Thomas Petazzoni | 2743282 | 2014-11-21 17:00:08 +0100 | [diff] [blame^] | 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); |