media: videobuf2: Add new uAPI for DVB streaming I/O

Adds a new uAPI for DVB to use streaming I/O which is implemented
based on videobuf2, using those new ioctls:

- DMX_REQBUFS:  Request kernel to allocate buffers which count and size
	        are dedicated by user.
- DMX_QUERYBUF: Get the buffer information like a memory offset which
		will mmap() and be shared with user-space.
- DMX_EXPBUF:   Just for testing whether buffer-exporting success or not.
- DMX_QBUF:     Pass the buffer to kernel-space.
- DMX_DQBUF:    Get back the buffer which may contain TS data.

Originally developed by: Junghak Sung <jh1009.sung@samsung.com>, as
seen at:
	https://patchwork.linuxtv.org/patch/31613/
	https://patchwork.kernel.org/patch/7334301/

The original patch was written before merging VB2-core functionalities
upstream. When such series was added, several adjustments were made,
fixing some issues with	V4L2, causing the original patch to be
non-trivially rebased.

After rebased, a few bugs in the patch were fixed. The patch was
also enhanced it and polling functionality got added.

The main changes over the original patch are:

dvb_vb2_fill_buffer():
	- Set the size of the outgoing buffer after while loop using
	  vb2_set_plane_payload;

	- Added NULL check for source buffer as per normal convention
	  of demux driver, this is called twice, first time with valid
	  buffer second time with NULL pointer, if its not handled,
	  it will result in  crash

	- Restricted spinlock for only list_* operations

dvb_vb2_init():
	- Restricted q->io_modes to only VB2_MMAP as its the only
	  supported mode

dvb_vb2_release():
	- Replaced the && in if condiion with &, because otherwise
	  it was always getting satisfied.

dvb_vb2_stream_off():
	- Added list_del code for enqueud buffers upon stream off

dvb_vb2_poll():
	- Added this new function in order to support polling

dvb_demux_poll() and dvb_dvr_poll()
	- dvb_vb2_poll() is now called from these functions

- Ported this patch and latest videobuf2 to lower kernel versions and
  tested auto scan.

Co-developed-by: Junghak Sung <jh1009.sung@samsung.com>

[mchehab@s-opensource.com: checkpatch fixes]
Signed-off-by: Junghak Sung <jh1009.sung@samsung.com>
Signed-off-by: Geunyoung Kim <nenggun.kim@samsung.com>
Acked-by: Seung-Woo Kim <sw0312.kim@samsung.com>
Acked-by: Inki Dae <inki.dae@samsung.com>
Signed-off-by: Satendra Singh Thakur <satendra.t@samsung.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>

