Staging: Yet another (third) dt3155 driver PCI/video4linux compliant

Kernel module (device driver) for dt3155 frame grabber
video4linux2 compliant (finally). Works with "xawtv -f".

======================================================

This driver is written (almost) from scratch, using the
allocator developed for dt3155pci see bellow). The driver
uses videobuf-dma-contig interface modified to use the above
mentioned allocator instead of dma_alloc_coheren().

The first thing to do was to design a new allocator based
on allocating a configurable number of 4MB chunks of memory,
that latter are broken into frame buffers of 768x576 bytes
kept in different FIFOs (queues). As far as the driver autoloads
as a kernel module during kernel boot, the allocation of 4MB
chunks succeeds.

The driver keeps three FIFOs: one for 4MB chunks, one for free
buffers (available for allocations) and one for buffers already
allocated. Allocation/deallocation is done automatically though
the video4linux videobuf subsystem (some pointers to functions
are replaced by driver supplied functions).

Sure, there are problems:

1. The device tested to work with "xawtv -f" either via read()
   method (DT3155_STREAMING not selected), or via mmap() method
   (DT3155_STREAMING is selected) only. This coresponds to either
   cap->capabilities = V4L2_CAP_VIDEO_CAPTURE | V4L2_CAP_READWRITE;
   or
   cap->capabilities = V4L2_CAP_VIDEO_CAPTURE | V4L2_CAP_STREAMING;
   but not when
   cap->capabilities = V4L2_CAP_VIDEO_CAPTURE |
                           V4L2_CAP_STREAMING |
                           V4L2_CAP_READWRITE;
   This is because xawtv calls poll() before starting streaming,
   but videobuf_poll_stream() automatically starts reading if streaming
   is not started.
   This selection is made during kernel configuration (for now).

2. Works for CCIR, but should work for RS-170 (not tested)
   This is made also during kernel configuration.

3. Could work for multiple dt3155 frame grabbers in a PC,
   (private data is allocated during PCI probe() method), but
   is not tested due to lack of a second board.

4. Not tested on a BIG ENDIAN architecture.

5. Many others you could find .... :-)

All critics, comments, suggestions are wellcome.

Signed-off-by: Marin Mitov <mitov@issp.bas.bg>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

drivers/staging/Kconfig

@@ -137,6 +137,8 @@ source "drivers/staging/sm7xx/Kconfig"
 
 source "drivers/staging/dt3155/Kconfig"
 
+source "drivers/staging/dt3155v4l/Kconfig"
+
 source "drivers/staging/crystalhd/Kconfig"
 
 source "drivers/staging/cxt1e1/Kconfig"

drivers/staging/dt3155v4l/Kconfig

@@ -0,0 +1,28 @@
+config VIDEO_DT3155
+	tristate "DT3155 frame grabber, Video4Linux interface"
+	depends on PCI && VIDEO_DEV && VIDEO_V4L2
+	select VIDEOBUF_DMA_CONTIG
+	default n
+	---help---
+	  Enables dt3155 device driver for the DataTranslation DT3155 frame grabber.
+	  Say Y here if you have this hardware.
+	  In doubt, say N.
+
+	  To compile this driver as a module, choose M here: the
+	  module will be called dt3155_v4l.
+
+config DT3155_CCIR
+	bool "Selects CCIR/50Hz vertical refresh"
+	depends on VIDEO_DT3155
+	default y
+	---help---
+	  Select it for CCIR/50Hz (European region),
+	  or leave it unselected for RS-170/60Hz (North America).
+
+config DT3155_STREAMING
+	bool "Selects mmap streaming instead of read method"
+	depends on VIDEO_DT3155
+	default y
+	---help---
+	  Select it if you wish to try mmap streaming, or
+	  or leave it unselected for using read method.

