1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  *  Copyright (C) 2021, Qing Zhang <zhangqing@loongson.cn>
4  *  Loongson-2K1000 reset support
5  */
6 
7 #include <linux/of_address.h>
8 #include <linux/pm.h>
9 #include <asm/reboot.h>
10 
11 #define	PM1_STS		0x0c /* Power Management 1 Status Register */
12 #define	PM1_CNT		0x14 /* Power Management 1 Control Register */
13 #define	RST_CNT		0x30 /* Reset Control Register */
14 
15 static void __iomem *base;
16 
ls2k_restart(char * command)17 static void ls2k_restart(char *command)
18 {
19 	writel(0x1, base + RST_CNT);
20 }
21 
ls2k_poweroff(void)22 static void ls2k_poweroff(void)
23 {
24 	/* Clear */
25 	writel((readl(base + PM1_STS) & 0xffffffff), base + PM1_STS);
26 	/* Sleep Enable | Soft Off*/
27 	writel(GENMASK(12, 10) | BIT(13), base + PM1_CNT);
28 }
29 
ls2k_reset_init(void)30 static int ls2k_reset_init(void)
31 {
32 	struct device_node *np;
33 
34 	np = of_find_compatible_node(NULL, NULL, "loongson,ls2k-pm");
35 	if (!np) {
36 		pr_info("Failed to get PM node\n");
37 		return -ENODEV;
38 	}
39 
40 	base = of_iomap(np, 0);
41 	of_node_put(np);
42 	if (!base) {
43 		pr_info("Failed to map PM register base address\n");
44 		return -ENOMEM;
45 	}
46 
47 	_machine_restart = ls2k_restart;
48 	pm_power_off = ls2k_poweroff;
49 
50 	return 0;
51 }
52 
53 arch_initcall(ls2k_reset_init);
54