Re: [PATCH v2 3/4] drivers: dma-coherent: add initialization from device tree

[Laura Abbott <lauraa-sgV2jX0FEOL9JmXXK+q4OQ@public.gmane.org>]

On 7/14/2014 12:12 AM, Marek Szyprowski wrote:
> Add support for handling 'shared-dma-pool' reserved-memory device tree
> nodes.
> 
> Based on previous code provided by Josh Cartwright <joshc-sgV2jX0FEOL9JmXXK+q4OQ@public.gmane.org>
> 
> Signed-off-by: Marek Szyprowski <m.szyprowski-Sze3O3UU22JBDgjK7y7TUQ@public.gmane.org>
> ---
>  drivers/base/dma-coherent.c | 40 ++++++++++++++++++++++++++++++++++++++++
>  1 file changed, 40 insertions(+)
> 
> diff --git a/drivers/base/dma-coherent.c b/drivers/base/dma-coherent.c
> index 7d6e84a51424..b20cbe095d86 100644
> --- a/drivers/base/dma-coherent.c
> +++ b/drivers/base/dma-coherent.c
> @@ -218,3 +218,43 @@ int dma_mmap_from_coherent(struct device *dev, struct vm_area_struct *vma,
>  	return 0;
>  }
>  EXPORT_SYMBOL(dma_mmap_from_coherent);
> +
> +/*
> + * Support for reserved memory regions defined in device tree
> + */
> +#ifdef CONFIG_OF_RESERVED_MEM
> +#include <linux/of.h>
> +#include <linux/of_fdt.h>
> +#include <linux/of_reserved_mem.h>
> +
> +static void rmem_dma_device_init(struct reserved_mem *rmem, struct device *dev)
> +{
> +	dma_declare_coherent_memory(dev, rmem->base, rmem->base,
> +		rmem->size, DMA_MEMORY_MAP | DMA_MEMORY_EXCLUSIVE);
> +}
> +
> +static void rmem_dma_device_release(struct reserved_mem *rmem,
> +				    struct device *dev)
> +{
> +	dma_release_declared_memory(dev);
> +}
> +
> +static const struct reserved_mem_ops rmem_dma_ops = {
> +	.device_init	= rmem_dma_device_init,
> +	.device_release	= rmem_dma_device_release,
> +};
> +
> +static int __init rmem_dma_setup(struct reserved_mem *rmem)
> +{
> +	unsigned long node = rmem->fdt_node;
> +
> +	if (of_get_flat_dt_prop(node, "reusable", NULL))
> +		return -EINVAL;
> +

Can we add a check for 'no-map' property here? At least on ARM, the
lack of the no-map property causes the ioremap to fail.

Thanks,
Laura

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