1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Board-level suspend/resume support.
4 *
5 * Copyright (C) 2014-2015 Marvell
6 *
7 * Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
8 */
9
10#include <linux/delay.h>
11#include <linux/err.h>
12#include <linux/gpio/consumer.h>
13#include <linux/init.h>
14#include <linux/io.h>
15#include <linux/of.h>
16#include <linux/of_address.h>
17#include <linux/slab.h>
18#include "common.h"
19
20#define ARMADA_PIC_NR_GPIOS 3
21
22static void __iomem *gpio_ctrl;
23static struct gpio_desc *pic_gpios[ARMADA_PIC_NR_GPIOS];
24static int pic_raw_gpios[ARMADA_PIC_NR_GPIOS];
25
26static void mvebu_armada_pm_enter(void __iomem *sdram_reg, u32 srcmd)
27{
28 u32 reg, ackcmd;
29 int i;
30
31 /* Put 001 as value on the GPIOs */
32 reg = readl(addr: gpio_ctrl);
33 for (i = 0; i < ARMADA_PIC_NR_GPIOS; i++)
34 reg &= ~BIT(pic_raw_gpios[i]);
35 reg |= BIT(pic_raw_gpios[0]);
36 writel(val: reg, addr: gpio_ctrl);
37
38 /* Prepare writing 111 to the GPIOs */
39 ackcmd = readl(addr: gpio_ctrl);
40 for (i = 0; i < ARMADA_PIC_NR_GPIOS; i++)
41 ackcmd |= BIT(pic_raw_gpios[i]);
42
43 srcmd = cpu_to_le32(srcmd);
44 ackcmd = cpu_to_le32(ackcmd);
45
46 /*
47 * Wait a while, the PIC needs quite a bit of time between the
48 * two GPIO commands.
49 */
50 mdelay(3000);
51
52 asm volatile (
53 /* Align to a cache line */
54 ".balign 32\n\t"
55
56 /* Enter self refresh */
57 "str %[srcmd], [%[sdram_reg]]\n\t"
58
59 /*
60 * Wait 100 cycles for DDR to enter self refresh, by
61 * doing 50 times two instructions.
62 */
63 "mov r1, #50\n\t"
64 "1: subs r1, r1, #1\n\t"
65 "bne 1b\n\t"
66
67 /* Issue the command ACK */
68 "str %[ackcmd], [%[gpio_ctrl]]\n\t"
69
70 /* Trap the processor */
71 "b .\n\t"
72 : : [srcmd] "r" (srcmd), [sdram_reg] "r" (sdram_reg),
73 [ackcmd] "r" (ackcmd), [gpio_ctrl] "r" (gpio_ctrl) : "r1");
74}
75
76static int __init mvebu_armada_pm_init(void)
77{
78 struct device_node *np;
79 struct device_node *gpio_ctrl_np = NULL;
80 int ret = 0, i;
81
82 if (!of_machine_is_compatible(compat: "marvell,axp-gp"))
83 return -ENODEV;
84
85 np = of_find_node_by_name(NULL, name: "pm_pic");
86 if (!np)
87 return -ENODEV;
88
89 for (i = 0; i < ARMADA_PIC_NR_GPIOS; i++) {
90 char *name;
91 struct of_phandle_args args;
92
93 name = kasprintf(GFP_KERNEL, fmt: "pic-pin%d", i);
94 if (!name) {
95 ret = -ENOMEM;
96 goto out;
97 }
98
99 pic_gpios[i] = fwnode_gpiod_get_index(of_fwnode_handle(np),
100 con_id: "ctrl", index: i, flags: GPIOD_OUT_HIGH,
101 label: name);
102 ret = PTR_ERR_OR_ZERO(ptr: pic_gpios[i]);
103 if (ret) {
104 kfree(objp: name);
105 goto out;
106 }
107
108 ret = of_parse_phandle_with_fixed_args(np, list_name: "ctrl-gpios", cell_count: 2,
109 index: i, out_args: &args);
110 if (ret < 0) {
111 gpiod_put(desc: pic_gpios[i]);
112 kfree(objp: name);
113 goto out;
114 }
115
116 if (gpio_ctrl_np)
117 of_node_put(node: gpio_ctrl_np);
118 gpio_ctrl_np = args.np;
119 pic_raw_gpios[i] = args.args[0];
120 }
121
122 gpio_ctrl = of_iomap(node: gpio_ctrl_np, index: 0);
123 if (!gpio_ctrl) {
124 ret = -ENOMEM;
125 goto out;
126 }
127
128 mvebu_pm_suspend_init(board_pm_enter: mvebu_armada_pm_enter);
129
130out:
131 of_node_put(node: np);
132 of_node_put(node: gpio_ctrl_np);
133 return ret;
134}
135
136/*
137 * Registering the mvebu_board_pm_enter callback must be done before
138 * the platform_suspend_ops will be registered. In the same time we
139 * also need to have the gpio devices registered. That's why we use a
140 * device_initcall_sync which is called after all the device_initcall
141 * (used by the gpio device) but before the late_initcall (used to
142 * register the platform_suspend_ops)
143 */
144device_initcall_sync(mvebu_armada_pm_init);
145

source code of linux/arch/arm/mach-mvebu/pm-board.c