spi: spi-imx: add DMA support

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Enable DMA support on i.mx6. The read speed can increase from 600KB/s
to 1.2MB/s on i.mx6q. You can disable or enable dma function in dts.
If not set "dma-names" in dts, spi will use PIO mode. This patch only
validate on i.mx6, not i.mx5, but encourage ones to apply this patch
on i.mx5 since they share the same IP.

Note:
  Sometime, there is a weid data in rxfifo after one full tx/rx
transfer finish by DMA on i.mx6dl, so we disable dma functhion on
i.mx6dl.

Signed-off-by: Frank Li <Frank.Li@freescale.com>
Signed-off-by: Robin Gong <b38343@freescale.com>
Acked-by: Marek Vasut <marex@denx.de>
Signed-off-by: Mark Brown <broonie@kernel.org>

...

This commit is contained in:

Robin Gong 2014-09-11 09:18:44 +08:00 • committed by Mark Brown

parent 7d1311b93e

commit f62caccd12

2 changed files with 285 additions and 6 deletions

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5

Documentation/devicetree/bindings/spi/fsl-imx-cspi.txt

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284

drivers/spi/spi-imx.c

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