From: yingjoe.chen@mediatek.com (Yingjoe Chen)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH v2 2/3] i2c: Add helper to ease DMA handling
Date: Thu, 9 Aug 2018 17:13:20 +0800 [thread overview]
Message-ID: <1533806000.3347.6.camel@mtksdaap41> (raw)
In-Reply-To: <20180808205752.llowh4bvu2wkuhga@ninjato>
On Wed, 2018-08-08 at 22:57 +0200, Wolfram Sang wrote:
> On Sat, Jul 07, 2018 at 05:29:54PM +0800, Jun Gao wrote:
> > From: Jun Gao <jun.gao@mediatek.com>
> >
> > This function is needed by i2c_get_dma_safe_msg_buf() potentially.
> > It is used to free DMA safe buffer when DMA operation fails.
> >
> > Signed-off-by: Jun Gao <jun.gao@mediatek.com>
>
> Right, we need something like this. This leaks in the sh_mobile driver,
> too :(
>
> I am still thinking if there is a nice way to put this functionality
> into i2c_release_dma_safe_msg_buf() itself somehow...
Wolfram,
I have second thought on these API now. Recently, we have saw similar
issue for spi device driver.
I believe the reason for these api is because some arch changed to can
not do DMA on stack recently. Maybe we should have dma_mapping to bounce
buffer like it bounce un-dma-able address for those arch? or we should
have a common driver API for this, not just for i2c?
Joe.C
next prev parent reply other threads:[~2018-08-09 9:13 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-07-07 9:29 [PATCH v2 0/3] Register i2c adapter driver earlier and use DMA safe buffers Jun Gao
2018-07-07 9:29 ` [PATCH v2 1/3] i2c: mediatek: Register i2c adapter driver earlier Jun Gao
2018-08-08 20:40 ` Wolfram Sang
2018-07-07 9:29 ` [PATCH v2 2/3] i2c: Add helper to ease DMA handling Jun Gao
2018-07-08 11:58 ` Peter Rosin
2018-07-08 12:46 ` Peter Rosin
2018-08-08 20:57 ` Wolfram Sang
2018-08-09 9:13 ` Yingjoe Chen [this message]
2018-08-09 9:23 ` Wolfram Sang
2018-07-07 9:29 ` [PATCH v2 3/3] i2c: mediatek: Use DMA safe buffers for i2c transactions Jun Gao
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