[net-next-2.6.git] / samples / kfifo / dma-example.c

/*
 * Sample fifo dma implementation
 *
 * Copyright (C) 2010 Stefani Seibold <stefani@seibold.net>
 *
 * Released under the GPL version 2 only.
 *
 */

#include <linux/init.h>
#include <linux/module.h>
#include <linux/kfifo.h>

/*
 * This module shows how to handle fifo dma operations.
 */

/* fifo size in elements (bytes) */
#define FIFO_SIZE	32

static struct kfifo fifo;

static int __init example_init(void)
{
	int			i;
	unsigned int		ret;
	struct scatterlist	sg[10];

	printk(KERN_INFO "DMA fifo test start\n");

	if (kfifo_alloc(&fifo, FIFO_SIZE, GFP_KERNEL)) {
		printk(KERN_ERR "error kfifo_alloc\n");
		return 1;
	}

	printk(KERN_INFO "queue size: %u\n", kfifo_size(&fifo));

	kfifo_in(&fifo, "test", 4);

	for (i = 0; i != 9; i++)
		kfifo_put(&fifo, &i);

	/* kick away first byte */
	ret = kfifo_get(&fifo, &i);

	printk(KERN_INFO "queue len: %u\n", kfifo_len(&fifo));

	sg_init_table(sg, ARRAY_SIZE(sg));
	ret = kfifo_dma_in_prepare(&fifo, sg, ARRAY_SIZE(sg), FIFO_SIZE);
	printk(KERN_INFO "DMA sgl entries: %d\n", ret);

	/* if 0 was returned, fifo is full and no sgl was created */
	if (ret) {
		printk(KERN_INFO "scatterlist for receive:\n");
		for (i = 0; i < ARRAY_SIZE(sg); i++) {
			printk(KERN_INFO
			"sg[%d] -> "
			"page_link 0x%.8lx offset 0x%.8x length 0x%.8x\n",
				i, sg[i].page_link, sg[i].offset, sg[i].length);

			if (sg_is_last(&sg[i]))
				break;
		}

		/* but here your code to setup and exectute the dma operation */
		/* ... */

		/* example: zero bytes received */
		ret = 0;

		/* finish the dma operation and update the received data */
		kfifo_dma_in_finish(&fifo, ret);
	}

	ret = kfifo_dma_out_prepare(&fifo, sg, ARRAY_SIZE(sg), 8);
	printk(KERN_INFO "DMA sgl entries: %d\n", ret);

	/* if 0 was returned, no data was available and no sgl was created */
	if (ret) {
		printk(KERN_INFO "scatterlist for transmit:\n");
		for (i = 0; i < ARRAY_SIZE(sg); i++) {
			printk(KERN_INFO
			"sg[%d] -> "
			"page_link 0x%.8lx offset 0x%.8x length 0x%.8x\n",
				i, sg[i].page_link, sg[i].offset, sg[i].length);

			if (sg_is_last(&sg[i]))
				break;
		}

		/* but here your code to setup and exectute the dma operation */
		/* ... */

		/* example: 5 bytes transmitted */
		ret = 5;

		/* finish the dma operation and update the transmitted data */
		kfifo_dma_out_finish(&fifo, ret);
	}

	printk(KERN_INFO "queue len: %u\n", kfifo_len(&fifo));

	return 0;
}

static void __exit example_exit(void)
{
#ifdef DYNAMIC
	kfifo_free(&test);
#endif
}

