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SubjectRe: [RFC/PATCH 5/9] of: dma: Split of_configure_dma() into mask and ops configuration
On Thu, May 14, 2015 at 6:00 PM, Laurent Pinchart
<laurent.pinchart+renesas@ideasonboard.com> wrote:
> The of_configure_dma() function configures both the DMA masks and ops.
> Moving DMA ops configuration to probe time would thus also delay
> configuration of the DMA masks, which might not be safe. To avoid issues
> split the configuration in two to allow keeping masks configuration at
> device add time and move ops configuration to device probe time.

Why is it not safe? The probe is deferred before drivers' probe happens.

Rob

> Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
> ---
> drivers/of/device.c | 48 ++++++++++++++++++++++++++++++++++-------------
> drivers/of/of_pci.c | 3 ++-
> drivers/of/platform.c | 6 ++++--
> include/linux/of_device.h | 11 +++++++++--
> 4 files changed, 50 insertions(+), 18 deletions(-)
>
> diff --git a/drivers/of/device.c b/drivers/of/device.c
> index f1b84f464fe1..3cb3f78a6d13 100644
> --- a/drivers/of/device.c
> +++ b/drivers/of/device.c
> @@ -70,7 +70,7 @@ int of_device_add(struct platform_device *ofdev)
> }
>
> /**
> - * of_dma_configure - Setup DMA configuration
> + * of_dma_configure - Setup DMA masks and offset
> * @dev: Device to apply DMA configuration
> * @np: Pointer to OF node having DMA configuration
> *
> @@ -81,13 +81,11 @@ int of_device_add(struct platform_device *ofdev)
> * can use a platform bus notifier and handle BUS_NOTIFY_ADD_DEVICE events
> * to fix up DMA configuration.
> */
> -void of_dma_configure(struct device *dev, struct device_node *np)
> +void of_dma_configure_masks(struct device *dev, struct device_node *np)
> {
> - u64 dma_addr, paddr, size;
> - int ret;
> - bool coherent;
> + u64 dma_addr, paddr, size, range_mask;
> unsigned long offset;
> - struct iommu_ops *iommu;
> + int ret;
>
> /*
> * Set default coherent_dma_mask to 32 bit. Drivers are expected to
> @@ -105,9 +103,10 @@ void of_dma_configure(struct device *dev, struct device_node *np)
>
> ret = of_dma_get_range(np, &dma_addr, &paddr, &size);
> if (ret < 0) {
> - dma_addr = offset = 0;
> - size = dev->coherent_dma_mask + 1;
> + range_mask = dev->coherent_dma_mask + 1;
> + offset = 0;
> } else {
> + range_mask = DMA_BIT_MASK(ilog2(dma_addr + size));
> offset = PFN_DOWN(paddr - dma_addr);
> dev_dbg(dev, "dma_pfn_offset(%#08lx)\n", offset);
> }
> @@ -118,10 +117,31 @@ void of_dma_configure(struct device *dev, struct device_node *np)
> * Limit coherent and dma mask based on size and default mask
> * set by the driver.
> */
> - dev->coherent_dma_mask = min(dev->coherent_dma_mask,
> - DMA_BIT_MASK(ilog2(dma_addr + size)));
> - *dev->dma_mask = min((*dev->dma_mask),
> - DMA_BIT_MASK(ilog2(dma_addr + size)));
> + dev->coherent_dma_mask = min(dev->coherent_dma_mask, range_mask);
> + *dev->dma_mask = min((*dev->dma_mask), range_mask);
> +}
> +EXPORT_SYMBOL_GPL(of_dma_configure_masks);
> +
> +/**
> + * of_dma_configure_ops - Setup DMA operations
> + * @dev: Device to apply DMA configuration
> + * @np: Pointer to OF node having DMA configuration
> + *
> + * Try to get devices's DMA configuration from DT and update it
> + * accordingly.
> + */
> +int of_dma_configure_ops(struct device *dev, struct device_node *np)
> +{
> + u64 dma_addr, paddr, size;
> + struct iommu_ops *iommu;
> + bool coherent;
> + int ret;
> +
