[PATCH v6 3/4] of: reserved_mem: Use unflatten_devicetree APIs to scan reserved memory nodes

[Oreoluwa Babatunde]

The unflatten_devicetree APIs have been setup and are available to be
used by the time the fdt_init_reserved_mem() function is called.
Since the unflatten_devicetree APIs are a more efficient way of scanning
through the DT nodes, switch to using these APIs to facilitate the rest
of the reserved memory processing.

Signed-off-by: Oreoluwa Babatunde <quic_obabatun@xxxxxxxxxxx>
---
 drivers/of/of_reserved_mem.c    | 93 ++++++++++++++++++++-------------
 include/linux/of_reserved_mem.h |  2 +-
 kernel/dma/coherent.c           | 10 ++--
 kernel/dma/contiguous.c         |  8 +--
 kernel/dma/swiotlb.c            | 10 ++--
 5 files changed, 72 insertions(+), 51 deletions(-)

diff --git a/drivers/of/of_reserved_mem.c b/drivers/of/of_reserved_mem.c
index 113d593ea031..05283cd24c3b 100644
--- a/drivers/of/of_reserved_mem.c
+++ b/drivers/of/of_reserved_mem.c
@@ -14,6 +14,7 @@
 #include <linux/err.h>
 #include <linux/libfdt.h>
 #include <linux/of.h>
+#include <linux/of_address.h>
 #include <linux/of_fdt.h>
 #include <linux/of_platform.h>
 #include <linux/mm.h>
@@ -99,7 +100,7 @@ static void __init alloc_reserved_mem_array(void)
 /*
  * fdt_reserved_mem_save_node() - save fdt node for second pass initialization
  */
-static void __init fdt_reserved_mem_save_node(unsigned long node, const char *uname,
+static void __init fdt_reserved_mem_save_node(struct device_node *node, const char *uname,
 					      phys_addr_t base, phys_addr_t size)
 {
 	struct reserved_mem *rmem = &reserved_mem[reserved_mem_count];
@@ -109,7 +110,7 @@ static void __init fdt_reserved_mem_save_node(unsigned long node, const char *un
 		return;
 	}
 
-	rmem->fdt_node = node;
+	rmem->dev_node = node;
 	rmem->name = uname;
 	rmem->base = base;
 	rmem->size = size;
@@ -178,11 +179,11 @@ static int __init __reserved_mem_reserve_reg(unsigned long node,
 }
 
 /*
- * __reserved_mem_check_root() - check if #size-cells, #address-cells provided
+ * __fdt_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)
+static int __init __fdt_reserved_mem_check_root(unsigned long node)
 {
 	const __be32 *prop;
 
@@ -200,6 +201,35 @@ static int __init __reserved_mem_check_root(unsigned long node)
 	return 0;
 }
 
+/*
+ * of_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 of_reserved_mem_check_root(struct device_node *node)
+{
+	u32 prop;
+	int ret;
+
+	ret = of_property_read_u32(node, "#size-cells", &prop);
+	if (ret)
+		return ret;
+
+	if (prop != dt_root_size_cells)
+		return -EINVAL;
+
+	ret = of_property_read_u32(node, "#address-cells", &prop);
+	if (ret)
+		return ret;
+
+	if (prop != dt_root_addr_cells)
+		return -EINVAL;
+
+	if (!of_property_present(node, "ranges"))
+		return -EINVAL;
+	return 0;
+}
+
 /**
  * fdt_scan_reserved_mem_reg_nodes() - Store info for the "reg" defined
  * reserved memory regions.
@@ -212,41 +242,40 @@ static int __init __reserved_mem_check_root(unsigned long node)
  */
 static void __init fdt_scan_reserved_mem_reg_nodes(void)
 {
-	int t_len = (dt_root_addr_cells + dt_root_size_cells) * sizeof(__be32);
-	const void *fdt = initial_boot_params;
+	struct device_node *node, *child;
 	phys_addr_t base, size;
-	const __be32 *prop;
-	int node, child;
-	int len;
 
-	node = fdt_path_offset(fdt, "/reserved-memory");
-	if (node < 0) {
+	node = of_find_node_by_path("/reserved-memory");
+	if (!node) {
 		pr_info("Reserved memory: No reserved-memory node in the DT\n");
 		return;
 	}
 
