1 /* 2 * AR71xx Reset Controller Driver 3 * Author: Alban Bedel 4 * 5 * Copyright (C) 2015 Alban Bedel <albeu@free.fr> 6 * 7 * This program is free software; you can redistribute it and/or modify 8 * it under the terms of the GNU General Public License as published by 9 * the Free Software Foundation; either version 2 of the License, or 10 * (at your option) any later version. 11 * 12 * This program is distributed in the hope that it will be useful, 13 * but WITHOUT ANY WARRANTY; without even the implied warranty of 14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 15 * GNU General Public License for more details. 16 */ 17 18 #include <linux/io.h> 19 #include <linux/init.h> 20 #include <linux/mod_devicetable.h> 21 #include <linux/platform_device.h> 22 #include <linux/reset-controller.h> 23 #include <linux/reboot.h> 24 25 struct ath79_reset { 26 struct reset_controller_dev rcdev; 27 struct notifier_block restart_nb; 28 void __iomem *base; 29 spinlock_t lock; 30 }; 31 32 #define FULL_CHIP_RESET 24 33 34 static int ath79_reset_update(struct reset_controller_dev *rcdev, 35 unsigned long id, bool assert) 36 { 37 struct ath79_reset *ath79_reset = 38 container_of(rcdev, struct ath79_reset, rcdev); 39 unsigned long flags; 40 u32 val; 41 42 spin_lock_irqsave(&ath79_reset->lock, flags); 43 val = readl(ath79_reset->base); 44 if (assert) 45 val |= BIT(id); 46 else 47 val &= ~BIT(id); 48 writel(val, ath79_reset->base); 49 spin_unlock_irqrestore(&ath79_reset->lock, flags); 50 51 return 0; 52 } 53 54 static int ath79_reset_assert(struct reset_controller_dev *rcdev, 55 unsigned long id) 56 { 57 return ath79_reset_update(rcdev, id, true); 58 } 59 60 static int ath79_reset_deassert(struct reset_controller_dev *rcdev, 61 unsigned long id) 62 { 63 return ath79_reset_update(rcdev, id, false); 64 } 65 66 static int ath79_reset_status(struct reset_controller_dev *rcdev, 67 unsigned long id) 68 { 69 struct ath79_reset *ath79_reset = 70 container_of(rcdev, struct ath79_reset, rcdev); 71 u32 val; 72 73 val = readl(ath79_reset->base); 74 75 return !!(val & BIT(id)); 76 } 77 78 static const struct reset_control_ops ath79_reset_ops = { 79 .assert = ath79_reset_assert, 80 .deassert = ath79_reset_deassert, 81 .status = ath79_reset_status, 82 }; 83 84 static int ath79_reset_restart_handler(struct notifier_block *nb, 85 unsigned long action, void *data) 86 { 87 struct ath79_reset *ath79_reset = 88 container_of(nb, struct ath79_reset, restart_nb); 89 90 ath79_reset_assert(&ath79_reset->rcdev, FULL_CHIP_RESET); 91 92 return NOTIFY_DONE; 93 } 94 95 static int ath79_reset_probe(struct platform_device *pdev) 96 { 97 struct ath79_reset *ath79_reset; 98 struct resource *res; 99 int err; 100 101 ath79_reset = devm_kzalloc(&pdev->dev, 102 sizeof(*ath79_reset), GFP_KERNEL); 103 if (!ath79_reset) 104 return -ENOMEM; 105 106 platform_set_drvdata(pdev, ath79_reset); 107 108 res = platform_get_resource(pdev, IORESOURCE_MEM, 0); 109 ath79_reset->base = devm_ioremap_resource(&pdev->dev, res); 110 if (IS_ERR(ath79_reset->base)) 111 return PTR_ERR(ath79_reset->base); 112 113 spin_lock_init(&ath79_reset->lock); 114 ath79_reset->rcdev.ops = &ath79_reset_ops; 115 ath79_reset->rcdev.owner = THIS_MODULE; 116 ath79_reset->rcdev.of_node = pdev->dev.of_node; 117 ath79_reset->rcdev.of_reset_n_cells = 1; 118 ath79_reset->rcdev.nr_resets = 32; 119 120 err = devm_reset_controller_register(&pdev->dev, &ath79_reset->rcdev); 121 if (err) 122 return err; 123 124 ath79_reset->restart_nb.notifier_call = ath79_reset_restart_handler; 125 ath79_reset->restart_nb.priority = 128; 126 127 err = register_restart_handler(&ath79_reset->restart_nb); 128 if (err) 129 dev_warn(&pdev->dev, "Failed to register restart handler\n"); 130 131 return 0; 132 } 133 134 static const struct of_device_id ath79_reset_dt_ids[] = { 135 { .compatible = "qca,ar7100-reset", }, 136 { }, 137 }; 138 139 static struct platform_driver ath79_reset_driver = { 140 .probe = ath79_reset_probe, 141 .driver = { 142 .name = "ath79-reset", 143 .of_match_table = ath79_reset_dt_ids, 144 .suppress_bind_attrs = true, 145 }, 146 }; 147 builtin_platform_driver(ath79_reset_driver); 148