From: Pierre Yves MORDRET <pierre-yves.mordret@st.com>
To: Wolfram Sang <wsa@the-dreams.de>
Cc: Maxime Coquelin <mcoquelin.stm32@gmail.com>,
Alexandre Torgue <alexandre.torgue@st.com>,
linux-i2c@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH v2 5/6] i2c: i2c-stm32f7: Add DMA support
Date: Wed, 4 Apr 2018 10:20:44 +0200 [thread overview]
Message-ID: <273ac8d2-6861-c1ad-c2fc-f9c5cc2ac3de@st.com> (raw)
In-Reply-To: <20180403153925.lg37rezuvs6hefks@ninjato>
On 04/03/2018 05:39 PM, Wolfram Sang wrote:
>
>> +#define STM32F7_I2C_DMA_LEN_MIN 0x1
> ...
>
>> + if (i2c_dev->dma && f7_msg->count >= STM32F7_I2C_DMA_LEN_MIN) {
>
> Are you using DMA for every message with a length >= 1? The setup of
> that might be more expensive than the DMA gain, if so.
>
Well yes. I am in charge of DMA IPs as well. I2C is the only devices that I had
to test DMA outside standard DMA Engine test. Quite convenient.
I believe to stress both I2C and DMA, this value was relevant.
Now I agree this value can be tuned a little bit. I might raise this threshold
in V3.
next prev parent reply other threads:[~2018-04-04 8:20 UTC|newest]
Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-03-21 16:48 [PATCH v2 0/6] Add different features for I2C Pierre-Yves MORDRET
2018-03-21 16:48 ` [PATCH v2 1/6] i2c: i2c-stm32f7: Add 10-bit address support Pierre-Yves MORDRET
2018-03-24 22:43 ` Wolfram Sang
2018-03-26 7:56 ` Pierre Yves MORDRET
2018-03-26 8:00 ` Wolfram Sang
2018-03-21 16:48 ` [PATCH v2 2/6] i2c: i2c-stm32f7: Add slave support Pierre-Yves MORDRET
2018-03-25 18:16 ` Wolfram Sang
2018-03-26 8:41 ` Pierre Yves MORDRET
2018-04-03 15:26 ` Wolfram Sang
2018-04-04 8:13 ` Pierre Yves MORDRET
2018-04-04 11:07 ` Wolfram Sang
2018-03-21 16:48 ` [PATCH v2 3/6] i2c: i2c-stm32f7: Add initial SMBus protocols support Pierre-Yves MORDRET
2018-03-24 22:49 ` Wolfram Sang
2018-03-26 8:13 ` Pierre Yves MORDRET
2018-04-03 15:31 ` Wolfram Sang
2018-04-04 8:16 ` Pierre Yves MORDRET
2018-04-04 9:04 ` Pierre Yves MORDRET
2018-04-27 20:48 ` Wolfram Sang
2018-03-21 16:48 ` [PATCH v2 4/6] i2c: i2c-stm32: Add generic DMA API Pierre-Yves MORDRET
2018-03-24 22:51 ` Wolfram Sang
2018-03-26 8:20 ` Pierre Yves MORDRET
2018-03-21 16:48 ` [PATCH v2 5/6] i2c: i2c-stm32f7: Add DMA support Pierre-Yves MORDRET
2018-04-03 15:39 ` Wolfram Sang
2018-04-04 8:20 ` Pierre Yves MORDRET [this message]
2018-03-21 16:49 ` [PATCH v2 6/6] i2c: i2c-stm32f7: Implement I2C recovery mechanism Pierre-Yves MORDRET
2018-03-24 22:56 ` Wolfram Sang
2018-03-26 8:21 ` Pierre Yves MORDRET
2018-03-24 22:57 ` [PATCH v2 0/6] Add different features for I2C Wolfram Sang
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