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Linux/drivers/reset/reset-sunxi.c

  1 /*
  2  * Allwinner SoCs Reset Controller driver
  3  *
  4  * Copyright 2013 Maxime Ripard
  5  *
  6  * Maxime Ripard <maxime.ripard@free-electrons.com>
  7  *
  8  * This program is free software; you can redistribute it and/or modify
  9  * it under the terms of the GNU General Public License as published by
 10  * the Free Software Foundation; either version 2 of the License, or
 11  * (at your option) any later version.
 12  */
 13 
 14 #include <linux/err.h>
 15 #include <linux/io.h>
 16 #include <linux/module.h>
 17 #include <linux/of.h>
 18 #include <linux/of_address.h>
 19 #include <linux/platform_device.h>
 20 #include <linux/reset-controller.h>
 21 #include <linux/slab.h>
 22 #include <linux/spinlock.h>
 23 #include <linux/types.h>
 24 
 25 struct sunxi_reset_data {
 26         spinlock_t                      lock;
 27         void __iomem                    *membase;
 28         struct reset_controller_dev     rcdev;
 29 };
 30 
 31 static int sunxi_reset_assert(struct reset_controller_dev *rcdev,
 32                               unsigned long id)
 33 {
 34         struct sunxi_reset_data *data = container_of(rcdev,
 35                                                      struct sunxi_reset_data,
 36                                                      rcdev);
 37         int bank = id / BITS_PER_LONG;
 38         int offset = id % BITS_PER_LONG;
 39         unsigned long flags;
 40         u32 reg;
 41 
 42         spin_lock_irqsave(&data->lock, flags);
 43 
 44         reg = readl(data->membase + (bank * 4));
 45         writel(reg & ~BIT(offset), data->membase + (bank * 4));
 46 
 47         spin_unlock_irqrestore(&data->lock, flags);
 48 
 49         return 0;
 50 }
 51 
 52 static int sunxi_reset_deassert(struct reset_controller_dev *rcdev,
 53                                 unsigned long id)
 54 {
 55         struct sunxi_reset_data *data = container_of(rcdev,
 56                                                      struct sunxi_reset_data,
 57                                                      rcdev);
 58         int bank = id / BITS_PER_LONG;
 59         int offset = id % BITS_PER_LONG;
 60         unsigned long flags;
 61         u32 reg;
 62 
 63         spin_lock_irqsave(&data->lock, flags);
 64 
 65         reg = readl(data->membase + (bank * 4));
 66         writel(reg | BIT(offset), data->membase + (bank * 4));
 67 
 68         spin_unlock_irqrestore(&data->lock, flags);
 69 
 70         return 0;
 71 }
 72 
 73 static struct reset_control_ops sunxi_reset_ops = {
 74         .assert         = sunxi_reset_assert,
 75         .deassert       = sunxi_reset_deassert,
 76 };
 77 
 78 static int sunxi_reset_init(struct device_node *np)
 79 {
 80         struct sunxi_reset_data *data;
 81         struct resource res;
 82         resource_size_t size;
 83         int ret;
 84 
 85         data = kzalloc(sizeof(*data), GFP_KERNEL);
 86         if (!data)
 87                 return -ENOMEM;
 88 
 89         ret = of_address_to_resource(np, 0, &res);
 90         if (ret)
 91                 goto err_alloc;
 92 
 93         size = resource_size(&res);
 94         if (!request_mem_region(res.start, size, np->name)) {
 95                 ret = -EBUSY;
 96                 goto err_alloc;
 97         }
 98 
 99         data->membase = ioremap(res.start, size);
100         if (!data->membase) {
101                 ret = -ENOMEM;
102                 goto err_alloc;
103         }
104 
105         spin_lock_init(&data->lock);
106 
107         data->rcdev.owner = THIS_MODULE;
108         data->rcdev.nr_resets = size * 32;
109         data->rcdev.ops = &sunxi_reset_ops;
110         data->rcdev.of_node = np;
111         reset_controller_register(&data->rcdev);
112 
113         return 0;
114 
115 err_alloc:
116         kfree(data);
117         return ret;
118 };
119 
120 /*
121  * These are the reset controller we need to initialize early on in
122  * our system, before we can even think of using a regular device
123  * driver for it.
124  */
125 static const struct of_device_id sunxi_early_reset_dt_ids[] __initdata = {
126         { .compatible = "allwinner,sun6i-a31-ahb1-reset", },
127         { /* sentinel */ },
128 };
129 
130 void __init sun6i_reset_init(void)
131 {
132         struct device_node *np;
133 
134         for_each_matching_node(np, sunxi_early_reset_dt_ids)
135                 sunxi_reset_init(np);
136 }
137 
138 /*
139  * And these are the controllers we can register through the regular
140  * device model.
141  */
142 static const struct of_device_id sunxi_reset_dt_ids[] = {
143          { .compatible = "allwinner,sun6i-a31-clock-reset", },
144          { /* sentinel */ },
145 };
146 MODULE_DEVICE_TABLE(of, sunxi_reset_dt_ids);
147 
148 static int sunxi_reset_probe(struct platform_device *pdev)
149 {
150         struct sunxi_reset_data *data;
151         struct resource *res;
152 
153         data = devm_kzalloc(&pdev->dev, sizeof(*data), GFP_KERNEL);
154         if (!data)
155                 return -ENOMEM;
156 
157         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
158         data->membase = devm_ioremap_resource(&pdev->dev, res);
159         if (IS_ERR(data->membase))
160                 return PTR_ERR(data->membase);
161 
162         spin_lock_init(&data->lock);
163 
164         data->rcdev.owner = THIS_MODULE;
165         data->rcdev.nr_resets = resource_size(res) * 32;
166         data->rcdev.ops = &sunxi_reset_ops;
167         data->rcdev.of_node = pdev->dev.of_node;
168 
169         return reset_controller_register(&data->rcdev);
170 }
171 
172 static int sunxi_reset_remove(struct platform_device *pdev)
173 {
174         struct sunxi_reset_data *data = platform_get_drvdata(pdev);
175 
176         reset_controller_unregister(&data->rcdev);
177 
178         return 0;
179 }
180 
181 static struct platform_driver sunxi_reset_driver = {
182         .probe  = sunxi_reset_probe,
183         .remove = sunxi_reset_remove,
184         .driver = {
185                 .name           = "sunxi-reset",
186                 .of_match_table = sunxi_reset_dt_ids,
187         },
188 };
189 module_platform_driver(sunxi_reset_driver);
190 
191 MODULE_AUTHOR("Maxime Ripard <maxime.ripard@free-electrons.com");
192 MODULE_DESCRIPTION("Allwinner SoCs Reset Controller Driver");
193 MODULE_LICENSE("GPL");
194 

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