Re: [PATCH] net: mvpp2: avoid bouncing buffers
From: Christoph Hellwig <hch@infradead.org>
Date: 2018-08-27 15:48:50
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Subsystem:
driver core, kobjects, debugfs and sysfs, the rest · Maintainers:
Greg Kroah-Hartman, "Rafael J. Wysocki", Danilo Krummrich, Linus Torvalds
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