m68k: use the coherent DMA code for coldfire without data cache

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Coldfire cores configured without a data cache are DMA coherent and
should thus simply use the simple coherent version of dma-direct.

Introduce a new COLDFIRE_COHERENT_DMA Kconfig symbol as a convenient
short hand for such configurations, and a M68K_NONCOHERENT_DMA symbol
for all cases where we need to build non-coherent DMA infrastructure
to simplify the Kconfig and code conditionals.

Not building the non-coherent DMA code slightly reduces the code
size for such configurations.

Numers for m5249evb_defconfig below:

  text	   data	    bss	    dec	    hex	filename
2896158	 401052	  65392	3362602	 334f2a	vmlinux.before
2895166	 400988	  65392	3361546	 334b0a	vmlinux.after

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Greg Ungerer <gerg@linux-m68k.org>
Acked-by: Geert Uytterhoeven <geert@linux-m68k.org>
Tested-by: Greg Ungerer <gerg@linux-m68k.org>

...

This commit is contained in:

Christoph Hellwig 2023-10-17 16:04:42 +02:00

parent 63f067e33c

commit 9e28bf8bdf

4 changed files with 18 additions and 6 deletions

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8

arch/m68k/Kconfig

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12

arch/m68k/Kconfig.cpu

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2

arch/m68k/kernel/Makefile

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2

arch/m68k/kernel/dma.c

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