drivers/hwspinlock/sprd_hwspinlock.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Spreadtrum hardware spinlock driver
   4  * Copyright (C) 2017 Spreadtrum  - http://www.spreadtrum.com
   5  */
   6
   7 #include <linux/clk.h>
   8 #include <linux/delay.h>
   9 #include <linux/device.h>
  10 #include <linux/hwspinlock.h>
  11 #include <linux/io.h>
  12 #include <linux/kernel.h>
  13 #include <linux/module.h>
  14 #include <linux/of.h>
  15 #include <linux/of_device.h>
  16 #include <linux/platform_device.h>
  17
  18 #include "hwspinlock_internal.h"
  19
  20 /* hwspinlock registers definition */
  21 #define HWSPINLOCK_RECCTRL              0x4
  22 #define HWSPINLOCK_MASTERID(_X_)        (0x80 + 0x4 * (_X_))
  23 #define HWSPINLOCK_TOKEN(_X_)           (0x800 + 0x4 * (_X_))
  24
  25 /* unlocked value */
  26 #define HWSPINLOCK_NOTTAKEN             0x55aa10c5
  27 /* bits definition of RECCTRL reg */
  28 #define HWSPINLOCK_USER_BITS            0x1
  29
  30 /* hwspinlock number */
  31 #define SPRD_HWLOCKS_NUM                32
  32
  33 struct sprd_hwspinlock_dev {
  34         void __iomem *base;
  35         struct clk *clk;
  36         struct hwspinlock_device bank;
  37 };
  38
  39 /* try to lock the hardware spinlock */
  40 static int sprd_hwspinlock_trylock(struct hwspinlock *lock)
  41 {
  42         struct sprd_hwspinlock_dev *sprd_hwlock =
  43                 dev_get_drvdata(lock->bank->dev);
  44         void __iomem *addr = lock->priv;
  45         int user_id, lock_id;
  46
  47         if (!readl(addr))
  48                 return 1;
  49
  50         lock_id = hwlock_to_id(lock);
  51         /* get the hardware spinlock master/user id */
  52         user_id = readl(sprd_hwlock->base + HWSPINLOCK_MASTERID(lock_id));
  53         dev_warn(sprd_hwlock->bank.dev,
  54                  "hwspinlock [%d] lock failed and master/user id = %d!\n",
  55                  lock_id, user_id);
  56         return 0;
  57 }
  58
  59 /* unlock the hardware spinlock */
  60 static void sprd_hwspinlock_unlock(struct hwspinlock *lock)
  61 {
  62         void __iomem *lock_addr = lock->priv;
  63
  64         writel(HWSPINLOCK_NOTTAKEN, lock_addr);
  65 }
  66
  67 /* The specs recommended below number as the retry delay time */
  68 static void sprd_hwspinlock_relax(struct hwspinlock *lock)
  69 {
  70         ndelay(10);
  71 }
  72
  73 static const struct hwspinlock_ops sprd_hwspinlock_ops = {
  74         .trylock = sprd_hwspinlock_trylock,
  75         .unlock = sprd_hwspinlock_unlock,
  76         .relax = sprd_hwspinlock_relax,
  77 };
  78
  79 static void sprd_hwspinlock_disable(void *data)
  80 {
  81         struct sprd_hwspinlock_dev *sprd_hwlock = data;
  82
  83         clk_disable_unprepare(sprd_hwlock->clk);
  84 }
  85
  86 static int sprd_hwspinlock_probe(struct platform_device *pdev)
  87 {
  88         struct sprd_hwspinlock_dev *sprd_hwlock;
  89         struct hwspinlock *lock;
  90         int i, ret;
  91
  92         if (!pdev->dev.of_node)
  93                 return -ENODEV;
  94
  95         sprd_hwlock = devm_kzalloc(&pdev->dev,
  96                                    sizeof(struct sprd_hwspinlock_dev) +
  97                                    SPRD_HWLOCKS_NUM * sizeof(*lock),
  98                                    GFP_KERNEL);
  99         if (!sprd_hwlock)
 100                 return -ENOMEM;
 101
 102         sprd_hwlock->base = devm_platform_ioremap_resource(pdev, 0);
 103         if (IS_ERR(sprd_hwlock->base))
 104                 return PTR_ERR(sprd_hwlock->base);
 105
 106         sprd_hwlock->clk = devm_clk_get(&pdev->dev, "enable");
 107         if (IS_ERR(sprd_hwlock->clk)) {
 108                 dev_err(&pdev->dev, "get hwspinlock clock failed!\n");
 109                 return PTR_ERR(sprd_hwlock->clk);
 110         }
 111
 112         ret = clk_prepare_enable(sprd_hwlock->clk);
 113         if (ret)
 114                 return ret;
 115
 116         ret = devm_add_action_or_reset(&pdev->dev, sprd_hwspinlock_disable,
 117                                        sprd_hwlock);
 118         if (ret) {
 119                 dev_err(&pdev->dev,
 120                         "Failed to add hwspinlock disable action\n");
 121                 return ret;
 122         }
 123
 124         /* set the hwspinlock to record user id to identify subsystems */
 125         writel(HWSPINLOCK_USER_BITS, sprd_hwlock->base + HWSPINLOCK_RECCTRL);
 126
 127         for (i = 0; i < SPRD_HWLOCKS_NUM; i++) {
 128                 lock = &sprd_hwlock->bank.lock[i];
 129                 lock->priv = sprd_hwlock->base + HWSPINLOCK_TOKEN(i);
 130         }
 131
 132         platform_set_drvdata(pdev, sprd_hwlock);
 133
 134         return devm_hwspin_lock_register(&pdev->dev, &sprd_hwlock->bank,
 135                                          &sprd_hwspinlock_ops, 0,
 136                                          SPRD_HWLOCKS_NUM);
 137 }
 138
 139 static const struct of_device_id sprd_hwspinlock_of_match[] = {
 140         { .compatible = "sprd,hwspinlock-r3p0", },
 141         { /* sentinel */ }
 142 };
 143 MODULE_DEVICE_TABLE(of, sprd_hwspinlock_of_match);
 144
 145 static struct platform_driver sprd_hwspinlock_driver = {
 146         .probe = sprd_hwspinlock_probe,
 147         .driver = {
 148                 .name = "sprd_hwspinlock",
 149                 .of_match_table = sprd_hwspinlock_of_match,
 150         },
 151 };
 152 module_platform_driver(sprd_hwspinlock_driver);
 153
 154 MODULE_LICENSE("GPL v2");
 155 MODULE_DESCRIPTION("Hardware spinlock driver for Spreadtrum");
 156 MODULE_AUTHOR("Baolin Wang <[email protected]>");
 157 MODULE_AUTHOR("Lanqing Liu <[email protected]>");
 158 MODULE_AUTHOR("Long Cheng <[email protected]>");