linux/drivers/hwspinlock/qcom_hwspinlock.c
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   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
  22static 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
  39static 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
  61static const struct hwspinlock_ops qcom_hwspinlock_ops = {
  62        .trylock        = qcom_hwspinlock_trylock,
  63        .unlock         = qcom_hwspinlock_unlock,
  64};
  65
  66static const struct of_device_id qcom_hwspinlock_of_match[] = {
  67        { .compatible = "qcom,sfpb-mutex" },
  68        { .compatible = "qcom,tcsr-mutex" },
  69        { }
  70};
  71MODULE_DEVICE_TABLE(of, qcom_hwspinlock_of_match);
  72
  73static 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
 104static 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
 112static 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
 129static 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
 166static 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
 174static 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 */
 179postcore_initcall(qcom_hwspinlock_init);
 180
 181static void __exit qcom_hwspinlock_exit(void)
 182{
 183        platform_driver_unregister(&qcom_hwspinlock_driver);
 184}
 185module_exit(qcom_hwspinlock_exit);
 186
 187MODULE_LICENSE("GPL v2");
 188MODULE_DESCRIPTION("Hardware spinlock driver for Qualcomm SoCs");
 189
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