RE: [PATCH v5 0/2] i2c: add DMA support for freescale i2c driver

From: Yao Yuan
Date: Wed Jul 23 2014 - 23:36:41 EST


Hi,

Marek Vasut wrote:
> On Wednesday, July 23, 2014 at 10:24:41 AM, Yuan Yao wrote:
> > Changed in v5:
> > - add "*chan_dev = dma->chan_using->device->dev" for reduce the call time.
>
> Did you check if the compiler generates different code ?
>

Sorry, I didn't compare the assembly code. It's a subtle change.
As you mentioned the "noodle" before.

Old:
dma_map_single(dma->chan_using->device->dev, ...);
dma_mapping_error(dma->chan_using->device->dev, ...);
dma_unmap_single(dma->chan_using->device->dev, ...);

New:
struct device *chan_dev = dma->chan_using->device->dev;
dma_map_single(chan_dev, ...);
dma_mapping_error(chan_dev, ...);
dma_unmap_single(chan_dev, ...);

> > - add the test logs.
>
> [...]
>
> Best regards,
> Marek Vasut
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