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 struct regmap *qcom_hwspinlock_probe_syscon(struct platform_device *pdev,
  74                                                    u32 *base, u32 *stride)
  75 {
  76         struct device_node *syscon;
  77         struct regmap *regmap;
  78         int ret;
  79
  80         syscon = of_parse_phandle(pdev->dev.of_node, "syscon", 0);
  81         if (!syscon)
  82                 return ERR_PTR(-ENODEV);
  83
  84         regmap = syscon_node_to_regmap(syscon);
  85         of_node_put(syscon);
  86         if (IS_ERR(regmap))
  87                 return regmap;
  88
  89         ret = of_property_read_u32_index(pdev->dev.of_node, "syscon", 1, base);
  90         if (ret < 0) {
  91                 dev_err(&pdev->dev, "no offset in syscon\n");
  92                 return ERR_PTR(-EINVAL);
  93         }
  94
  95         ret = of_property_read_u32_index(pdev->dev.of_node, "syscon", 2, stride);
  96         if (ret < 0) {
  97                 dev_err(&pdev->dev, "no stride syscon\n");
  98                 return ERR_PTR(-EINVAL);
  99         }
 100
 101         return regmap;
 102 }
 103
 104 static const struct regmap_config tcsr_mutex_config = {
 105         .reg_bits               = 32,
 106         .reg_stride             = 4,
 107         .val_bits               = 32,
 108         .max_register           = 0x40000,
 109         .fast_io                = true,
 110 };
 111
 112 static struct regmap *qcom_hwspinlock_probe_mmio(struct platform_device *pdev,
 113                                                  u32 *offset, u32 *stride)
 114 {
 115         struct device *dev = &pdev->dev;
 116         void __iomem *base;
 117
 118         /* All modern platform has offset 0 and stride of 4k */
 119         *offset = 0;
 120         *stride = 0x1000;
 121
 122         base = devm_platform_ioremap_resource(pdev, 0);
 123         if (IS_ERR(base))
 124                 return ERR_CAST(base);
 125
 126         return devm_regmap_init_mmio(dev, base, &tcsr_mutex_config);
 127 }
 128
 129 static int qcom_hwspinlock_probe(struct platform_device *pdev)
 130 {
 131         struct hwspinlock_device *bank;
 132         struct reg_field field;
 133         struct regmap *regmap;
 134         size_t array_size;
 135         u32 stride;
 136         u32 base;
 137         int i;
 138
 139         regmap = qcom_hwspinlock_probe_syscon(pdev, &base, &stride);
 140         if (IS_ERR(regmap) && PTR_ERR(regmap) == -ENODEV)
 141                 regmap = qcom_hwspinlock_probe_mmio(pdev, &base, &stride);
 142
 143         if (IS_ERR(regmap))
 144                 return PTR_ERR(regmap);
 145
 146         array_size = QCOM_MUTEX_NUM_LOCKS * sizeof(struct hwspinlock);
 147         bank = devm_kzalloc(&pdev->dev, sizeof(*bank) + array_size, GFP_KERNEL);
 148         if (!bank)
 149                 return -ENOMEM;
 150
 151         platform_set_drvdata(pdev, bank);
 152
 153         for (i = 0; i < QCOM_MUTEX_NUM_LOCKS; i++) {
 154                 field.reg = base + i * stride;
 155                 field.lsb = 0;
 156                 field.msb = 31;
 157
 158                 bank->lock[i].priv = devm_regmap_field_alloc(&pdev->dev,
 159                                                              regmap, field);
 160         }
 161
 162         return devm_hwspin_lock_register(&pdev->dev, bank, &qcom_hwspinlock_ops,
 163                                          0, QCOM_MUTEX_NUM_LOCKS);
 164 }
 165
 166 static struct platform_driver qcom_hwspinlock_driver = {
 167         .probe          = qcom_hwspinlock_probe,
 168         .driver         = {
 169                 .name   = "qcom_hwspinlock",
 170                 .of_match_table = qcom_hwspinlock_of_match,
 171         },
 172 };
 173
 174 static int __init qcom_hwspinlock_init(void)
 175 {
 176         return platform_driver_register(&qcom_hwspinlock_driver);
 177 }
 178 /* board init code might need to reserve hwspinlocks for predefined purposes */
 179 postcore_initcall(qcom_hwspinlock_init);
 180
 181 static void __exit qcom_hwspinlock_exit(void)
 182 {
 183         platform_driver_unregister(&qcom_hwspinlock_driver);
 184 }
 185 module_exit(qcom_hwspinlock_exit);
 186
 187 MODULE_LICENSE("GPL v2");
 188 MODULE_DESCRIPTION("Hardware spinlock driver for Qualcomm SoCs");