kfifo: add example files to the kernel sample directory
Add four examples to the kernel sample directory. It shows how to handle: - a byte stream fifo - a integer type fifo - a dynamic record sized fifo - the fifo DMA functions [akpm@linux-foundation.org: coding-style fixes] Signed-off-by: Stefani Seibold <stefani@seibold.net> Cc: Greg KH <greg@kroah.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Stefani Seibold
Linus Torvalds
parent
2e956fb320
commit
5bf2b19320
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@ -44,4 +44,14 @@ config SAMPLE_HW_BREAKPOINT
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help
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This builds kernel hardware breakpoint example modules.
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config SAMPLE_KFIFO
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tristate "Build kfifo examples -- loadable modules only"
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depends on m
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help
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This config option will allow you to build a number of
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different kfifo sample modules showing how to use the
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generic kfifo API.
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If in doubt, say "N" here.
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endif # SAMPLES
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@ -1,4 +1,4 @@
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# Makefile for Linux samples code
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obj-$(CONFIG_SAMPLES) += kobject/ kprobes/ tracepoints/ trace_events/ \
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hw_breakpoint/
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hw_breakpoint/ kfifo/
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@ -0,0 +1 @@
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obj-$(CONFIG_SAMPLE_KFIFO) += bytestream-example.o dma-example.o inttype-example.o record-example.o
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@ -0,0 +1,163 @@
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/*
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* Sample kfifo byte stream implementation
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*
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* Copyright (C) 2010 Stefani Seibold <stefani@seibold.net>
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*
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* Released under the GPL version 2 only.
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*
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*/
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#include <linux/init.h>
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#include <linux/module.h>
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#include <linux/proc_fs.h>
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#include <linux/mutex.h>
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#include <linux/kfifo.h>
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/*
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* This module shows how to create a byte stream fifo.
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*/
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/* fifo size in elements (bytes) */
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#define FIFO_SIZE 32
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/* name of the proc entry */
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#define PROC_FIFO "bytestream-fifo"
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/* lock for procfs read access */
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static DEFINE_MUTEX(read_lock);
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/* lock for procfs write access */
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static DEFINE_MUTEX(write_lock);
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/*
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* define DYNAMIC in this example for a dynamically allocated fifo.
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*
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* Otherwise the fifo storage will be a part of the fifo structure.
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*/
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#if 0
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#define DYNAMIC
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#endif
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#ifdef DYNAMIC
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static struct kfifo test;
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#else
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static DECLARE_KFIFO(test, unsigned char, FIFO_SIZE);
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#endif
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static int __init testfunc(void)
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{
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unsigned char buf[6];
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unsigned char i;
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unsigned int ret;
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printk(KERN_INFO "byte stream fifo test start\n");
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/* put string into the fifo */
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kfifo_in(&test, "hello", 5);
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/* put values into the fifo */
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for (i = 0; i != 10; i++)
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kfifo_put(&test, &i);
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/* show the number of used elements */
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printk(KERN_INFO "fifo len: %u\n", kfifo_len(&test));
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/* get max of 5 bytes from the fifo */
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i = kfifo_out(&test, buf, 5);
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printk(KERN_INFO "buf: %.*s\n", i, buf);
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/* get max of 2 elements from the fifo */
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ret = kfifo_out(&test, buf, 2);
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printk(KERN_INFO "ret: %d\n", ret);
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/* and put it back to the end of the fifo */
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ret = kfifo_in(&test, buf, ret);
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printk(KERN_INFO "ret: %d\n", ret);
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/* put values into the fifo until is full */
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for (i = 20; kfifo_put(&test, &i); i++)
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;
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printk(KERN_INFO "queue len: %u\n", kfifo_len(&test));
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/* print out all values in the fifo */
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while (kfifo_get(&test, &i))
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printk("%d ", i);
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printk("\n");
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return 0;
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}
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static ssize_t fifo_write(struct file *file, const char __user *buf,
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size_t count, loff_t *ppos)
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{
