| Message ID | 20200331183844.30488-2-ulf.hansson@linaro.org (mailing list archive) |
|---|---|
| State | Not Applicable |
| Headers | show |
| Series | amba/platform: Initialize dma_parms at the bus level | expand |
> -----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
On Tue, Mar 31, 2020 at 8:38 PM Ulf Hansson <ulf.hansson@linaro.org> wrote: > > 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> Reviewed-by: Arnd Bergmann <arnd@arndb.de>
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;
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> --- 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(+)