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/init.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 reg_width = sizeof(u32);
  38         int bank = id / (reg_width * BITS_PER_BYTE);
  39         int offset = id % (reg_width * BITS_PER_BYTE);
  40         unsigned long flags;
  41         u32 reg;
  42
  43         spin_lock_irqsave(&data->lock, flags);
  44
  45         reg = readl(data->membase + (bank * reg_width));
  46         writel(reg & ~BIT(offset), data->membase + (bank * reg_width));
  47
  48         spin_unlock_irqrestore(&data->lock, flags);
  49
  50         return 0;
  51 }
  52
  53 static int sunxi_reset_deassert(struct reset_controller_dev *rcdev,
  54                                 unsigned long id)
  55 {
  56         struct sunxi_reset_data *data = container_of(rcdev,
  57                                                      struct sunxi_reset_data,
  58                                                      rcdev);
  59         int reg_width = sizeof(u32);
  60         int bank = id / (reg_width * BITS_PER_BYTE);
  61         int offset = id % (reg_width * BITS_PER_BYTE);
  62         unsigned long flags;
  63         u32 reg;
  64
  65         spin_lock_irqsave(&data->lock, flags);
  66
  67         reg = readl(data->membase + (bank * reg_width));
  68         writel(reg | BIT(offset), data->membase + (bank * reg_width));
  69
  70         spin_unlock_irqrestore(&data->lock, flags);
  71
  72         return 0;
  73 }
  74
  75 static const struct reset_control_ops sunxi_reset_ops = {
  76         .assert         = sunxi_reset_assert,
  77         .deassert       = sunxi_reset_deassert,
  78 };
  79
  80 static int sunxi_reset_init(struct device_node *np)
  81 {
  82         struct sunxi_reset_data *data;
  83         struct resource res;
  84         resource_size_t size;
  85         int ret;
  86
  87         data = kzalloc(sizeof(*data), GFP_KERNEL);
  88         if (!data)
  89                 return -ENOMEM;
  90
  91         ret = of_address_to_resource(np, 0, &res);
  92         if (ret)
  93                 goto err_alloc;
  94
  95         size = resource_size(&res);
  96         if (!request_mem_region(res.start, size, np->name)) {
  97                 ret = -EBUSY;
  98                 goto err_alloc;
  99         }
 100
 101         data->membase = ioremap(res.start, size);
 102         if (!data->membase) {
 103                 ret = -ENOMEM;
 104                 goto err_alloc;
 105         }
 106
 107         spin_lock_init(&data->lock);
 108
 109         data->rcdev.owner = THIS_MODULE;
 110         data->rcdev.nr_resets = size * 8;
 111         data->rcdev.ops = &sunxi_reset_ops;
 112         data->rcdev.of_node = np;
 113
 114         return reset_controller_register(&data->rcdev);
 115
 116 err_alloc:
 117         kfree(data);
 118         return ret;
 119 };
 120
 121 /*
 122  * These are the reset controller we need to initialize early on in
 123  * our system, before we can even think of using a regular device
 124  * driver for it.
 125  */
 126 static const struct of_device_id sunxi_early_reset_dt_ids[] __initconst = {
 127         { .compatible = "allwinner,sun6i-a31-ahb1-reset", },
 128         { /* sentinel */ },
 129 };
 130
 131 void __init sun6i_reset_init(void)
 132 {
 133         struct device_node *np;
 134
 135         for_each_matching_node(np, sunxi_early_reset_dt_ids)
 136                 sunxi_reset_init(np);
 137 }
 138
 139 /*
 140  * And these are the controllers we can register through the regular
 141  * device model.
 142  */
 143 static const struct of_device_id sunxi_reset_dt_ids[] = {
 144          { .compatible = "allwinner,sun6i-a31-clock-reset", },
 145          { /* sentinel */ },
 146 };
 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) * 8;
 166         data->rcdev.ops = &sunxi_reset_ops;
 167         data->rcdev.of_node = pdev->dev.of_node;
 168
 169         return devm_reset_controller_register(&pdev->dev, &data->rcdev);
 170 }
 171
 172 static struct platform_driver sunxi_reset_driver = {
 173         .probe  = sunxi_reset_probe,
 174         .driver = {
 175                 .name           = "sunxi-reset",
 176                 .of_match_table = sunxi_reset_dt_ids,
 177         },
 178 };
 179 builtin_platform_driver(sunxi_reset_driver);