of/fdt: Rework early_init_dt_scan_memory() to call directly

Use of the of_scan_flat_dt() function predates libfdt and is discouraged
as libfdt provides a nicer set of APIs. Rework
early_init_dt_scan_memory() to be called directly and use libfdt.

Cc: John Crispin <john@phrozen.org>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Frank Rowand <frowand.list@gmail.com>
Cc: linux-mips@vger.kernel.org
Cc: linuxppc-dev@lists.ozlabs.org
Reviewed-by: Frank Rowand <frank.rowand@sony.com>
Signed-off-by: Rob Herring <robh@kernel.org>
Tested-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20211215150102.1303588-1-robh@kernel.org

1 files changed, 36 insertions, 32 deletions

diff --git a/drivers/of/fdt.c b/drivers/of/fdt.c
index 5e216555fe4f..a835c458f50a 100644
--- a/drivers/of/fdt.c
+++ b/drivers/of/fdt.c
@@ -1078,49 +1078,53 @@ u64 __init dt_mem_next_cell(int s, const __be32 **cellp)
 /*
  * early_init_dt_scan_memory - Look for and parse memory nodes
  */
-int __init early_init_dt_scan_memory(unsigned long node, const char *uname,
-				     int depth, void *data)
+int __init early_init_dt_scan_memory(void)
 {
-	const char *type = of_get_flat_dt_prop(node, "device_type", NULL);
-	const __be32 *reg, *endp;
-	int l;
-	bool hotpluggable;
+	int node;
+	const void *fdt = initial_boot_params;
 
-	/* We are scanning "memory" nodes only */
-	if (type == NULL || strcmp(type, "memory") != 0)
-		return 0;
+	fdt_for_each_subnode(node, fdt, 0) {
+		const char *type = of_get_flat_dt_prop(node, "device_type", NULL);
+		const __be32 *reg, *endp;
+		int l;
+		bool hotpluggable;
 
-	reg = of_get_flat_dt_prop(node, "linux,usable-memory", &l);
-	if (reg == NULL)
-		reg = of_get_flat_dt_prop(node, "reg", &l);
-	if (reg == NULL)
-		return 0;
+		/* We are scanning "memory" nodes only */
+		if (type == NULL || strcmp(type, "memory") != 0)
+			continue;
 
-	endp = reg + (l / sizeof(__be32));
-	hotpluggable = of_get_flat_dt_prop(node, "hotpluggable", NULL);
+		reg = of_get_flat_dt_prop(node, "linux,usable-memory", &l);
+		if (reg == NULL)
+			reg = of_get_flat_dt_prop(node, "reg", &l);
+		if (reg == NULL)
+			continue;
 
-	pr_debug("memory scan node %s, reg size %d,\n", uname, l);
+		endp = reg + (l / sizeof(__be32));
+		hotpluggable = of_get_flat_dt_prop(node, "hotpluggable", NULL);
 
-	while ((endp - reg) >= (dt_root_addr_cells + dt_root_size_cells)) {
-		u64 base, size;
+		pr_debug("memory scan node %s, reg size %d,\n",
+			 fdt_get_name(fdt, node, NULL), l);
 
-		base = dt_mem_next_cell(dt_root_addr_cells, &reg);
-		size = dt_mem_next_cell(dt_root_size_cells, &reg);
+		while ((endp - reg) >= (dt_root_addr_cells + dt_root_size_cells)) {
+			u64 base, size;
 
-		if (size == 0)
-			continue;
-		pr_debug(" - %llx, %llx\n", base, size);
+			base = dt_mem_next_cell(dt_root_addr_cells, &reg);
+			size = dt_mem_next_cell(dt_root_size_cells, &reg);
 
-		early_init_dt_add_memory_arch(base, size);
+			if (size == 0)
+				continue;
+			pr_debug(" - %llx, %llx\n", base, size);
 
-		if (!hotpluggable)
-			continue;
+			early_init_dt_add_memory_arch(base, size);
 
-		if (memblock_mark_hotplug(base, size))
-			pr_warn("failed to mark hotplug range 0x%llx - 0x%llx\n",
-				base, base + size);
-	}
+			if (!hotpluggable)
+				continue;
 
+			if (memblock_mark_hotplug(base, size))
+				pr_warn("failed to mark hotplug range 0x%llx - 0x%llx\n",
+					base, base + size);
+		}
+	}
 	return 0;
 }
 
@@ -1271,7 +1275,7 @@ void __init early_init_dt_scan_nodes(void)
 		pr_warn("No chosen node found, continuing without\n");
 
 	/* Setup memory, calling early_init_dt_add_memory_arch */
-	of_scan_flat_dt(early_init_dt_scan_memory, NULL);
+	early_init_dt_scan_memory();
 
 	/* Handle linux,usable-memory-range property */
 	memblock_cap_memory_range(cap_mem_addr, cap_mem_size);