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 NR_BANKS 4 29 30 struct socfpga_reset_data { 31 spinlock_t lock; 32 void __iomem *membase; 33 struct reset_controller_dev rcdev; 34 }; 35 36 static int socfpga_reset_assert(struct reset_controller_dev *rcdev, 37 unsigned long id) 38 { 39 struct socfpga_reset_data *data = container_of(rcdev, 40 struct socfpga_reset_data, 41 rcdev); 42 int bank = id / BITS_PER_LONG; 43 int offset = id % BITS_PER_LONG; 44 unsigned long flags; 45 u32 reg; 46 47 spin_lock_irqsave(&data->lock, flags); 48 49 reg = readl(data->membase + (bank * NR_BANKS)); 50 writel(reg | BIT(offset), data->membase + (bank * NR_BANKS)); 51 spin_unlock_irqrestore(&data->lock, flags); 52 53 return 0; 54 } 55 56 static int socfpga_reset_deassert(struct reset_controller_dev *rcdev, 57 unsigned long id) 58 { 59 struct socfpga_reset_data *data = container_of(rcdev, 60 struct socfpga_reset_data, 61 rcdev); 62 63 int bank = id / BITS_PER_LONG; 64 int offset = id % BITS_PER_LONG; 65 unsigned long flags; 66 u32 reg; 67 68 spin_lock_irqsave(&data->lock, flags); 69 70 reg = readl(data->membase + (bank * NR_BANKS)); 71 writel(reg & ~BIT(offset), data->membase + (bank * NR_BANKS)); 72 73 spin_unlock_irqrestore(&data->lock, flags); 74 75 return 0; 76 } 77 78 static int socfpga_reset_status(struct reset_controller_dev *rcdev, 79 unsigned long id) 80 { 81 struct socfpga_reset_data *data = container_of(rcdev, 82 struct socfpga_reset_data, rcdev); 83 int bank = id / BITS_PER_LONG; 84 int offset = id % BITS_PER_LONG; 85 u32 reg; 86 87 reg = readl(data->membase + (bank * NR_BANKS)); 88 89 return !(reg & BIT(offset)); 90 } 91 92 static const struct reset_control_ops socfpga_reset_ops = { 93 .assert = socfpga_reset_assert, 94 .deassert = socfpga_reset_deassert, 95 .status = socfpga_reset_status, 96 }; 97 98 static int socfpga_reset_probe(struct platform_device *pdev) 99 { 100 struct socfpga_reset_data *data; 101 struct resource *res; 102 struct device *dev = &pdev->dev; 103 struct device_node *np = dev->of_node; 104 u32 modrst_offset; 105 106 /* 107 * The binding was mainlined without the required property. 108 * Do not continue, when we encounter an old DT. 109 */ 110 if (!of_find_property(pdev->dev.of_node, "#reset-cells", NULL)) { 111 dev_err(&pdev->dev, "%s missing #reset-cells property\n", 112 pdev->dev.of_node->full_name); 113 return -EINVAL; 114 } 115 116 data = devm_kzalloc(&pdev->dev, sizeof(*data), GFP_KERNEL); 117 if (!data) 118 return -ENOMEM; 119 120 res = platform_get_resource(pdev, IORESOURCE_MEM, 0); 121 data->membase = devm_ioremap_resource(&pdev->dev, res); 122 if (IS_ERR(data->membase)) 123 return PTR_ERR(data->membase); 124 125 if (of_property_read_u32(np, "altr,modrst-offset", &modrst_offset)) { 126 dev_warn(dev, "missing altr,modrst-offset property, assuming 0x10!\n"); 127 modrst_offset = 0x10; 128 } 129 data->membase += modrst_offset; 130 131 spin_lock_init(&data->lock); 132 133 data->rcdev.owner = THIS_MODULE; 134 data->rcdev.nr_resets = NR_BANKS * BITS_PER_LONG; 135 data->rcdev.ops = &socfpga_reset_ops; 136 data->rcdev.of_node = pdev->dev.of_node; 137 138 return devm_reset_controller_register(dev, &data->rcdev); 139 } 140 141 static const struct of_device_id socfpga_reset_dt_ids[] = { 142 { .compatible = "altr,rst-mgr", }, 143 { /* sentinel */ }, 144 }; 145 146 static struct platform_driver socfpga_reset_driver = { 147 .probe = socfpga_reset_probe, 148 .driver = { 149 .name = "socfpga-reset", 150 .of_match_table = socfpga_reset_dt_ids, 151 }, 152 }; 153 builtin_platform_driver(socfpga_reset_driver); 154