DMA mem to mem copy instead of copy_to_user() ...

[hanguytv]

Posted on February 04, 2008 at 08:50

DMA mem to mem copy instead of copy_to_user() ...

[hanguytv]

Posted on January 29, 2008 at 13:41

Hi all,

I'm trying FDMA to do a memory-to-memory copy function instead of using copy_to_user(). I followed the stlinux example below (http://www.stlinux.com/docs/manual/distribution/fdma_sh_exmpl1.php)

unsigned long flags=

STM_DMA_SETUP_CONTEXT_TASK

| DIM_1_x_1

| MODE_SH_COMPATIBILITY;

unsigned long xfer_bytes =4096;

void* src_buff = kmalloc(xfer_bytes,GFP_KERNEL);

void * dst_buff = kmalloc(xfer_bytes,GFP_KERNEL);

int ch_num = request_dma(0,__FUNCTION__);

if(!ch_num ==0)

return -ENODEV;

if(src_buff){

memset(src_buff,0x4,xfer_bytes);

dma_cache_wback(&src_buff[0],sizeof(u32)*xfer_bytes);

dma_cache_wback(&dst_buff[0],sizeof(u32)*xfer_bytes);

dma_configure_channel(ch_num,flags);

dma_xfer(ch_num,

virt_to_phys((void*)src_buff),

virt_to_phys((void*)dst_buff)

,xfer_bytes,

MODE_SH_COMPATIBILITY);

dma_wait_for_completion(ch_num);

if(memcmp((void*)src_buff,(void*)dst_buff,xfer_bytes)!=0){

dump_srcbuff(src_buff,xfer_bytes);

dump_dstbuff(dst_buff,xfer_bytes);

panic('' memory does not compare\n'');

}

printk(''woken up from DMA - TEST OK\n'');

kfree((void*)src_buff);

kfree((void*)dst_buff);

free_dma(ch_num);

return 0;

}

return -ENOMEM;

then got an error that looks like this:

..

Unable to handle kernel NULL pointer dereference at virtual address 00000000

pc = 86cd56aa

*pde = 00000000

Oops: 0001 [#1]

Pid : 818, Comm: udhcpc

PC is at create_llu_list+0x86/0x8c

PC : 86cd56aa SP : 8f633d38 SR : 40008001 TEA : c0103a64 Not tainted

R0 : 00000000 R1 : 00000000 R2 : 8f633d80 R3 : 00000001

R4 : 8f633d80 R5 : 00000000 R6 : 00000000 R7 : 00000000

R8 : 00000001 R9 : 8f633d40 R10 : 00000030 R11 : 86d6616c

R12 : 0f516ae0 R13 : 86d6616c R14 : 8fbc6000

MACH: 00000000 MACL: 00000000 GBR : 295737e8 PR : 86cd696c

my box use STB710x, SH architecture and stlinux-2.6.17.14. Could someone tell me a clue to my problem, please?

If I change the flag to use ''MODE_FREERUNNING'', then I got another error: CH_0 invalid descriptor

How should I configure the flags then?

Thank you very much and sorry if this is not the right place to ask this kind of problems!

/ha

[seb13_colin]

Posted on February 04, 2008 at 08:50

Hello hanguytv,

I think that your request is not for this forum. Maybe the ST40 or the STR7 forum will be more appropriate.

Thank you,

Seb