[PATCH v6 6/8] dma-mapping: detect and configure IOMMU in of_dma_configure

Rob Clark
2014-12-10T14:52:56Z

On Mon, Dec 1, 2014 at 11:57 AM, Will Deacon <will.deacon@arm.com> wrote:
> This patch extends of_dma_configure so that it sets up the IOMMU for a
> device, as well as the coherent/non-coherent DMA mapping ops.
>
> Acked-by: Arnd Bergmann <arnd@arndb.de>
> Acked-by: Marek Szyprowski <m.szyprowski@samsung.com>
> Tested-by: Robin Murphy <robin.murphy@arm.com>
> Signed-off-by: Will Deacon <will.deacon@arm.com>
> ---
> arch/arm/include/asm/dma-mapping.h | 4 +++-
> drivers/of/platform.c | 21 ++++++++++++++-------
> include/linux/dma-mapping.h | 8 +++++++-
> 3 files changed, 24 insertions(+), 9 deletions(-)
>
> diff --git a/arch/arm/include/asm/dma-mapping.h b/arch/arm/include/asm/dma-mapping.h
> index dc3420e77758..f3c0d953f6a2 100644
> --- a/arch/arm/include/asm/dma-mapping.h
> +++ b/arch/arm/include/asm/dma-mapping.h
> @@ -121,7 +121,9 @@ static inline unsigned long dma_max_pfn(struct device *dev)
> }
> #define dma_max_pfn(dev) dma_max_pfn(dev)
>
> -static inline void arch_setup_dma_ops(struct device *dev, bool coherent)
> +static inline void arch_setup_dma_ops(struct device *dev, u64 dma_base,
> + u64 size, struct iommu_ops *iommu,
> + bool coherent)
> {
> if (coherent)
> set_dma_ops(dev, &arm_coherent_dma_ops);
> diff --git a/drivers/of/platform.c b/drivers/of/platform.c
> index ff1f4e9afccb..b89caf8c7586 100644
> --- a/drivers/of/platform.c
> +++ b/drivers/of/platform.c
> @@ -19,6 +19,7 @@
> #include <linux/slab.h>
> #include <linux/of_address.h>
> #include <linux/of_device.h>
> +#include <linux/of_iommu.h>
> #include <linux/of_irq.h>
> #include <linux/of_platform.h>
> #include <linux/platform_device.h>
> @@ -166,6 +167,7 @@ static void of_dma_configure(struct device *dev)
> int ret;
> bool coherent;
> unsigned long offset;
> + struct iommu_ops *iommu;
>
> /*
> * Set default dma-mask to 32 bit. Drivers are expected to setup
> @@ -194,7 +196,16 @@ static void of_dma_configure(struct device *dev)
> dev_dbg(dev, "device is%sdma coherent\n",
> coherent ? " " : " not ");
>
> - arch_setup_dma_ops(dev, coherent);
> + iommu = of_iommu_configure(dev);
> + dev_dbg(dev, "device is%sbehind an iommu\n",
> + iommu ? " " : " not ");
> +
> + arch_setup_dma_ops(dev, dma_addr, size, iommu, coherent);

so, what is the way for a driver that explicitly wants to manage it's
own device virtual address space to opt out of this? I suspect that
won't be the common case, but for a gpu, if dma layer all of a sudden
thinks it is in control of the gpu's virtual address space, things are
going to end in tears..

BR,
-R

> +}
> +
> +static void of_dma_deconfigure(struct device *dev)
> +{
> + arch_teardown_dma_ops(dev);
> }
>
> /**
> @@ -223,16 +234,12 @@ static struct platform_device *of_platform_device_create_pdata(
> if (!dev)
> goto err_clear_flag;
>
> - of_dma_configure(&dev->dev);
> dev->dev.bus = &platform_bus_type;
> dev->dev.platform_data = platform_data;
> -
> - /* We do not fill the DMA ops for platform devices by default.
> - * This is currently the responsibility of the platform code
> - * to do such, possibly using a device notifier
> - */
> + of_dma_configure(&dev->dev);
>
> if (of_device_add(dev) != 0) {
> + of_dma_deconfigure(&dev->dev);
> platform_device_put(dev);
> goto err_clear_flag;
> }
> diff --git a/include/linux/dma-mapping.h b/include/linux/dma-mapping.h
> index 8a1560f95d4a..c3007cb4bfa6 100644
> --- a/include/linux/dma-mapping.h
> +++ b/include/linux/dma-mapping.h
> @@ -130,7 +130,13 @@ static inline int dma_coerce_mask_and_coherent(struct device *dev, u64 mask)
> extern u64 dma_get_required_mask(struct device *dev);
>
> #ifndef arch_setup_dma_ops
> -static inline void arch_setup_dma_ops(struct device *dev, bool coherent) { }
> +static inline void arch_setup_dma_ops(struct device *dev, u64 dma_base,
> + u64 size, struct iommu_ops *iommu,
> + bool coherent) { }
> +#endif
> +
> +#ifndef arch_teardown_dma_ops
> +static inline void arch_teardown_dma_ops(struct device *dev) { }
> #endif
>
> static inline unsigned int dma_get_max_seg_size(struct device *dev)
> --
> 2.1.1
>
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