1 // SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause) 2 /* 3 * SP7021 reset driver 4 * 5 * Copyright (C) Sunplus Technology Co., Ltd. 6 * All rights reserved. 7 */ 8 9 #include <linux/io.h> 10 #include <linux/init.h> 11 #include <linux/mod_devicetable.h> 12 #include <linux/platform_device.h> 13 #include <linux/reset-controller.h> 14 #include <linux/reboot.h> 15 16 /* HIWORD_MASK_REG BITS */ 17 #define BITS_PER_HWM_REG 16 18 19 /* resets HW info: reg_index_shift */ 20 static const u32 sp_resets[] = { 21 /* SP7021: mo_reset0 ~ mo_reset9 */ 22 0x00, 23 0x02, 24 0x03, 25 0x04, 26 0x05, 27 0x06, 28 0x07, 29 0x08, 30 0x09, 31 0x0a, 32 0x0b, 33 0x0d, 34 0x0e, 35 0x0f, 36 0x10, 37 0x12, 38 0x14, 39 0x15, 40 0x16, 41 0x17, 42 0x18, 43 0x19, 44 0x1a, 45 0x1b, 46 0x1c, 47 0x1d, 48 0x1e, 49 0x1f, 50 0x20, 51 0x21, 52 0x22, 53 0x23, 54 0x24, 55 0x25, 56 0x26, 57 0x2a, 58 0x2b, 59 0x2d, 60 0x2e, 61 0x30, 62 0x31, 63 0x32, 64 0x33, 65 0x3d, 66 0x3e, 67 0x3f, 68 0x42, 69 0x44, 70 0x4b, 71 0x4c, 72 0x4d, 73 0x4e, 74 0x4f, 75 0x50, 76 0x55, 77 0x60, 78 0x61, 79 0x6a, 80 0x6f, 81 0x70, 82 0x73, 83 0x74, 84 0x86, 85 0x8a, 86 0x8b, 87 0x8d, 88 0x8e, 89 0x8f, 90 0x90, 91 0x92, 92 0x93, 93 0x94, 94 0x95, 95 0x96, 96 0x97, 97 0x98, 98 0x99, 99 }; 100 101 struct sp_reset { 102 struct reset_controller_dev rcdev; 103 struct notifier_block notifier; 104 void __iomem *base; 105 }; 106 107 static inline struct sp_reset *to_sp_reset(struct reset_controller_dev *rcdev) 108 { 109 return container_of(rcdev, struct sp_reset, rcdev); 110 } 111 112 static int sp_reset_update(struct reset_controller_dev *rcdev, 113 unsigned long id, bool assert) 114 { 115 struct sp_reset *reset = to_sp_reset(rcdev); 116 int index = sp_resets[id] / BITS_PER_HWM_REG; 117 int shift = sp_resets[id] % BITS_PER_HWM_REG; 118 u32 val; 119 120 val = (1 << (16 + shift)) | (assert << shift); 121 writel(val, reset->base + (index * 4)); 122 123 return 0; 124 } 125 126 static int sp_reset_assert(struct reset_controller_dev *rcdev, 127 unsigned long id) 128 { 129 return sp_reset_update(rcdev, id, true); 130 } 131 132 static int sp_reset_deassert(struct reset_controller_dev *rcdev, 133 unsigned long id) 134 { 135 return sp_reset_update(rcdev, id, false); 136 } 137 138 static int sp_reset_status(struct reset_controller_dev *rcdev, 139 unsigned long id) 140 { 141 struct sp_reset *reset = to_sp_reset(rcdev); 142 int index = sp_resets[id] / BITS_PER_HWM_REG; 143 int shift = sp_resets[id] % BITS_PER_HWM_REG; 144 u32 reg; 145 146 reg = readl(reset->base + (index * 4)); 147 148 return !!(reg & BIT(shift)); 149 } 150 151 static const struct reset_control_ops sp_reset_ops = { 152 .assert = sp_reset_assert, 153 .deassert = sp_reset_deassert, 154 .status = sp_reset_status, 155 }; 156 157 static int sp_restart(struct notifier_block *nb, unsigned long mode, 158 void *cmd) 159 { 160 struct sp_reset *reset = container_of(nb, struct sp_reset, notifier); 161 162 sp_reset_assert(&reset->rcdev, 0); 163 sp_reset_deassert(&reset->rcdev, 0); 164 165 return NOTIFY_DONE; 166 } 167 168 static int sp_reset_probe(struct platform_device *pdev) 169 { 170 struct device *dev = &pdev->dev; 171 struct sp_reset *reset; 172 struct resource *res; 173 int ret; 174 175 reset = devm_kzalloc(dev, sizeof(*reset), GFP_KERNEL); 176 if (!reset) 177 return -ENOMEM; 178 179 res = platform_get_resource(pdev, IORESOURCE_MEM, 0); 180 reset->base = devm_ioremap_resource(dev, res); 181 if (IS_ERR(reset->base)) 182 return PTR_ERR(reset->base); 183 184 reset->rcdev.ops = &sp_reset_ops; 185 reset->rcdev.owner = THIS_MODULE; 186 reset->rcdev.of_node = dev->of_node; 187 reset->rcdev.nr_resets = resource_size(res) / 4 * BITS_PER_HWM_REG; 188 189 ret = devm_reset_controller_register(dev, &reset->rcdev); 190 if (ret) 191 return ret; 192 193 reset->notifier.notifier_call = sp_restart; 194 reset->notifier.priority = 192; 195 196 return register_restart_handler(&reset->notifier); 197 } 198 199 static const struct of_device_id sp_reset_dt_ids[] = { 200 {.compatible = "sunplus,sp7021-reset",}, 201 { /* sentinel */ }, 202 }; 203 204 static struct platform_driver sp_reset_driver = { 205 .probe = sp_reset_probe, 206 .driver = { 207 .name = "sunplus-reset", 208 .of_match_table = sp_reset_dt_ids, 209 .suppress_bind_attrs = true, 210 }, 211 }; 212 builtin_platform_driver(sp_reset_driver); 213