1 files changed, 58 insertions, 2 deletions

diff --git a/drivers/of/of_reserved_mem.c b/drivers/of/of_reserved_mem.c
index 948efa9f99e3..7ec94cfcbddb 100644
--- a/drivers/of/of_reserved_mem.c
+++ b/drivers/of/of_reserved_mem.c
@@ -78,6 +78,57 @@ void __init fdt_reserved_mem_save_node(unsigned long node, const char *uname,
 }
 
 /*
+ * __reserved_mem_alloc_in_range() - allocate reserved memory described with
+ *	'alloc-ranges'. Choose bottom-up/top-down depending on nearby existing
+ *	reserved regions to keep the reserved memory contiguous if possible.
+ */
+static int __init __reserved_mem_alloc_in_range(phys_addr_t size,
+	phys_addr_t align, phys_addr_t start, phys_addr_t end, bool nomap,
+	phys_addr_t *res_base)
+{
+	bool prev_bottom_up = memblock_bottom_up();
+	bool bottom_up = false, top_down = false;
+	int ret, i;
+
+	for (i = 0; i < reserved_mem_count; i++) {
+		struct reserved_mem *rmem = &reserved_mem[i];
+
+		/* Skip regions that were not reserved yet */
+		if (rmem->size == 0)
+			continue;
+
+		/*
+		 * If range starts next to an existing reservation, use bottom-up:
+		 *	|....RRRR................RRRRRRRR..............|
+		 *	       --RRRR------
+		 */
+		if (start >= rmem->base && start <= (rmem->base + rmem->size))
+			bottom_up = true;
+
+		/*
+		 * If range ends next to an existing reservation, use top-down:
+		 *	|....RRRR................RRRRRRRR..............|
+		 *	              -------RRRR-----
+		 */
+		if (end >= rmem->base && end <= (rmem->base + rmem->size))
+			top_down = true;
+	}
+
+	/* Change setting only if either bottom-up or top-down was selected */
+	if (bottom_up != top_down)
+		memblock_set_bottom_up(bottom_up);
+
+	ret = early_init_dt_alloc_reserved_memory_arch(size, align,
+			start, end, nomap, res_base);
+
+	/* Restore old setting if needed */
+	if (bottom_up != top_down)
+		memblock_set_bottom_up(prev_bottom_up);
+
+	return ret;
+}
+
+/*
  * __reserved_mem_alloc_size() - allocate reserved memory described by
  *	'size', 'alignment'  and 'alloc-ranges' properties.
  */
@@ -137,8 +188,8 @@ static int __init __reserved_mem_alloc_size(unsigned long node,
 			end = start + dt_mem_next_cell(dt_root_size_cells,
 						       &prop);
 
-			ret = early_init_dt_alloc_reserved_memory_arch(size,
-					align, start, end, nomap, &base);
+			ret = __reserved_mem_alloc_in_range(size, align,
+					start, end, nomap, &base);
 			if (ret == 0) {
 				pr_debug("allocated memory for '%s' node: base %pa, size %lu MiB\n",
 					uname, &base,
@@ -217,6 +268,11 @@ static int __init __rmem_cmp(const void *a, const void *b)
 	if (ra->size > rb->size)
 		return 1;
 
+	if (ra->fdt_node < rb->fdt_node)
+		return -1;
+	if (ra->fdt_node > rb->fdt_node)
+		return 1;
+
 	return 0;
 }