LXR linux/drivers/hwspinlock/sprd

   1// SPDX-License-Identifier: GPL-2.0
   2/*
   3 * Spreadtrum hardware spinlock driver
   4 * Copyright (C) 2017 Spreadtrum  - http://www.spreadtrum.com
   5 */
   6
   7#include <linux/clk.h>
   8#include <linux/delay.h>
   9#include <linux/device.h>
  10#include <linux/hwspinlock.h>
  11#include <linux/io.h>
  12#include <linux/kernel.h>
  13#include <linux/module.h>
  14#include <linux/of.h>
  15#include <linux/of_device.h>
  16#include <linux/platform_device.h>
  17
  18#include "hwspinlock_internal.h"
  19
  20/* hwspinlock registers definition */
  21#define HWSPINLOCK_RECCTRL              0x4
  22#define HWSPINLOCK_MASTERID(_X_)        (0x80 + 0x4 * (_X_))
  23#define HWSPINLOCK_TOKEN(_X_)           (0x800 + 0x4 * (_X_))
  24
  25/* unlocked value */
  26#define HWSPINLOCK_NOTTAKEN             0x55aa10c5
  27/* bits definition of RECCTRL reg */
  28#define HWSPINLOCK_USER_BITS            0x1
  29
  30/* hwspinlock number */
  31#define SPRD_HWLOCKS_NUM                32
  32
  33struct sprd_hwspinlock_dev {
  34        void __iomem *base;
  35        struct clk *clk;
  36        struct hwspinlock_device bank;
  37};
  38
  39/* try to lock the hardware spinlock */
  40static int sprd_hwspinlock_trylock(struct hwspinlock *lock)
  41{
  42        struct sprd_hwspinlock_dev *sprd_hwlock =
  43                dev_get_drvdata(lock->bank->dev);
  44        void __iomem *addr = lock->priv;
  45        int user_id, lock_id;
  46
  47        if (!readl(addr))
  48                return 1;
  49
  50        lock_id = hwlock_to_id(lock);
  51        /* get the hardware spinlock master/user id */
  52        user_id = readl(sprd_hwlock->base + HWSPINLOCK_MASTERID(lock_id));
  53        dev_warn(sprd_hwlock->bank.dev,
  54                 "hwspinlock [%d] lock failed and master/user id = %d!\n",
  55                 lock_id, user_id);
  56        return 0;
  57}
  58
  59/* unlock the hardware spinlock */
  60static void sprd_hwspinlock_unlock(struct hwspinlock *lock)
  61{
  62        void __iomem *lock_addr = lock->priv;
  63
  64        writel(HWSPINLOCK_NOTTAKEN, lock_addr);
  65}
  66
  67/* The specs recommended below number as the retry delay time */
  68static void sprd_hwspinlock_relax(struct hwspinlock *lock)
  69{
  70        ndelay(10);
  71}
  72
  73static const struct hwspinlock_ops sprd_hwspinlock_ops = {
  74        .trylock = sprd_hwspinlock_trylock,
  75        .unlock = sprd_hwspinlock_unlock,
  76        .relax = sprd_hwspinlock_relax,
  77};
  78
  79static void sprd_hwspinlock_disable(void *data)
  80{
  81        struct sprd_hwspinlock_dev *sprd_hwlock = data;
  82
  83        clk_disable_unprepare(sprd_hwlock->clk);
  84}
  85
  86static int sprd_hwspinlock_probe(struct platform_device *pdev)
  87{
  88        struct sprd_hwspinlock_dev *sprd_hwlock;
  89        struct hwspinlock *lock;
  90        int i, ret;
  91
  92        if (!pdev->dev.of_node)
  93                return -ENODEV;
  94
  95        sprd_hwlock = devm_kzalloc(&pdev->dev,
  96                                   sizeof(struct sprd_hwspinlock_dev) +
  97                                   SPRD_HWLOCKS_NUM * sizeof(*lock),
  98                                   GFP_KERNEL);
  99        if (!sprd_hwlock)
 100                return -ENOMEM;
 101
 102        sprd_hwlock->base = devm_platform_ioremap_resource(pdev, 0);
 103        if (IS_ERR(sprd_hwlock->base))
 104                return PTR_ERR(sprd_hwlock->base);
 105
 106        sprd_hwlock->clk = devm_clk_get(&pdev->dev, "enable");
 107        if (IS_ERR(sprd_hwlock->clk)) {
 108                dev_err(&pdev->dev, "get hwspinlock clock failed!\n");
 109                return PTR_ERR(sprd_hwlock->clk);
 110        }
 111
 112        ret = clk_prepare_enable(sprd_hwlock->clk);
 113        if (ret)
 114                return ret;
 115
 116        ret = devm_add_action_or_reset(&pdev->dev, sprd_hwspinlock_disable,
 117                                       sprd_hwlock);
 118        if (ret) {
 119                dev_err(&pdev->dev,
 120                        "Failed to add hwspinlock disable action\n");
 121                return ret;
 122        }
 123
 124        /* set the hwspinlock to record user id to identify subsystems */
 125        writel(HWSPINLOCK_USER_BITS, sprd_hwlock->base + HWSPINLOCK_RECCTRL);
 126
 127        for (i = 0; i < SPRD_HWLOCKS_NUM; i++) {
 128                lock = &sprd_hwlock->bank.lock[i];
 129                lock->priv = sprd_hwlock->base + HWSPINLOCK_TOKEN(i);
 130        }
 131
 132        platform_set_drvdata(pdev, sprd_hwlock);
 133
 134        return devm_hwspin_lock_register(&pdev->dev, &sprd_hwlock->bank,
 135                                         &sprd_hwspinlock_ops, 0,
 136                                         SPRD_HWLOCKS_NUM);
 137}
 138
 139static const struct of_device_id sprd_hwspinlock_of_match[] = {
 140        { .compatible = "sprd,hwspinlock-r3p0", },
 141        { /* sentinel */ }
 142};
 143MODULE_DEVICE_TABLE(of, sprd_hwspinlock_of_match);
 144
 145static struct platform_driver sprd_hwspinlock_driver = {
 146        .probe = sprd_hwspinlock_probe,
 147        .driver = {
 148                .name = "sprd_hwspinlock",
 149                .of_match_table = sprd_hwspinlock_of_match,
 150        },
 151};
 152module_platform_driver(sprd_hwspinlock_driver);
 153
 154MODULE_LICENSE("GPL v2");
 155MODULE_DESCRIPTION("Hardware spinlock driver for Spreadtrum");
 156MODULE_AUTHOR("Baolin Wang <baolin.wang@spreadtrum.com>");
 157MODULE_AUTHOR("Lanqing Liu <lanqing.liu@spreadtrum.com>");
 158MODULE_AUTHOR("Long Cheng <aiden.cheng@spreadtrum.com>");
 159