[PATCH 06/10] MXS-DMA : add more flags for MXS-DMA
Huang Shijie
b32955 at freescale.com
Thu Jan 19 04:31:19 EST 2012
hi,
> Err, the 'flags' argument to device_prep_slave_sg() is supposed to be
> from the set of enum dma_ctrl_flags. What this means is that your
> MXS_DMA_F_APPEND is equivalent to DMA_PREP_INTERRUPT, and
> MXS_DMA_F_WAIT4END is equivalent to DMA_CTRL_ACK.
>
thanks a lot.
I will reuse the dma_ctrl_flags in the next version.
> What this does is make your drivers completely dependent on your DMA
> engine implementation. That's not a good idea when devices get
> reused in different SoCs.
>
Frankly speaking, the APBH-DMA is more coupled with the GPMI then any
other modules.
In the MX6Q, the GPMI is the ONLY user of APBH-DMA.
You even can see the NAND_LOCK bit in the DMA command structure which is
only used by the GPMI
NAND controller,.
To Shawn & Wolfram:
thanks very much for your comments.
Best Regards
Huang Shijie
> If you need to supply extra flags which aren't in the dma_ctrl_flags,
> at least make sure that they're using different bits. For bonus points,
> also have your driver_check_ the DMA engine it's connected to before
> it passes these flags.
>
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