Just found that I missed Sascha's mail address in my TO list of last reply. So resend it. And sorry for the duplicated mails. ----- Forwarded message from Nicolin Chen <b42378@freescale.com> ----- Date: Wed, 30 Oct 2013 12:48:48 +0800 From: Nicolin Chen <b42378@freescale.com> Subject: Re: [PATCH 1/3] dma: imx-sdma: Add ssi dual fifo script support User-Agent: Mutt/1.5.21 (2010-09-15) Hi Sascha, On Tue, Oct 29, 2013 at 02:51:43PM +0100, Sascha Hauer wrote:

Look at drivers/dma/imx-sdma.c:

...

/** * struct sdma_firmware_header - Layout of the firmware image * * @magic "SDMA" * @version_major increased whenever layout of struct * sdma_script_start_addrs * changes.

Can you image why this firmware has a version field? Right, it's because it encodes the layout of struct sdma_script_start_addrs.

As the comment clearly states you have to *increase this field* when you add scripts.

Obviously you missed that, as the firmware on lkml posted recently shows:

...

00000000: 414d4453 00000001 00000001 0000001c SDMA............ ^^^^^^^^ Still '1'

...

00000010: 00000026 000000b4 0000067a 00000282 &.......z....... 00000020: ffffffff 00000000 ffffffff ffffffff ................ 00000030: ffffffff ffffffff ffffffff ffffffff ................ 00000040: ffffffff ffffffff 00001a6a ffffffff ........j....... 00000050: 000002eb 000018bb ffffffff 00000408 ................ 00000060: ffffffff 000003c0 ffffffff ffffffff ................ 00000070: ffffffff 000002ab ffffffff 0000037b ............{... 00000080: ffffffff ffffffff 0000044c 0000046e ........L...n... 00000090: ffffffff 00001800 ffffffff ffffffff ................ 000000a0: 00000000 00001800 00001862 00001a16 ........b....... ^^^^^^^^^^^^^^^^^ new script addresses introduced

...

-#define SDMA_SCRIPT_ADDRS_ARRAY_SIZE_V1 34 +#define SDMA_SCRIPT_ADDRS_ARRAY_SIZE_V1 37

And no, this is not a bug. It's your firmware header that is buggy.

I wasn't aware that the problem is far more complicated than I thought. And thank you for telling me all this.

What you need is:

#define SDMA_SCRIPT_ADDRS_ARRAY_SIZE_V2 37

You (you as a company, not you as a person) knew that it was me who created this firmware format. So it was absolutely unnecessary to create an incompatible firmware instead of dropping me a short note.

Please add a version check to the driver as necessary and provide a proper firmware.

Just currently it's not easy for me to create a new proper firmware, and I's been told that besides this version number, it also lacks a decent license info. So may I just refine this patch as you suggested to add a version check and add those new scripts first? Thank you, Nicolin Chen

Sascha

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