[PATCH 01/11] of: reserved_mem: fix region count for nodes with multiple reg entries

[Chen Wandun <chenwandun1@gmail.com>]

When a reserved-memory node contains multiple reg entries (e.g.,
reg = <base1 size1>, <base2 size2>), the count used for
total_reserved_mem_cnt is wrong in two places:

1) __reserved_mem_reserve_reg() returns 0 on success regardless of how
   many regions it reserved in memblock. The caller in
   fdt_scan_reserved_mem() then increments count by just 1.

2) fdt_scan_reserved_mem_late() uses of_flat_dt_get_addr_size() which
   only reads the first reg entry. Subsequent entries are never
   initialized via fdt_init_reserved_mem_node(), so their metadata is
   lost.

Fix both issues:
 - Make __reserved_mem_reserve_reg() return the actual number of
   regions successfully reserved. Update the caller to accumulate
   the returned count.
 - Rewrite fdt_scan_reserved_mem_late() to use
   of_flat_dt_get_addr_size_prop() and iterate all reg entries,
   initializing each one via fdt_init_reserved_mem_node().

Fixes: 8a6e02d0c00e ("of: reserved_mem: Restructure how the reserved memory regions are processed")
Fixes: 00c9a452a235 ("of: reserved_mem: Add code to dynamically allocate reserved_mem array")
Signed-off-by: Chen Wandun <chenwandun@lixiang.com>
Tested-by: Zhao Meijing <zhaomeijing@lixiang.com>
---
 drivers/of/of_reserved_mem.c | 37 +++++++++++++++++++++++-------------
 1 file changed, 24 insertions(+), 13 deletions(-)

diff --git a/drivers/of/of_reserved_mem.c b/drivers/of/of_reserved_mem.c
index 8d5777cb5d1b..9d1b0193864c 100644
--- a/drivers/of/of_reserved_mem.c
+++ b/drivers/of/of_reserved_mem.c
@@ -129,6 +129,8 @@ static int __init early_init_dt_reserve_memory(phys_addr_t base,
 
 /*
  * __reserved_mem_reserve_reg() - reserve all memory described in 'reg' property
+ *
+ * Returns: number of regions successfully reserved, or negative error code
  */
 static int __init __reserved_mem_reserve_reg(unsigned long node,
 					     const char *uname)
@@ -137,6 +139,7 @@ static int __init __reserved_mem_reserve_reg(unsigned long node,
 	int i, len, err;
 	const __be32 *prop;
 	bool nomap;
+	int reserved_count = 0;
 
 	prop = of_flat_dt_get_addr_size_prop(node, "reg", &len);
 	if (!prop)
@@ -160,12 +163,13 @@ static int __init __reserved_mem_reserve_reg(unsigned long node,
 			fdt_fixup_reserved_mem_node(node, base, size);
 			pr_debug("Reserved memory: reserved region for node '%s': base %pa, size %lu MiB\n",
 				uname, &base, (unsigned long)(size / SZ_1M));
+			reserved_count++;
 		} 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;
+	return reserved_count;
 }
 
 /*
@@ -275,25 +279,32 @@ void __init fdt_scan_reserved_mem_late(void)
 
 	fdt_for_each_subnode(child, fdt, node) {
 		const char *uname;
-		u64 b, s;
+		int i, len;
+		const __be32 *prop;
 		int ret;
 
 		if (!of_fdt_device_is_available(fdt, child))
 			continue;
 
-		if (!of_flat_dt_get_addr_size(child, "reg", &b, &s))
+		prop = of_flat_dt_get_addr_size_prop(child, "reg", &len);
+		if (!prop)
 			continue;
 
 		ret = fdt_validate_reserved_mem_node(child, NULL);
 		if (ret && ret != -ENODEV)
 			continue;
 
-		base = b;
-		size = s;
+		uname = fdt_get_name(fdt, child, NULL);
+		for (i = 0; i < len; i++) {
+			u64 b, s;
 
-		if (size) {
-			uname = fdt_get_name(fdt, child, NULL);
-			fdt_init_reserved_mem_node(child, uname, base, size);
+			of_flat_dt_read_addr_size(prop, i, &b, &s);
+
+			base = b;
+			size = s;
+
+			if (size)
+				fdt_init_reserved_mem_node(child, uname, base, size);
 		}
 	}
 
@@ -331,16 +342,16 @@ int __init fdt_scan_reserved_mem(void)
 
 	fdt_for_each_subnode(child, fdt, node) {
 		const char *uname;
-		int err;
+		int ret;
 
 		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++;
+		ret = __reserved_mem_reserve_reg(child, uname);
+		if (ret > 0)
+			count += ret;
 		/*
 		 * Save the nodes for the dynamically-placed regions
 		 * into an array which will be used for allocation right
@@ -348,7 +359,7 @@ int __init fdt_scan_reserved_mem(void)
 		 * 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)) {
+		if (ret == -ENOENT && of_get_flat_dt_prop(child, "size", NULL)) {
 			dynamic_nodes[dynamic_nodes_cnt] = child;
 			dynamic_nodes_cnt++;
 		}
-- 
2.43.0