platform_device vimc_pdev = {
	.name = VIMC_PDEV_NAME,
	.dev.release = vimc_dev_release,
	};

	static struct platform_driver vimc_pdrv = {
	.probe = vimc_probe,
	.remove = vimc_remove,
	.driver = {
	.name = VIMC_PDEV_NAME,
	},
	};

	static int __init vimc_init(void)
	{
	int ret;

	ret = platform_device_register(&vimc_pdev);
	if (ret) {
	dev_err(&vimc_pdev.dev,
	"platform device registration failed (err=%d)\n", ret);
	return ret;
	}

	ret = platform_driver_register(&vimc_pdrv);
	if (ret) {
	dev_err(&vimc_pdev.dev,
	"platform driver registration failed (err=%d)\n", ret);
	platform_driver_unregister(&vimc_pdrv);
	return ret;
	}

	return 0;
	}

	static void __exit vimc_exit(void)
	{
	platform_driver_unregister(&vimc_pdrv);

	platform_device_unregister(&vimc_pdev);
	}

	module_init(vimc_init);
	module_exit(vimc_exit);

	MODULE_DESCRIPTION("Virtual Media Controller Driver (VIMC)");
	MODULE_AUTHOR("Helen Fornazier <helen.fornazier@gmail.com>");
	MODULE_LICENSE("GPL");