| Message ID | 20200325113407.26996-2-ulf.hansson@linaro.org (mailing list archive) |
|---|---|
| State | Not Applicable |
| Headers | show |
| Series | amba/platform: Initialize dma_parms at the bus level | expand |
Le 3/25/20 à 12:34 PM, Ulf Hansson a écrit : > 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(). tested with mmc: mmci_sdmmc fix Tested-by: Ludovic Barre <ludovic.barre@st.com> > 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; > >
On Wed, Mar 25, 2020 at 12:34 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> This seems in line with what Christoph said. Reviewed-by: Linus Walleij <linus.walleij@linaro.org> I imagine we can eventually set up more of the DMA config such as segment size based on config from the device tree, but I'm not sure about that yet. Yours, Linus Walleij
On Wed, Mar 25, 2020 at 12:34 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> Acked-by: Arnd Bergmann <arnd@arndb.de>
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;
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(+)