1 /* 2 * Socfpga Reset Controller Driver 3 * 4 * Copyright 2014 Steffen Trumtrar <s.trumtrar@pengutronix.de> 5 * 6 * based on 7 * Allwinner SoCs Reset Controller driver 8 * 9 * Copyright 2013 Maxime Ripard 10 * 11 * Maxime Ripard <maxime.ripard@free-electrons.com> 12 * 13 * This program is free software; you can redistribute it and/or modify 14 * it under the terms of the GNU General Public License as published by 15 * the Free Software Foundation; either version 2 of the License, or 16 * (at your option) any later version. 17 */ 18 19 #include <linux/err.h> 20 #include <linux/io.h> 21 #include <linux/init.h> 22 #include <linux/of.h> 23 #include <linux/platform_device.h> 24 #include <linux/reset-controller.h> 25 #include <linux/spinlock.h> 26 #include <linux/types.h> 27 28 #define BANK_INCREMENT 4 29 #define NR_BANKS 8 30 31 struct socfpga_reset_data { 32 spinlock_t lock; 33 void __iomem *membase; 34 struct reset_controller_dev rcdev; 35 }; 36 37 static int socfpga_reset_assert(struct reset_controller_dev *rcdev, 38 unsigned long id) 39 { 40 struct socfpga_reset_data *data = container_of(rcdev, 41 struct socfpga_reset_data, 42 rcdev); 43 int bank = id / BITS_PER_LONG; 44 int offset = id % BITS_PER_LONG; 45 unsigned long flags; 46 u32 reg; 47 48 spin_lock_irqsave(&data->lock, flags); 49 50 reg = readl(data->membase + (bank * BANK_INCREMENT)); 51 writel(reg | BIT(offset), data->membase + (bank * BANK_INCREMENT)); 52 spin_unlock_irqrestore(&data->lock, flags); 53 54 return 0; 55 } 56 57 static int socfpga_reset_deassert(struct reset_controller_dev *rcdev, 58 unsigned long id) 59 { 60 struct socfpga_reset_data *data = container_of(rcdev, 61 struct socfpga_reset_data, 62 rcdev); 63 64 int bank = id / BITS_PER_LONG; 65 int offset = id % BITS_PER_LONG; 66 unsigned long flags; 67 u32 reg; 68 69 spin_lock_irqsave(&data->lock, flags); 70 71 reg = readl(data->membase + (bank * BANK_INCREMENT)); 72 writel(reg & ~BIT(offset), data->membase + (bank * BANK_INCREMENT)); 73 74 spin_unlock_irqrestore(&data->lock, flags); 75 76 return 0; 77 } 78 79 static int socfpga_reset_status(struct reset_controller_dev *rcdev, 80 unsigned long id) 81 { 82 struct socfpga_reset_data *data = container_of(rcdev, 83 struct socfpga_reset_data, rcdev); 84 int bank = id / BITS_PER_LONG; 85 int offset = id % BITS_PER_LONG; 86 u32 reg; 87 88 reg = readl(data->membase + (bank * BANK_INCREMENT)); 89 90 return !(reg & BIT(offset)); 91 } 92 93 static const struct reset_control_ops socfpga_reset_ops = { 94 .assert = socfpga_reset_assert, 95 .deassert = socfpga_reset_deassert, 96 .status = socfpga_reset_status, 97 }; 98 99 static int socfpga_reset_probe(struct platform_device *pdev) 100 { 101 struct socfpga_reset_data *data; 102 struct resource *res; 103 struct device *dev = &pdev->dev; 104 struct device_node *np = dev->of_node; 105 u32 modrst_offset; 106 107 /* 108 * The binding was mainlined without the required property. 109 * Do not continue, when we encounter an old DT. 110 */ 111 if (!of_find_property(pdev->dev.of_node, "#reset-cells", NULL)) { 112 dev_err(&pdev->dev, "%s missing #reset-cells property\n", 113 pdev->dev.of_node->full_name); 114 return -EINVAL; 115 } 116 117 data = devm_kzalloc(&pdev->dev, sizeof(*data), GFP_KERNEL); 118 if (!data) 119 return -ENOMEM; 120 121 res = platform_get_resource(pdev, IORESOURCE_MEM, 0); 122 data->membase = devm_ioremap_resource(&pdev->dev, res); 123 if (IS_ERR(data->membase)) 124 return PTR_ERR(data->membase); 125 126 if (of_property_read_u32(np, "altr,modrst-offset", &modrst_offset)) { 127 dev_warn(dev, "missing altr,modrst-offset property, assuming 0x10!\n"); 128 modrst_offset = 0x10; 129 } 130 data->membase += modrst_offset; 131 132 spin_lock_init(&data->lock); 133 134 data->rcdev.owner = THIS_MODULE; 135 data->rcdev.nr_resets = NR_BANKS * BITS_PER_LONG; 136 data->rcdev.ops = &socfpga_reset_ops; 137 data->rcdev.of_node = pdev->dev.of_node; 138 139 return devm_reset_controller_register(dev, &data->rcdev); 140 } 141 142 static const struct of_device_id socfpga_reset_dt_ids[] = { 143 { .compatible = "altr,rst-mgr", }, 144 { /* sentinel */ }, 145 }; 146 147 static struct platform_driver socfpga_reset_driver = { 148 .probe = socfpga_reset_probe, 149 .driver = { 150 .name = "socfpga-reset", 151 .of_match_table = socfpga_reset_dt_ids, 152 }, 153 }; 154 builtin_platform_driver(socfpga_reset_driver); 155