drivers/staging/dt3155v4l/Makefile

@@ -0,0 +1,4 @@
+obj-$(CONFIG_VIDEO_DT3155)	+= dt3155_v4l.o
+dt3155_v4l-objs :=	\
+		dt3155-bufs.o	\
+		dt3155v4l.o

drivers/staging/dt3155v4l/dt3155-bufs.c

@@ -0,0 +1,256 @@
+/***************************************************************************
+ *   Copyright (C) 2006-2010 by Marin Mitov                                *
+ *   mitov@issp.bas.bg                                                     *
+ *                                                                         *
+ *   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.                          *
+ *                                                                         *
+ *   You should have received a copy of the GNU General Public License     *
+ *   along with this program; if not, write to the                         *
+ *   Free Software Foundation, Inc.,                                       *
+ *   59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.             *
+ ***************************************************************************/
+
+#include "dt3155-bufs.h"
+
+/**
+ * dt3155_init_chunks_buf - creates a chunk buffer and allocates memory for it
+ *
+ * returns:	a pointer to the struct dt3155_buf or NULL if failed
+ *
+ * Creates a struct dt3155_buf, then allocates a chunk of memory of
+ * size DT3155_CHUNK_SIZE and sets all the pages in it as Reserved.
+ * This is done to be able to use remap_pfn_range() on these buffers
+ * (which do not work on normal memory if Reserved bit is not set)
+ */
+struct dt3155_buf *
+dt3155_init_chunks_buf(void)
+{	/*  could sleep  */
+	struct dt3155_buf *buf;
+	int i;
+
+	buf = kzalloc(sizeof(*buf), GFP_KERNEL);
+	if (!buf)
+		return NULL;
+	buf->cpu = (void *)__get_free_pages(DT3155_CHUNK_FLAGS,
+					get_order(DT3155_CHUNK_SIZE));
+	if (!buf->cpu) {
+		kfree(buf);
+		return NULL;
+	}
+	for (i = 0; i < DT3155_CHUNK_SIZE; i += PAGE_SIZE)
+		SetPageReserved(virt_to_page(buf->cpu + i));
+	return buf;  /*   success  */
+}
+
+/**
+ * dt3155_free_chunks_buf - destroys the specified buffer
+ *
+ * @buf:	the buffer to be freed
+ *
+ * Clears Reserved bit of all pages in the chunk, frees the chunk memory
+ * and destroys struct dt3155_buf.
+ */
+void
+dt3155_free_chunks_buf(struct dt3155_buf *buf)
+{
+	int i;
+
+	for (i = 0; i < DT3155_CHUNK_SIZE; i += PAGE_SIZE)
+		ClearPageReserved(virt_to_page(buf->cpu + i));
+	free_pages((unsigned long)buf->cpu, get_order(DT3155_CHUNK_SIZE));
+	kfree(buf);
+}
+
+/**
+ * dt3155_init_fifo - creates and initializes a fifo
+ *
+ * returns:	a pointer to the crated and initialized struct dt3155_fifo
+ *		or NULL if failed
+ */
+struct dt3155_fifo *
+dt3155_init_fifo(void)
+{	/* could sleep  */
+	struct dt3155_fifo *fifo = kzalloc(sizeof(*fifo), GFP_KERNEL);
+	if (fifo)
+		spin_lock_init(&fifo->lock);
+	return fifo;
+}
+
+/*	dt3155_free_fifo(x)  defined as macro in dt3155.h   */
+
+/**
+ * dt3155_get_buf - gets a buffer from the fifo
+ *
+ * @fifo:	the fifo to get a buffer from
+ *
+ * returns:	a pointer to the buffer or NULL if failed
+ *
+ * dt3155_get_buf gets the fifo's spin_lock and returns the
+ * buffer pointed by the head. Could be used in any context.
+ */
+struct dt3155_buf *
+dt3155_get_buf(struct dt3155_fifo *fifo)
+{
+	unsigned long flags;
+	struct dt3155_buf *tmp_buf;
+
+	spin_lock_irqsave(&fifo->lock, flags);
+	tmp_buf = fifo->head;
+	if (fifo->head)
+		fifo->head = fifo->head->next;
+	if (!fifo->head)
+		fifo->tail = NULL;
+	spin_unlock_irqrestore(&fifo->lock, flags);
