kernel/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");