Linux-USB Archive on lore.kernel.org
 help / color / Atom feed
From: Robin Murphy <robin.murphy@arm.com>
To: Christoph Hellwig <hch@lst.de>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	Maxime Chevallier <maxime.chevallier@bootlin.com>
Cc: linux-arch@vger.kernel.org, Olav Kongas <ok@artecdesign.ee>,
	Gavin Li <git@thegavinli.com>,
	linuxppc-dev@lists.ozlabs.org,
	Mathias Nyman <mathias.nyman@intel.com>,
	Geoff Levand <geoff@infradead.org>,
	Fabio Estevam <festevam@gmail.com>,
	Sascha Hauer <s.hauer@pengutronix.de>,
	linux-usb@vger.kernel.org, Michal Simek <michal.simek@xilinx.com>,
	linux-kernel@vger.kernel.org, Tony Prisk <linux@prisktech.co.nz>,
	iommu@lists.linux-foundation.org,
	Alan Stern <stern@rowland.harvard.edu>,
	NXP Linux Team <linux-imx@nxp.com>,
	Pengutronix Kernel Team <kernel@pengutronix.de>,
	Minas Harutyunyan <hminas@synopsys.com>,
	Shawn Guo <shawnguo@kernel.org>, Bin Liu <b-liu@ti.com>,
	linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH 6/6] driver core: initialize a default DMA mask for platform device
Date: Wed, 14 Aug 2019 16:49:13 +0100
Message-ID: <fbea6e6d-7721-b51d-0501-582e8446e9c9@arm.com> (raw)
In-Reply-To: <20190811080520.21712-7-hch@lst.de>

On 11/08/2019 09:05, Christoph Hellwig wrote:
> We still treat devices without a DMA mask as defaulting to 32-bits for
> both mask, but a few releases ago we've started warning about such
> cases, as they require special cases to work around this sloppyness.
> Add a dma_mask field to struct platform_object so that we can initialize

s/object/device/

> the dma_mask pointer in struct device and initialize both masks to
> 32-bits by default.  Architectures can still override this in
> arch_setup_pdev_archdata if needed.
> 
> Note that the code looks a little odd with the various conditionals
> because we have to support platform_device structures that are
> statically allocated.

This would be a good point to also get rid of the long-standing bodge in 
platform_device_register_full().

> Signed-off-by: Christoph Hellwig <hch@lst.de>
> ---
>   drivers/base/platform.c         | 15 +++++++++++++--
>   include/linux/platform_device.h |  1 +
>   2 files changed, 14 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/base/platform.c b/drivers/base/platform.c
> index ec974ba9c0c4..b216fcb0a8af 100644
> --- a/drivers/base/platform.c
> +++ b/drivers/base/platform.c
> @@ -264,6 +264,17 @@ struct platform_object {
>   	char name[];
>   };
>   
> +static void setup_pdev_archdata(struct platform_device *pdev)

Bikeshed: painting the generic DMA API properties as "archdata" feels a 
bit off-target :/

> +{
> +	if (!pdev->dev.coherent_dma_mask)
> +		pdev->dev.coherent_dma_mask = DMA_BIT_MASK(32);
> +	if (!pdev->dma_mask)
> +		pdev->dma_mask = DMA_BIT_MASK(32);
> +	if (!pdev->dev.dma_mask)
> +		pdev->dev.dma_mask = &pdev->dma_mask;
> +	arch_setup_pdev_archdata(pdev);

AFAICS m68k's implementation of that arch hook becomes entirely 
redundant after this change, so may as well go. That would just leave 
powerpc's actual archdata, which at a glance looks like it could 
probably be cleaned up with not *too* much trouble.

Robin.

> +};
> +
>   /**
>    * platform_device_put - destroy a platform device
>    * @pdev: platform device to free
> @@ -310,7 +321,7 @@ struct platform_device *platform_device_alloc(const char *name, int id)
>   		pa->pdev.id = id;
>   		device_initialize(&pa->pdev.dev);
>   		pa->pdev.dev.release = platform_device_release;
> -		arch_setup_pdev_archdata(&pa->pdev);
> +		setup_pdev_archdata(&pa->pdev);
>   	}
>   
>   	return pa ? &pa->pdev : NULL;
> @@ -512,7 +523,7 @@ EXPORT_SYMBOL_GPL(platform_device_del);
>   int platform_device_register(struct platform_device *pdev)
>   {
>   	device_initialize(&pdev->dev);
> -	arch_setup_pdev_archdata(pdev);
> +	setup_pdev_archdata(pdev);
>   	return platform_device_add(pdev);
>   }
>   EXPORT_SYMBOL_GPL(platform_device_register);
> diff --git a/include/linux/platform_device.h b/include/linux/platform_device.h
> index 9bc36b589827..a2abde2aef25 100644
> --- a/include/linux/platform_device.h
> +++ b/include/linux/platform_device.h
> @@ -24,6 +24,7 @@ struct platform_device {
>   	int		id;
>   	bool		id_auto;
>   	struct device	dev;
> +	u64		dma_mask;
>   	u32		num_resources;
>   	struct resource	*resource;
>   
> 