module_init(example_init);
module_exit(example_exit);
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Stefani Seibold <stefani@seibold.net>");
Commit	Line	Data
5bf2b193 SS	1	/*
	2	* Sample fifo dma implementation
	3	*
	4	* Copyright (C) 2010 Stefani Seibold <stefani@seibold.net>
	5	*
	6	* Released under the GPL version 2 only.
	7	*
	8	*/
	9
	10	#include <linux/init.h>
	11	#include <linux/module.h>
	12	#include <linux/kfifo.h>
	13
	14	/*
	15	* This module shows how to handle fifo dma operations.
	16	*/
	17
	18	/* fifo size in elements (bytes) */
	19	#define FIFO_SIZE 32
	20
	21	static struct kfifo fifo;
	22
	23	static int __init example_init(void)
	24	{
	25	int i;
	26	unsigned int ret;
	27	struct scatterlist sg[10];
	28
	29	printk(KERN_INFO "DMA fifo test start\n");
	30
	31	if (kfifo_alloc(&fifo, FIFO_SIZE, GFP_KERNEL)) {
	32	printk(KERN_ERR "error kfifo_alloc\n");
	33	return 1;
	34	}
	35
	36	printk(KERN_INFO "queue size: %u\n", kfifo_size(&fifo));
	37
	38	kfifo_in(&fifo, "test", 4);
	39
	40	for (i = 0; i != 9; i++)
	41	kfifo_put(&fifo, &i);
	42
	43	/* kick away first byte */
	44	ret = kfifo_get(&fifo, &i);
	45
	46	printk(KERN_INFO "queue len: %u\n", kfifo_len(&fifo));
	47
7b34d525	48	sg_init_table(sg, ARRAY_SIZE(sg));
5bf2b193 SS	49	ret = kfifo_dma_in_prepare(&fifo, sg, ARRAY_SIZE(sg), FIFO_SIZE);
	50	printk(KERN_INFO "DMA sgl entries: %d\n", ret);
	51
	52	/* if 0 was returned, fifo is full and no sgl was created */
	53	if (ret) {
	54	printk(KERN_INFO "scatterlist for receive:\n");
	55	for (i = 0; i < ARRAY_SIZE(sg); i++) {
	56	printk(KERN_INFO
	57	"sg[%d] -> "
	58	"page_link 0x%.8lx offset 0x%.8x length 0x%.8x\n",
	59	i, sg[i].page_link, sg[i].offset, sg[i].length);
	60
	61	if (sg_is_last(&sg[i]))
	62	break;
	63	}
	64
	65	/* but here your code to setup and exectute the dma operation */
	66	/* ... */
	67
	68	/* example: zero bytes received */
	69	ret = 0;
	70
	71	/* finish the dma operation and update the received data */
	72	kfifo_dma_in_finish(&fifo, ret);
	73	}
	74
	75	ret = kfifo_dma_out_prepare(&fifo, sg, ARRAY_SIZE(sg), 8);
	76	printk(KERN_INFO "DMA sgl entries: %d\n", ret);
	77
	78	/* if 0 was returned, no data was available and no sgl was created */
	79	if (ret) {
	80	printk(KERN_INFO "scatterlist for transmit:\n");
	81	for (i = 0; i < ARRAY_SIZE(sg); i++) {
	82	printk(KERN_INFO
	83	"sg[%d] -> "
	84	"page_link 0x%.8lx offset 0x%.8x length 0x%.8x\n",
	85	i, sg[i].page_link, sg[i].offset, sg[i].length);
	86
	87	if (sg_is_last(&sg[i]))
	88	break;
	89	}
	90
	91	/* but here your code to setup and exectute the dma operation */
	92	/* ... */
	93
	94	/* example: 5 bytes transmitted */
	95	ret = 5;
	96
	97	/* finish the dma operation and update the transmitted data */
	98	kfifo_dma_out_finish(&fifo, ret);
	99	}
	100
	101	printk(KERN_INFO "queue len: %u\n", kfifo_len(&fifo));
	102
	103	return 0;
	104	}
	105
	106	static void __exit example_exit(void)
	107	{
	108	#ifdef DYNAMIC
	109	kfifo_free(&test);
	110	#endif
	111	}
	112
113	module_init(example_init);
114	module_exit(example_exit);
115	MODULE_LICENSE("GPL");
116	MODULE_AUTHOR("Stefani Seibold <stefani@seibold.net>");