From: Ludovic BARRE <ludovic.barre@st.com>
To: Ulf Hansson <ulf.hansson@linaro.org>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
"Rafael J . Wysocki" <rafael@kernel.org>,
<linux-kernel@vger.kernel.org>
Cc: Arnd Bergmann <arnd@arndb.de>,
Linus Walleij <linus.walleij@linaro.org>,
Russell King <linux@armlinux.org.uk>,
Haibo Chen <haibo.chen@nxp.com>, Vinod Koul <vkoul@kernel.org>,
stable@vger.kernel.org, dmaengine@vger.kernel.org,
Christoph Hellwig <hch@lst.de>,
linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH 1/2] driver core: platform: Initialize dma_parms for platform devices
Date: Wed, 25 Mar 2020 16:23:46 +0100 [thread overview]
Message-ID: <598b3a55-0321-d7ea-8758-edaba5d5cb2c@st.com> (raw)
In-Reply-To: <20200325113407.26996-2-ulf.hansson@linaro.org>
Le 3/25/20 à 12:34 PM, Ulf Hansson a écrit :
> 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().
tested with mmc: mmci_sdmmc fix
Tested-by: Ludovic Barre <ludovic.barre@st.com>
> Suggested-by: Christoph Hellwig <hch@lst.de>
> Cc: <stable@vger.kernel.org>
> Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
> ---
> drivers/base/platform.c | 1 +
> include/linux/platform_device.h | 1 +
> 2 files changed, 2 insertions(+)
>
> diff --git a/drivers/base/platform.c b/drivers/base/platform.c
> index b5ce7b085795..46abbfb52655 100644
> --- a/drivers/base/platform.c
> +++ b/drivers/base/platform.c
> @@ -512,6 +512,7 @@ int platform_device_add(struct platform_device *pdev)
> pdev->dev.parent = &platform_bus;
>
> pdev->dev.bus = &platform_bus_type;
> + pdev->dev.dma_parms = &pdev->dma_parms;
>
> switch (pdev->id) {
> default:
> diff --git a/include/linux/platform_device.h b/include/linux/platform_device.h
> index 041bfa412aa0..81900b3cbe37 100644
> --- a/include/linux/platform_device.h
> +++ b/include/linux/platform_device.h
> @@ -25,6 +25,7 @@ struct platform_device {
> bool id_auto;
> struct device dev;
> u64 platform_dma_mask;
> + struct device_dma_parameters dma_parms;
> u32 num_resources;
> struct resource *resource;
>
>
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next prev parent reply other threads:[~2020-03-25 15:24 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 [this message]
2020-03-26 11:01 ` Linus Walleij
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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