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int ret;
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unsigned int copied;
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if (mutex_lock_interruptible(&write_lock))
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return -ERESTARTSYS;
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ret = kfifo_from_user(&test, buf, count, &copied);
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mutex_unlock(&write_lock);
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return ret ? ret : copied;
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}
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static ssize_t fifo_read(struct file *file, char __user *buf,
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size_t count, loff_t *ppos)
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{
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int ret;
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unsigned int copied;
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if (mutex_lock_interruptible(&read_lock))
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return -ERESTARTSYS;
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ret = kfifo_to_user(&test, buf, count, &copied);
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mutex_unlock(&read_lock);
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return ret ? ret : copied;
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}
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static const struct file_operations fifo_fops = {
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.owner = THIS_MODULE,
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.read = fifo_read,
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.write = fifo_write,
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};
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static int __init example_init(void)
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{
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#ifdef DYNAMIC
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int ret;
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ret = kfifo_alloc(&test, FIFO_SIZE, GFP_KERNEL);
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if (ret) {
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printk(KERN_ERR "error kfifo_alloc\n");
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return ret;
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}
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#else
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INIT_KFIFO(test);
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#endif
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testfunc();
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if (proc_create(PROC_FIFO, 0, NULL, &fifo_fops) == NULL) {
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#ifdef DYNAMIC
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kfifo_free(&test);
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#endif
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return -ENOMEM;
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}
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return 0;
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}
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static void __exit example_exit(void)
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{
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remove_proc_entry(PROC_FIFO, NULL);
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#ifdef DYNAMIC
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kfifo_free(&test);
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#endif
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}
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module_init(example_init);
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module_exit(example_exit);
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MODULE_LICENSE("GPL");
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MODULE_AUTHOR("Stefani Seibold <stefani@seibold.net>");
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@ -0,0 +1,115 @@
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/*
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* Sample fifo dma implementation
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*
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* Copyright (C) 2010 Stefani Seibold <stefani@seibold.net>
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*
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* Released under the GPL version 2 only.
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*
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*/
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#include <linux/init.h>
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#include <linux/module.h>
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#include <linux/kfifo.h>
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/*
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* This module shows how to handle fifo dma operations.
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*/
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/* fifo size in elements (bytes) */
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#define FIFO_SIZE 32
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static struct kfifo fifo;
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static int __init example_init(void)
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{
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int i;
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unsigned int ret;
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struct scatterlist sg[10];
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printk(KERN_INFO "DMA fifo test start\n");
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if (kfifo_alloc(&fifo, FIFO_SIZE, GFP_KERNEL)) {
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printk(KERN_ERR "error kfifo_alloc\n");
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return 1;
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}
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printk(KERN_INFO "queue size: %u\n", kfifo_size(&fifo));
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kfifo_in(&fifo, "test", 4);
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for (i = 0; i != 9; i++)
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kfifo_put(&fifo, &i);
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/* kick away first byte */
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ret = kfifo_get(&fifo, &i);
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printk(KERN_INFO "queue len: %u\n", kfifo_len(&fifo));
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ret = kfifo_dma_in_prepare(&fifo, sg, ARRAY_SIZE(sg), FIFO_SIZE);
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printk(KERN_INFO "DMA sgl entries: %d\n", ret);
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/* if 0 was returned, fifo is full and no sgl was created */
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if (ret) {
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printk(KERN_INFO "scatterlist for receive:\n");
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for (i = 0; i < ARRAY_SIZE(sg); i++) {
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printk(KERN_INFO
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"sg[%d] -> "
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"page_link 0x%.8lx offset 0x%.8x length 0x%.8x\n",
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i, sg[i].page_link, sg[i].offset, sg[i].length);
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if (sg_is_last(&sg[i]))
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break;
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}
