1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * 4 * Copyright (C) 2010 John Crispin <blogic@phrozen.org> 5 * Copyright (C) 2013-2015 Lantiq Beteiligungs-GmbH & Co.KG 6 * Copyright (C) 2016 Martin Blumenstingl <martin.blumenstingl@googlemail.com> 7 * Copyright (C) 2017 Hauke Mehrtens <hauke@hauke-m.de> 8 */ 9 10 #include <linux/mfd/syscon.h> 11 #include <linux/module.h> 12 #include <linux/regmap.h> 13 #include <linux/reset-controller.h> 14 #include <linux/of_address.h> 15 #include <linux/of_platform.h> 16 #include <linux/platform_device.h> 17 #include <linux/property.h> 18 19 #define LANTIQ_RCU_RESET_TIMEOUT 10000 20 21 struct lantiq_rcu_reset_priv { 22 struct reset_controller_dev rcdev; 23 struct device *dev; 24 struct regmap *regmap; 25 u32 reset_offset; 26 u32 status_offset; 27 }; 28 29 static struct lantiq_rcu_reset_priv *to_lantiq_rcu_reset_priv( 30 struct reset_controller_dev *rcdev) 31 { 32 return container_of(rcdev, struct lantiq_rcu_reset_priv, rcdev); 33 } 34 35 static int lantiq_rcu_reset_status(struct reset_controller_dev *rcdev, 36 unsigned long id) 37 { 38 struct lantiq_rcu_reset_priv *priv = to_lantiq_rcu_reset_priv(rcdev); 39 unsigned int status = (id >> 8) & 0x1f; 40 u32 val; 41 int ret; 42 43 ret = regmap_read(priv->regmap, priv->status_offset, &val); 44 if (ret) 45 return ret; 46 47 return !!(val & BIT(status)); 48 } 49 50 static int lantiq_rcu_reset_status_timeout(struct reset_controller_dev *rcdev, 51 unsigned long id, bool assert) 52 { 53 int ret; 54 int retry = LANTIQ_RCU_RESET_TIMEOUT; 55 56 do { 57 ret = lantiq_rcu_reset_status(rcdev, id); 58 if (ret < 0) 59 return ret; 60 if (ret == assert) 61 return 0; 62 usleep_range(20, 40); 63 } while (--retry); 64 65 return -ETIMEDOUT; 66 } 67 68 static int lantiq_rcu_reset_update(struct reset_controller_dev *rcdev, 69 unsigned long id, bool assert) 70 { 71 struct lantiq_rcu_reset_priv *priv = to_lantiq_rcu_reset_priv(rcdev); 72 unsigned int set = id & 0x1f; 73 u32 val = assert ? BIT(set) : 0; 74 int ret; 75 76 ret = regmap_update_bits(priv->regmap, priv->reset_offset, BIT(set), 77 val); 78 if (ret) { 79 dev_err(priv->dev, "Failed to set reset bit %u\n", set); 80 return ret; 81 } 82 83 84 ret = lantiq_rcu_reset_status_timeout(rcdev, id, assert); 85 if (ret) 86 dev_err(priv->dev, "Failed to %s bit %u\n", 87 assert ? "assert" : "deassert", set); 88 89 return ret; 90 } 91 92 static int lantiq_rcu_reset_assert(struct reset_controller_dev *rcdev, 93 unsigned long id) 94 { 95 return lantiq_rcu_reset_update(rcdev, id, true); 96 } 97 98 static int lantiq_rcu_reset_deassert(struct reset_controller_dev *rcdev, 99 unsigned long id) 100 { 101 return lantiq_rcu_reset_update(rcdev, id, false); 102 } 103 104 static int lantiq_rcu_reset_reset(struct reset_controller_dev *rcdev, 105 unsigned long id) 106 { 107 int ret; 108 109 ret = lantiq_rcu_reset_assert(rcdev, id); 110 if (ret) 111 return ret; 112 113 return lantiq_rcu_reset_deassert(rcdev, id); 114 } 115 116 static const struct reset_control_ops lantiq_rcu_reset_ops = { 117 .assert = lantiq_rcu_reset_assert, 118 .deassert = lantiq_rcu_reset_deassert, 119 .status = lantiq_rcu_reset_status, 120 .reset = lantiq_rcu_reset_reset, 121 }; 122 123 static int lantiq_rcu_reset_of_parse(struct platform_device *pdev, 124 struct lantiq_rcu_reset_priv *priv) 125 { 126 struct device *dev = &pdev->dev; 127 const __be32 *offset; 128 129 priv->regmap = syscon_node_to_regmap(dev->of_node->parent); 130 if (IS_ERR(priv->regmap)) { 131 dev_err(&pdev->dev, "Failed to lookup RCU regmap\n"); 132 return PTR_ERR(priv->regmap); 133 } 134 135 offset = of_get_address(dev->of_node, 0, NULL, NULL); 136 if (!offset) { 137 dev_err(&pdev->dev, "Failed to get RCU reset offset\n"); 138 return -ENOENT; 139 } 140 priv->reset_offset = __be32_to_cpu(*offset); 141 142 offset = of_get_address(dev->of_node, 1, NULL, NULL); 143 if (!offset) { 144 dev_err(&pdev->dev, "Failed to get RCU status offset\n"); 145 return -ENOENT; 146 } 147 priv->status_offset = __be32_to_cpu(*offset); 148 149 return 0; 150 } 151 152 static int lantiq_rcu_reset_xlate(struct reset_controller_dev *rcdev, 153 const struct of_phandle_args *reset_spec) 154 { 155 unsigned int status, set; 156 157 set = reset_spec->args[0]; 158 status = reset_spec->args[1]; 159 160 if (set >= rcdev->nr_resets || status >= rcdev->nr_resets) 161 return -EINVAL; 162 163 return (status << 8) | set; 164 } 165 166 static int lantiq_rcu_reset_probe(struct platform_device *pdev) 167 { 168 struct lantiq_rcu_reset_priv *priv; 169 int err; 170 171 priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL); 172 if (!priv) 173 return -ENOMEM; 174 175 priv->dev = &pdev->dev; 176 177 err = lantiq_rcu_reset_of_parse(pdev, priv); 178 if (err) 179 return err; 180 181 priv->rcdev.ops = &lantiq_rcu_reset_ops; 182 priv->rcdev.owner = THIS_MODULE; 183 priv->rcdev.of_node = pdev->dev.of_node; 184 priv->rcdev.nr_resets = 32; 185 priv->rcdev.of_xlate = lantiq_rcu_reset_xlate; 186 priv->rcdev.of_reset_n_cells = 2; 187 188 return devm_reset_controller_register(&pdev->dev, &priv->rcdev); 189 } 190 191 static const struct of_device_id lantiq_rcu_reset_dt_ids[] = { 192 { .compatible = "lantiq,danube-reset", }, 193 { .compatible = "lantiq,xrx200-reset", }, 194 { }, 195 }; 196 MODULE_DEVICE_TABLE(of, lantiq_rcu_reset_dt_ids); 197 198 static struct platform_driver lantiq_rcu_reset_driver = { 199 .probe = lantiq_rcu_reset_probe, 200 .driver = { 201 .name = "lantiq-reset", 202 .of_match_table = lantiq_rcu_reset_dt_ids, 203 }, 204 }; 205 module_platform_driver(lantiq_rcu_reset_driver); 206 207 MODULE_AUTHOR("Martin Blumenstingl <martin.blumenstingl@googlemail.com>"); 208 MODULE_DESCRIPTION("Lantiq XWAY RCU Reset Controller Driver"); 209