linux-kernel - Re: [PATCH v2 06/10] spi/pxa2xx: add support for DMA engine

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Date:	Mon, 21 Jan 2013 18:14:01 +0200
From:	Mika Westerberg <mika.westerberg@...ux.intel.com>
To:	Russell King - ARM Linux <linux@....linux.org.uk>
Cc:	linux-kernel@...r.kernel.org,
	Grant Likely <grant.likely@...retlab.ca>,
	Eric Miao <eric.y.miao@...il.com>,
	Haojian Zhuang <haojian.zhuang@...il.com>,
	Mark Brown <broonie@...nsource.wolfsonmicro.com>,
	Linus Walleij <linus.walleij@...aro.org>,
	"Rafael J. Wysocki" <rafael.j.wysocki@...el.com>, chao.bi@...el.com
Subject: Re: [PATCH v2 06/10] spi/pxa2xx: add support for DMA engine

On Mon, Jan 21, 2013 at 03:44:36PM +0000, Russell King - ARM Linux wrote:
> On Mon, Jan 21, 2013 at 11:31:59AM +0200, Mika Westerberg wrote:
> > +bool dma_is_possible(size_t len)
> > +int map_dma_buffers(struct driver_data *drv_data)
> > +irqreturn_t dma_transfer(struct driver_data *drv_data)
> > +int dma_prepare(struct driver_data *drv_data, u32 dma_burst)
> > +void dma_start(struct driver_data *drv_data)
> > +int dma_setup(struct driver_data *drv_data)
> > +void dma_release(struct driver_data *drv_data)
> > +void dma_resume(struct driver_data *drv_data)
> > +int set_dma_burst_and_threshold(struct chip_data *chip,
> > +				struct spi_device *spi,
> > +				u8 bits_per_word, u32 *burst_code,
> > +				u32 *threshold)
> 
> All the above function names end up in the global namespace in the kernel
> image.  They're rather _too_ generic and non-specific for them to leak to
> that visibility.  I think this needs fixing.

Indeed, good point. I will fix this.

> Also, I'd suggest that the long term plan is for PXA to move over to the
> DMA engine API, so I'd recommend that the pxa2xx SPI driver have the
> DMA engine API usage built into it, and let's treat the old PXA DMA
> stuff as legacy code.

In the previous version I had the old PXA DMA stuff behind #ifdef
CONFIG_ARCH_PXA and otherwise it used the DMA engine stuff. Do you mean
something like that (e.g keep both DMA in the single file)?
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