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/* but here your code to setup and exectute the dma operation */
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/* ... */
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/* example: zero bytes received */
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ret = 0;
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/* finish the dma operation and update the received data */
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kfifo_dma_in_finish(&fifo, ret);
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}
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ret = kfifo_dma_out_prepare(&fifo, sg, ARRAY_SIZE(sg), 8);
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printk(KERN_INFO "DMA sgl entries: %d\n", ret);
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/* if 0 was returned, no data was available and no sgl was created */
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if (ret) {
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printk(KERN_INFO "scatterlist for transmit:\n");
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for (i = 0; i < ARRAY_SIZE(sg); i++) {
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printk(KERN_INFO
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"sg[%d] -> "
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"page_link 0x%.8lx offset 0x%.8x length 0x%.8x\n",
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i, sg[i].page_link, sg[i].offset, sg[i].length);
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if (sg_is_last(&sg[i]))
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break;
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}
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/* but here your code to setup and exectute the dma operation */
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/* ... */
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/* example: 5 bytes transmitted */
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ret = 5;
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/* finish the dma operation and update the transmitted data */
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kfifo_dma_out_finish(&fifo, ret);
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}
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printk(KERN_INFO "queue len: %u\n", kfifo_len(&fifo));
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return 0;
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}
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static void __exit example_exit(void)
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{
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#ifdef DYNAMIC
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kfifo_free(&test);
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#endif
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}
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module_init(example_init);
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module_exit(example_exit);
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MODULE_LICENSE("GPL");
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MODULE_AUTHOR("Stefani Seibold <stefani@seibold.net>");
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@ -0,0 +1,157 @@
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/*
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* Sample kfifo int type implementation
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*
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* Copyright (C) 2010 Stefani Seibold <stefani@seibold.net>
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*
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* Released under the GPL version 2 only.
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*
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*/
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#include <linux/init.h>
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#include <linux/module.h>
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#include <linux/proc_fs.h>
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#include <linux/mutex.h>
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#include <linux/kfifo.h>
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/*
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* This module shows how to create a int type fifo.
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*/
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/* fifo size in elements (ints) */
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#define FIFO_SIZE 32
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/* name of the proc entry */
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#define PROC_FIFO "int-fifo"
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/* lock for procfs read access */
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static DEFINE_MUTEX(read_lock);
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/* lock for procfs write access */
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static DEFINE_MUTEX(write_lock);
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/*
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* define DYNAMIC in this example for a dynamically allocated fifo.
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*
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* Otherwise the fifo storage will be a part of the fifo structure.
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*/
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#if 0
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#define DYNAMIC
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#endif
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#ifdef DYNAMIC
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static DECLARE_KFIFO_PTR(test, int);
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#else
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static DEFINE_KFIFO(test, int, FIFO_SIZE);
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#endif
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static int __init testfunc(void)
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{
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int buf[6];
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int i;
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unsigned int ret;
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printk(KERN_INFO "int fifo test start\n");
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/* put values into the fifo */
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for (i = 0; i != 10; i++)
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kfifo_put(&test, &i);
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/* show the number of used elements */
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printk(KERN_INFO "fifo len: %u\n", kfifo_len(&test));
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/* get max of 2 elements from the fifo */
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ret = kfifo_out(&test, buf, 2);
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printk(KERN_INFO "ret: %d\n", ret);
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/* and put it back to the end of the fifo */
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ret = kfifo_in(&test, buf, ret);
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printk(KERN_INFO "ret: %d\n", ret);
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for (i = 20; i != 30; i++)
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kfifo_put(&test, &i);
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printk(KERN_INFO "queue len: %u\n", kfifo_len(&test));
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/* show the first value without removing from the fifo */
