xref: /openbmc/linux/arch/arm/mach-mvebu/cpu-reset.c (revision 6774def6)
1 /*
2  * Copyright (C) 2014 Marvell
3  *
4  * Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
5  *
6  * This file is licensed under the terms of the GNU General Public
7  * License version 2.  This program is licensed "as is" without any
8  * warranty of any kind, whether express or implied.
9  */
10 
11 #define pr_fmt(fmt) "mvebu-cpureset: " fmt
12 
13 #include <linux/kernel.h>
14 #include <linux/init.h>
15 #include <linux/of_address.h>
16 #include <linux/io.h>
17 #include <linux/resource.h>
18 #include "armada-370-xp.h"
19 
20 static void __iomem *cpu_reset_base;
21 static size_t cpu_reset_size;
22 
23 #define CPU_RESET_OFFSET(cpu) (cpu * 0x8)
24 #define CPU_RESET_ASSERT      BIT(0)
25 
26 int mvebu_cpu_reset_deassert(int cpu)
27 {
28 	u32 reg;
29 
30 	if (!cpu_reset_base)
31 		return -ENODEV;
32 
33 	if (CPU_RESET_OFFSET(cpu) >= cpu_reset_size)
34 		return -EINVAL;
35 
36 	reg = readl(cpu_reset_base + CPU_RESET_OFFSET(cpu));
37 	reg &= ~CPU_RESET_ASSERT;
38 	writel(reg, cpu_reset_base + CPU_RESET_OFFSET(cpu));
39 
40 	return 0;
41 }
42 
43 static int mvebu_cpu_reset_map(struct device_node *np, int res_idx)
44 {
45 	struct resource res;
46 
47 	if (of_address_to_resource(np, res_idx, &res)) {
48 		pr_err("unable to get resource\n");
49 		return -ENOENT;
50 	}
51 
52 	if (!request_mem_region(res.start, resource_size(&res),
53 				np->full_name)) {
54 		pr_err("unable to request region\n");
55 		return -EBUSY;
56 	}
57 
58 	cpu_reset_base = ioremap(res.start, resource_size(&res));
59 	if (!cpu_reset_base) {
60 		pr_err("unable to map registers\n");
61 		release_mem_region(res.start, resource_size(&res));
62 		return -ENOMEM;
63 	}
64 
65 	cpu_reset_size = resource_size(&res);
66 
67 	return 0;
68 }
69 
70 static int __init mvebu_cpu_reset_init(void)
71 {
72 	struct device_node *np;
73 	int res_idx;
74 	int ret;
75 
76 	np = of_find_compatible_node(NULL, NULL,
77 				     "marvell,armada-370-cpu-reset");
78 	if (np) {
79 		res_idx = 0;
80 	} else {
81 		/*
82 		 * This code is kept for backward compatibility with
83 		 * old Device Trees.
84 		 */
85 		np = of_find_compatible_node(NULL, NULL,
86 					     "marvell,armada-370-xp-pmsu");
87 		if (np) {
88 			pr_warn(FW_WARN "deprecated pmsu binding\n");
89 			res_idx = 1;
90 		}
91 	}
92 
93 	/* No reset node found */
94 	if (!np)
95 		return -ENODEV;
96 
97 	ret = mvebu_cpu_reset_map(np, res_idx);
98 	of_node_put(np);
99 
100 	return ret;
101 }
102 
103 early_initcall(mvebu_cpu_reset_init);
104