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
19 #include "common.h"
20
21 static void __iomem *cpu_reset_base;
22 static size_t cpu_reset_size;
23
24 #define CPU_RESET_OFFSET(cpu) (cpu * 0x8)
25 #define CPU_RESET_ASSERT BIT(0)
26
mvebu_cpu_reset_deassert(int cpu)27 int mvebu_cpu_reset_deassert(int cpu)
28 {
29 u32 reg;
30
31 if (!cpu_reset_base)
32 return -ENODEV;
33
34 if (CPU_RESET_OFFSET(cpu) >= cpu_reset_size)
35 return -EINVAL;
36
37 reg = readl(cpu_reset_base + CPU_RESET_OFFSET(cpu));
38 reg &= ~CPU_RESET_ASSERT;
39 writel(reg, cpu_reset_base + CPU_RESET_OFFSET(cpu));
40
41 return 0;
42 }
43
mvebu_cpu_reset_map(struct device_node * np,int res_idx)44 static int mvebu_cpu_reset_map(struct device_node *np, int res_idx)
45 {
46 struct resource res;
47
48 if (of_address_to_resource(np, res_idx, &res)) {
49 pr_err("unable to get resource\n");
50 return -ENOENT;
51 }
52
53 if (!request_mem_region(res.start, resource_size(&res),
54 np->full_name)) {
55 pr_err("unable to request region\n");
56 return -EBUSY;
57 }
58
59 cpu_reset_base = ioremap(res.start, resource_size(&res));
60 if (!cpu_reset_base) {
61 pr_err("unable to map registers\n");
62 release_mem_region(res.start, resource_size(&res));
63 return -ENOMEM;
64 }
65
66 cpu_reset_size = resource_size(&res);
67
68 return 0;
69 }
70
mvebu_cpu_reset_init(void)71 static int __init mvebu_cpu_reset_init(void)
72 {
73 struct device_node *np;
74 int res_idx;
75 int ret;
76
77 np = of_find_compatible_node(NULL, NULL,
78 "marvell,armada-370-cpu-reset");
79 if (np) {
80 res_idx = 0;
81 } else {
82 /*
83 * This code is kept for backward compatibility with
84 * old Device Trees.
85 */
86 np = of_find_compatible_node(NULL, NULL,
87 "marvell,armada-370-xp-pmsu");
88 if (np) {
89 pr_warn(FW_WARN "deprecated pmsu binding\n");
90 res_idx = 1;
91 }
92 }
93
94 /* No reset node found */
95 if (!np)
96 return -ENODEV;
97
98 ret = mvebu_cpu_reset_map(np, res_idx);
99 of_node_put(np);
100
101 return ret;
102 }
103
104 early_initcall(mvebu_cpu_reset_init);
105