How to access MPC8555 DMA register ?

[Kumar Gala]

On Feb 6, 2007, at 2:44 AM, Shinji Watanabe wrote:

> Hi, all.
>
> I used MPC8555CDS.
>
> How to access DMA registers of MPC8555 ?
>
> I can't read/write these registers on LINUX.
>
> I called request_mem_region( 0xE0000000, LENGTH, ... ) in my device  
> driver.
>
> When I set LENGTH 0x21100, this function call succeded.
>
> But When I set LENGTH 0x21200, this function call failed.
>
> "e0021100-e002117f : fsl-dma0" is part of /proc/iomem log.
>
> I guess my driver can't access fsl-dma0 area.
>
> But fsl-dma0 area encompassed DMA registers I want to access.
>
> I must find remove simbols like fsl-dma0.
> Or I must find how to use modules encompass fsl-dma0.
>
> Counld you give me some help/hint/tips ?

You need to have your driver bind to the fsl-dma0 device.  The  
platform code is setting up a device for each dma channel (fsl-dma0,  
fsl-dma1, ..) and you need to have your driver be setup to bind to  
that device.

Take a look at drivers/i2c/busses/i2c-mpc.c, drivers/net/gianfar.c  
for an examples of how drivers are setup to do the binding.

- k