1 files changed, 549 insertions, 140 deletions

diff --git a/drivers/of/of_reserved_mem.c b/drivers/of/of_reserved_mem.c
index d507c3569a88..5619ec917858 100644
--- a/drivers/of/of_reserved_mem.c
+++ b/drivers/of/of_reserved_mem.c
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0+
 /*
  * Device tree based initialization code for reserved memory.
  *
@@ -6,16 +7,13 @@
  *		http://www.samsung.com
  * Author: Marek Szyprowski <m.szyprowski@samsung.com>
  * Author: Josh Cartwright <joshc@codeaurora.org>
- *
- * This program is free software; you can redistribute it and/or
- * modify it under the terms of the GNU General Public License as
- * published by the Free Software Foundation; either version 2 of the
- * License or (at your optional) any later version of the license.
  */
 
 #define pr_fmt(fmt)	"OF: reserved mem: " fmt
 
 #include <linux/err.h>
+#include <linux/ioport.h>
+#include <linux/libfdt.h>
 #include <linux/of.h>
 #include <linux/of_fdt.h>
 #include <linux/of_platform.h>
@@ -24,61 +22,99 @@
 #include <linux/of_reserved_mem.h>
 #include <linux/sort.h>
 #include <linux/slab.h>
+#include <linux/memblock.h>
+#include <linux/kmemleak.h>
+#include <linux/cma.h>
+#include <linux/dma-map-ops.h>
 
-#define MAX_RESERVED_REGIONS	16
-static struct reserved_mem reserved_mem[MAX_RESERVED_REGIONS];
+#include "of_private.h"
+
+static struct reserved_mem reserved_mem_array[MAX_RESERVED_REGIONS] __initdata;
+static struct reserved_mem *reserved_mem __refdata = reserved_mem_array;
+static int total_reserved_mem_cnt = MAX_RESERVED_REGIONS;
 static int reserved_mem_count;
 
-#if defined(CONFIG_HAVE_MEMBLOCK)
-#include <linux/memblock.h>
-int __init __weak early_init_dt_alloc_reserved_memory_arch(phys_addr_t size,
+static int __init early_init_dt_alloc_reserved_memory_arch(phys_addr_t size,
 	phys_addr_t align, phys_addr_t start, phys_addr_t end, bool nomap,
 	phys_addr_t *res_base)
 {
 	phys_addr_t base;
-	/*
-	 * We use __memblock_alloc_base() because memblock_alloc_base()
-	 * panic()s on allocation failure.
-	 */
+	int err = 0;
+
 	end = !end ? MEMBLOCK_ALLOC_ANYWHERE : end;
-	base = __memblock_alloc_base(size, align, end);
+	align = !align ? SMP_CACHE_BYTES : align;
+	base = memblock_phys_alloc_range(size, align, start, end);
 	if (!base)
 		return -ENOMEM;
 
-	/*
-	 * Check if the allocated region fits in to start..end window
-	 */
-	if (base < start) {
-		memblock_free(base, size);
-		return -ENOMEM;
+	*res_base = base;
+	if (nomap) {
+		err = memblock_mark_nomap(base, size);
+		if (err)
+			memblock_phys_free(base, size);
 	}
 
-	*res_base = base;
-	if (nomap)
-		return memblock_remove(base, size);
-	return 0;
+	if (!err)
+		kmemleak_ignore_phys(base);
+
+	return err;
 }
-#else
-int __init __weak early_init_dt_alloc_reserved_memory_arch(phys_addr_t size,
-	phys_addr_t align, phys_addr_t start, phys_addr_t end, bool nomap,
-	phys_addr_t *res_base)
+
+/*
+ * alloc_reserved_mem_array() - allocate memory for the reserved_mem
+ * array using memblock
+ *
+ * This function is used to allocate memory for the reserved_mem
+ * array according to the total number of reserved memory regions
+ * defined in the DT.
+ * After the new array is allocated, the information stored in
+ * the initial static array is copied over to this new array and
+ * the new array is used from this point on.
+ */
+static void __init alloc_reserved_mem_array(void)
 {
-	pr_err("Reserved memory not supported, ignoring region 0x%llx%s\n",
-		  size, nomap ? " (nomap)" : "");
-	return -ENOSYS;
+	struct reserved_mem *new_array;
+	size_t alloc_size, copy_size, memset_size;
+
+	alloc_size = array_size(total_reserved_mem_cnt, sizeof(*new_array));
+	if (alloc_size == SIZE_MAX) {
+		pr_err("Failed to allocate memory for reserved_mem array with err: %d", -EOVERFLOW);
+		return;
+	}
+
+	new_array = memblock_alloc(alloc_size, SMP_CACHE_BYTES);
+	if (!new_array) {
+		pr_err("Failed to allocate memory for reserved_mem array with err: %d", -ENOMEM);
+		return;
+	}
+
+	copy_size = array_size(reserved_mem_count, sizeof(*new_array));
+	if (copy_size == SIZE_MAX) {
+		memblock_free(new_array, alloc_size);
+		total_reserved_mem_cnt = MAX_RESERVED_REGIONS;
+		pr_err("Failed to allocate memory for reserved_mem array with err: %d", -EOVERFLOW);
+		return;
+	}
+
+	memset_size = alloc_size - copy_size;
+
+	memcpy(new_array, reserved_mem, copy_size);
+	memset(new_array + reserved_mem_count, 0, memset_size);
+
+	reserved_mem = new_array;
 }
-#endif
 
