Add support for handling 'shared-dma-pool' reserved-memory device tree
nodes.

Based on previous code provided by Josh Cartwright <jo...@codeaurora.org>

Signed-off-by: Marek Szyprowski <m.szyprow...@samsung.com>
---
 drivers/base/dma-coherent.c |   41 +++++++++++++++++++++++++++++++++++++++++
 1 file changed, 41 insertions(+)

diff --git a/drivers/base/dma-coherent.c b/drivers/base/dma-coherent.c
index bc256b641027..2343ba5d6d43 100644
--- a/drivers/base/dma-coherent.c
+++ b/drivers/base/dma-coherent.c
@@ -218,3 +218,44 @@ 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, struct of_phandle_args *args)
+{
+       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,
+                                const char *uname)
+{
+       if (of_get_flat_dt_prop(node, "reusable", NULL))
+               return -EINVAL;
+
+       rmem->ops = &rmem_dma_ops;
+       pr_info("Reserved memory: created DMA memory pool at %pa, size %ld 
MiB\n",
+               &rmem->base, (unsigned long)rmem->size / SZ_1M);
+       return 0;
+}
+RESERVEDMEM_OF_DECLARE(dma, "shared-dma-pool", rmem_dma_setup);
+#endif
-- 
1.7.9.5

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