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         data->rcdev.owner = THIS_MODULE;
 106         data->rcdev.nr_resets = size * 32;
 107         data->rcdev.ops = &sunxi_reset_ops;
 108         data->rcdev.of_node = np;
 109         reset_controller_register(&data->rcdev);
 110
 111         return 0;
 112
 113 err_alloc:
 114         kfree(data);
 115         return ret;
 116 };
 117
 118 /*
 119  * These are the reset controller we need to initialize early on in
 120  * our system, before we can even think of using a regular device
 121  * driver for it.
 122  */
 123 static const struct of_device_id sunxi_early_reset_dt_ids[] __initdata = {
 124         { .compatible = "allwinner,sun6i-a31-ahb1-reset", },
 125         { /* sentinel */ },
 126 };
 127
 128 void __init sun6i_reset_init(void)
 129 {
 130         struct device_node *np;
 131
 132         for_each_matching_node(np, sunxi_early_reset_dt_ids)
 133                 sunxi_reset_init(np);
 134 }
 135
 136 /*
 137  * And these are the controllers we can register through the regular
 138  * device model.
 139  */
 140 static const struct of_device_id sunxi_reset_dt_ids[] = {
 141          { .compatible = "allwinner,sun6i-a31-clock-reset", },
 142          { /* sentinel */ },
 143 };
 144 MODULE_DEVICE_TABLE(of, sunxi_reset_dt_ids);
 145
 146 static int sunxi_reset_probe(struct platform_device *pdev)
 147 {
 148         return sunxi_reset_init(pdev->dev.of_node);
 149 }
 150
 151 static int sunxi_reset_remove(struct platform_device *pdev)
 152 {
 153         struct sunxi_reset_data *data = platform_get_drvdata(pdev);
 154
 155         reset_controller_unregister(&data->rcdev);
 156         iounmap(data->membase);
 157         kfree(data);
 158
 159         return 0;
 160 }
 161
 162 static struct platform_driver sunxi_reset_driver = {
 163         .probe  = sunxi_reset_probe,
 164         .remove = sunxi_reset_remove,
 165         .driver = {
 166                 .name           = "sunxi-reset",
 167                 .owner          = THIS_MODULE,
 168                 .of_match_table = sunxi_reset_dt_ids,
 169         },
 170 };
 171 module_platform_driver(sunxi_reset_driver);
 172
 173 MODULE_AUTHOR("Maxime Ripard <maxime.ripard@free-electrons.com");
 174 MODULE_DESCRIPTION("Allwinner SoCs Reset Controller Driver");
 175 MODULE_LICENSE("GPL");