-/**
- * res_mem_save_node() - save fdt node for second pass initialization
+static void __init fdt_init_reserved_mem_node(struct reserved_mem *rmem);
+/*
+ * fdt_reserved_mem_save_node() - save fdt node for second pass initialization
  */
-void __init fdt_reserved_mem_save_node(unsigned long node, const char *uname,
-				      phys_addr_t base, phys_addr_t size)
+static void __init fdt_reserved_mem_save_node(unsigned long node, const char *uname,
+					      phys_addr_t base, phys_addr_t size)
 {
 	struct reserved_mem *rmem = &reserved_mem[reserved_mem_count];
 
-	if (reserved_mem_count == ARRAY_SIZE(reserved_mem)) {
-		pr_err("not enough space all defined regions.\n");
+	if (reserved_mem_count == total_reserved_mem_cnt) {
+		pr_err("not enough space for all defined regions.\n");
 		return;
 	}
 
@@ -87,23 +123,273 @@ void __init fdt_reserved_mem_save_node(unsigned long node, const char *uname,
 	rmem->base = base;
 	rmem->size = size;
 
+	/* Call the region specific initialization function */
+	fdt_init_reserved_mem_node(rmem);
+
 	reserved_mem_count++;
 	return;
 }
 
+static int __init early_init_dt_reserve_memory(phys_addr_t base,
+					       phys_addr_t size, bool nomap)
+{
+	if (nomap) {
+		/*
+		 * If the memory is already reserved (by another region), we
+		 * should not allow it to be marked nomap, but don't worry
+		 * if the region isn't memory as it won't be mapped.
+		 */
+		if (memblock_overlaps_region(&memblock.memory, base, size) &&
+		    memblock_is_region_reserved(base, size))
+			return -EBUSY;
+
+		return memblock_mark_nomap(base, size);
+	}
+	return memblock_reserve(base, size);
+}
+
+/*
+ * __reserved_mem_reserve_reg() - reserve all memory described in 'reg' property
+ */
+static int __init __reserved_mem_reserve_reg(unsigned long node,
+					     const char *uname)
+{
+	phys_addr_t base, size;
+	int i, len;
+	const __be32 *prop;
+	bool nomap;
+
+	prop = of_flat_dt_get_addr_size_prop(node, "reg", &len);
+	if (!prop)
+		return -ENOENT;
+
+	nomap = of_get_flat_dt_prop(node, "no-map", NULL) != NULL;
+
+	for (i = 0; i < len; i++) {
+		u64 b, s;
+
+		of_flat_dt_read_addr_size(prop, i, &b, &s);
+
+		base = b;
+		size = s;
+
+		if (size && early_init_dt_reserve_memory(base, size, nomap) == 0) {
+			/* Architecture specific contiguous memory fixup. */
+			if (of_flat_dt_is_compatible(node, "shared-dma-pool") &&
+			    of_get_flat_dt_prop(node, "reusable", NULL))
+				dma_contiguous_early_fixup(base, size);
+			pr_debug("Reserved memory: reserved region for node '%s': base %pa, size %lu MiB\n",
+				uname, &base, (unsigned long)(size / SZ_1M));
+		} else {
+			pr_err("Reserved memory: failed to reserve memory for node '%s': base %pa, size %lu MiB\n",
+			       uname, &base, (unsigned long)(size / SZ_1M));
+		}
+	}
+	return 0;
+}
+
+/*
+ * __reserved_mem_check_root() - check if #size-cells, #address-cells provided
+ * in /reserved-memory matches the values supported by the current implementation,
+ * also check if ranges property has been provided
+ */
+static int __init __reserved_mem_check_root(unsigned long node)
+{
+	const __be32 *prop;
+
+	prop = of_get_flat_dt_prop(node, "#size-cells", NULL);
+	if (!prop || be32_to_cpup(prop) != dt_root_size_cells)
+		return -EINVAL;
+
+	prop = of_get_flat_dt_prop(node, "#address-cells", NULL);
+	if (!prop || be32_to_cpup(prop) != dt_root_addr_cells)
+		return -EINVAL;
+
+	prop = of_get_flat_dt_prop(node, "ranges", NULL);
+	if (!prop)
+		return -EINVAL;
+	return 0;
+}
+
+static void __init __rmem_check_for_overlap(void);
+
 /**
- * res_mem_alloc_size() - allocate reserved memory described by 'size', 'align'
