[PATCH 1/3] dmaengine: mmp-pdma support

On Thu, 2012-07-26 at 15:02 +0800, zhangfei gao wrote:

On Thu, Jul 26, 2012 at 2:51 PM, Vinod Koul [off-list ref] wrote:

quoted

On Fri, 2012-07-20 at 13:46 +0800, Zhangfei Gao wrote:

quoted

+struct mmp_dma_platdata {
+       int chancnt;
+};
+
+struct mmp_dma_slave_config {
+       struct dma_slave_config slave_config;
+       u32 drcmr;
+};

Why do you need these definitions?

What is drcmr used for?

Hi, Vinod

"drcmr" is request_line, we used to select which channel map to
specific peripheral.
Is it possible adding request_line to slave_config?

Can you use the slave_id.

Refer mail with Arnd before.

quoted

For peripheral dma, one special requirement of DMA_RCMRx
The register is used select which channel is mapped to the peripheral.
The channel can be alloc dynamically, but the register is constant to
specific peripheral.
For example, nand_dma, pxa910 use DRCMR97 (0x1184), what's worse,
pxa688 use DRCMR28 (0x170).

There is no connection between channel number and drcmr, since channel
is dynamically allocated.
So we encapsulating the slave config parsing drcmr to dma-engine driver.

[Arnd]
Ah, so it is the request line. Now the current plan for this is to go
into the "dmas" property of the child device using the dma engine binding.

quoted

--
~Vinod


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-- 
~Vinod