-	if (__reserved_mem_check_root(node)) {
+	if (of_reserved_mem_check_root(node)) {
 		pr_err("Reserved memory: unsupported node format, ignoring\n");
 		return;
 	}
 
-	fdt_for_each_subnode(child, fdt, node) {
+	for_each_child_of_node(node, child) {
+		int ret = 0;
 		const char *uname;
+		struct resource res;
+		struct reserved_mem *rmem;
 
-		prop = of_get_flat_dt_prop(child, "reg", &len);
-		if (!prop)
-			continue;
-		if (!of_fdt_device_is_available(fdt, child))
+		if (!of_device_is_available(child))
 			continue;
 
-		uname = fdt_get_name(fdt, child, NULL);
-		if (len && len % t_len != 0) {
-			pr_err("Reserved memory: invalid reg property in '%s', skipping node.\n",
-			       uname);
+		ret = of_address_to_resource(child, 0, &res);
+		if (ret) {
+			rmem = of_reserved_mem_lookup(child);
+			if (rmem)
+				rmem->dev_node = child;
 			continue;
 		}
-		base = dt_mem_next_cell(dt_root_addr_cells, &prop);
-		size = dt_mem_next_cell(dt_root_size_cells, &prop);
+		uname = of_node_full_name(child);
+
+		base = res.start;
+		size = res.end - res.start + 1;
 
 		if (size)
 			fdt_reserved_mem_save_node(child, uname, base, size);
@@ -269,7 +298,7 @@ int __init fdt_scan_reserved_mem(void)
 	if (node < 0)
 		return -ENODEV;
 
-	if (__reserved_mem_check_root(node) != 0) {
+	if (__fdt_reserved_mem_check_root(node) != 0) {
 		pr_err("Reserved memory: unsupported node format, ignoring\n");
 		return -EINVAL;
 	}
@@ -447,7 +476,7 @@ static int __init __reserved_mem_alloc_size(unsigned long node, const char *unam
 		       uname, (unsigned long)(size / SZ_1M));
 		return -ENOMEM;
 	}
-	fdt_reserved_mem_save_node(node, uname, base, size);
+	fdt_reserved_mem_save_node(NULL, uname, base, size);
 	return 0;
 }
 
@@ -467,7 +496,7 @@ static int __init __reserved_mem_init_node(struct reserved_mem *rmem)
 		reservedmem_of_init_fn initfn = i->data;
 		const char *compat = i->compatible;
 
-		if (!of_flat_dt_is_compatible(rmem->fdt_node, compat))
+		if (!of_device_is_compatible(rmem->dev_node, compat))
 			continue;
 
 		ret = initfn(rmem);
@@ -500,11 +529,6 @@ 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;
 }
 
@@ -551,11 +575,11 @@ void __init fdt_init_reserved_mem(void)
 
 	for (i = 0; i < reserved_mem_count; i++) {
 		struct reserved_mem *rmem = &reserved_mem[i];
-		unsigned long node = rmem->fdt_node;
+		struct device_node *node = rmem->dev_node;
 		int err = 0;
 		bool nomap;
 
-		nomap = of_get_flat_dt_prop(node, "no-map", NULL) != NULL;
+		nomap = of_property_present(node, "no-map");
 
 		err = __reserved_mem_init_node(rmem);
 		if (err != 0 && err != -ENOENT) {
@@ -566,8 +590,7 @@ void __init fdt_init_reserved_mem(void)
 				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;
+			bool reusable = of_property_present(node, "reusable");
 
 			pr_info("%pa..%pa (%lu KiB) %s %s %s\n",
 				&rmem->base, &end, (unsigned long)(rmem->size / SZ_1K),
diff --git a/include/linux/of_reserved_mem.h b/include/linux/of_reserved_mem.h
index e338282da652..769b8f67c8d3 100644
--- a/include/linux/of_reserved_mem.h
+++ b/include/linux/of_reserved_mem.h
@@ -10,7 +10,7 @@ struct reserved_mem_ops;
 