+	return tmp_buf;
+}
+
+/**
+ * dt3155_put_buf - puts a buffer into a fifo
+ *
+ * @buf:	the buffer to put
+ * @fifo:	the fifo to put the buffer in
+ *
+ * dt3155_put_buf gets the fifo's spin_lock and puts the buf
+ * at the tail of the fifo. Could be used in any context.
+ */
+void
+dt3155_put_buf(struct dt3155_buf *buf, struct dt3155_fifo *fifo)
+{
+	unsigned long flags;
+
+	spin_lock_irqsave(&fifo->lock, flags);
+	buf->next = NULL;
+	if (fifo->tail)
+		fifo->tail->next = buf;
+	fifo->tail = buf;
+	if (!fifo->head)
+		fifo->head = buf;
+	spin_unlock_irqrestore(&fifo->lock, flags);
+}
+
+/**
+ * dt3155_init_chunks_fifo - creates and fills a chunks_fifo
+ *
+ * returns:	a pointer to the fifo or NULL if failed
+ *
+ * dt3155_init_chunks_fifo creates and fills the fifo with
+ * a number of chunks <= DT3155_CHUNK_NUM. The returned fifo
+ * contains at least one chunk.
+ */
+struct dt3155_fifo *
+dt3155_init_chunks_fifo(void)
+{	/*  could sleep  */
+	int i;
+
+	struct dt3155_fifo *chunks;
+	struct dt3155_buf *tmp_buf;
+
+	chunks = dt3155_init_fifo();
+	if (!chunks)
+		return NULL;
+	tmp_buf = dt3155_init_chunks_buf();
+	if (!tmp_buf) {
+		dt3155_free_fifo(chunks);
+		return NULL;
+	}
+	dt3155_put_buf(tmp_buf, chunks);
+	for (i = 1; i < DT3155_CHUNK_NUM; i++) {
+		tmp_buf = dt3155_init_chunks_buf();
+		if (!tmp_buf)
+			break;
+		dt3155_put_buf(tmp_buf, chunks);
+	}
+	return chunks;
+}
+
+/**
+ * dt3155_free_chunks_fifo - empties and destroys the chunks_fifo
+ *
+ * @chunks:	the chunks_fifo to be freed
+ *
+ * dt3155_free_chunks_fifo deallocates all chunks in the fifo and
+ * destroys it.
+ */
+void
+dt3155_free_chunks_fifo(struct dt3155_fifo *chunks)
+{
+	int buf_count = 0;
+	struct dt3155_buf *buf;
+
+	while ((buf = dt3155_get_buf(chunks))) {
+		dt3155_free_chunks_buf(buf);
+		buf_count++;
+	}
+	dt3155_free_fifo(chunks);
+	printk(KERN_INFO "dt3155: %i chunks freed\n", buf_count);
+}
+
+/**
+ * dt3155_init_ibufs_fifo - creates and fills an image buffer fifo
+ *
+ * @chunks:	chunks_fifo to take memory from
+ * @buf_size:	the size of image buffers
+ *
+ * returns:	a pointer to the fifo filled with image buffers
+ *
+ * dt3155_init_ibufs_fifo takes chunks from chunks_fifo, chops them
+ * into pieces of size buf_size and fills image fifo with them.
+ */
+struct dt3155_fifo *
+dt3155_init_ibufs_fifo(struct dt3155_fifo *chunks, int buf_size)
+{	/*  could sleep  */
+	int i, buf_count = 0;
+	struct dt3155_buf *tmp_ibuf, *chunks_buf, *last_chunk;
+	struct dt3155_fifo *tmp_fifo;
+
+	tmp_fifo = dt3155_init_fifo();
+	if (!tmp_fifo)
+		return NULL;
+	last_chunk = chunks->tail;
+	do {
+		chunks_buf = dt3155_get_buf(chunks);
+		dt3155_put_buf(chunks_buf, chunks);
+		for (i = 0; i < DT3155_CHUNK_SIZE / buf_size; i++) {
+			tmp_ibuf = kzalloc(sizeof(*tmp_ibuf), GFP_KERNEL);
+			if (tmp_ibuf) {
+				tmp_ibuf->cpu =
+					chunks_buf->cpu + DT3155_BUF_SIZE * i;
+				dt3155_put_buf(tmp_ibuf, tmp_fifo);
+				buf_count++;
+			} else {
+				if (buf_count) {
+					goto print_num_bufs;
+				} else {
+					dt3155_free_fifo(tmp_fifo);
+					return NULL;
+				}
+			}
+		}
+	} while (chunks_buf != last_chunk);
+print_num_bufs:
+	printk(KERN_INFO "dt3155: %i image buffers available\n", buf_count);
+	return tmp_fifo;
+}
+
+/**
+ * dt3155_free_ibufs_fifo - empties and destroys an image fifo
+ *
+ * @fifo:	the fifo to free
+ */
+void
+dt3155_free_ibufs_fifo(struct dt3155_fifo *fifo)
+{
+	struct dt3155_buf *tmp_ibuf;
+
+	while ((tmp_ibuf = dt3155_get_buf(fifo)))
+		kfree(tmp_ibuf);
+	kfree(fifo);
+}