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if (kfifo_peek(&test, &i))
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printk(KERN_INFO "%d\n", i);
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/* print out all values in the fifo */
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while (kfifo_get(&test, &i))
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printk("%d ", i);
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printk("\n");
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return 0;
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}
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static ssize_t fifo_write(struct file *file, const char __user *buf,
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size_t count, loff_t *ppos)
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{
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int ret;
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unsigned int copied;
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if (mutex_lock_interruptible(&write_lock))
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return -ERESTARTSYS;
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ret = kfifo_from_user(&test, buf, count, &copied);
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mutex_unlock(&write_lock);
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return ret ? ret : copied;
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}
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static ssize_t fifo_read(struct file *file, char __user *buf,
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size_t count, loff_t *ppos)
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{
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int ret;
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unsigned int copied;
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if (mutex_lock_interruptible(&read_lock))
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return -ERESTARTSYS;
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ret = kfifo_to_user(&test, buf, count, &copied);
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mutex_unlock(&read_lock);
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return ret ? ret : copied;
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}
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static const struct file_operations fifo_fops = {
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.owner = THIS_MODULE,
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.read = fifo_read,
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.write = fifo_write,
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};
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static int __init example_init(void)
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{
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#ifdef DYNAMIC
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int ret;
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ret = kfifo_alloc(&test, FIFO_SIZE, GFP_KERNEL);
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if (ret) {
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printk(KERN_ERR "error kfifo_alloc\n");
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return ret;
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}
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#endif
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testfunc();
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if (proc_create(PROC_FIFO, 0, NULL, &fifo_fops) == NULL) {
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#ifdef DYNAMIC
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kfifo_free(&test);
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#endif
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return -ENOMEM;
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}
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return 0;
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}
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static void __exit example_exit(void)
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{
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remove_proc_entry(PROC_FIFO, NULL);
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#ifdef DYNAMIC
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kfifo_free(&test);
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#endif
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}
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module_init(example_init);
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module_exit(example_exit);
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MODULE_LICENSE("GPL");
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MODULE_AUTHOR("Stefani Seibold <stefani@seibold.net>");
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@ -0,0 +1,167 @@
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/*
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* Sample dynamic sized record fifo implementation
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*
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* Copyright (C) 2010 Stefani Seibold <stefani@seibold.net>
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*
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* Released under the GPL version 2 only.
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*
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*/
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#include <linux/init.h>
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#include <linux/module.h>
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#include <linux/proc_fs.h>
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#include <linux/mutex.h>
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#include <linux/kfifo.h>
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/*
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* This module shows how to create a variable sized record fifo.
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*/
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/* fifo size in elements (bytes) */
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#define FIFO_SIZE 128
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/* name of the proc entry */
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#define PROC_FIFO "record-fifo"
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/* lock for procfs read access */
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static DEFINE_MUTEX(read_lock);
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/* lock for procfs write access */
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static DEFINE_MUTEX(write_lock);
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/*
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* define DYNAMIC in this example for a dynamically allocated fifo.
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*
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* Otherwise the fifo storage will be a part of the fifo structure.
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*/
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#if 0
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#define DYNAMIC
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#endif
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/*
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* struct kfifo_rec_ptr_1 and STRUCT_KFIFO_REC_1 can handle records of a
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* length between 0 and 255 bytes.
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*
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* struct kfifo_rec_ptr_2 and STRUCT_KFIFO_REC_2 can handle records of a
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* length between 0 and 65535 bytes.
