drivers/reset/reset-rockchip.c

   1 /*
   2  * Copyright (c) 2014 ROCKCHIP, Inc.
   3  * Author: Dai Kelin <dkl@rock-chips.com>
   4  * Based on codes from Heiko Stuebner <heiko@sntech.de>.
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License as published by
   8  * the Free Software Foundation; either version 2 of the License, or
   9  * (at your option) any later version.
  10  *
  11  * This program is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  * GNU General Public License for more details.
  15  */
  16
  17 #include <linux/slab.h>
  18 #include <linux/io.h>
  19 #include <linux/reset-controller.h>
  20 #include <linux/spinlock.h>
  21 #include <linux/of_address.h>
  22 #include <linux/platform_device.h>
  23 #include <linux/module.h>
  24
  25 #include <dt-bindings/clock/rockchip.h>
  26
  27
  28 struct rockchip_reset {
  29         struct reset_controller_dev     rcdev;
  30         void __iomem                    *reg_base;
  31         int                             num_regs;
  32         int                             num_per_reg;
  33         u8                              flags;
  34         spinlock_t                      lock;
  35 };
  36
  37 static int rockchip_reset_assert(struct reset_controller_dev *rcdev,
  38                               unsigned long id)
  39 {
  40         struct rockchip_reset *reset = container_of(rcdev,
  41                                                      struct rockchip_reset,
  42                                                      rcdev);
  43         int bank = id / reset->num_per_reg;
  44         int offset = id % reset->num_per_reg;
  45
  46         if (reset->flags & ROCKCHIP_RESET_HIWORD_MASK) {
  47                 writel(BIT(offset) | (BIT(offset) << 16),
  48                        reset->reg_base + (bank * 4));
  49         } else {
  50                 unsigned long flags;
  51                 u32 reg;
  52
  53                 spin_lock_irqsave(&reset->lock, flags);
  54
  55                 reg = readl(reset->reg_base + (bank * 4));
  56                 writel(reg | BIT(offset), reset->reg_base + (bank * 4));
  57
  58                 spin_unlock_irqrestore(&reset->lock, flags);
  59         }
  60
  61         return 0;
  62 }
  63
  64 static int rockchip_reset_deassert(struct reset_controller_dev *rcdev,
  65                                 unsigned long id)
  66 {
  67         struct rockchip_reset *reset = container_of(rcdev,
  68                                                      struct rockchip_reset,
  69                                                      rcdev);
  70         int bank = id / reset->num_per_reg;
  71         int offset = id % reset->num_per_reg;
  72
  73         if (reset->flags & ROCKCHIP_RESET_HIWORD_MASK) {
  74                 writel((BIT(offset) << 16), reset->reg_base + (bank * 4));
  75         } else {
  76                 unsigned long flags;
  77                 u32 reg;
  78
  79                 spin_lock_irqsave(&reset->lock, flags);
  80
  81                 reg = readl(reset->reg_base + (bank * 4));
  82                 writel(reg & ~BIT(offset), reset->reg_base + (bank * 4));
  83
  84                 spin_unlock_irqrestore(&reset->lock, flags);
  85         }
  86
  87         return 0;
  88 }
  89
  90 static struct reset_control_ops rockchip_reset_ops = {
  91         .assert         = rockchip_reset_assert,
  92         .deassert       = rockchip_reset_deassert,
  93 };
  94
  95 static int rockchip_register_reset(struct device_node *np,
  96                                       unsigned int num_regs,
  97                                       void __iomem *base, u8 flags)
  98 {
  99         struct rockchip_reset *reset;
 100         int ret;
 101
 102         reset = kzalloc(sizeof(*reset), GFP_KERNEL);
 103         if (!reset)
 104                 return -ENOMEM;
 105
 106         reset->flags = flags;
 107         reset->reg_base = base;
 108         reset->num_regs = num_regs;
 109         reset->num_per_reg = (flags & ROCKCHIP_RESET_HIWORD_MASK) ? 16 : 32;
 110         spin_lock_init(&reset->lock);
 111
 112         reset->rcdev.owner = THIS_MODULE;
 113         reset->rcdev.nr_resets =  num_regs * reset->num_per_reg;
 114         reset->rcdev.ops = &rockchip_reset_ops;
 115         reset->rcdev.of_node = np;
 116         ret = reset_controller_register(&reset->rcdev);
 117         if (ret) {
 118                 pr_err("%s: could not register reset controller, %d\n",
 119                        __func__, ret);
 120                 kfree(reset);
 121                 return ret;
 122         }
 123
 124         return 0;
 125 };
 126
 127 static int rockchip_reset_probe(struct platform_device *pdev)
 128 {
 129         struct resource *res;
 130         void __iomem *base;
 131         resource_size_t size;
 132         u32 flag = 0;
 133
 134
 135         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 136         base = devm_ioremap_resource(&pdev->dev, res);
 137         if (IS_ERR(base)) {
 138                 pr_err("%s: ioremap err\n", __func__);
 139                 return PTR_ERR(base);
 140         }
 141
 142         size = resource_size(res);
 143         if (size%4) {
 144                 pr_err("%s: wrong size value\n", __func__);
 145                 return -EINVAL;
 146         }
 147
 148         of_property_read_u32(pdev->dev.of_node, "rockchip,reset-flag", &flag);
 149
 150         return rockchip_register_reset(pdev->dev.of_node, size/4, base, flag);
 151 }
 152
 153 static const struct of_device_id rockchip_reset_dt_ids[]  = {
 154         { .compatible = "rockchip,reset", },
 155         { /* sentinel */ },
 156 };
 157 MODULE_DEVICE_TABLE(of, rockchip_reset_dt_ids);
 158
 159 static struct platform_driver rockchip_reset_driver = {
 160         .probe  = rockchip_reset_probe,
 161         .driver = {
 162                 .name           = "rockchip-reset",
 163                 .owner          = THIS_MODULE,
 164                 .of_match_table = rockchip_reset_dt_ids,
 165         },
 166 };
 167 module_platform_driver(rockchip_reset_driver);
 168