Messages in this thread Patch in this message | | | From | BOUGH CHEN <> | Subject | RE: [PATCH v2 1/2] driver core: platform: Initialize dma_parms for platform devices | Date | Wed, 1 Apr 2020 04:06:58 +0000 |
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> -----Original Message----- > From: Ulf Hansson <ulf.hansson@linaro.org> > Sent: 2020年4月1日 2:39 > 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>; Robin Murphy <robin.murphy@arm.com>; Vinod > Koul <vkoul@kernel.org>; BOUGH 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 v2 1/2] driver core: platform: Initialize dma_parms for > platform devices > > 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> >
Hi Ulf,
I test both on our local 5.4.24 branch and the latest Linux-next, both works fine.
Tested-by: Haibo Chen <haibo.chen@nxp.com>
Best Regards Haibo Chen
> --- > > Changes in v2: > - Move initialization to setup_pdev_dma_masks(). This means the > initialization is done also in the OF path. > > --- > drivers/base/platform.c | 2 ++ > include/linux/platform_device.h | 1 + > 2 files changed, 3 insertions(+) > > diff --git a/drivers/base/platform.c b/drivers/base/platform.c index > b5ce7b085795..c81b68d5d66d 100644 > --- a/drivers/base/platform.c > +++ b/drivers/base/platform.c > @@ -361,6 +361,8 @@ struct platform_object { > */ > static void setup_pdev_dma_masks(struct platform_device *pdev) { > + pdev->dev.dma_parms = &pdev->dma_parms; > + > if (!pdev->dev.coherent_dma_mask) > pdev->dev.coherent_dma_mask = DMA_BIT_MASK(32); > if (!pdev->dev.dma_mask) { > 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
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