SPI, DMA and an i.MX31

Magnus Lilja lilja.magnus at gmail.com
Tue Sep 22 15:45:01 EDT 2009

Hi Bill

2009/9/22 Bill Gatliff <bgat at billgatliff.com>:
> Magnus Lilja wrote:
>> That might be a problem. Binary firmware can be handled in Linux, as
>> an example one can load it from user space but that makes it difficult
>> to enable the SDMA before userspace has started. Another example is to
>> let the bootloader load the SDMA scripts but that's not a nice
>> solution. Don't know if this firmware can be accepted as a binary
>> within the kernel.
> It couldn't be a "binary" in the kernel per se, it would be a constant
> character array that gets compiled into a binary chunk.

Correct. That's the way Freescale has done it in their BSP, a char[]
array that eventually gets downloaded into the SDMA engine.

>  Sort of like
> how, for example, Keyspan's drivers are done.  See
> linux/firmware/README.AddingFirmware, linux/firmware/keyspan and
> drivers/usb/serial/keyspan*.

The README states that new firmware shall be added to Davids
linux-firmware tree, but that would mean that the DMA scripts would be
outside of the Linux source tree. Should one merge Davids
linux-firmware tree with the standard Linux-tree locally or how is it
supposed to work?

Thanks, Magnus

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