1 /*
2 * Board-level suspend/resume support.
3 *
4 * Copyright (C) 2014-2015 Marvell
5 *
6 * Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
7 *
8 * This file is licensed under the terms of the GNU General Public
9 * License version 2. This program is licensed "as is" without any
10 * warranty of any kind, whether express or implied.
11 */
12
13 #include <linux/delay.h>
14 #include <linux/gpio.h>
15 #include <linux/init.h>
16 #include <linux/io.h>
17 #include <linux/of.h>
18 #include <linux/of_address.h>
19 #include <linux/of_gpio.h>
20 #include <linux/slab.h>
21 #include "common.h"
22
23 #define ARMADA_PIC_NR_GPIOS 3
24
25 static void __iomem *gpio_ctrl;
26 static int pic_gpios[ARMADA_PIC_NR_GPIOS];
27 static int pic_raw_gpios[ARMADA_PIC_NR_GPIOS];
28
mvebu_armada_pm_enter(void __iomem * sdram_reg,u32 srcmd)29 static void mvebu_armada_pm_enter(void __iomem *sdram_reg, u32 srcmd)
30 {
31 u32 reg, ackcmd;
32 int i;
33
34 /* Put 001 as value on the GPIOs */
35 reg = readl(gpio_ctrl);
36 for (i = 0; i < ARMADA_PIC_NR_GPIOS; i++)
37 reg &= ~BIT(pic_raw_gpios[i]);
38 reg |= BIT(pic_raw_gpios[0]);
39 writel(reg, gpio_ctrl);
40
41 /* Prepare writing 111 to the GPIOs */
42 ackcmd = readl(gpio_ctrl);
43 for (i = 0; i < ARMADA_PIC_NR_GPIOS; i++)
44 ackcmd |= BIT(pic_raw_gpios[i]);
45
46 srcmd = cpu_to_le32(srcmd);
47 ackcmd = cpu_to_le32(ackcmd);
48
49 /*
50 * Wait a while, the PIC needs quite a bit of time between the
51 * two GPIO commands.
52 */
53 mdelay(3000);
54
55 asm volatile (
56 /* Align to a cache line */
57 ".balign 32\n\t"
58
59 /* Enter self refresh */
60 "str %[srcmd], [%[sdram_reg]]\n\t"
61
62 /*
63 * Wait 100 cycles for DDR to enter self refresh, by
64 * doing 50 times two instructions.
65 */
66 "mov r1, #50\n\t"
67 "1: subs r1, r1, #1\n\t"
68 "bne 1b\n\t"
69
70 /* Issue the command ACK */
71 "str %[ackcmd], [%[gpio_ctrl]]\n\t"
72
73 /* Trap the processor */
74 "b .\n\t"
75 : : [srcmd] "r" (srcmd), [sdram_reg] "r" (sdram_reg),
76 [ackcmd] "r" (ackcmd), [gpio_ctrl] "r" (gpio_ctrl) : "r1");
77 }
78
mvebu_armada_pm_init(void)79 static int __init mvebu_armada_pm_init(void)
80 {
81 struct device_node *np;
82 struct device_node *gpio_ctrl_np = NULL;
83 int ret = 0, i;
84
85 if (!of_machine_is_compatible("marvell,axp-gp"))
86 return -ENODEV;
87
88 np = of_find_node_by_name(NULL, "pm_pic");
89 if (!np)
90 return -ENODEV;
91
92 for (i = 0; i < ARMADA_PIC_NR_GPIOS; i++) {
93 char *name;
94 struct of_phandle_args args;
95
96 pic_gpios[i] = of_get_named_gpio(np, "ctrl-gpios", i);
97 if (pic_gpios[i] < 0) {
98 ret = -ENODEV;
99 goto out;
100 }
101
102 name = kasprintf(GFP_KERNEL, "pic-pin%d", i);
103 if (!name) {
104 ret = -ENOMEM;
105 goto out;
106 }
107
108 ret = gpio_request(pic_gpios[i], name);
109 if (ret < 0) {
110 kfree(name);
111 goto out;
112 }
113
114 ret = gpio_direction_output(pic_gpios[i], 0);
115 if (ret < 0) {
116 gpio_free(pic_gpios[i]);
117 kfree(name);
118 goto out;
119 }
120
121 ret = of_parse_phandle_with_fixed_args(np, "ctrl-gpios", 2,
122 i, &args);
123 if (ret < 0) {
124 gpio_free(pic_gpios[i]);
125 kfree(name);
126 goto out;
127 }
128
129 if (gpio_ctrl_np)
130 of_node_put(gpio_ctrl_np);
131 gpio_ctrl_np = args.np;
132 pic_raw_gpios[i] = args.args[0];
133 }
134
135 gpio_ctrl = of_iomap(gpio_ctrl_np, 0);
136 if (!gpio_ctrl) {
137 ret = -ENOMEM;
138 goto out;
139 }
140
141 mvebu_pm_suspend_init(mvebu_armada_pm_enter);
142
143 out:
144 of_node_put(np);
145 of_node_put(gpio_ctrl_np);
146 return ret;
147 }
148
149 /*
150 * Registering the mvebu_board_pm_enter callback must be done before
151 * the platform_suspend_ops will be registered. In the same time we
152 * also need to have the gpio devices registered. That's why we use a
153 * device_initcall_sync which is called after all the device_initcall
154 * (used by the gpio device) but before the late_initcall (used to
155 * register the platform_suspend_ops)
156 */
157 device_initcall_sync(mvebu_armada_pm_init);
158