1 files changed, 423 insertions, 0 deletions

diff --git a/drivers/media/dvb-core/dvb_vb2.c b/drivers/media/dvb-core/dvb_vb2.c
new file mode 100644
index 000000000000..34193a4acc47
--- /dev/null
+++ b/drivers/media/dvb-core/dvb_vb2.c
@@ -0,0 +1,423 @@
+/*
+ * dvb-vb2.c - dvb-vb2
+ *
+ * Copyright (C) 2015 Samsung Electronics
+ *
+ * Author: jh1009.sung@samsung.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.
+ */
+
+#include <linux/err.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/mm.h>
+
+#include "dvbdev.h"
+#include "dvb_vb2.h"
+
+static int vb2_debug;
+module_param(vb2_debug, int, 0644);
+
+#define dprintk(level, fmt, arg...)					      \
+	do {								      \
+		if (vb2_debug >= level)					      \
+			pr_info("vb2: %s: " fmt, __func__, ## arg); \
+	} while (0)
+
+static int _queue_setup(struct vb2_queue *vq,
+			unsigned int *nbuffers, unsigned int *nplanes,
+			unsigned int sizes[], struct device *alloc_devs[])
+{
+	struct dvb_vb2_ctx *ctx = vb2_get_drv_priv(vq);
+
+	*nbuffers = ctx->buf_cnt;
+	*nplanes = 1;
+	sizes[0] = ctx->buf_siz;
+
+	/*
+	 * videobuf2-vmalloc allocator is context-less so no need to set
+	 * alloc_ctxs array.
+	 */
+
+	dprintk(3, "[%s] count=%d, size=%d\n", ctx->name,
+		*nbuffers, sizes[0]);
+
+	return 0;
+}
+
+static int _buffer_prepare(struct vb2_buffer *vb)
+{
+	struct dvb_vb2_ctx *ctx = vb2_get_drv_priv(vb->vb2_queue);
+	unsigned long size = ctx->buf_siz;
+
+	if (vb2_plane_size(vb, 0) < size) {
+		dprintk(1, "[%s] data will not fit into plane (%lu < %lu)\n",
+			ctx->name, vb2_plane_size(vb, 0), size);
+		return -EINVAL;
+	}
+
+	vb2_set_plane_payload(vb, 0, size);
+	dprintk(3, "[%s]\n", ctx->name);
+
+	return 0;
+}
+
+static void _buffer_queue(struct vb2_buffer *vb)
+{
+	struct dvb_vb2_ctx *ctx = vb2_get_drv_priv(vb->vb2_queue);
+	struct dvb_buffer *buf = container_of(vb, struct dvb_buffer, vb);
+	unsigned long flags = 0;
+
+	spin_lock_irqsave(&ctx->slock, flags);
+	list_add_tail(&buf->list, &ctx->dvb_q);
+	spin_unlock_irqrestore(&ctx->slock, flags);
+
+	dprintk(3, "[%s]\n", ctx->name);
+}
+
+static int _start_streaming(struct vb2_queue *vq, unsigned int count)
+{
+	struct dvb_vb2_ctx *ctx = vb2_get_drv_priv(vq);
+
+	dprintk(3, "[%s] count=%d\n", ctx->name, count);
+	return 0;
+}
+
+static void _stop_streaming(struct vb2_queue *vq)
+{
+	struct dvb_vb2_ctx *ctx = vb2_get_drv_priv(vq);
+
+	dprintk(3, "[%s]\n", ctx->name);
+}
+
+static void _dmxdev_lock(struct vb2_queue *vq)
+{
+	struct dvb_vb2_ctx *ctx = vb2_get_drv_priv(vq);
+
+	mutex_lock(&ctx->mutex);
+	dprintk(3, "[%s]\n", ctx->name);
+}
+
+static void _dmxdev_unlock(struct vb2_queue *vq)
+{
+	struct dvb_vb2_ctx *ctx = vb2_get_drv_priv(vq);
+
+	if (mutex_is_locked(&ctx->mutex))
+		mutex_unlock(&ctx->mutex);
+	dprintk(3, "[%s]\n", ctx->name);
+}
+
+static const struct vb2_ops dvb_vb2_qops = {
+	.queue_setup		= _queue_setup,
+	.buf_prepare		= _buffer_prepare,
+	.buf_queue		= _buffer_queue,
+	.start_streaming	= _start_streaming,
+	.stop_streaming		= _stop_streaming,
+	.wait_prepare		= _dmxdev_unlock,
+	.wait_finish		= _dmxdev_lock,
+};
+
+static void _fill_dmx_buffer(struct vb2_buffer *vb, void *pb)
+{
+	struct dvb_vb2_ctx *ctx = vb2_get_drv_priv(vb->vb2_queue);
+	struct dmx_buffer *b = pb;
+
+	b->index = vb->index;
+	b->length = vb->planes[0].length;
+	b->bytesused = vb->planes[0].bytesused;
+	b->offset = vb->planes[0].m.offset;
+	memset(b->reserved, 0, sizeof(b->reserved));
+	dprintk(3, "[%s]\n", ctx->name);