- *			  and 'alloc-ranges' properties
+ * fdt_scan_reserved_mem_reg_nodes() - Store info for the "reg" defined
+ * reserved memory regions.
+ *
+ * This function is used to scan through the DT and store the
+ * information for the reserved memory regions that are defined using
+ * the "reg" property. The region node number, name, base address, and
+ * size are all stored in the reserved_mem array by calling the
+ * fdt_reserved_mem_save_node() function.
+ */
+void __init fdt_scan_reserved_mem_reg_nodes(void)
+{
+	const void *fdt = initial_boot_params;
+	phys_addr_t base, size;
+	int node, child;
+
+	if (!fdt)
+		return;
+
+	node = fdt_path_offset(fdt, "/reserved-memory");
+	if (node < 0) {
+		pr_info("Reserved memory: No reserved-memory node in the DT\n");
+		return;
+	}
+
+	/* Attempt dynamic allocation of a new reserved_mem array */
+	alloc_reserved_mem_array();
+
+	if (__reserved_mem_check_root(node)) {
+		pr_err("Reserved memory: unsupported node format, ignoring\n");
+		return;
+	}
+
+	fdt_for_each_subnode(child, fdt, node) {
+		const char *uname;
+		u64 b, s;
+
+		if (!of_fdt_device_is_available(fdt, child))
+			continue;
+
+		if (!of_flat_dt_get_addr_size(child, "reg", &b, &s))
+			continue;
+
+		base = b;
+		size = s;
+
+		if (size) {
+			uname = fdt_get_name(fdt, child, NULL);
+			fdt_reserved_mem_save_node(child, uname, base, size);
+		}
+	}
+
+	/* check for overlapping reserved regions */
+	__rmem_check_for_overlap();
+}
+
+static int __init __reserved_mem_alloc_size(unsigned long node, const char *uname);
+
+/*
+ * fdt_scan_reserved_mem() - scan a single FDT node for reserved memory
+ */
+int __init fdt_scan_reserved_mem(void)
+{
+	int node, child;
+	int dynamic_nodes_cnt = 0, count = 0;
+	int dynamic_nodes[MAX_RESERVED_REGIONS];
+	const void *fdt = initial_boot_params;
+
+	node = fdt_path_offset(fdt, "/reserved-memory");
+	if (node < 0)
+		return -ENODEV;
+
+	if (__reserved_mem_check_root(node) != 0) {
+		pr_err("Reserved memory: unsupported node format, ignoring\n");
+		return -EINVAL;
+	}
+
+	fdt_for_each_subnode(child, fdt, node) {
+		const char *uname;
+		int err;
+
+		if (!of_fdt_device_is_available(fdt, child))
+			continue;
+
+		uname = fdt_get_name(fdt, child, NULL);
+
+		err = __reserved_mem_reserve_reg(child, uname);
+		if (!err)
+			count++;
+		/*
+		 * Save the nodes for the dynamically-placed regions
+		 * into an array which will be used for allocation right
+		 * after all the statically-placed regions are reserved
+		 * or marked as no-map. This is done to avoid dynamically
+		 * allocating from one of the statically-placed regions.
+		 */
+		if (err == -ENOENT && of_get_flat_dt_prop(child, "size", NULL)) {
+			dynamic_nodes[dynamic_nodes_cnt] = child;
+			dynamic_nodes_cnt++;
+		}
+	}
+	for (int i = 0; i < dynamic_nodes_cnt; i++) {
+		const char *uname;
+		int err;
+
+		child = dynamic_nodes[i];
+		uname = fdt_get_name(fdt, child, NULL);
+		err = __reserved_mem_alloc_size(child, uname);
+		if (!err)
+			count++;
+	}
+	total_reserved_mem_cnt = count;
+	return 0;
+}
+
+/*
+ * __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_size(unsigned long node,
-	const char *uname, phys_addr_t *res_base, phys_addr_t *res_size)
+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.
+ */
+static int __init __reserved_mem_alloc_size(unsigned long node, const char *uname)
 {
-	int t_len = (dt_root_addr_cells + dt_root_size_cells) * sizeof(__be32);
 	phys_addr_t start = 0, end = 0;
 	phys_addr_t base = 0, align = 0, size;
-	int len;
+	int i, len;
 	const __be32 *prop;
-	int nomap;
+	bool nomap;
 	int ret;
 
