[PATCH v1 01/10] imx: Add helper to get watchdog base address from DT alias

[alice.guo at oss.nxp.com]

From: Alice Guo <alice.guo at nxp.com>

Add imx_wdog_alias_to_addr() to get watchdog register base address from
device tree aliases. This function is used by mx7ulp, imx8ulp and imx9
SoCs to locate watchdog hardware.

The function supports:
- Matching specific alias (e.g., "wdog0") or any "wdog*" if name is
  NULL.
- Optional device tree status check via check_status parameter.

Signed-off-by: Alice Guo <alice.guo at nxp.com>
---
 arch/arm/include/asm/mach-imx/sys_proto.h |  2 ++
 arch/arm/mach-imx/Makefile                |  4 +--
 arch/arm/mach-imx/fdt.c                   | 51 +++++++++++++++++++++++++++++++
 3 files changed, 54 insertions(+), 3 deletions(-)

diff --git a/arch/arm/include/asm/mach-imx/sys_proto.h b/arch/arm/include/asm/mach-imx/sys_proto.h
index 46da7a1eff5..8b88b333b4f 100644
--- a/arch/arm/include/asm/mach-imx/sys_proto.h
+++ b/arch/arm/include/asm/mach-imx/sys_proto.h
@@ -10,6 +10,7 @@
 #include <asm/io.h>
 #include <asm/mach-imx/regs-common.h>
 #include <asm/mach-imx/module_fuse.h>
+#include <fdtdec.h>
 #include <linux/bitops.h>
 #include "../arch-imx/cpu.h"
 
@@ -327,4 +328,5 @@ enum boot_device get_boot_device(void);
 int disable_cpu_nodes(void *blob, const char * const *nodes_path,
 		      u32 num_disabled_cores, u32 max_cores);
 int fixup_thermal_trips(void *blob, const char *name);
+fdt_addr_t imx_wdog_alias_to_addr(char *name, bool check_status);
 #endif
diff --git a/arch/arm/mach-imx/Makefile b/arch/arm/mach-imx/Makefile
index 0f6e737c0b9..b4f316d8c47 100644
--- a/arch/arm/mach-imx/Makefile
+++ b/arch/arm/mach-imx/Makefile
@@ -21,11 +21,9 @@ obj-$(CONFIG_IMX_HAB) += hab.o
 obj-y += cpu.o
 endif
 
-ifeq ($(SOC),$(filter $(SOC),imx8m imx9))
-ifneq ($(CONFIG_XPL_BUILD),y)
+ifeq ($(SOC),$(filter $(SOC),mx7ulp imx8m imx8ulp imx9))
 obj-y += fdt.o
 endif
-endif
 
 ifeq ($(SOC),$(filter $(SOC),mx5 mx6))
 obj-y	+= cpu.o speed.o
diff --git a/arch/arm/mach-imx/fdt.c b/arch/arm/mach-imx/fdt.c
index f19ab9edce4..93016a11acc 100644
--- a/arch/arm/mach-imx/fdt.c
+++ b/arch/arm/mach-imx/fdt.c
@@ -6,8 +6,11 @@
 #include <errno.h>
 #include <fdtdec.h>
 #include <malloc.h>
+#include <asm/global_data.h>
 #include <asm/arch/sys_proto.h>
 
+DECLARE_GLOBAL_DATA_PTR;
+
 static void disable_thermal_cpu_nodes(void *blob, u32 num_disabled_cores, u32 max_cores)
 {
 	static const char * const thermal_path[] = {
@@ -127,3 +130,51 @@ int fixup_thermal_trips(void *blob, const char *name)
 
 	return 0;
 }
+
+fdt_addr_t imx_wdog_alias_to_addr(char *name, bool check_status)
+{
+	const void *fdt = gd->fdt_blob;
+	int aliases_off, prop_off;
+	char *wdog_name_to_match;
+	fdt_addr_t addr;
+
+	if (!fdt || fdt_check_header(fdt))
+		return FDT_ADDR_T_NONE;
+
+	aliases_off = fdt_path_offset(fdt, "/aliases");
+	if (aliases_off < 0)
+		return FDT_ADDR_T_NONE;
+
+	wdog_name_to_match = name ? name : "wdog";
+
+	fdt_for_each_property_offset(prop_off, fdt, aliases_off) {
+		const char *alias_name;
+		const char *path;
+		int len;
+		int node_off;
+
+		path = fdt_getprop_by_offset(fdt, prop_off, &alias_name, &len);
+		if (!path || !alias_name)
+			continue;
+
+		if (strncmp(alias_name, wdog_name_to_match, strlen(wdog_name_to_match)) != 0)
+			continue;
+
+		node_off = fdt_path_offset(fdt, path);
+		if (node_off < 0)
+			continue;
+
+		if (check_status) {
+			if (!fdtdec_get_is_enabled(fdt, node_off))
+				continue;
+		}
+
+		addr = fdtdec_get_addr_size_auto_noparent(fdt, node_off, "reg", 0, NULL, true);
+		if (addr == FDT_ADDR_T_NONE)
+			continue;
+
+		return addr;
+	}
+
+	return FDT_ADDR_T_NONE;
+}

-- 
2.43.0