How to use EDMA in my HPI driver

Bo Yang

Other Parts Discussed in Thread: TMS320DM355

hello,

I am writing a HPI driver on TMS320DM355. I want to use the EDMA in my driver.

there are some functions in the file lsp/ti-davinci/include/asm-arm/arch-davinci/edma.h, (davinci_request_dma(), davinci_set_dma_src_params() etc..) but I do not know how to use these fuctions in my HPI driver. can anyone give me any infoamtion about the fuctions? Document is appreciate.Thanks a lot.

Merry christmas!

over 16 years ago

0 Juan Gonzales over 16 years ago

TI__Mastermind 37340 points

Unfortunately, I do not believe there is any documentation available for this driver. The source code is included under .../ti-davinci/arch/arm/mach-davinci (per my recollection). Also, I should point out that this driver functions are only accessible by other kernel drivers... (not accessible by user applications).

0 Bo Yang over 16 years ago in reply to Juan Gonzales

Prodigy 120 points

Yes, i just access the fuctions in my HPI driver.

0 Bo Yang over 16 years ago in reply to Bo Yang

Prodigy 120 points

the struct edmacc_paramentry_regs in asm-arm/arch-davinci/edma.h includes src and dst members, but I don't know should I pass the physics address or virtual address.

0 Juan Gonzales over 16 years ago in reply to Bo Yang

TI__Mastermind 37340 points

I believe you pass the virtual address, but to be sure, I would refer to sound OSS driver or MMC driver; they both use dma driver.

0 BrandonAzbell over 16 years ago in reply to Juan Gonzales

TI__Guru 64480 points

The davinci_set_dma_params() function operates on the edmacc_paramentry_regs structure. It copies the values of this structure directly into the EDMA Parameter RAM table. Since the EDMA operates on physical addresses, I would say the edmacc_paramentry_regs.src and .dst are physical addresses.

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How to use EDMA in my HPI driver