linux-kernel - Re: [PATCH v5] spi: spi-ti-qspi: Add DMA support for QSPI mmap read

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Message-ID: <7f441117-8fd9-6681-70c8-85fb6de40631@ti.com>
Date:	Wed, 17 Aug 2016 10:43:12 +0530
From:	Vignesh R <vigneshr@...com>
To:	Mark Brown <broonie@...nel.org>
CC:	"linux-spi@...r.kernel.org" <linux-spi@...r.kernel.org>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	"linux-omap@...r.kernel.org" <linux-omap@...r.kernel.org>
Subject: Re: [PATCH v5] spi: spi-ti-qspi: Add DMA support for QSPI mmap read



On Wednesday 17 August 2016 12:12 AM, Mark Brown wrote:
> On Tue, Aug 09, 2016 at 06:20:01PM +0530, Vignesh R wrote:
>>
>>
> 
>> According to this thread[1], converting virtual address
>> pointer into scatterlist which is then DMA mapped is unsafe on systems
>> with certain cache architecture. Hence, I added code to handle kmap
>> buffers inside the driver rather than updating generic spi-core code.
> 
> That's saying that things that aren't covered aren't DMAable safely at
> all which is a more general issue...
> 
>> If its okay to update the spi_map_buf() to handle kmap buffers as above
>> then I can submit the patch accordingly.
> 
> Yes, the whole point is that this is all in generic code so drivers
> don't need to worry about it.

Ok, I will send another version updating spi_map_buf() to handle kmap
buffers. Thanks!

-- 
Regards
Vignesh