 struct reserved_mem {
 	const char			*name;
-	unsigned long			fdt_node;
+	struct device_node              *dev_node;
 	const struct reserved_mem_ops	*ops;
 	phys_addr_t			base;
 	phys_addr_t			size;
diff --git a/kernel/dma/coherent.c b/kernel/dma/coherent.c
index ff5683a57f77..8f99586204fb 100644
--- a/kernel/dma/coherent.c
+++ b/kernel/dma/coherent.c
@@ -362,20 +362,18 @@ static const struct reserved_mem_ops rmem_dma_ops = {
 
 static int __init rmem_dma_setup(struct reserved_mem *rmem)
 {
-	unsigned long node = rmem->fdt_node;
+	struct device_node *node = rmem->dev_node;
 
-	if (of_get_flat_dt_prop(node, "reusable", NULL))
+	if (of_property_present(node, "reusable"))
 		return -EINVAL;
 
-#ifdef CONFIG_ARM
-	if (!of_get_flat_dt_prop(node, "no-map", NULL)) {
+	if (IS_ENABLED(CONFIG_ARM) && !of_property_present(node, "no-map")) {
 		pr_err("Reserved memory: regions without no-map are not yet supported\n");
 		return -EINVAL;
 	}
-#endif
 
 #ifdef CONFIG_DMA_GLOBAL_POOL
-	if (of_get_flat_dt_prop(node, "linux,dma-default", NULL)) {
+	if (of_property_present(node, "linux,dma-default")) {
 		WARN(dma_reserved_default_memory,
 		     "Reserved memory: region for default DMA coherent area is redefined\n");
 		dma_reserved_default_memory = rmem;
diff --git a/kernel/dma/contiguous.c b/kernel/dma/contiguous.c
index 055da410ac71..450e9e4be79c 100644
--- a/kernel/dma/contiguous.c
+++ b/kernel/dma/contiguous.c
@@ -456,8 +456,8 @@ static const struct reserved_mem_ops rmem_cma_ops = {
 
 static int __init rmem_cma_setup(struct reserved_mem *rmem)
 {
-	unsigned long node = rmem->fdt_node;
-	bool default_cma = of_get_flat_dt_prop(node, "linux,cma-default", NULL);
+	struct device_node *node = rmem->dev_node;
+	bool default_cma = of_property_read_bool(node, "linux,cma-default");
 	struct cma *cma;
 	int err;
 
@@ -467,8 +467,8 @@ static int __init rmem_cma_setup(struct reserved_mem *rmem)
 		return -EBUSY;
 	}
 
-	if (!of_get_flat_dt_prop(node, "reusable", NULL) ||
-	    of_get_flat_dt_prop(node, "no-map", NULL))
+	if (!of_property_present(node, "reusable") ||
+	    of_property_present(node, "no-map"))
 		return -EINVAL;
 
 	if (!IS_ALIGNED(rmem->base | rmem->size, CMA_MIN_ALIGNMENT_BYTES)) {
diff --git a/kernel/dma/swiotlb.c b/kernel/dma/swiotlb.c
index fe1ccb53596f..9949ddc14272 100644
--- a/kernel/dma/swiotlb.c
+++ b/kernel/dma/swiotlb.c
@@ -1859,12 +1859,12 @@ static const struct reserved_mem_ops rmem_swiotlb_ops = {
 
 static int __init rmem_swiotlb_setup(struct reserved_mem *rmem)
 {
-	unsigned long node = rmem->fdt_node;
+	struct device_node *node = rmem->dev_node;
 
-	if (of_get_flat_dt_prop(node, "reusable", NULL) ||
-	    of_get_flat_dt_prop(node, "linux,cma-default", NULL) ||
-	    of_get_flat_dt_prop(node, "linux,dma-default", NULL) ||
-	    of_get_flat_dt_prop(node, "no-map", NULL))
+	if (of_property_present(node, "reusable") ||
+	    of_property_present(node, "linux,cma-default") ||
+	    of_property_present(node, "linux,dma-default") ||
+	    of_property_present(node, "no-map"))
 		return -EINVAL;
 
 	rmem->ops = &rmem_swiotlb_ops;
-- 
2.34.1