1 files changed, 66 insertions, 0 deletions

diff --git a/drivers/base/dma-contiguous.c b/drivers/base/dma-contiguous.c
index 6606abdf880c..473ff4892401 100644
--- a/drivers/base/dma-contiguous.c
+++ b/drivers/base/dma-contiguous.c
@@ -211,3 +211,69 @@ bool dma_release_from_contiguous(struct device *dev, struct page *pages,
 {
         return cma_release(dev_get_cma_area(dev), pages, count);
 }
+
+/*
+ * 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>
+
+#undef pr_fmt
+#define pr_fmt(fmt) fmt
+
+static void rmem_cma_device_init(struct reserved_mem *rmem, struct device *dev)
+{
+        dev_set_cma_area(dev, rmem->priv);
+}
+
+static void rmem_cma_device_release(struct reserved_mem *rmem,
+                                    struct device *dev)
+{
+        dev_set_cma_area(dev, NULL);
+}
+
+static const struct reserved_mem_ops rmem_cma_ops = {
+        .device_init    = rmem_cma_device_init,
+        .device_release = rmem_cma_device_release,
+};
+
+static int __init rmem_cma_setup(struct reserved_mem *rmem)
+{
+        phys_addr_t align = PAGE_SIZE << max(MAX_ORDER - 1, pageblock_order);
+        phys_addr_t mask = align - 1;
+        unsigned long node = rmem->fdt_node;
+        struct cma *cma;
+        int err;
+
+        if (!of_get_flat_dt_prop(node, "reusable", NULL) ||
+            of_get_flat_dt_prop(node, "no-map", NULL))
+                return -EINVAL;
+
+        if ((rmem->base & mask) || (rmem->size & mask)) {
+                pr_err("Reserved memory: incorrect alignment of CMA region\n");
+                return -EINVAL;
+        }
+
+        err = cma_init_reserved_mem(rmem->base, rmem->size, 0, &cma);
+        if (err) {
+                pr_err("Reserved memory: unable to setup CMA region\n");
+                return err;
+        }
+        /* Architecture specific contiguous memory fixup. */
+        dma_contiguous_early_fixup(rmem->base, rmem->size);
+
+        if (of_get_flat_dt_prop(node, "linux,cma-default", NULL))
+                dma_contiguous_set_default(cma);
+
+        rmem->ops = &rmem_cma_ops;
+        rmem->priv = cma;
+
+        pr_info("Reserved memory: created CMA memory pool at %pa, size %ld MiB\n",
+                &rmem->base, (unsigned long)rmem->size / SZ_1M);
+
+        return 0;
+}
+RESERVEDMEM_OF_DECLARE(cma, "shared-dma-pool", rmem_cma_setup);
+#endif