utils/reset: Add SG2042 hwmon MCU support.

SG2042 uses an onboard MCU to provide reset function.
Add reset driver to support this onboard MCU.

Signed-off-by: Inochi Amaoto <inochiama@outlook.com>
Reviewed-by: Anup Patel <anup@brainfault.org>

lib/utils/reset/Kconfig

@@ -24,6 +24,10 @@ config FDT_RESET_HTIF
 	select SYS_HTIF
 	default n
 
+config FDT_RESET_SG2042_HWMON_MCU
+	bool "Sophgo SG2042 hwmon MCU FDT reset driver"
+	default n
+
 config FDT_RESET_SUNXI_WDT
 	bool "Sunxi WDT FDT reset driver"
 	default n

lib/utils/reset/fdt_reset_sg2042_hwmon_mcu.c

@@ -0,0 +1,114 @@
+/*
+ * SPDX-License-Identifier: BSD-2-Clause
+ *
+ * Copyright (c) 2023 Lin Chunzhi <chunzhi.lin@sophgo.com>
+ */
+
+#include <libfdt.h>
+#include <sbi/sbi_hart.h>
+#include <sbi/sbi_types.h>
+#include <sbi/sbi_error.h>
+#include <sbi/sbi_system.h>
+#include <sbi/sbi_console.h>
+#include <sbi_utils/fdt/fdt_helper.h>
+#include <sbi_utils/reset/fdt_reset.h>
+#include <sbi_utils/i2c/fdt_i2c.h>
+
+#define MANGO_BOARD_TYPE_MASK		0x80
+
+#define REG_BOARD_TYPE			0x00
+#define REG_CMD				0x03
+
+#define CMD_POWEROFF			0x02
+#define CMD_RESET			0x03
+#define CMD_REBOOT			0x07
+
+static struct i2c_adapter *mcu_adapter = NULL;
+static uint32_t mcu_reg = 0;
+
+static int sg2042_mcu_reset_check(u32 type, u32 reason)
+{
+	switch (type) {
+	case SBI_SRST_RESET_TYPE_SHUTDOWN:
+		return 1;
+	case SBI_SRST_RESET_TYPE_COLD_REBOOT:
+	case SBI_SRST_RESET_TYPE_WARM_REBOOT:
+		return 255;
+	}
+
+	return 0;
+}
+
+static void sg2042_mcu_reset(u32 type, u32 reason)
+{
+	switch (type) {
+	case SBI_SRST_RESET_TYPE_SHUTDOWN:
+		i2c_adapter_reg_write(mcu_adapter, mcu_reg,
+				      REG_CMD, CMD_POWEROFF);
+		break;
+	case SBI_SRST_RESET_TYPE_COLD_REBOOT:
+	case SBI_SRST_RESET_TYPE_WARM_REBOOT:
+		i2c_adapter_reg_write(mcu_adapter, mcu_reg,
+				      REG_CMD, CMD_REBOOT);
+		break;
+	}
+}
+
+static struct sbi_system_reset_device sg2042_mcu_reset_device = {
+	.name = "sg2042-mcu-reset",
+	.system_reset_check = sg2042_mcu_reset_check,
+	.system_reset = sg2042_mcu_reset
+};
+
+static int sg2042_mcu_reset_check_board(struct i2c_adapter *adap, uint32_t reg)
+{
+	static uint8_t val;
+	int ret;
+
+	/* check board type */
+	ret = i2c_adapter_reg_read(adap, reg, REG_BOARD_TYPE, &val);
+	if (ret)
+		return ret;
+
+	if (!(val & MANGO_BOARD_TYPE_MASK))
+		return SBI_ENODEV;
+
+	return 0;
+}
+
+static int sg2042_mcu_reset_init(void *fdt, int nodeoff,
+				 const struct fdt_match *match)
+{
+	int ret, i2c_bus;
+	uint64_t addr;
+
+	ret = fdt_get_node_addr_size(fdt, nodeoff, 0, &addr, NULL);
+	if (ret)
+		return ret;
+
+	mcu_reg = addr;
+
+	i2c_bus = fdt_parent_offset(fdt, nodeoff);
+	if (i2c_bus < 0)
+		return i2c_bus;
+
+	ret = fdt_i2c_adapter_get(fdt, i2c_bus, &mcu_adapter);
+	if (ret)
+		return ret;
+
+	ret = sg2042_mcu_reset_check_board(mcu_adapter, mcu_reg);
+
+	sbi_system_reset_add_device(&sg2042_mcu_reset_device);
+
+	return 0;
+}
+
+static const struct fdt_match sg2042_mcu_reset_match[] = {
+	{ .compatible = "sophgo,sg2042-hwmon-mcu", .data = (void *)true},
+	{ },
+};
+
+struct fdt_reset fdt_reset_sg2042_mcu = {
+	.match_table = sg2042_mcu_reset_match,
+	.init = sg2042_mcu_reset_init,
+};

lib/utils/reset/objects.mk

@@ -20,6 +20,9 @@ libsbiutils-objs-$(CONFIG_FDT_RESET_GPIO) += reset/fdt_reset_gpio.o
 carray-fdt_reset_drivers-$(CONFIG_FDT_RESET_HTIF) += fdt_reset_htif
 libsbiutils-objs-$(CONFIG_FDT_RESET_HTIF) += reset/fdt_reset_htif.o
 
+carray-fdt_reset_drivers-$(CONFIG_FDT_RESET_SG2042_HWMON_MCU) += fdt_reset_sg2042_mcu
+libsbiutils-objs-$(CONFIG_FDT_RESET_SG2042_HWMON_MCU) += reset/fdt_reset_sg2042_hwmon_mcu.o
+
 carray-fdt_reset_drivers-$(CONFIG_FDT_RESET_SUNXI_WDT) += fdt_reset_sunxi_wdt
 libsbiutils-objs-$(CONFIG_FDT_RESET_SUNXI_WDT) += reset/fdt_reset_sunxi_wdt.o