DaVinci EDMA

jalexander

Prodigy 200 points

Dear DaVinci'ites:

Have a DaVinci 6446 board that needs to set up a DMA channel via the EMIF between

an fpga and the SDRAM. The fpga talks to the PCI bus and DMA's data to/from the board.

Need to DMA the data into memory.

Apparently there are available Davinci DMA calls, e.g. davinci_request_dma, davinci_start_dma,

to do this.

Does anyone have documentation and or code on how to implement this.

Thanks

Jerry

over 16 years ago

Juan Gonzales over 16 years ago

TI__Mastermind 37340 points

Hi Jerry,

The Linux DMA driver actually resides under

.../lsp/ti-davinci/arch/arm/mach-davinci

It is a kernel driver that is used by other kernel drivers (as opposed to user applications); therefore, your best bet is to look at the other kernel drivers that make use of this DMA driver as reference code. I believe the sound driver (../ti-davinci/sound/oss/dm644x) and the MMC driver (.../ti-davinci/drivers/mmc) both use the DMA driver.

Let us know if there is anything else we can assist you with

Sundar7561 over 16 years ago in reply to Juan Gonzales

Prodigy 230 points

You can check if this post helps

http://mail.directfb.org/pipermail/directfb-users/2007-November/000123.html

Thanx!

Sundar

jalexander over 16 years ago in reply to Juan Gonzales

Prodigy 200 points

Sundar,

The calls I referenced in my email, davinci_request_dma and davinci_start_dma are from the code in mach-davinci/dma.c and I have looked

at other drivers that utilize these calls.

What I was seeking was documentation, preferably from TI, on these interfaces.

Pretty sure none exists.

Thanks,

Jerry

Bernie Thompson TI over 16 years ago in reply to jalexander

TI__Mastermind 41665 points

From a driver level DMA documentation perspective you are probably correct, I have not seen any documentation on the DMA driver itself for within other drivers.

On the other hand if you were using DMA in an algorithm or user application than you would want to take a look at http://wiki.davincidsp.com/index.php?title=DMA_Framework_Components

Sundar7561 over 16 years ago in reply to Bernie Thompson TI

Prodigy 230 points

As far as the low level driver in linux is concerned, it is pretty much the same as the EDMA data sheet that is available. The low level calls which are referenced in the other drivers are prrtty much as described in the EDMA sprue giudes :).

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