LXR linux/drivers/hwspinlock/stm32

   1// SPDX-License-Identifier: GPL-2.0
   2/*
   3 * Copyright (C) STMicroelectronics SA 2018
   4 * Author: Benjamin Gaignard <benjamin.gaignard@st.com> for STMicroelectronics.
   5 */
   6
   7#include <linux/clk.h>
   8#include <linux/hwspinlock.h>
   9#include <linux/io.h>
  10#include <linux/kernel.h>
  11#include <linux/module.h>
  12#include <linux/of.h>
  13#include <linux/platform_device.h>
  14#include <linux/pm_runtime.h>
  15
  16#include "hwspinlock_internal.h"
  17
  18#define STM32_MUTEX_COREID      BIT(8)
  19#define STM32_MUTEX_LOCK_BIT    BIT(31)
  20#define STM32_MUTEX_NUM_LOCKS   32
  21
  22struct stm32_hwspinlock {
  23        struct clk *clk;
  24        struct hwspinlock_device bank;
  25};
  26
  27static int stm32_hwspinlock_trylock(struct hwspinlock *lock)
  28{
  29        void __iomem *lock_addr = lock->priv;
  30        u32 status;
  31
  32        writel(STM32_MUTEX_LOCK_BIT | STM32_MUTEX_COREID, lock_addr);
  33        status = readl(lock_addr);
  34
  35        return status == (STM32_MUTEX_LOCK_BIT | STM32_MUTEX_COREID);
  36}
  37
  38static void stm32_hwspinlock_unlock(struct hwspinlock *lock)
  39{
  40        void __iomem *lock_addr = lock->priv;
  41
  42        writel(STM32_MUTEX_COREID, lock_addr);
  43}
  44
  45static const struct hwspinlock_ops stm32_hwspinlock_ops = {
  46        .trylock        = stm32_hwspinlock_trylock,
  47        .unlock         = stm32_hwspinlock_unlock,
  48};
  49
  50static int stm32_hwspinlock_probe(struct platform_device *pdev)
  51{
  52        struct stm32_hwspinlock *hw;
  53        void __iomem *io_base;
  54        struct resource *res;
  55        size_t array_size;
  56        int i, ret;
  57
  58        res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
  59        io_base = devm_ioremap_resource(&pdev->dev, res);
  60        if (IS_ERR(io_base))
  61                return PTR_ERR(io_base);
  62
  63        array_size = STM32_MUTEX_NUM_LOCKS * sizeof(struct hwspinlock);
  64        hw = devm_kzalloc(&pdev->dev, sizeof(*hw) + array_size, GFP_KERNEL);
  65        if (!hw)
  66                return -ENOMEM;
  67
  68        hw->clk = devm_clk_get(&pdev->dev, "hsem");
  69        if (IS_ERR(hw->clk))
  70                return PTR_ERR(hw->clk);
  71
  72        for (i = 0; i < STM32_MUTEX_NUM_LOCKS; i++)
  73                hw->bank.lock[i].priv = io_base + i * sizeof(u32);
  74
  75        platform_set_drvdata(pdev, hw);
  76        pm_runtime_enable(&pdev->dev);
  77
  78        ret = hwspin_lock_register(&hw->bank, &pdev->dev, &stm32_hwspinlock_ops,
  79                                   0, STM32_MUTEX_NUM_LOCKS);
  80
  81        if (ret)
  82                pm_runtime_disable(&pdev->dev);
  83
  84        return ret;
  85}
  86
  87static int stm32_hwspinlock_remove(struct platform_device *pdev)
  88{
  89        struct stm32_hwspinlock *hw = platform_get_drvdata(pdev);
  90        int ret;
  91
  92        ret = hwspin_lock_unregister(&hw->bank);
  93        if (ret)
  94                dev_err(&pdev->dev, "%s failed: %d\n", __func__, ret);
  95
  96        pm_runtime_disable(&pdev->dev);
  97
  98        return 0;
  99}
 100
 101static int __maybe_unused stm32_hwspinlock_runtime_suspend(struct device *dev)
 102{
 103        struct stm32_hwspinlock *hw = dev_get_drvdata(dev);
 104
 105        clk_disable_unprepare(hw->clk);
 106
 107        return 0;
 108}
 109
 110static int __maybe_unused stm32_hwspinlock_runtime_resume(struct device *dev)
 111{
 112        struct stm32_hwspinlock *hw = dev_get_drvdata(dev);
 113
 114        clk_prepare_enable(hw->clk);
 115
 116        return 0;
 117}
 118
 119static const struct dev_pm_ops stm32_hwspinlock_pm_ops = {
 120        SET_RUNTIME_PM_OPS(stm32_hwspinlock_runtime_suspend,
 121                           stm32_hwspinlock_runtime_resume,
 122                           NULL)
 123};
 124
 125static const struct of_device_id stm32_hwpinlock_ids[] = {
 126        { .compatible = "st,stm32-hwspinlock", },
 127        {},
 128};
 129MODULE_DEVICE_TABLE(of, stm32_hwpinlock_ids);
 130
 131static struct platform_driver stm32_hwspinlock_driver = {
 132        .probe          = stm32_hwspinlock_probe,
 133        .remove         = stm32_hwspinlock_remove,
 134        .driver         = {
 135                .name   = "stm32_hwspinlock",
 136                .of_match_table = stm32_hwpinlock_ids,
 137                .pm     = &stm32_hwspinlock_pm_ops,
 138        },
 139};
 140
 141static int __init stm32_hwspinlock_init(void)
 142{
 143        return platform_driver_register(&stm32_hwspinlock_driver);
 144}
 145/* board init code might need to reserve hwspinlocks for predefined purposes */
 146postcore_initcall(stm32_hwspinlock_init);
 147
 148static void __exit stm32_hwspinlock_exit(void)
 149{
 150        platform_driver_unregister(&stm32_hwspinlock_driver);
 151}
 152module_exit(stm32_hwspinlock_exit);
 153
 154MODULE_LICENSE("GPL v2");
 155MODULE_DESCRIPTION("Hardware spinlock driver for STM32 SoCs");
 156MODULE_AUTHOR("Benjamin Gaignard <benjamin.gaignard@st.com>");
 157