From: Christoph Hellwig <hch@infradead.org>
To: Brian Brooks <brian.brooks@linaro.org>
Cc: Christoph Hellwig <hch@infradead.org>,
David Miller <davem@davemloft.net>,
antoine.tenart@bootlin.com, maxime.chevallier@bootlin.com,
ymarkman@marvell.com, stefanc@marvell.com,
netdev@vger.kernel.org, linux-kernel@vger.kernel.org,
bjorn.topel@intel.com, brian.brooks@arm.com
Subject: Re: [PATCH] net: mvpp2: avoid bouncing buffers
Date: Mon, 27 Aug 2018 08:48:43 -0700 [thread overview]
Message-ID: <20180827154843.GA25821@infradead.org> (raw)
In-Reply-To: <20180827135524.fv4mxkwjn5bv7p5e@di3>
WE should basically never have dev->dma_mask = &dev->coherent_dma_mask,
so until that is the case you are doctoring around the symptoms and
not the problem.
Does the patch below help your case?
----
From 6294e0e330851ee06e66ab85b348f1d92d375d7a Mon Sep 17 00:00:00 2001
From: Christoph Hellwig <hch@lst.de>
Date: Mon, 27 Aug 2018 17:23:24 +0200
Subject: driver core: initialize a default DMA mask for platform device
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
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.
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 dff82a3c2caa..baf4b06cf2d9 100644
--- a/drivers/base/platform.c
+++ b/drivers/base/platform.c
@@ -225,6 +225,17 @@ struct platform_object {
char name[];
};
+static void setup_pdev_archdata(struct platform_device *pdev)
+{
+ 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);
+};
+
/**
* platform_device_put - destroy a platform device
* @pdev: platform device to free
@@ -271,7 +282,7 @@ 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;
@@ -472,7 +483,7 @@ 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 1a9f38f27f65..d84ec1de6022 100644
--- a/include/linux/platform_device.h
+++ b/include/linux/platform_device.h
@@ -25,6 +25,7 @@ struct platform_device {
int id;
bool id_auto;
struct device dev;
+ dma_addr_t dma_mask;
u32 num_resources;
struct resource *resource;
--
2.18.0
next prev parent reply other threads:[~2018-08-27 15:48 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-08-20 2:47 [PATCH] net: mvpp2: avoid bouncing buffers Brian Brooks
2018-08-20 2:55 ` David Miller
2018-08-20 6:23 ` Christoph Hellwig
2018-08-20 7:02 ` Yan Markman
2018-08-27 13:55 ` Brian Brooks
2018-08-27 15:48 ` Christoph Hellwig [this message]
2018-09-02 2:10 ` Brian Brooks
2019-03-01 14:26 ` Antoine Tenart
2019-03-11 15:46 ` Christoph Hellwig
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