From mboxrd@z Thu Jan  1 00:00:00 1970
From: Shawn Lin <shawn.lin@rock-chips.com>
Subject: Re: [RFC PATCH v3 1/5] mmc: dw_mmc: Add external dma interface
 support
Date: Wed, 5 Aug 2015 17:11:50 +0800
Message-ID: <55C1D356.5030302@rock-chips.com>
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To: =?UTF-8?Q?Heiko_St=c3=bcbner?= <heiko@sntech.de>
Cc: shawn.lin@rock-chips.com, Ulf Hansson <ulf.hansson@linaro.org>, Jaehoon Chung <jh80.chung@samsung.com>, Seungwon Jeon <tgih.jun@samsung.com>, dianders@chromium.org, linux-mips@linux-mips.org, Arnd Bergmann <arnd@arndb.de>, Alexandre Belloni <alexandre.belloni@free-electrons.com>, Alexey Brodkin <abrodkin@synopsys.com>, Stefan Agner <stefan@agner.ch>, Zhou Wang <wangzhou.bry@gmail.com>, Kumar Gala <galak@codeaurora.org>, Alim Akhtar <alim.akhtar@samsung.com>, Ian Campbell <ijc+devicetree@hellion.org.uk>, Wang Long <long.wanglong@huawei.com>, Rob Herring <robh+dt@kernel.org>, Chaotian Jing <chaotian.jing@mediatek.com>, Lukasz Majewski <l.majewski@samsung.com>, Jun Nie <jun.nie@linaro.org>, Catalin Marinas <catalin.marinas@arm.com>, Kevin Hao <haokexin@>
List-Id: devicetree@vger.kernel.org

=E5=9C=A8 2015/8/5 16:49, Heiko St=C3=BCbner =E5=86=99=E9=81=93:
> Am Mittwoch, 5. August 2015, 16:17:28 schrieb Shawn Lin:
>> DesignWare MMC Controller can supports two types of DMA
>> mode: external dma and internal dma. We get a RK312x platform
>> integrated dw_mmc and ARM pl330 dma controller. This patch add
>> edmac ops to support these platforms. I've tested it on RK312x
>> platform with edmac mode and RK3288 platform with idmac mode.
>>
>> Signed-off-by: Shawn Lin <shawn.lin@rock-chips.com>
>>
>> ---
> [...]
>
>> diff --git a/include/linux/mmc/dw_mmc.h b/include/linux/mmc/dw_mmc.h
>> index 5be9767..6c1c7ea 100644
>> --- a/include/linux/mmc/dw_mmc.h
>> +++ b/include/linux/mmc/dw_mmc.h
>> @@ -16,6 +16,7 @@
>>
>>   #include <linux/scatterlist.h>
>>   #include <linux/mmc/core.h>
>> +#include <linux/dmaengine.h>
>>
>>   #define MAX_MCI_SLOTS	2
>>
>> @@ -40,6 +41,17 @@ enum {
>>
>>   struct mmc_data;
>>
>> +enum {
>> +	TRANS_MODE_PIO =3D 0,
>> +	TRANS_MODE_IDMAC,
>> +	TRANS_MODE_EDMAC
>> +};
>> +
>> +struct dw_mci_dma_slave {
>> +	struct dma_chan *ch;
>> +	enum dma_transfer_direction direction;
>> +};
>> +
>>   /**
>>    * struct dw_mci - MMC controller state shared between all slots
>>    * @lock: Spinlock protecting the queue and associated data.
>> @@ -147,17 +159,23 @@ struct dw_mci {
>>
>>   	/* DMA interface members*/
>>   	int			use_dma;
>> +	int			trans_mode;
> you're introducing this new trans_mode, but we have "use_dma" already=
=2E
>
> So you could just define
>
> enum {
> 	TRANS_DMA_PIO =3D 0,
> 	TRANS_DMA_IDMAC,
> 	TRANS_DMA_EDMAC
> };
>
> and fill use_dma appropriately. "0" is meaning PIO already, which I a=
lso did fix
> up some days ago in "[PATCH] mmc: dw_mmc: fix pio mode when internal =
dmac is
> enabled" [0].
    I  agree.  "trans_mode" is redundant here since it does the same=20
work as "use_dma" to some degree.
    Thanks.
>
> Heiko
>
> [0] https://lkml.org/lkml/2015/8/3/407
>
>
>


--=20
Shawn Lin