 	prop = of_get_flat_dt_prop(node, "size", &len);
@@ -116,8 +402,6 @@ static int __init __reserved_mem_alloc_size(unsigned long node,
 	}
 	size = dt_mem_next_cell(dt_root_size_cells, &prop);
 
-	nomap = of_get_flat_dt_prop(node, "no-map", NULL) != NULL;
-
 	prop = of_get_flat_dt_prop(node, "alignment", &len);
 	if (prop) {
 		if (len != dt_root_addr_cells * sizeof(__be32)) {
@@ -128,73 +412,68 @@ static int __init __reserved_mem_alloc_size(unsigned long node,
 		align = dt_mem_next_cell(dt_root_addr_cells, &prop);
 	}
 
+	nomap = of_get_flat_dt_prop(node, "no-map", NULL) != NULL;
+
 	/* Need adjust the alignment to satisfy the CMA requirement */
 	if (IS_ENABLED(CONFIG_CMA)
 	    && of_flat_dt_is_compatible(node, "shared-dma-pool")
 	    && of_get_flat_dt_prop(node, "reusable", NULL)
-	    && !of_get_flat_dt_prop(node, "no-map", NULL)) {
-		unsigned long order =
-			max_t(unsigned long, MAX_ORDER - 1, pageblock_order);
-
-		align = max(align, (phys_addr_t)PAGE_SIZE << order);
-	}
+	    && !nomap)
+		align = max_t(phys_addr_t, align, CMA_MIN_ALIGNMENT_BYTES);
 
-	prop = of_get_flat_dt_prop(node, "alloc-ranges", &len);
+	prop = of_flat_dt_get_addr_size_prop(node, "alloc-ranges", &len);
 	if (prop) {
+		for (i = 0; i < len; i++) {
+			u64 b, s;
 
-		if (len % t_len != 0) {
-			pr_err("invalid alloc-ranges property in '%s', skipping node.\n",
-			       uname);
-			return -EINVAL;
-		}
-
-		base = 0;
+			of_flat_dt_read_addr_size(prop, i, &b, &s);
 
-		while (len > 0) {
-			start = dt_mem_next_cell(dt_root_addr_cells, &prop);
-			end = start + dt_mem_next_cell(dt_root_size_cells,
-						       &prop);
+			start = b;
+			end = b + s;
 
-			ret = early_init_dt_alloc_reserved_memory_arch(size,
-					align, start, end, nomap, &base);
+			base = 0;
+			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 %ld MiB\n",
+				pr_debug("allocated memory for '%s' node: base %pa, size %lu MiB\n",
 					uname, &base,
-					(unsigned long)size / SZ_1M);
+					(unsigned long)(size / SZ_1M));
 				break;
 			}
-			len -= t_len;
 		}
-
 	} else {
 		ret = early_init_dt_alloc_reserved_memory_arch(size, align,
 							0, 0, nomap, &base);
 		if (ret == 0)
-			pr_debug("allocated memory for '%s' node: base %pa, size %ld MiB\n",
-				uname, &base, (unsigned long)size / SZ_1M);
+			pr_debug("allocated memory for '%s' node: base %pa, size %lu MiB\n",
+				uname, &base, (unsigned long)(size / SZ_1M));
 	}
 
