[DM8168] access video frame in A8

Ra

Rafael,

If the configuration is not enabled for addr translation, addr[][] will be null, and only physical address is populated. While configuring the component, if translation is enabled you should get host memory adresss for those buffers.

Regards

Vimal

Thanks Vimal,

Is the configuration you mean exportOnlyPhyAddr in ipcFramesInHost_createParams?

If I set it to false, the addr[ ][ ] gets populated with some value, but when I access the address, my A8 side application halts immediately.

Later I use Memory_translate(phyAddr[ ][ ], Memory_XltFlags_Phys2Virt) that is provided by syslink, but it returns NULL pointer.

So I still cannot access the frame buffer that passed from VPSS_M3 to Host.

Can you help?

Hi  Vimal,

I also have the same issue. The address is null and I can't get raw data from link.

Jack,

As Rafel in above post is able to get the buffer pointer, you would have to do same enabling. 

Please check IpcFramesInLink_setVirtBufAddr function, this will convert physical address to virtual adress to access on Linux. 

Regards

Vimal

Hi Vimal,

I set exportOnlyPhyAddr = FALSE and get address of addr[0][0], but I still can't get raw data of frame buffer.

hi Rafael_Han

I have the same problem with you !

You say to use mmap to get the Linux side virtual address from the passed in physical address .

but i can not do it 

can you explain it Clearly

thank you  for any help 

Hi Rafael_Han,

Thanks for your suggestion, but I still have mmap issue. My address always get 0xffffffff when I use mmap to map.

Can you tell me how to set it ?

Thanks.

Hi Jack,

    For the VIDFrame_Buf passed in, check phyAddr[0][0] field. Do you mean it is 0xffffffff always? Should not be that. In such case, please recheck your link create params, or post it here if you will.

    If it is some resonable value, then maybe mmap fails with the phyAddr. This is correct, because actually the passed in physical address is not at the page boundary, so some offset adjustment should also apply.

    Hope it helps.

Rafael

Hi Jim,

    In case you use chains like: capture -> dei, then you can add links to create chains like: capture ->ipcFramesOutRTOS->ipcFramesInHLOS->ipcFramesOutHLOS->ipcFramesInRTOS->dei, with correct link create params, the frame buffer wrapped in VIDFrame_Buf structure should get passed in the A8 side.

    Then use mmap with the phyAddr[0][0] field.

    Hope it helps,

Rafael

As Rafael mentioned, the best approach is to mmap the buffer phyAddr after it has reached A8. While doing mmap, need to ensure the page size alignment, so you need to map the physical address with the floor offset to the page size.  Look at the step below which shows a mmap example. We are aligning phyAddr with 4K boundary.

mmap(      0, framesize,PROT_READ|PROT_WRITE|PROT_EXEC,MAP_SHARED,fd,OSA_align((unsigned int)buf->phyAddr[0][0],4096));

Regards,

Anshuman

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How do you solve this problem？ I have the same problem with you！