1. 根目录:
2. arch
3. arm
4. plat-samsung
5. s3c-dma-ops.c

/* linux/arch/arm/plat-samsung/s3c-dma-ops.c
 *
 * Copyright (c) 2011 Samsung Electronics Co., Ltd.
 *		http://www.samsung.com
 *
 * Samsung S3C-DMA Operations
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 */

#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/slab.h>
#include <linux/types.h>
#include <linux/export.h>

#include <mach/dma.h>

struct cb_data {
	void (*fp) (void *);
	void *fp_param;
	unsigned ch;
	struct list_head node;
};

static LIST_HEAD(dma_list);

static void s3c_dma_cb(struct s3c2410_dma_chan *channel, void *param,
		       int size, enum s3c2410_dma_buffresult res)
{
	struct cb_data *data = param;

	data->fp(data->fp_param);
}

static unsigned s3c_dma_request(enum dma_ch dma_ch,
				 struct samsung_dma_info *info)
{
	struct cb_data *data;

	if (s3c2410_dma_request(dma_ch, info->client, NULL) < 0) {
		s3c2410_dma_free(dma_ch, info->client);
		return 0;
	}

	data = kzalloc(sizeof(struct cb_data), GFP_KERNEL);
	data->ch = dma_ch;
	list_add_tail(&data->node, &dma_list);

	s3c2410_dma_devconfig(dma_ch, info->direction, info->fifo);

	if (info->cap == DMA_CYCLIC)
		s3c2410_dma_setflags(dma_ch, S3C2410_DMAF_CIRCULAR);

	s3c2410_dma_config(dma_ch, info->width);

	return (unsigned)dma_ch;
}

static int s3c_dma_release(unsigned ch, struct s3c2410_dma_client *client)
{
	struct cb_data *data;

	list_for_each_entry(data, &dma_list, node)
		if (data->ch == ch)
			break;
	list_del(&data->node);

	s3c2410_dma_free(ch, client);
	kfree(data);

	return 0;
}

static int s3c_dma_prepare(unsigned ch, struct samsung_dma_prep_info *info)
{
	struct cb_data *data;
	int len = (info->cap == DMA_CYCLIC) ? info->period : info->len;

	list_for_each_entry(data, &dma_list, node)
		if (data->ch == ch)
			break;

	if (!data->fp) {
		s3c2410_dma_set_buffdone_fn(ch, s3c_dma_cb);
		data->fp = info->fp;
		data->fp_param = info->fp_param;
	}

	s3c2410_dma_enqueue(ch, (void *)data, info->buf, len);

	return 0;
}

static inline int s3c_dma_trigger(unsigned ch)
{
	return s3c2410_dma_ctrl(ch, S3C2410_DMAOP_START);
}

static inline int s3c_dma_started(unsigned ch)
{
	return s3c2410_dma_ctrl(ch, S3C2410_DMAOP_STARTED);
}

static inline int s3c_dma_flush(unsigned ch)
{
	return s3c2410_dma_ctrl(ch, S3C2410_DMAOP_FLUSH);
}

static inline int s3c_dma_stop(unsigned ch)
{
	return s3c2410_dma_ctrl(ch, S3C2410_DMAOP_STOP);
}

static struct samsung_dma_ops s3c_dma_ops = {
	.request	= s3c_dma_request,
	.release	= s3c_dma_release,
	.prepare	= s3c_dma_prepare,
	.trigger	= s3c_dma_trigger,
	.started	= s3c_dma_started,
	.flush		= s3c_dma_flush,
	.stop		= s3c_dma_stop,
};

void *s3c_dma_get_ops(void)
{
	return &s3c_dma_ops;
}
EXPORT_SYMBOL(s3c_dma_get_ops);