 	if (base == 0) {
-		pr_info("failed to allocate memory for node '%s'\n", uname);
+		pr_err("failed to allocate memory for node '%s': size %lu MiB\n",
+		       uname, (unsigned long)(size / SZ_1M));
 		return -ENOMEM;
 	}
-
-	*res_base = base;
-	*res_size = size;
-
+	/* Architecture specific contiguous memory fixup. */
+	if (of_flat_dt_is_compatible(node, "shared-dma-pool") &&
+	    of_get_flat_dt_prop(node, "reusable", NULL))
+		dma_contiguous_early_fixup(base, size);
+	/* Save region in the reserved_mem array */
+	fdt_reserved_mem_save_node(node, uname, base, size);
 	return 0;
 }
 
 static const struct of_device_id __rmem_of_table_sentinel
-	__used __section(__reservedmem_of_table_end);
+	__used __section("__reservedmem_of_table_end");
 
-/**
- * res_mem_init_node() - call region specific reserved memory init code
+/*
+ * __reserved_mem_init_node() - call region specific reserved memory init code
  */
 static int __init __reserved_mem_init_node(struct reserved_mem *rmem)
 {
 	extern const struct of_device_id __reservedmem_of_table[];
 	const struct of_device_id *i;
+	int ret = -ENOENT;
 
 	for (i = __reservedmem_of_table; i < &__rmem_of_table_sentinel; i++) {
 		reservedmem_of_init_fn initfn = i->data;
@@ -203,13 +482,14 @@ static int __init __reserved_mem_init_node(struct reserved_mem *rmem)
 		if (!of_flat_dt_is_compatible(rmem->fdt_node, compat))
 			continue;
 
-		if (initfn(rmem) == 0) {
+		ret = initfn(rmem);
+		if (ret == 0) {
 			pr_info("initialized node %s, compatible id %s\n",
 				rmem->name, compat);
-			return 0;
+			break;
 		}
 	}
-	return -ENOENT;
+	return ret;
 }
 
 static int __init __rmem_cmp(const void *a, const void *b)
@@ -222,6 +502,21 @@ static int __init __rmem_cmp(const void *a, const void *b)
 	if (ra->base > rb->base)
 		return 1;
 
+	/*
+	 * Put the dynamic allocations (address == 0, size == 0) before static
+	 * allocations at address 0x0 so that overlap detection works
+	 * correctly.
+	 */
+	if (ra->size < rb->size)
+		return -1;
+	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;
 }
 
@@ -239,8 +534,7 @@ static void __init __rmem_check_for_overlap(void)
 
 		this = &reserved_mem[i];
 		next = &reserved_mem[i + 1];
-		if (!(this->base && next->base))
-			continue;
+
 		if (this->base + this->size > next->base) {
 			phys_addr_t this_end, next_end;
 
@@ -254,49 +548,40 @@ static void __init __rmem_check_for_overlap(void)
 }
 
 /**
- * fdt_init_reserved_mem - allocate and init all saved reserved memory regions
+ * fdt_init_reserved_mem_node() - Initialize a reserved memory region
+ * @rmem: reserved_mem struct of the memory region to be initialized.
+ *
+ * This function is used to call the region specific initialization
+ * function for a reserved memory region.
  */
-void __init fdt_init_reserved_mem(void)
+static void __init fdt_init_reserved_mem_node(struct reserved_mem *rmem)
 {
-	int i;
-
-	/* check for overlapping reserved regions */
-	__rmem_check_for_overlap();
-
-	for (i = 0; i < reserved_mem_count; i++) {
-		struct reserved_mem *rmem = &reserved_mem[i];
-		unsigned long node = rmem->fdt_node;
-		int len;
-		const __be32 *prop;
-		int err = 0;
+	unsigned long node = rmem->fdt_node;
+	int err = 0;
+	bool nomap;
 
-		prop = of_get_flat_dt_prop(node, "phandle", &len);
-		if (!prop)
-			prop = of_get_flat_dt_prop(node, "linux,phandle", &len);
-		if (prop)
-			rmem->phandle = of_read_number(prop, len/4);
+	nomap = of_get_flat_dt_prop(node, "no-map", NULL) != NULL;
 
