From: okaya@codeaurora.org (Sinan Kaya)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH V3 3/4] dmaselftest: add memcpy selftest support functions
Date: Mon, 9 Nov 2015 23:49:54 -0500 [thread overview]
Message-ID: <56417772.7050905@codeaurora.org> (raw)
In-Reply-To: <5640A429.6090302@codeaurora.org>
On 11/9/2015 8:48 AM, Timur Tabi wrote:
> Sinan Kaya wrote:
>>>
>>> And why kmalloc anyway? Why not leave it on the stack?
>>>
>>> char src[] = "hello world";
>>>
>>> ?
>>
>> I need to call dma_map_single on this address to convert it to a DMA
>> address. That's why.
>
> And you can't do that with an object that's on the stack?
>
no, pasting from here.
https://www.kernel.org/doc/Documentation/DMA-API-HOWTO.txt
under 'What memory is DMA'able?'
This rule also means that you may use neither kernel image addresses
(items in data/text/bss segments), nor module image addresses, nor
stack addresses for DMA.
--
Sinan Kaya
Qualcomm Technologies, Inc. on behalf of Qualcomm Innovation Center, Inc.
Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, a
Linux Foundation Collaborative Project
next prev parent reply other threads:[~2015-11-10 4:49 UTC|newest]
Thread overview: 33+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-11-08 4:52 [PATCH V3 0/4] *ma: add Qualcomm Technologies HIDMA driver Sinan Kaya
2015-11-08 4:52 ` [PATCH V3 1/4] dma: qcom_bam_dma: move to qcom directory Sinan Kaya
2015-11-08 5:02 ` Timur Tabi
2015-11-08 4:52 ` [PATCH V3 2/4] dma: add Qualcomm Technologies HIDMA management driver Sinan Kaya
2015-11-08 5:08 ` Timur Tabi
2015-11-09 2:17 ` Sinan Kaya
2015-11-09 18:25 ` Rob Herring
2015-11-10 4:57 ` Sinan Kaya
2015-11-08 9:32 ` kbuild test robot
2015-11-08 4:52 ` [PATCH V3 3/4] dmaselftest: add memcpy selftest support functions Sinan Kaya
2015-11-08 5:13 ` Timur Tabi
2015-11-09 2:46 ` Sinan Kaya
2015-11-09 13:48 ` Timur Tabi
2015-11-10 4:49 ` Sinan Kaya [this message]
2015-11-10 10:13 ` Arnd Bergmann
2015-11-08 20:09 ` Andy Shevchenko
2015-11-09 3:07 ` Sinan Kaya
2015-11-09 9:26 ` Andy Shevchenko
2015-11-10 4:55 ` Sinan Kaya
2015-11-10 4:59 ` Timur Tabi
2015-11-08 4:53 ` [PATCH V3 4/4] dma: add Qualcomm Technologies HIDMA channel driver Sinan Kaya
2015-11-08 19:13 ` kbuild test robot
2015-11-09 0:43 ` Sinan Kaya
2015-11-11 2:21 ` [kbuild-all] " Fengguang Wu
2015-11-11 8:42 ` Arnd Bergmann
2015-11-12 8:20 ` Fengguang Wu
2015-11-12 13:49 ` Arnd Bergmann
2015-11-08 20:47 ` Andy Shevchenko
2015-11-08 21:51 ` Sinan Kaya
2015-11-08 22:00 ` Andy Shevchenko
2015-11-09 0:31 ` Sinan Kaya
2015-11-09 18:19 ` Rob Herring
2015-11-10 4:44 ` Sinan Kaya
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