From: Linus Walleij <linus.walleij@linaro.org>
To: Ulf Hansson <ulf.hansson@linaro.org>
Cc: Arnd Bergmann <arnd@arndb.de>,
"Rafael J . Wysocki" <rafael@kernel.org>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Russell King <linux@armlinux.org.uk>,
Haibo Chen <haibo.chen@nxp.com>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
Vinod Koul <vkoul@kernel.org>,
Linux ARM <linux-arm-kernel@lists.infradead.org>,
dmaengine <dmaengine@vger.kernel.org>,
stable <stable@vger.kernel.org>, Christoph Hellwig <hch@lst.de>,
Ludovic Barre <ludovic.barre@st.com>
Subject: Re: [PATCH 1/2] driver core: platform: Initialize dma_parms for platform devices
Date: Thu, 26 Mar 2020 12:01:28 +0100 [thread overview]
Message-ID: <CACRpkdbFQ4kjgxxwrTjXZWAt38AM2kyMbeaCX6wjMgyyRmE55Q@mail.gmail.com> (raw)
In-Reply-To: <20200325113407.26996-2-ulf.hansson@linaro.org>
On Wed, Mar 25, 2020 at 12:34 PM Ulf Hansson <ulf.hansson@linaro.org> wrote:
> It's currently the platform driver's responsibility to initialize the
> pointer, dma_parms, for its corresponding struct device. The benefit with
> this approach allows us to avoid the initialization and to not waste memory
> for the struct device_dma_parameters, as this can be decided on a case by
> case basis.
>
> However, it has turned out that this approach is not very practical. Not
> only does it lead to open coding, but also to real errors. In principle
> callers of dma_set_max_seg_size() doesn't check the error code, but just
> assumes it succeeds.
>
> For these reasons, let's do the initialization from the common platform bus
> at the device registration point. This also follows the way the PCI devices
> are being managed, see pci_device_add().
>
> Suggested-by: Christoph Hellwig <hch@lst.de>
> Cc: <stable@vger.kernel.org>
> Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
This seems in line with what Christoph said.
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
I imagine we can eventually set up more of the DMA config such
as segment size based on config from the device tree, but I'm not
sure about that yet.
Yours,
Linus Walleij
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next prev parent reply other threads:[~2020-03-26 11:01 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-03-25 11:34 [PATCH 0/2] amba/platform: Initialize dma_parms at the bus level Ulf Hansson
2020-03-25 11:34 ` [PATCH 1/2] driver core: platform: Initialize dma_parms for platform devices Ulf Hansson
2020-03-25 15:23 ` Ludovic BARRE
2020-03-26 11:01 ` Linus Walleij [this message]
2020-03-26 11:06 ` Arnd Bergmann
2020-03-25 11:34 ` [PATCH 2/2] amba: Initialize dma_parms for amba devices Ulf Hansson
2020-03-25 15:24 ` Ludovic BARRE
2020-03-26 11:02 ` Linus Walleij
2020-03-26 11:07 ` Arnd Bergmann
2020-03-26 4:41 ` [PATCH 0/2] amba/platform: Initialize dma_parms at the bus level BOUGH CHEN
2020-03-27 3:02 ` BOUGH CHEN
2020-03-27 15:34 ` Ulf Hansson
2020-03-27 19:15 ` Robin Murphy
2020-03-31 18:08 ` Ulf Hansson
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