-		if (rmem->size == 0)
-			err = __reserved_mem_alloc_size(node, rmem->name,
-						 &rmem->base, &rmem->size);
-		if (err == 0)
-			__reserved_mem_init_node(rmem);
+	err = __reserved_mem_init_node(rmem);
+	if (err != 0 && err != -ENOENT) {
+		pr_info("node %s compatible matching fail\n", rmem->name);
+		if (nomap)
+			memblock_clear_nomap(rmem->base, rmem->size);
+		else
+			memblock_phys_free(rmem->base, rmem->size);
+	} else {
+		phys_addr_t end = rmem->base + rmem->size - 1;
+		bool reusable =
+			(of_get_flat_dt_prop(node, "reusable", NULL)) != NULL;
+
+		pr_info("%pa..%pa (%lu KiB) %s %s %s\n",
+			&rmem->base, &end, (unsigned long)(rmem->size / SZ_1K),
+			nomap ? "nomap" : "map",
+			reusable ? "reusable" : "non-reusable",
+			rmem->name ? rmem->name : "unknown");
 	}
 }
 
-static inline struct reserved_mem *__find_rmem(struct device_node *node)
-{
-	unsigned int i;
-
-	if (!node->phandle)
-		return NULL;
-
-	for (i = 0; i < reserved_mem_count; i++)
-		if (reserved_mem[i].phandle == node->phandle)
-			return &reserved_mem[i];
-	return NULL;
-}
-
 struct rmem_assigned_device {
 	struct device *dev;
 	struct reserved_mem *rmem;
@@ -336,7 +621,12 @@ int of_reserved_mem_device_init_by_idx(struct device *dev,
 	if (!target)
 		return -ENODEV;
 
-	rmem = __find_rmem(target);
+	if (!of_device_is_available(target)) {
+		of_node_put(target);
+		return 0;
+	}
+
+	rmem = of_reserved_mem_lookup(target);
 	of_node_put(target);
 
 	if (!rmem || !rmem->ops || !rmem->ops->device_init)
@@ -354,10 +644,6 @@ int of_reserved_mem_device_init_by_idx(struct device *dev,
 		mutex_lock(&of_rmem_assigned_device_mutex);
 		list_add(&rd->list, &of_rmem_assigned_device_list);
 		mutex_unlock(&of_rmem_assigned_device_mutex);
-		/* ensure that dma_ops is set for virtual devices
-		 * using reserved memory
-		 */
-		of_dma_configure(dev, np);
 
 		dev_info(dev, "assigned reserved memory node %s\n", rmem->name);
 	} else {
@@ -369,6 +655,25 @@ int of_reserved_mem_device_init_by_idx(struct device *dev,
 EXPORT_SYMBOL_GPL(of_reserved_mem_device_init_by_idx);
 
 /**
+ * of_reserved_mem_device_init_by_name() - assign named reserved memory region
+ *					   to given device
+ * @dev: pointer to the device to configure
+ * @np: pointer to the device node with 'memory-region' property
+ * @name: name of the selected memory region
+ *
+ * Returns: 0 on success or a negative error-code on failure.
+ */
+int of_reserved_mem_device_init_by_name(struct device *dev,
+					struct device_node *np,
+					const char *name)
+{
+	int idx = of_property_match_string(np, "memory-region-names", name);
+
+	return of_reserved_mem_device_init_by_idx(dev, np, idx);
+}
+EXPORT_SYMBOL_GPL(of_reserved_mem_device_init_by_name);
+
+/**
  * of_reserved_mem_device_release() - release reserved memory device structures
  * @dev:	Pointer to the device to deconfigure
  *
@@ -377,23 +682,127 @@ EXPORT_SYMBOL_GPL(of_reserved_mem_device_init_by_idx);
  */
 void of_reserved_mem_device_release(struct device *dev)
 {
-	struct rmem_assigned_device *rd;
-	struct reserved_mem *rmem = NULL;
+	struct rmem_assigned_device *rd, *tmp;
+	LIST_HEAD(release_list);
 
 	mutex_lock(&of_rmem_assigned_device_mutex);
-	list_for_each_entry(rd, &of_rmem_assigned_device_list, list) {
-		if (rd->dev == dev) {
-			rmem = rd->rmem;
-			list_del(&rd->list);
-			kfree(rd);
-			break;
-		}
+	list_for_each_entry_safe(rd, tmp, &of_rmem_assigned_device_list, list) {
+		if (rd->dev == dev)
+			list_move_tail(&rd->list, &release_list);
 	}
 	mutex_unlock(&of_rmem_assigned_device_mutex);
 