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*/
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#ifdef DYNAMIC
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struct kfifo_rec_ptr_1 test;
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#else
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typedef STRUCT_KFIFO_REC_1(FIFO_SIZE) mytest;
|
||||
|
||||
static mytest test;
|
||||
#endif
|
||||
|
||||
static int __init testfunc(void)
|
||||
{
|
||||
char buf[100];
|
||||
unsigned int i;
|
||||
unsigned int ret;
|
||||
struct { unsigned char buf[6]; } hello = { "hello" };
|
||||
|
||||
printk(KERN_INFO "record fifo test start\n");
|
||||
|
||||
kfifo_in(&test, &hello, sizeof(hello));
|
||||
|
||||
/* show the size of the next record in the fifo */
|
||||
printk(KERN_INFO "fifo peek len: %u\n", kfifo_peek_len(&test));
|
||||
|
||||
/* put in variable length data */
|
||||
for (i = 0; i < 10; i++) {
|
||||
memset(buf, 'a' + i, i + 1);
|
||||
kfifo_in(&test, buf, i + 1);
|
||||
}
|
||||
|
||||
printk(KERN_INFO "fifo len: %u\n", kfifo_len(&test));
|
||||
|
||||
/* show the first record without removing from the fifo */
|
||||
ret = kfifo_out_peek(&test, buf, sizeof(buf));
|
||||
if (ret)
|
||||
printk(KERN_INFO "%.*s\n", ret, buf);
|
||||
|
||||
/* print out all records in the fifo */
|
||||
while (!kfifo_is_empty(&test)) {
|
||||
ret = kfifo_out(&test, buf, sizeof(buf));
|
||||
printk(KERN_INFO "%.*s\n", ret, buf);
|
||||
}
|
||||
|
||||
return 0;
|
||||
}
|
||||
|
||||
static ssize_t fifo_write(struct file *file, const char __user *buf,
|
||||
size_t count, loff_t *ppos)
|
||||
{
|
||||
int ret;
|
||||
unsigned int copied;
|
||||
|
||||
if (mutex_lock_interruptible(&write_lock))
|
||||
return -ERESTARTSYS;
|
||||
|
||||
ret = kfifo_from_user(&test, buf, count, &copied);
|
||||
|
||||
mutex_unlock(&write_lock);
|
||||
|
||||
return ret ? ret : copied;
|
||||
}
|
||||
|
||||
static ssize_t fifo_read(struct file *file, char __user *buf,
|
||||
size_t count, loff_t *ppos)
|
||||
{
|
||||
int ret;
|
||||
unsigned int copied;
|
||||
|
||||
if (mutex_lock_interruptible(&read_lock))
|
||||
return -ERESTARTSYS;
|
||||
|
||||
ret = kfifo_to_user(&test, buf, count, &copied);
|
||||
|
||||
mutex_unlock(&read_lock);
|
||||
|
||||
return ret ? ret : copied;
|
||||
}
|
||||
|
||||
static const struct file_operations fifo_fops = {
|
||||
.owner = THIS_MODULE,
|
||||
.read = fifo_read,
|
||||
.write = fifo_write,
|
||||
};
|
||||
|
||||
static int __init example_init(void)
|
||||
{
|
||||
#ifdef DYNAMIC
|
||||
int ret;
|
||||
|
||||
ret = kfifo_alloc(&test, FIFO_SIZE, GFP_KERNEL);
|
||||
if (ret) {
|
||||
printk(KERN_ERR "error kfifo_alloc\n");
|
||||
return ret;
|
||||
}
|
||||
#else
|
||||
INIT_KFIFO(test);
|
||||
#endif
|
||||
testfunc();
|
||||
|
||||
if (proc_create(PROC_FIFO, 0, NULL, &fifo_fops) == NULL) {
|
||||
#ifdef DYNAMIC
|
||||
kfifo_free(&test);
|
||||
#endif
|
||||
return -ENOMEM;
|
||||
}
|
||||
return 0;
|
||||
}
|
||||
|
||||
static void __exit example_exit(void)
|
||||
{
|
||||
remove_proc_entry(PROC_FIFO, NULL);
|
||||
#ifdef DYNAMIC
|
||||
kfifo_free(&test);
|
||||
#endif
|
||||
}
|
||||
|
||||
module_init(example_init);
|
||||
module_exit(example_exit);
|
||||
MODULE_LICENSE("GPL");
|
||||
MODULE_AUTHOR("Stefani Seibold <stefani@seibold.net>");
|
||||
Loading…
Reference in New Issue