From: yjin <yanjiang.jin@windriver.com>
Subject: Re: [PATCH 2/3] crypto: caam_rng: fix rng_unmap_ctx's DMA_UNMAP size
 problem
Date: Thu, 5 Mar 2015 10:52:37 +0800
Message-ID: <54F7C4F5.1040204@windriver.com>
References: <1425365453-19358-1-git-send-email-yanjiang.jin@windriver.com>	<1425365453-19358-3-git-send-email-yanjiang.jin@windriver.com>	<20150303133120.6706da49d0f7188a8213fe36@freescale.com>	<54F69922.6080404@windriver.com> <20150304123623.324ab9594f04dd95c587b628@freescale.com>
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Cc: <horia.geanta@freescale.com>, <herbert@gondor.apana.org.au>,
	<davem@davemloft.net>, <ruchika.gupta@freescale.com>,
	<cristian.stoica@freescale.com>, <NiteshNarayanLal@freescale.com>,
	<linux-crypto@vger.kernel.org>, <linux-kernel@vger.kernel.org>,
	<jinyanjiang@gmail.com>
To: Kim Phillips <kim.phillips@freescale.com>
Return-path: <linux-kernel-owner@vger.kernel.org>
In-Reply-To: <20150304123623.324ab9594f04dd95c587b628@freescale.com>
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On 2015=E5=B9=B403=E6=9C=8805=E6=97=A5 02:36, Kim Phillips wrote:
> On Wed, 4 Mar 2015 13:33:22 +0800
> yjin <yanjiang.jin@windriver.com> wrote:
>
>> On 2015=E5=B9=B403=E6=9C=8804=E6=97=A5 03:31, Kim Phillips wrote:
>>> On Tue, 3 Mar 2015 14:50:52 +0800
>>> <yanjiang.jin@windriver.com> wrote:
>>>
>>>> -		dma_unmap_single(jrdev, ctx->sh_desc_dma, DESC_RNG_LEN,
>>>> -				 DMA_TO_DEVICE);
>>>> +		dma_unmap_single(jrdev, ctx->sh_desc_dma,
>>>> +				desc_bytes(ctx->sh_desc), DMA_TO_DEVICE);
>>> alignment: the 'd' in desc_bytes should fall directly under the 'j'
>>> in jrdev.
>>>
>>> Also, DESC_RNG_LEN should be corrected to (4 * CAAM_CMD_SZ).
>> Hi Kim,
>>
>> I can't find the obvious limitation for the RNG descriptor length in
>> Freescale documents, could you point out it?
> ?  rng_create_sh_desc() creates a fixed descriptor of exactly 4
> command-lengths.

Hi Kim,

Do you mean that the code itself limits the descriptor length? Not a=20
hardware limitation.
If so, I prefer to dma_unmap with desc_bytes(ctx->sh_desc) as my=20
previous patch, and correct DESC_RNG_LEN to (4 * CAAM_CMD_SZ).

Thanks!
Yanjiang

>
> Kim