-	if (!rmem || !rmem->ops || !rmem->ops->device_release)
-		return;
+	list_for_each_entry_safe(rd, tmp, &release_list, list) {
+		if (rd->rmem && rd->rmem->ops && rd->rmem->ops->device_release)
+			rd->rmem->ops->device_release(rd->rmem, dev);
 
-	rmem->ops->device_release(rmem, dev);
+		kfree(rd);
+	}
 }
 EXPORT_SYMBOL_GPL(of_reserved_mem_device_release);
+
+/**
+ * of_reserved_mem_lookup() - acquire reserved_mem from a device node
+ * @np:		node pointer of the desired reserved-memory region
+ *
+ * This function allows drivers to acquire a reference to the reserved_mem
+ * struct based on a device node handle.
+ *
+ * Returns a reserved_mem reference, or NULL on error.
+ */
+struct reserved_mem *of_reserved_mem_lookup(struct device_node *np)
+{
+	const char *name;
+	int i;
+
+	if (!np->full_name)
+		return NULL;
+
+	name = kbasename(np->full_name);
+	for (i = 0; i < reserved_mem_count; i++)
+		if (!strcmp(reserved_mem[i].name, name))
+			return &reserved_mem[i];
+
+	return NULL;
+}
+EXPORT_SYMBOL_GPL(of_reserved_mem_lookup);
+
+/**
+ * of_reserved_mem_region_to_resource() - Get a reserved memory region as a resource
+ * @np:		node containing 'memory-region' property
+ * @idx:	index of 'memory-region' property to lookup
+ * @res:	Pointer to a struct resource to fill in with reserved region
+ *
+ * This function allows drivers to lookup a node's 'memory-region' property
+ * entries by index and return a struct resource for the entry.
+ *
+ * Returns 0 on success with @res filled in. Returns -ENODEV if 'memory-region'
+ * is missing or unavailable, -EINVAL for any other error.
+ */
+int of_reserved_mem_region_to_resource(const struct device_node *np,
+				       unsigned int idx, struct resource *res)
+{
+	struct reserved_mem *rmem;
+
+	if (!np)
+		return -EINVAL;
+
+	struct device_node __free(device_node) *target = of_parse_phandle(np, "memory-region", idx);
+	if (!target || !of_device_is_available(target))
+		return -ENODEV;
+
+	rmem = of_reserved_mem_lookup(target);
+	if (!rmem)
+		return -EINVAL;
+
+	resource_set_range(res, rmem->base, rmem->size);
+	res->flags = IORESOURCE_MEM;
+	res->name = rmem->name;
+	return 0;
+}
+EXPORT_SYMBOL_GPL(of_reserved_mem_region_to_resource);
+
+/**
+ * of_reserved_mem_region_to_resource_byname() - Get a reserved memory region as a resource
+ * @np:		node containing 'memory-region' property
+ * @name:	name of 'memory-region' property entry to lookup
+ * @res:	Pointer to a struct resource to fill in with reserved region
+ *
+ * This function allows drivers to lookup a node's 'memory-region' property
+ * entries by name and return a struct resource for the entry.
+ *
+ * Returns 0 on success with @res filled in, or a negative error-code on
+ * failure.
+ */
+int of_reserved_mem_region_to_resource_byname(const struct device_node *np,
+					      const char *name,
+					      struct resource *res)
+{
+	int idx;
+
+	if (!name)
+		return -EINVAL;
+
+	idx = of_property_match_string(np, "memory-region-names", name);
+	if (idx < 0)
+		return idx;
+
+	return of_reserved_mem_region_to_resource(np, idx, res);
+}
+EXPORT_SYMBOL_GPL(of_reserved_mem_region_to_resource_byname);
+
+/**
+ * of_reserved_mem_region_count() - Return the number of 'memory-region' entries
+ * @np:		node containing 'memory-region' property
+ *
+ * This function allows drivers to retrieve the number of entries for a node's
+ * 'memory-region' property.
+ *
+ * Returns the number of entries on success, or negative error code on a
+ * malformed property.
+ */
+int of_reserved_mem_region_count(const struct device_node *np)
+{
+	return of_count_phandle_with_args(np, "memory-region", NULL);
+}
+EXPORT_SYMBOL_GPL(of_reserved_mem_region_count);