  reply index

Thread overview: 19+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-08-11  8:05 next take at setting up a dma mask by default for platform devices Christoph Hellwig
2019-08-11  8:05 ` [PATCH 1/6] usb: don't create dma pools for HCDs with a localmem_pool Christoph Hellwig
2019-08-11  8:05 ` [PATCH 2/6] usb: add a hcd_uses_dma helper Christoph Hellwig
2019-08-11  8:05 ` [PATCH 3/6] usb: add a HCD_DMA flag instead of guestimating DMA capabilities Christoph Hellwig
2019-08-12 11:57   ` Christoph Hellwig
2019-08-11  8:05 ` [PATCH 4/6] usb/max3421: remove the dummy {un,}map_urb_for_dma methods Christoph Hellwig
2019-08-11  8:05 ` [PATCH 5/6] dma-mapping: remove is_device_dma_capable Christoph Hellwig
2019-08-11  8:05 ` [PATCH 6/6] driver core: initialize a default DMA mask for platform device Christoph Hellwig
2019-08-14 15:49   ` Robin Murphy [this message]
2019-08-15 13:32     ` Christoph Hellwig
2019-08-15 13:03   ` Greg Kroah-Hartman
2019-08-15 13:38     ` Christoph Hellwig
2019-08-15 14:05       ` Greg Kroah-Hartman
2019-08-15 13:23 ` next take at setting up a dma mask by default for platform devices Greg Kroah-Hartman
2019-08-15 13:25   ` Christoph Hellwig
2019-08-15 14:05     ` Greg Kroah-Hartman
2019-08-15 14:39     ` Alan Stern
2019-08-16  6:24 next take at setting up a dma mask by default for platform devices v2 Christoph Hellwig
2019-08-16  6:24 ` [PATCH 6/6] driver core: initialize a default DMA mask for platform device Christoph Hellwig
2019-08-16  7:39   ` Geert Uytterhoeven

Reply instructions:

You may reply publically to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=fbea6e6d-7721-b51d-0501-582e8446e9c9@arm.com \
    --to=robin.murphy@arm.com \
    --cc=b-liu@ti.com \
    --cc=festevam@gmail.com \
    --cc=geoff@infradead.org \
    --cc=git@thegavinli.com \
    --cc=gregkh@linuxfoundation.org \
    --cc=hch@lst.de \
    --cc=hminas@synopsys.com \
    --cc=iommu@lists.linux-foundation.org \
    --cc=kernel@pengutronix.de \
    --cc=linux-arch@vger.kernel.org \
    --cc=linux-arm-kernel@lists.infradead.org \
    --cc=linux-imx@nxp.com \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-usb@vger.kernel.org \
    --cc=linux@prisktech.co.nz \
    --cc=linuxppc-dev@lists.ozlabs.org \
    --cc=mathias.nyman@intel.com \
    --cc=maxime.chevallier@bootlin.com \
    --cc=michal.simek@xilinx.com \
    --cc=ok@artecdesign.ee \
    --cc=s.hauer@pengutronix.de \
    --cc=shawnguo@kernel.org \
    --cc=stern@rowland.harvard.edu \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

Linux-USB Archive on lore.kernel.org

Archives are clonable:
	git clone --mirror https://lore.kernel.org/linux-usb/0 linux-usb/git/0.git

	# If you have public-inbox 1.1+ installed, you may
	# initialize and index your mirror using the following commands:
	public-inbox-init -V2 linux-usb linux-usb/ https://lore.kernel.org/linux-usb \
		linux-usb@vger.kernel.org
	public-inbox-index linux-usb

Example config snippet for mirrors

Newsgroup available over NNTP:
	nntp://nntp.lore.kernel.org/org.kernel.vger.linux-usb


AGPL code for this site: git clone https://public-inbox.org/public-inbox.git