bybrooklyn/linux
1
0
Fork 0
mirror of https://github.com/torvalds/linux.git synced 2026-04-18 14:53:58 -04:00
Code Issues Packages Projects Releases Wiki Activity

kfifo: add explicit error checking in all the examples

Browse Source 
Provide a check in all the kfifo examples to validate the correct
execution of each testcase.

Signed-off-by: Andrea Righi <arighi@develer.com>
Acked-by: Stefani Seibold <stefani@seibold.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Andrea Righi
2010-08-19 14:13:30 -07:00
committed by Linus Torvalds
parent d83a71c421
commit a25effa4d2
4 changed files with 152 additions and 59 deletions
Download Patch File Download Diff File Expand all files Collapse all files

122
samples/kfifo/dma-example.c
View File

@@ -29,8 +29,8 @@ static int __init example_init(void)
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_WARNING "error kfifo_alloc\n");
return -ENOMEM;
}
printk(KERN_INFO "queue size: %u\n", kfifo_size(&fifo));
@@ -41,65 +41,93 @@ static int __init example_init(void)
kfifo_put(&fifo, &i);
/* kick away first byte */
ret = kfifo_get(&fifo, &i);
kfifo_skip(&fifo);
printk(KERN_INFO "queue len: %u\n", kfifo_len(&fifo));
/*
* Configure the kfifo buffer to receive data from DMA input.
*
* .--------------------------------------.
* | 0 | 1 | 2 | ... | 12 | 13 | ... | 31 |
* |---|------------------|---------------|
* \_/ \________________/ \_____________/
* \ \ \
* \ \_allocated data \
* \_*free space* \_*free space*
*
* We need two different SG entries: one for the free space area at the
* end of the kfifo buffer (19 bytes) and another for the first free
* byte at the beginning, after the kfifo_skip().
*/
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);
if (!ret) {
/* fifo is full and no sgl was created */
printk(KERN_WARNING "error kfifo_dma_in_prepare\n");
return -EIO;
}
/* receive data */
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;
}
/* put 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);
/* Prepare to transmit data, example: 8 bytes */
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);
if (!ret) {
/* no data was available and no sgl was created */
printk(KERN_WARNING "error kfifo_dma_out_prepare\n");
return -EIO;
}
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;
}
/* put 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);
ret = kfifo_len(&fifo);
printk(KERN_INFO "queue len: %u\n", kfifo_len(&fifo));
if (ret != 7) {
printk(KERN_WARNING "size mismatch: test failed");
return -EIO;
}
printk(KERN_INFO "test passed\n");
return 0;
}