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