> + ret = of_dma_get_range(np, &dma_addr, &paddr, &size);
> + if (ret < 0) {
> + dma_addr = 0;
> + size = dev->coherent_dma_mask + 1;
> + }
>
> coherent = of_dma_is_coherent(np);
> dev_dbg(dev, "device is%sdma coherent\n",
> @@ -132,8 +152,10 @@ void of_dma_configure(struct device *dev, struct device_node *np)
> iommu ? " " : " not ");
>
> arch_setup_dma_ops(dev, dma_addr, size, iommu, coherent);
> +
> + return 0;
> }
> -EXPORT_SYMBOL_GPL(of_dma_configure);
> +EXPORT_SYMBOL_GPL(of_dma_configure_ops);
>
> /**
> * of_dma_deconfigure - Clean up DMA configuration
> diff --git a/drivers/of/of_pci.c b/drivers/of/of_pci.c
> index 5751dc5b6494..c65803da2067 100644
> --- a/drivers/of/of_pci.c
> +++ b/drivers/of/of_pci.c
> @@ -132,7 +132,8 @@ void of_pci_dma_configure(struct pci_dev *pci_dev)
> if (!bridge->parent)
> return;
>
> - of_dma_configure(dev, bridge->parent->of_node);
> + of_dma_configure_masks(dev, bridge->parent->of_node);
> + of_dma_configure_ops(dev, bridge->parent->of_node);
> pci_put_host_bridge_device(bridge);
> }
> EXPORT_SYMBOL_GPL(of_pci_dma_configure);
> diff --git a/drivers/of/platform.c b/drivers/of/platform.c
> index 7a660c79ff84..9a29f09b7723 100644
> --- a/drivers/of/platform.c
> +++ b/drivers/of/platform.c
> @@ -177,7 +177,8 @@ static struct platform_device *of_platform_device_create_pdata(
>
> dev->dev.bus = &platform_bus_type;
> dev->dev.platform_data = platform_data;
> - of_dma_configure(&dev->dev, dev->dev.of_node);
> + of_dma_configure_masks(&dev->dev, dev->dev.of_node);
> + of_dma_configure_ops(&dev->dev, dev->dev.of_node);
>
> if (of_device_add(dev) != 0) {
> of_dma_deconfigure(&dev->dev);
> @@ -240,7 +241,8 @@ static struct amba_device *of_amba_device_create(struct device_node *node,
> dev_set_name(&dev->dev, "%s", bus_id);
> else
> of_device_make_bus_id(&dev->dev);
> - of_dma_configure(&dev->dev, dev->dev.of_node);
> + of_dma_configure_masks(&dev->dev, dev->dev.of_node);
> + of_dma_configure_ops(&dev->dev, dev->dev.of_node);
>
> /* Allow the HW Peripheral ID to be overridden */
> prop = of_get_property(node, "arm,primecell-periphid", NULL);
> diff --git a/include/linux/of_device.h b/include/linux/of_device.h
> index 6710807b0653..794f234c7c7d 100644
> --- a/include/linux/of_device.h
> +++ b/include/linux/of_device.h
> @@ -53,7 +53,8 @@ static inline struct device_node *of_cpu_device_node_get(int cpu)
> return of_node_get(cpu_dev->of_node);
> }
>
> -void of_dma_configure(struct device *dev, struct device_node *np);
> +void of_dma_configure_masks(struct device *dev, struct device_node *np);
> +int of_dma_configure_ops(struct device *dev, struct device_node *np);
> void of_dma_deconfigure(struct device *dev);
> #else /* CONFIG_OF */
>
> @@ -92,8 +93,14 @@ static inline struct device_node *of_cpu_device_node_get(int cpu)
> {
> return NULL;
> }
> -static inline void of_dma_configure(struct device *dev, struct device_node *np)
> +static inline void of_dma_configure_masks(struct device *dev,
> + struct device_node *np)
> {}
> +static inline int of_dma_configure_ops(struct device *dev,
> + struct device_node *np)
> +{
> + return 0;
> +}
> static inline void of_dma_deconfigure(struct device *dev)
> {}
> #endif /* CONFIG_OF */
> --
> 2.3.6
>
>
> _______________________________________________
> linux-arm-kernel mailing list
> linux-arm-kernel@lists.infradead.org
> http://lists.infradead.org/mailman/listinfo/linux-arm-kernel


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