[media] vimc: Virtual Media Controller core, capture and sensor

First version of the Virtual Media Controller.
Add a simple version of the core of the driver, the capture and
sensor nodes in the topology, generating a grey image in a hardcoded
format.

Signed-off-by: Helen Koike <helen.koike@collabora.com>
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
[hans.verkuil@cisco.com: fix small typo in Kconfig]

Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>

1 files changed, 112 insertions, 0 deletions

diff --git a/drivers/media/platform/vimc/vimc-core.h b/drivers/media/platform/vimc/vimc-core.h
new file mode 100644
index 000000000000..4525d23211ca
--- /dev/null
+++ b/drivers/media/platform/vimc/vimc-core.h
@@ -0,0 +1,112 @@
+/*
+ * vimc-core.h Virtual Media Controller Driver
+ *
+ * Copyright (C) 2015-2017 Helen Koike <helen.fornazier@gmail.com>
+ *
+ * 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.
+ *
+ */
+
+#ifndef _VIMC_CORE_H_
+#define _VIMC_CORE_H_
+
+#include <linux/slab.h>
+#include <media/v4l2-device.h>
+
+/**
+ * struct vimc_pix_map - maps media bus code with v4l2 pixel format
+ *
+ * @code:		media bus format code defined by MEDIA_BUS_FMT_* macros
+ * @bbp:		number of bytes each pixel occupies
+ * @pixelformat:	pixel format devined by V4L2_PIX_FMT_* macros
+ *
+ * Struct which matches the MEDIA_BUS_FMT_* codes with the corresponding
+ * V4L2_PIX_FMT_* fourcc pixelformat and its bytes per pixel (bpp)
+ */
+struct vimc_pix_map {
+	unsigned int code;
+	unsigned int bpp;
+	u32 pixelformat;
+};
+
+/**
+ * struct vimc_ent_device - core struct that represents a node in the topology
+ *
+ * @ent:		the pointer to struct media_entity for the node
+ * @pads:		the list of pads of the node
+ * @destroy:		callback to destroy the node
+ * @process_frame:	callback send a frame to that node
+ *
+ * Each node of the topology must create a vimc_ent_device struct. Depending on
+ * the node it will be of an instance of v4l2_subdev or video_device struct
+ * where both contains a struct media_entity.
+ * Those structures should embedded the vimc_ent_device struct through
+ * v4l2_set_subdevdata() and video_set_drvdata() respectivaly, allowing the
+ * vimc_ent_device struct to be retrieved from the corresponding struct
+ * media_entity
+ */
+struct vimc_ent_device {
+	struct media_entity *ent;
+	struct media_pad *pads;
+	void (*destroy)(struct vimc_ent_device *);
+	void (*process_frame)(struct vimc_ent_device *ved,
+			      struct media_pad *sink, const void *frame);
+};
+
+/**
+ * vimc_propagate_frame - propagate a frame through the topology
+ *
+ * @src:	the source pad where the frame is being originated
+ * @frame:	the frame to be propagated
+ *
+ * This function will call the process_frame callback from the vimc_ent_device
+ * struct of the nodes directly connected to the @src pad
+ */
+int vimc_propagate_frame(struct media_pad *src, const void *frame);
+
+/**
+ * vimc_pads_init - initialize pads
+ *
+ * @num_pads:	number of pads to initialize
+ * @pads_flags:	flags to use in each pad
+ *
+ * Helper functions to allocate/initialize pads
+ */
+struct media_pad *vimc_pads_init(u16 num_pads,
+				 const unsigned long *pads_flag);
+
+/**
+ * vimc_pads_cleanup - free pads
+ *
+ * @pads: pointer to the pads
+ *
+ * Helper function to free the pads initialized with vimc_pads_init
+ */
+static inline void vimc_pads_cleanup(struct media_pad *pads)
+{
+	kfree(pads);
+}
+
+/**
+ * vimc_pix_map_by_code - get vimc_pix_map struct by media bus code
+ *
+ * @code:		media bus format code defined by MEDIA_BUS_FMT_* macros
+ */
+const struct vimc_pix_map *vimc_pix_map_by_code(u32 code);
+
+/**
+ * vimc_pix_map_by_pixelformat - get vimc_pix_map struct by v4l2 pixel format
+ *
+ * @pixelformat:	pixel format devined by V4L2_PIX_FMT_* macros
+ */
+const struct vimc_pix_map *vimc_pix_map_by_pixelformat(u32 pixelformat);
+
+#endif