drivers/staging/dt3155v4l/dt3155-bufs.h

@@ -0,0 +1,88 @@
+/***************************************************************************
+ *   Copyright (C) 2006-2010 by Marin Mitov                                *
+ *   mitov@issp.bas.bg                                                     *
+ *                                                                         *
+ *   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.                          *
+ *                                                                         *
+ *   You should have received a copy of the GNU General Public License     *
+ *   along with this program; if not, write to the                         *
+ *   Free Software Foundation, Inc.,                                       *
+ *   59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.             *
+ ***************************************************************************/
+
+#ifndef _DT3155_BUFS_H_
+#define _DT3155_BUFS_H_
+
+#include <linux/pci.h>
+
+/* 4 chunks of 4MB, 9 buffers each = 36 buffers (> VIDEO_MAX_FRAME) */
+#define DT3155_CHUNK_NUM 4
+
+/* DT3155_CHUNK_SIZE should be 4M (2^22) or less, but more than image size */
+#define DT3155_CHUNK_SIZE (1U << 22)
+#define DT3155_CHUNK_FLAGS (GFP_KERNEL | GFP_DMA32 | __GFP_COLD | __GFP_NOWARN)
+
+/* DT3155_BUF_SIZE = 108 * PAGE_SIZE, so each buf is PAGE_SIZE alligned  */
+#define DT3155_BUF_SIZE (768 * 576)
+
+/**
+ * struct dt3155_buf - image buffer structure
+ *
+ * @cpu:	virtual kernel address of the buffer
+ * @dma:	dma (bus) address of the buffer
+ * @next:	pointer to the next buffer in the fifo
+ * @tv:		time value when the image has been acquired
+ */
+struct dt3155_buf {
+	void *cpu;
+	dma_addr_t dma;
+	struct dt3155_buf *next;
+	struct timeval tv;
+};
+
+/**
+ * struct dt3155_fifo - fifo structure
+ *
+ * @head:	pointer to the head of the fifo
+ * @tail:	pionter to the tail of the fifo
+ * @lock:	spin_lock to protect the fifo
+ */
+struct dt3155_fifo {
+	struct dt3155_buf *head;
+	struct dt3155_buf *tail;
+	spinlock_t lock;
+};
+
+struct dt3155_buf * __must_check
+dt3155_init_chunks_buf(void);
+void
+dt3155_free_chunks_buf(struct dt3155_buf *buf);
+
+struct dt3155_fifo * __must_check
+dt3155_init_fifo(void);
+#define dt3155_free_fifo(x) kfree(x)
+
+struct dt3155_buf * __must_check
+dt3155_get_buf(struct dt3155_fifo *fifo);
+void
+dt3155_put_buf(struct dt3155_buf *buf, struct dt3155_fifo *fifo);
+
+struct dt3155_fifo * __must_check
+dt3155_init_chunks_fifo(void);
+void
+dt3155_free_chunks_fifo(struct dt3155_fifo *chunks);
+
+struct dt3155_fifo * __must_check
+dt3155_init_ibufs_fifo(struct dt3155_fifo *chunks, int buf_size);
+void
+dt3155_free_ibufs_fifo(struct dt3155_fifo *fifo);
+
+#endif /*  _DT3155_BUFS_H_  */