From af4353ab19aaf29dc68ff89a0d581102ca5be43c Mon Sep 17 00:00:00 2001
From: "Thang Q. Nguyen" <thang@os.amperecomputing.com>
Date: Wed, 6 Jan 2021 06:33:36 +0000
Subject: [PATCH] aspeed: support passing system reset status to kernel via
 bootargs

This is a backport of the patch file from
openbmc/meta-yadro/meta-nicole/recipes-bsp/u-boot/
to add the Aspeed reset reason to bootargs so kernel applications
can query it.

Test case: /proc/cmdline must contain:
     - resetreason=power after cold bmc boot
     - resetreason=watchdog after warm bmc reboot

Signed-off-by: Chanh Nguyen <chanh@os.amperecomputing.com>
Signed-off-by: Thang Q. Nguyen <thang@os.amperecomputing.com>
---
 arch/arm/include/asm/arch-aspeed/ast_scu.h |  2 +-
 arch/arm/mach-aspeed/ast-scu.c             |  6 +-
 board/aspeed/ast-g5/ast-g5.c               | 81 ++++++++++++++++++++++
 3 files changed, 87 insertions(+), 2 deletions(-)

diff --git a/arch/arm/include/asm/arch-aspeed/ast_scu.h b/arch/arm/include/asm/arch-aspeed/ast_scu.h
index d2c010a0dc..f5c9126ec0 100644
--- a/arch/arm/include/asm/arch-aspeed/ast_scu.h
+++ b/arch/arm/include/asm/arch-aspeed/ast_scu.h
@@ -29,7 +29,7 @@
 #define __AST_SCU_H
 
 extern void ast_scu_show_system_info (void);
-extern void ast_scu_sys_rest_info(void);
+extern u32 ast_scu_sys_rest_info(void);
 extern void ast_scu_security_info(void);
 extern u32 ast_scu_revision_id(void);
 extern u32 ast_scu_get_vga_memsize(void);
diff --git a/arch/arm/mach-aspeed/ast-scu.c b/arch/arm/mach-aspeed/ast-scu.c
index ef90ef3805..c7ab66415f 100644
--- a/arch/arm/mach-aspeed/ast-scu.c
+++ b/arch/arm/mach-aspeed/ast-scu.c
@@ -494,22 +494,26 @@ void ast_scu_security_info(void)
 	}
 }
 
-void ast_scu_sys_rest_info(void)
+u32 ast_scu_sys_rest_info(void)
 {
 	u32 rest = ast_scu_read(AST_SCU_SYS_CTRL);
 
 	if (rest & SCU_SYS_EXT_RESET_FLAG) {
 		printf("RST : External\n");
 		ast_scu_write(SCU_SYS_EXT_RESET_FLAG, AST_SCU_SYS_CTRL);
+		rest = SCU_SYS_EXT_RESET_FLAG;
 	} else if (rest & SCU_SYS_WDT_RESET_FLAG) {
 		printf("RST : Watchdog\n");
 		ast_scu_write(SCU_SYS_WDT_RESET_FLAG, AST_SCU_SYS_CTRL);
+		rest = SCU_SYS_WDT_RESET_FLAG;
 	} else if (rest & SCU_SYS_PWR_RESET_FLAG) {
 		printf("RST : Power On\n");
 		ast_scu_write(SCU_SYS_PWR_RESET_FLAG, AST_SCU_SYS_CTRL);
+		rest = SCU_SYS_PWR_RESET_FLAG;
 	} else {
 		printf("RST : CLK en\n");
 	}
+	return rest;
 }
 
 u32 ast_scu_get_vga_memsize(void)
diff --git a/board/aspeed/ast-g5/ast-g5.c b/board/aspeed/ast-g5/ast-g5.c
index 9bf6c905fe..9e27bce0f5 100644
--- a/board/aspeed/ast-g5/ast-g5.c
+++ b/board/aspeed/ast-g5/ast-g5.c
@@ -8,6 +8,8 @@
  */
 
 #include <common.h>
+#include <stdlib.h>
+#include <asm/arch/regs-scu.h>
 #include <netdev.h>
 
 #include <asm/arch/ast_scu.h>
@@ -25,9 +27,76 @@ int board_init(void)
 }
 
 #ifdef CONFIG_BOARD_LATE_INIT
+static void update_bootargs_cmd(const char *key, const char *value)
+{
+	int buf_len;
+	char *buf;
+	char *cmdline;
+	char *end = NULL;
+
+	if (!key || (key[0] == '\0')) {
+		printf("%s: Empty key not allowed\n", __func__);
+		return;
+	}
+
+	cmdline = getenv("bootargs");
+
+	/* Allocate space for maximum possible new command line */
+	buf_len = (cmdline ? strlen(cmdline) : 0)
+		+ 1 /* spacebar as delimiter */
+		+ strlen(key)
+		+ (value ? 1 /* equal sign */ + strlen(value) : 0)
+		+ 1 /* terminating null */;
+
+	buf = calloc(buf_len, sizeof(char));
+	if (!buf) {
+		printf("%s: out of memory\n", __func__);
+		return;
+	}
+
+	if (cmdline)
+	{
+		char *start = strstr(cmdline, key);
+
+		/* Check for full word match. Match should be start of cmdline
+		 * or there should be space before match
+		 **/
+		if (start && ((start == cmdline) || (*(start - 1) == ' '))) {
+			strncat(buf, cmdline, (start - cmdline));
+
+			/* Find the end of the keyword[=value] pair,
+			 * including a single training space character, if any.
+			 * Skip the found substring, mark the tail of cmdline.
+			 **/
+			end = strchr(start, ' ');
+			if (end) {
+				end++;
+			}
+		} else {
+			strcat(buf, cmdline);
+			strcat(buf, " ");
+		}
+	}
+
+	strcat(buf, key);
+	if (value) {
+		strcat(buf, "=");
+		strcat(buf, value);
+	}
+
+	if (end) {
+		strcat(buf, " ");
+		strcat(buf, end);
+	}
+
+	setenv("bootargs", buf);
+	free(buf);
+}
+
 int board_late_init(void)
 {
 	u32 val;
+	u32 reset_reason = ast_scu_sys_rest_info();
 
 	/* Switch PWM to GPIO mode to make FAN run in max speed */
 	ast_scu_switch_pwm_to_gpio_mode();
@@ -44,6 +113,18 @@ int board_late_init(void)
 	writel(0xaa, AST_SCU_BASE);
 #endif
 
+	if (reset_reason & SCU_SYS_EXT_RESET_FLAG) {
+		update_bootargs_cmd("resetreason", "external");
+	} else if (reset_reason & SCU_SYS_WDT_RESET_FLAG) {
+		update_bootargs_cmd("resetreason", "watchdog");
+	} else if (reset_reason & SCU_SYS_PWR_RESET_FLAG) {
+		update_bootargs_cmd("resetreason", "power");
+	} else {
+		char value[32];
+		snprintf(value, sizeof(value) - 1, "0x%x", reset_reason);
+		update_bootargs_cmd("resetreason", value);
+	}
+
 	return 0;
 }
 #endif
-- 
2.25.1