dmaengine Archive on lore.kernel.org
 help / color / Atom feed
From: Ulf Hansson <ulf.hansson@linaro.org>
To: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	"Rafael J . Wysocki" <rafael@kernel.org>,
	linux-kernel@vger.kernel.org
Cc: Arnd Bergmann <arnd@arndb.de>, Christoph Hellwig <hch@lst.de>,
	Russell King <linux@armlinux.org.uk>,
	Linus Walleij <linus.walleij@linaro.org>,
	Vinod Koul <vkoul@kernel.org>, Haibo Chen <haibo.chen@nxp.com>,
	Ludovic Barre <ludovic.barre@st.com>,
	linux-arm-kernel@lists.infradead.org, dmaengine@vger.kernel.org,
	Ulf Hansson <ulf.hansson@linaro.org>,
	stable@vger.kernel.org
Subject: [PATCH 1/2] driver core: platform: Initialize dma_parms for platform devices
Date: Wed, 25 Mar 2020 12:34:06 +0100
Message-ID: <20200325113407.26996-2-ulf.hansson@linaro.org> (raw)
In-Reply-To: <20200325113407.26996-1-ulf.hansson@linaro.org>

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>
---
 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;
 
-- 
2.20.1


  reply index

Thread overview: 13+ 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 ` Ulf Hansson [this message]
2020-03-25 15:23   ` [PATCH 1/2] driver core: platform: Initialize dma_parms for platform devices Ludovic BARRE
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

Reply instructions:

You may reply publicly 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=20200325113407.26996-2-ulf.hansson@linaro.org \
    --to=ulf.hansson@linaro.org \
    --cc=arnd@arndb.de \
    --cc=dmaengine@vger.kernel.org \
    --cc=gregkh@linuxfoundation.org \
    --cc=haibo.chen@nxp.com \
    --cc=hch@lst.de \
    --cc=linus.walleij@linaro.org \
    --cc=linux-arm-kernel@lists.infradead.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux@armlinux.org.uk \
    --cc=ludovic.barre@st.com \
    --cc=rafael@kernel.org \
    --cc=stable@vger.kernel.org \
    --cc=vkoul@kernel.org \
    /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

dmaengine Archive on lore.kernel.org

Archives are clonable:
	git clone --mirror https://lore.kernel.org/dmaengine/0 dmaengine/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 dmaengine dmaengine/ https://lore.kernel.org/dmaengine \
		dmaengine@vger.kernel.org
	public-inbox-index dmaengine

Example config snippet for mirrors

Newsgroup available over NNTP:
	nntp://nntp.lore.kernel.org/org.kernel.vger.dmaengine


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