arch/arm/mach-mvebu/pm-board.c

   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
  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
  79 static int __init mvebu_armada_pm_init(void)
  80 {
  81         struct device_node *np;
  82         struct device_node *gpio_ctrl_np;
  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                 gpio_ctrl_np = args.np;
 130                 pic_raw_gpios[i] = args.args[0];
 131         }
 132
 133         gpio_ctrl = of_iomap(gpio_ctrl_np, 0);
 134         if (!gpio_ctrl)
 135                 return -ENOMEM;
 136
 137         mvebu_pm_suspend_init(mvebu_armada_pm_enter);
 138
 139 out:
 140         of_node_put(np);
 141         return ret;
 142 }
 143
 144 /*
 145  * Registering the mvebu_board_pm_enter callback must be done before
 146  * the platform_suspend_ops will be registered. In the same time we
 147  * also need to have the gpio devices registered. That's why we use a
 148  * device_initcall_sync which is called after all the device_initcall
 149  * (used by the gpio device) but before the late_initcall (used to
 150  * register the platform_suspend_ops)
 151  */
 152 device_initcall_sync(mvebu_armada_pm_init);