drivers/hwspinlock/qcom_hwspinlock.c

   1 /*
   2  * Copyright (c) 2013, The Linux Foundation. All rights reserved.
   3  * Copyright (c) 2015, Sony Mobile Communications AB
   4  *
   5  * This software is licensed under the terms of the GNU General Public
   6  * License version 2, as published by the Free Software Foundation, and
   7  * may be copied, distributed, and modified under those terms.
   8  *
   9  * This program is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  * GNU General Public License for more details.
  13  */
  14
  15 #include <linux/hwspinlock.h>
  16 #include <linux/io.h>
  17 #include <linux/kernel.h>
  18 #include <linux/mfd/syscon.h>
  19 #include <linux/module.h>
  20 #include <linux/of.h>
  21 #include <linux/of_device.h>
  22 #include <linux/platform_device.h>
  23 #include <linux/pm_runtime.h>
  24 #include <linux/regmap.h>
  25
  26 #include "hwspinlock_internal.h"
  27
  28 #define QCOM_MUTEX_APPS_PROC_ID 1
  29 #define QCOM_MUTEX_NUM_LOCKS    32
  30
  31 static int qcom_hwspinlock_trylock(struct hwspinlock *lock)
  32 {
  33         struct regmap_field *field = lock->priv;
  34         u32 lock_owner;
  35         int ret;
  36
  37         ret = regmap_field_write(field, QCOM_MUTEX_APPS_PROC_ID);
  38         if (ret)
  39                 return ret;
  40
  41         ret = regmap_field_read(field, &lock_owner);
  42         if (ret)
  43                 return ret;
  44
  45         return lock_owner == QCOM_MUTEX_APPS_PROC_ID;
  46 }
  47
  48 static void qcom_hwspinlock_unlock(struct hwspinlock *lock)
  49 {
  50         struct regmap_field *field = lock->priv;
  51         u32 lock_owner;
  52         int ret;
  53
  54         ret = regmap_field_read(field, &lock_owner);
  55         if (ret) {
  56                 pr_err("%s: unable to query spinlock owner\n", __func__);
  57                 return;
  58         }
  59
  60         if (lock_owner != QCOM_MUTEX_APPS_PROC_ID) {
  61                 pr_err("%s: spinlock not owned by us (actual owner is %d)\n",
  62                                 __func__, lock_owner);
  63         }
  64
  65         ret = regmap_field_write(field, 0);
  66         if (ret)
  67                 pr_err("%s: failed to unlock spinlock\n", __func__);
  68 }
  69
  70 static const struct hwspinlock_ops qcom_hwspinlock_ops = {
  71         .trylock        = qcom_hwspinlock_trylock,
  72         .unlock         = qcom_hwspinlock_unlock,
  73 };
  74
  75 static const struct of_device_id qcom_hwspinlock_of_match[] = {
  76         { .compatible = "qcom,sfpb-mutex" },
  77         { .compatible = "qcom,tcsr-mutex" },
  78         { }
  79 };
  80 MODULE_DEVICE_TABLE(of, qcom_hwspinlock_of_match);
  81
  82 static int qcom_hwspinlock_probe(struct platform_device *pdev)
  83 {
  84         struct hwspinlock_device *bank;
  85         struct device_node *syscon;
  86         struct reg_field field;
  87         struct regmap *regmap;
  88         size_t array_size;
  89         u32 stride;
  90         u32 base;
  91         int ret;
  92         int i;
  93
  94         syscon = of_parse_phandle(pdev->dev.of_node, "syscon", 0);
  95         if (!syscon) {
  96                 dev_err(&pdev->dev, "no syscon property\n");
  97                 return -ENODEV;
  98         }
  99
 100         regmap = syscon_node_to_regmap(syscon);
 101         of_node_put(syscon);
 102         if (IS_ERR(regmap))
 103                 return PTR_ERR(regmap);
 104
 105         ret = of_property_read_u32_index(pdev->dev.of_node, "syscon", 1, &base);
 106         if (ret < 0) {
 107                 dev_err(&pdev->dev, "no offset in syscon\n");
 108                 return -EINVAL;
 109         }
 110
 111         ret = of_property_read_u32_index(pdev->dev.of_node, "syscon", 2, &stride);
 112         if (ret < 0) {
 113                 dev_err(&pdev->dev, "no stride syscon\n");
 114                 return -EINVAL;
 115         }
 116
 117         array_size = QCOM_MUTEX_NUM_LOCKS * sizeof(struct hwspinlock);
 118         bank = devm_kzalloc(&pdev->dev, sizeof(*bank) + array_size, GFP_KERNEL);
 119         if (!bank)
 120                 return -ENOMEM;
 121
 122         platform_set_drvdata(pdev, bank);
 123
 124         for (i = 0; i < QCOM_MUTEX_NUM_LOCKS; i++) {
 125                 field.reg = base + i * stride;
 126                 field.lsb = 0;
 127                 field.msb = 31;
 128
 129                 bank->lock[i].priv = devm_regmap_field_alloc(&pdev->dev,
 130                                                              regmap, field);
 131         }
 132
 133         pm_runtime_enable(&pdev->dev);
 134
 135         ret = hwspin_lock_register(bank, &pdev->dev, &qcom_hwspinlock_ops,
 136                                    0, QCOM_MUTEX_NUM_LOCKS);
 137         if (ret)
 138                 pm_runtime_disable(&pdev->dev);
 139
 140         return ret;
 141 }
 142
 143 static int qcom_hwspinlock_remove(struct platform_device *pdev)
 144 {
 145         struct hwspinlock_device *bank = platform_get_drvdata(pdev);
 146         int ret;
 147
 148         ret = hwspin_lock_unregister(bank);
 149         if (ret) {
 150                 dev_err(&pdev->dev, "%s failed: %d\n", __func__, ret);
 151                 return ret;
 152         }
 153
 154         pm_runtime_disable(&pdev->dev);
 155
 156         return 0;
 157 }
 158
 159 static struct platform_driver qcom_hwspinlock_driver = {
 160         .probe          = qcom_hwspinlock_probe,
 161         .remove         = qcom_hwspinlock_remove,
 162         .driver         = {
 163                 .name   = "qcom_hwspinlock",
 164                 .of_match_table = qcom_hwspinlock_of_match,
 165         },
 166 };
 167
 168 static int __init qcom_hwspinlock_init(void)
 169 {
 170         return platform_driver_register(&qcom_hwspinlock_driver);
 171 }
 172 /* board init code might need to reserve hwspinlocks for predefined purposes */
 173 postcore_initcall(qcom_hwspinlock_init);
 174
 175 static void __exit qcom_hwspinlock_exit(void)
 176 {
 177         platform_driver_unregister(&qcom_hwspinlock_driver);
 178 }
 179 module_exit(qcom_hwspinlock_exit);
 180
 181 MODULE_LICENSE("GPL v2");
 182 MODULE_DESCRIPTION("Hardware spinlock driver for Qualcomm SoCs");