drivers/hwspinlock/qcom_hwspinlock.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Copyright (c) 2013, The Linux Foundation. All rights reserved.
   4  * Copyright (c) 2015, Sony Mobile Communications AB
   5  */
   6
   7 #include <linux/hwspinlock.h>
   8 #include <linux/io.h>
   9 #include <linux/kernel.h>
  10 #include <linux/mfd/syscon.h>
  11 #include <linux/module.h>
  12 #include <linux/of.h>
  13 #include <linux/of_device.h>
  14 #include <linux/platform_device.h>
  15 #include <linux/pm_runtime.h>
  16 #include <linux/regmap.h>
  17
  18 #include "hwspinlock_internal.h"
  19
  20 #define QCOM_MUTEX_APPS_PROC_ID 1
  21 #define QCOM_MUTEX_NUM_LOCKS    32
  22
  23 static int qcom_hwspinlock_trylock(struct hwspinlock *lock)
  24 {
  25         struct regmap_field *field = lock->priv;
  26         u32 lock_owner;
  27         int ret;
  28
  29         ret = regmap_field_write(field, QCOM_MUTEX_APPS_PROC_ID);
  30         if (ret)
  31                 return ret;
  32
  33         ret = regmap_field_read(field, &lock_owner);
  34         if (ret)
  35                 return ret;
  36
  37         return lock_owner == QCOM_MUTEX_APPS_PROC_ID;
  38 }
  39
  40 static void qcom_hwspinlock_unlock(struct hwspinlock *lock)
  41 {
  42         struct regmap_field *field = lock->priv;
  43         u32 lock_owner;
  44         int ret;
  45
  46         ret = regmap_field_read(field, &lock_owner);
  47         if (ret) {
  48                 pr_err("%s: unable to query spinlock owner\n", __func__);
  49                 return;
  50         }
  51
  52         if (lock_owner != QCOM_MUTEX_APPS_PROC_ID) {
  53                 pr_err("%s: spinlock not owned by us (actual owner is %d)\n",
  54                                 __func__, lock_owner);
  55         }
  56
  57         ret = regmap_field_write(field, 0);
  58         if (ret)
  59                 pr_err("%s: failed to unlock spinlock\n", __func__);
  60 }
  61
  62 static const struct hwspinlock_ops qcom_hwspinlock_ops = {
  63         .trylock        = qcom_hwspinlock_trylock,
  64         .unlock         = qcom_hwspinlock_unlock,
  65 };
  66
  67 static const struct of_device_id qcom_hwspinlock_of_match[] = {
  68         { .compatible = "qcom,sfpb-mutex" },
  69         { .compatible = "qcom,tcsr-mutex" },
  70         { }
  71 };
  72 MODULE_DEVICE_TABLE(of, qcom_hwspinlock_of_match);
  73
  74 static int qcom_hwspinlock_probe(struct platform_device *pdev)
  75 {
  76         struct hwspinlock_device *bank;
  77         struct device_node *syscon;
  78         struct reg_field field;
  79         struct regmap *regmap;
  80         size_t array_size;
  81         u32 stride;
  82         u32 base;
  83         int ret;
  84         int i;
  85
  86         syscon = of_parse_phandle(pdev->dev.of_node, "syscon", 0);
  87         if (!syscon) {
  88                 dev_err(&pdev->dev, "no syscon property\n");
  89                 return -ENODEV;
  90         }
  91
  92         regmap = syscon_node_to_regmap(syscon);
  93         of_node_put(syscon);
  94         if (IS_ERR(regmap))
  95                 return PTR_ERR(regmap);
  96
  97         ret = of_property_read_u32_index(pdev->dev.of_node, "syscon", 1, &base);
  98         if (ret < 0) {
  99                 dev_err(&pdev->dev, "no offset in syscon\n");
 100                 return -EINVAL;
 101         }
 102
 103         ret = of_property_read_u32_index(pdev->dev.of_node, "syscon", 2, &stride);
 104         if (ret < 0) {
 105                 dev_err(&pdev->dev, "no stride syscon\n");
 106                 return -EINVAL;
 107         }
 108
 109         array_size = QCOM_MUTEX_NUM_LOCKS * sizeof(struct hwspinlock);
 110         bank = devm_kzalloc(&pdev->dev, sizeof(*bank) + array_size, GFP_KERNEL);
 111         if (!bank)
 112                 return -ENOMEM;
 113
 114         platform_set_drvdata(pdev, bank);
 115
 116         for (i = 0; i < QCOM_MUTEX_NUM_LOCKS; i++) {
 117                 field.reg = base + i * stride;
 118                 field.lsb = 0;
 119                 field.msb = 31;
 120
 121                 bank->lock[i].priv = devm_regmap_field_alloc(&pdev->dev,
 122                                                              regmap, field);
 123         }
 124
 125         pm_runtime_enable(&pdev->dev);
 126
 127         ret = hwspin_lock_register(bank, &pdev->dev, &qcom_hwspinlock_ops,
 128                                    0, QCOM_MUTEX_NUM_LOCKS);
 129         if (ret)
 130                 pm_runtime_disable(&pdev->dev);
 131
 132         return ret;
 133 }
 134
 135 static int qcom_hwspinlock_remove(struct platform_device *pdev)
 136 {
 137         struct hwspinlock_device *bank = platform_get_drvdata(pdev);
 138         int ret;
 139
 140         ret = hwspin_lock_unregister(bank);
 141         if (ret) {
 142                 dev_err(&pdev->dev, "%s failed: %d\n", __func__, ret);
 143                 return ret;
 144         }
 145
 146         pm_runtime_disable(&pdev->dev);
 147
 148         return 0;
 149 }
 150
 151 static struct platform_driver qcom_hwspinlock_driver = {
 152         .probe          = qcom_hwspinlock_probe,
 153         .remove         = qcom_hwspinlock_remove,
 154         .driver         = {
 155                 .name   = "qcom_hwspinlock",
 156                 .of_match_table = qcom_hwspinlock_of_match,
 157         },
 158 };
 159
 160 static int __init qcom_hwspinlock_init(void)
 161 {
 162         return platform_driver_register(&qcom_hwspinlock_driver);
 163 }
 164 /* board init code might need to reserve hwspinlocks for predefined purposes */
 165 postcore_initcall(qcom_hwspinlock_init);
 166
 167 static void __exit qcom_hwspinlock_exit(void)
 168 {
 169         platform_driver_unregister(&qcom_hwspinlock_driver);
 170 }
 171 module_exit(qcom_hwspinlock_exit);
 172
 173 MODULE_LICENSE("GPL v2");
 174 MODULE_DESCRIPTION("Hardware spinlock driver for Qualcomm SoCs");