+}
+
+static int _fill_vb2_buffer(struct vb2_buffer *vb,
+			    const void *pb, struct vb2_plane *planes)
+{
+	struct dvb_vb2_ctx *ctx = vb2_get_drv_priv(vb->vb2_queue);
+
+	planes[0].bytesused = 0;
+	dprintk(3, "[%s]\n", ctx->name);
+
+	return 0;
+}
+
+static const struct vb2_buf_ops dvb_vb2_buf_ops = {
+	.fill_user_buffer	= _fill_dmx_buffer,
+	.fill_vb2_buffer	= _fill_vb2_buffer,
+};
+
+/*
+ * Videobuf operations
+ */
+int dvb_vb2_init(struct dvb_vb2_ctx *ctx, const char *name, int nonblocking)
+{
+	struct vb2_queue *q = &ctx->vb_q;
+	int ret;
+
+	memset(ctx, 0, sizeof(struct dvb_vb2_ctx));
+	q->type = DVB_BUF_TYPE_CAPTURE;
+	/**capture type*/
+	q->is_output = 0;
+	/**only mmap is supported currently*/
+	q->io_modes = VB2_MMAP;
+	q->drv_priv = ctx;
+	q->buf_struct_size = sizeof(struct dvb_buffer);
+	q->min_buffers_needed = 1;
+	q->ops = &dvb_vb2_qops;
+	q->mem_ops = &vb2_vmalloc_memops;
+	q->buf_ops = &dvb_vb2_buf_ops;
+	q->num_buffers = 0;
+	ret = vb2_core_queue_init(q);
+	if (ret) {
+		ctx->state = DVB_VB2_STATE_NONE;
+		dprintk(1, "[%s] errno=%d\n", ctx->name, ret);
+		return ret;
+	}
+
+	mutex_init(&ctx->mutex);
+	spin_lock_init(&ctx->slock);
+	INIT_LIST_HEAD(&ctx->dvb_q);
+
+	strncpy(ctx->name, name, DVB_VB2_NAME_MAX);
+	ctx->nonblocking = nonblocking;
+	ctx->state = DVB_VB2_STATE_INIT;
+
+	dprintk(3, "[%s]\n", ctx->name);
+
+	return 0;
+}
+
+int dvb_vb2_release(struct dvb_vb2_ctx *ctx)
+{
+	struct vb2_queue *q = (struct vb2_queue *)&ctx->vb_q;
+
+	if (ctx->state & DVB_VB2_STATE_INIT)
+		vb2_core_queue_release(q);
+
+	ctx->state = DVB_VB2_STATE_NONE;
+	dprintk(3, "[%s]\n", ctx->name);
+
+	return 0;
+}
+
+int dvb_vb2_stream_on(struct dvb_vb2_ctx *ctx)
+{
+	struct vb2_queue *q = &ctx->vb_q;
+	int ret;
+
+	ret = vb2_core_streamon(q, q->type);
+	if (ret) {
+		ctx->state = DVB_VB2_STATE_NONE;
+		dprintk(1, "[%s] errno=%d\n", ctx->name, ret);
+		return ret;
+	}
+	ctx->state |= DVB_VB2_STATE_STREAMON;
+	dprintk(3, "[%s]\n", ctx->name);
+
+	return 0;
+}
+
+int dvb_vb2_stream_off(struct dvb_vb2_ctx *ctx)
+{
+	struct vb2_queue *q = (struct vb2_queue *)&ctx->vb_q;
+	int ret;
+	unsigned long flags = 0;
+
+	ctx->state &= ~DVB_VB2_STATE_STREAMON;
+	spin_lock_irqsave(&ctx->slock, flags);
+	while (!list_empty(&ctx->dvb_q)) {
+		struct dvb_buffer       *buf;
+
+		buf = list_entry(ctx->dvb_q.next,
+				 struct dvb_buffer, list);
+		list_del(&buf->list);
+		spin_unlock_irqrestore(&ctx->slock, flags);
+		vb2_buffer_done(&buf->vb, VB2_BUF_STATE_ERROR);
+		spin_lock_irqsave(&ctx->slock, flags);
+	}
+	spin_unlock_irqrestore(&ctx->slock, flags);
+	ret = vb2_core_streamoff(q, q->type);
+	if (ret) {
+		ctx->state = DVB_VB2_STATE_NONE;
+		dprintk(1, "[%s] errno=%d\n", ctx->name, ret);
+		return ret;
+	}
+	dprintk(3, "[%s]\n", ctx->name);
+
+	return 0;
+}
+
+int dvb_vb2_is_streaming(struct dvb_vb2_ctx *ctx)
+{
+	return (ctx->state & DVB_VB2_STATE_STREAMON);
+}
+
+int dvb_vb2_fill_buffer(struct dvb_vb2_ctx *ctx,
+			const unsigned char *src, int len)
+{
+	unsigned long flags = 0;
+	void *vbuf = NULL;
+	int todo = len;
+	unsigned char *psrc = (unsigned char *)src;
+	int ll = 0;
+
+	dprintk(3, "[%s] %d bytes are rcvd\n", ctx->name, len);
+	if (!src) {
+		dprintk(3, "[%s]:NULL pointer src\n", ctx->name);
+		/**normal case: This func is called twice from demux driver
+		 * once with valid src pointer, second time with NULL pointer
+		 */
+		return 0;
+	}
+	while (todo) {
+		if (!ctx->buf) {
+			spin_lock_irqsave(&ctx->slock, flags);
