2008-05-24 10:33:34 video in-out.

Pranay Upadhyay (INDIA)

Message: 56249

Hello ,

Can you explained me about the function used in the file "arch/blackfin/mach-bf561/coreb.c" .The function is

static ssize_t coreb_write(struct file *file, const char *buf, size_t count, loff_t * ppos)

and

static ssize_t coreb_read(struct file *file, char *buf, size_t count, loff_t * ppos)

in these two function I am not getting the term "CH_MEM_STREAM2_SRC, coreb_base + p

and CH_MEM_STREAM2_DEST.

I am not getting that in the same read and write function ,How can we use source and destination channel for transmit.I want to use the ppi driver for video in-out.

please reply soon.May be my problem will be solve after this issue.

Regards

Pranay

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2008-05-26 00:16:20 Re: video in-out.

Yi Li (CHINA)

Message: 56260

arch/blackfin/mach-bf561/coreb.c is a driver used by uclinux-dist/user/blkfin-apps/corebld to excecute a specially program on coreb. It has nothing to do with PPI.

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2008-05-26 08:58:54 Re: video in-out.

Pranay Upadhyay (INDIA)

Message: 56272

Hello YiLi,

Ok,I am asking that what is the meaning of that term used in this read and write function.Because when I am using the read and write function in the ppi driver for reading and writing function in same core B.Please explain about these two terms used in that function"CH_MEM_STREAM2_SRC, coreb_base + p and CH_MEM_STREAM2_DEST. My ppi0 and ppi1 driver working properly but know I want real time video in-out after using these two driver.If you have any idea about than please explain me clearly or tell me about some link.Thanks for your kind response.

-Regards

Pranay

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2008-05-26 14:30:37 Re: video in-out.

Mike Frysinger (UNITED STATES)

Message: 56278

just grep for them in the Blackfin headers ... they are simply numbers which represent some DMA channel

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2008-05-27 08:56:03 Re: video in-out.

Pranay Upadhyay (INDIA)

Message: 56302

Hello sir,

In this read functoin may I use /* Source Channel */ and /* Destination Channel */ in the same functon. If in ppio I am using the dma1_0 channel for source and in ppi1 driver I am using the dma1_1 for destination.Then why In this function there are both, source and destination. And also I have no clear about the "loff_t * ppos".

In my case ppi0 recieve the one frame and send to the ppi1 driver but just after sendinfg one frame there is not able to read the next frame.

In read function I am using only one /* Source Channel */ , there is no any /* Destination Channel */ .If I got idea about this then I want to use the both source and destination in the read function and only destination channel in the write function.

I am attatching the, my view for the video in-out for real time video. I am telling you that for single frame my both driver is working properly .

static ssize_t coreb_read(struct file *file, char *buf, size_t count,

loff_t * ppos)

{

unsigned long p = *ppos;

ssize_t read = 0;

if ((p + count) > coreb_size)

return -EFAULT;

while (count > 0) {

int len = count;

if (len > PAGE_SIZE)

len = PAGE_SIZE;