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

   1 /*
   2  * Board-level suspend/resume support.
   3  *
   4  * Copyright (C) 2014 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_XP_GP_PIC_NR_GPIOS 3
  24
  25 static void __iomem *gpio_ctrl;
  26 static int pic_gpios[ARMADA_XP_GP_PIC_NR_GPIOS];
  27 static int pic_raw_gpios[ARMADA_XP_GP_PIC_NR_GPIOS];
  28
  29 static void mvebu_armada_xp_gp_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_XP_GP_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_XP_GP_PIC_NR_GPIOS; i++)
  44                 ackcmd |= BIT(pic_raw_gpios[i]);
  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
  76 static int mvebu_armada_xp_gp_pm_init(void)
  77 {
  78         struct device_node *np;
  79         struct device_node *gpio_ctrl_np;
  80         int ret = 0, i;
  81
  82         if (!of_machine_is_compatible("marvell,axp-gp"))
  83                 return -ENODEV;
  84
  85         np = of_find_node_by_name(NULL, "pm_pic");
  86         if (!np)
  87                 return -ENODEV;
  88
  89         for (i = 0; i < ARMADA_XP_GP_PIC_NR_GPIOS; i++) {
  90                 char *name;
  91                 struct of_phandle_args args;
  92
  93                 pic_gpios[i] = of_get_named_gpio(np, "ctrl-gpios", i);
  94                 if (pic_gpios[i] < 0) {
  95                         ret = -ENODEV;
  96                         goto out;
  97                 }
  98
  99                 name = kasprintf(GFP_KERNEL, "pic-pin%d", i);
 100                 if (!name) {
 101                         ret = -ENOMEM;
 102                         goto out;
 103                 }
 104
 105                 ret = gpio_request(pic_gpios[i], name);
 106                 if (ret < 0) {
 107                         kfree(name);
 108                         goto out;
 109                 }
 110
 111                 ret = gpio_direction_output(pic_gpios[i], 0);
 112                 if (ret < 0) {
 113                         gpio_free(pic_gpios[i]);
 114                         kfree(name);
 115                         goto out;
 116                 }
 117
 118                 ret = of_parse_phandle_with_fixed_args(np, "ctrl-gpios", 2,
 119                                                        i, &args);
 120                 if (ret < 0) {
 121                         gpio_free(pic_gpios[i]);
 122                         kfree(name);
 123                         goto out;
 124                 }
 125
 126                 gpio_ctrl_np = args.np;
 127                 pic_raw_gpios[i] = args.args[0];
 128         }
 129
 130         gpio_ctrl = of_iomap(gpio_ctrl_np, 0);
 131         if (!gpio_ctrl)
 132                 return -ENOMEM;
 133
 134         mvebu_pm_init(mvebu_armada_xp_gp_pm_enter);
 135
 136 out:
 137         of_node_put(np);
 138         return ret;
 139 }
 140
 141 late_initcall(mvebu_armada_xp_gp_pm_init);