+			if (list_empty(&ctx->dvb_q)) {
+				spin_unlock_irqrestore(&ctx->slock, flags);
+				dprintk(3, "[%s] Buffer overflow!!!\n",
+					ctx->name);
+				break;
+			}
+
+			ctx->buf = list_entry(ctx->dvb_q.next,
+					      struct dvb_buffer, list);
+			list_del(&ctx->buf->list);
+			spin_unlock_irqrestore(&ctx->slock, flags);
+			ctx->remain = vb2_plane_size(&ctx->buf->vb, 0);
+			ctx->offset = 0;
+		}
+
+		if (!dvb_vb2_is_streaming(ctx)) {
+			vb2_buffer_done(&ctx->buf->vb, VB2_BUF_STATE_ERROR);
+			ctx->buf = NULL;
+			break;
+		}
+
+		/* Fill buffer */
+		ll = min(todo, ctx->remain);
+		vbuf = vb2_plane_vaddr(&ctx->buf->vb, 0);
+		memcpy(vbuf + ctx->offset, psrc, ll);
+		todo -= ll;
+		psrc += ll;
+
+		ctx->remain -= ll;
+		ctx->offset += ll;
+
+		if (ctx->remain == 0) {
+			vb2_buffer_done(&ctx->buf->vb, VB2_BUF_STATE_DONE);
+			ctx->buf = NULL;
+		}
+	}
+
+	if (ctx->nonblocking && ctx->buf) {
+		vb2_set_plane_payload(&ctx->buf->vb, 0, ll);
+		vb2_buffer_done(&ctx->buf->vb, VB2_BUF_STATE_DONE);
+		ctx->buf = NULL;
+	}
+
+	if (todo)
+		dprintk(1, "[%s] %d bytes are dropped.\n", ctx->name, todo);
+	else
+		dprintk(3, "[%s]\n", ctx->name);
+
+	dprintk(3, "[%s] %d bytes are copied\n", ctx->name, len - todo);
+	return (len - todo);
+}
+
+int dvb_vb2_reqbufs(struct dvb_vb2_ctx *ctx, struct dmx_requestbuffers *req)
+{
+	int ret;
+
+	ctx->buf_siz = req->size;
+	ctx->buf_cnt = req->count;
+	ret = vb2_core_reqbufs(&ctx->vb_q, VB2_MEMORY_MMAP, &req->count);
+	if (ret) {
+		ctx->state = DVB_VB2_STATE_NONE;
+		dprintk(1, "[%s] count=%d size=%d errno=%d\n", ctx->name,
+			ctx->buf_cnt, ctx->buf_siz, ret);
+		return ret;
+	}
+	ctx->state |= DVB_VB2_STATE_REQBUFS;
+	dprintk(3, "[%s] count=%d size=%d\n", ctx->name,
+		ctx->buf_cnt, ctx->buf_siz);
+
+	return 0;
+}
+
+int dvb_vb2_querybuf(struct dvb_vb2_ctx *ctx, struct dmx_buffer *b)
+{
+	vb2_core_querybuf(&ctx->vb_q, b->index, b);
+	dprintk(3, "[%s] index=%d\n", ctx->name, b->index);
+	return 0;
+}
+
+int dvb_vb2_expbuf(struct dvb_vb2_ctx *ctx, struct dmx_exportbuffer *exp)
+{
+	struct vb2_queue *q = &ctx->vb_q;
+	int ret;
+
+	ret = vb2_core_expbuf(&ctx->vb_q, &exp->fd, q->type, exp->index,
+			      0, exp->flags);
+	if (ret) {
+		dprintk(1, "[%s] index=%d errno=%d\n", ctx->name,
+			exp->index, ret);
+		return ret;
+	}
+	dprintk(3, "[%s] index=%d fd=%d\n", ctx->name, exp->index, exp->fd);
+
+	return 0;
+}
+
+int dvb_vb2_qbuf(struct dvb_vb2_ctx *ctx, struct dmx_buffer *b)
+{
+	int ret;
+
+	ret = vb2_core_qbuf(&ctx->vb_q, b->index, b);
+	if (ret) {
+		dprintk(1, "[%s] index=%d errno=%d\n", ctx->name,
+			b->index, ret);
+		return ret;
+	}
+	dprintk(5, "[%s] index=%d\n", ctx->name, b->index);
+
+	return 0;
+}
+
+int dvb_vb2_dqbuf(struct dvb_vb2_ctx *ctx, struct dmx_buffer *b)
+{
+	int ret;
+
+	ret = vb2_core_dqbuf(&ctx->vb_q, &b->index, b, ctx->nonblocking);
+	if (ret) {
+		dprintk(1, "[%s] errno=%d\n", ctx->name, ret);
+		return ret;
+	}
+	dprintk(5, "[%s] index=%d\n", ctx->name, b->index);
+
+	return 0;
+}
+
+int dvb_vb2_mmap(struct dvb_vb2_ctx *ctx, struct vm_area_struct *vma)
+{
+	int ret;
+
+	ret = vb2_mmap(&ctx->vb_q, vma);
+	if (ret) {
+		dprintk(1, "[%s] errno=%d\n", ctx->name, ret);
+		return ret;
+	}
+	dprintk(3, "[%s] ret=%d\n", ctx->name, ret);
+
+	return 0;
+}
+
+unsigned int dvb_vb2_poll(struct dvb_vb2_ctx *ctx, struct file *file,
+			  poll_table *wait)
+{
+	dprintk(3, "[%s]\n", ctx->name);
+	return vb2_core_poll(&ctx->vb_q, file, wait);
+}
+