root/drivers/hwspinlock/qcom_hwspinlock.c
// SPDX-License-Identifier: GPL-2.0
/*
 * Copyright (c) 2013, The Linux Foundation. All rights reserved.
 * Copyright (c) 2015, Sony Mobile Communications AB
 */

#include <linux/hwspinlock.h>
#include <linux/io.h>
#include <linux/kernel.h>
#include <linux/mfd/syscon.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/of_device.h>
#include <linux/platform_device.h>
#include <linux/regmap.h>

#include "hwspinlock_internal.h"

#define QCOM_MUTEX_APPS_PROC_ID 1
#define QCOM_MUTEX_NUM_LOCKS    32

struct qcom_hwspinlock_of_data {
        u32 offset;
        u32 stride;
        const struct regmap_config *regmap_config;
};

static int qcom_hwspinlock_trylock(struct hwspinlock *lock)
{
        struct regmap_field *field = lock->priv;
        u32 lock_owner;
        int ret;

        ret = regmap_field_write(field, QCOM_MUTEX_APPS_PROC_ID);
        if (ret)
                return ret;

        ret = regmap_field_read(field, &lock_owner);
        if (ret)
                return ret;

        return lock_owner == QCOM_MUTEX_APPS_PROC_ID;
}

static void qcom_hwspinlock_unlock(struct hwspinlock *lock)
{
        struct regmap_field *field = lock->priv;
        u32 lock_owner;
        int ret;

        ret = regmap_field_read(field, &lock_owner);
        if (ret) {
                pr_err("%s: unable to query spinlock owner\n", __func__);
                return;
        }

        if (lock_owner != QCOM_MUTEX_APPS_PROC_ID) {
                pr_err("%s: spinlock not owned by us (actual owner is %d)\n",
                                __func__, lock_owner);
        }

        ret = regmap_field_write(field, 0);
        if (ret)
                pr_err("%s: failed to unlock spinlock\n", __func__);
}

static int qcom_hwspinlock_bust(struct hwspinlock *lock, unsigned int id)
{
        struct regmap_field *field = lock->priv;
        u32 owner;
        int ret;

        ret = regmap_field_read(field, &owner);
        if (ret) {
                dev_err(lock->bank->dev, "unable to query spinlock owner\n");
                return ret;
        }

        if (owner != id)
                return 0;

        ret = regmap_field_write(field, 0);
        if (ret) {
                dev_err(lock->bank->dev, "failed to bust spinlock\n");
                return ret;
        }

        return 0;
}

static const struct hwspinlock_ops qcom_hwspinlock_ops = {
        .trylock        = qcom_hwspinlock_trylock,
        .unlock         = qcom_hwspinlock_unlock,
        .bust           = qcom_hwspinlock_bust,
};

static const struct regmap_config sfpb_mutex_config = {
        .reg_bits               = 32,
        .reg_stride             = 4,
        .val_bits               = 32,
        .max_register           = 0x100,
        .fast_io                = true,
};

static const struct qcom_hwspinlock_of_data of_sfpb_mutex = {
        .offset = 0x4,
        .stride = 0x4,
        .regmap_config = &sfpb_mutex_config,
};

static const struct regmap_config tcsr_msm8226_mutex_config = {
        .reg_bits               = 32,
        .reg_stride             = 4,
        .val_bits               = 32,
        .max_register           = 0x1000,
        .fast_io                = true,
};

static const struct qcom_hwspinlock_of_data of_msm8226_tcsr_mutex = {
        .offset = 0,
        .stride = 0x80,
        .regmap_config = &tcsr_msm8226_mutex_config,
};

static const struct regmap_config tcsr_mutex_config = {
        .reg_bits               = 32,
        .reg_stride             = 4,
        .val_bits               = 32,
        .max_register           = 0x20000,
        .fast_io                = true,
};

static const struct qcom_hwspinlock_of_data of_tcsr_mutex = {
        .offset = 0,
        .stride = 0x1000,
        .regmap_config = &tcsr_mutex_config,
};

static const struct of_device_id qcom_hwspinlock_of_match[] = {
        { .compatible = "qcom,sfpb-mutex", .data = &of_sfpb_mutex },
        { .compatible = "qcom,tcsr-mutex", .data = &of_tcsr_mutex },
        { .compatible = "qcom,apq8084-tcsr-mutex", .data = &of_msm8226_tcsr_mutex },
        { .compatible = "qcom,msm8226-tcsr-mutex", .data = &of_msm8226_tcsr_mutex },
        { .compatible = "qcom,msm8974-tcsr-mutex", .data = &of_msm8226_tcsr_mutex },
        { .compatible = "qcom,msm8994-tcsr-mutex", .data = &of_msm8226_tcsr_mutex },
        { }
};
MODULE_DEVICE_TABLE(of, qcom_hwspinlock_of_match);

static struct regmap *qcom_hwspinlock_probe_syscon(struct platform_device *pdev,
                                                   u32 *base, u32 *stride)
{
        struct device_node *syscon;
        struct regmap *regmap;
        int ret;

        syscon = of_parse_phandle(pdev->dev.of_node, "syscon", 0);
        if (!syscon)
                return ERR_PTR(-ENODEV);

        regmap = syscon_node_to_regmap(syscon);
        of_node_put(syscon);
        if (IS_ERR(regmap))
                return regmap;

        ret = of_property_read_u32_index(pdev->dev.of_node, "syscon", 1, base);
        if (ret < 0) {
                dev_err(&pdev->dev, "no offset in syscon\n");
                return ERR_PTR(-EINVAL);
        }

        ret = of_property_read_u32_index(pdev->dev.of_node, "syscon", 2, stride);
        if (ret < 0) {
                dev_err(&pdev->dev, "no stride syscon\n");
                return ERR_PTR(-EINVAL);
        }

        return regmap;
}

static struct regmap *qcom_hwspinlock_probe_mmio(struct platform_device *pdev,
                                                 u32 *offset, u32 *stride)
{
        const struct qcom_hwspinlock_of_data *data;
        struct device *dev = &pdev->dev;
        void __iomem *base;

        data = of_device_get_match_data(dev);
        if (!data->regmap_config)
                return ERR_PTR(-EINVAL);

        *offset = data->offset;
        *stride = data->stride;

        base = devm_platform_ioremap_resource(pdev, 0);
        if (IS_ERR(base))
                return ERR_CAST(base);

        return devm_regmap_init_mmio(dev, base, data->regmap_config);
}

static int qcom_hwspinlock_probe(struct platform_device *pdev)
{
        struct hwspinlock_device *bank;
        struct reg_field field;
        struct regmap *regmap;
        size_t array_size;
        u32 stride;
        u32 base;
        int i;

        regmap = qcom_hwspinlock_probe_syscon(pdev, &base, &stride);
        if (IS_ERR(regmap) && PTR_ERR(regmap) == -ENODEV)
                regmap = qcom_hwspinlock_probe_mmio(pdev, &base, &stride);

        if (IS_ERR(regmap))
                return PTR_ERR(regmap);

        array_size = QCOM_MUTEX_NUM_LOCKS * sizeof(struct hwspinlock);
        bank = devm_kzalloc(&pdev->dev, sizeof(*bank) + array_size, GFP_KERNEL);
        if (!bank)
                return -ENOMEM;

        platform_set_drvdata(pdev, bank);

        for (i = 0; i < QCOM_MUTEX_NUM_LOCKS; i++) {
                field.reg = base + i * stride;
                field.lsb = 0;
                field.msb = 31;

                bank->lock[i].priv = devm_regmap_field_alloc(&pdev->dev,
                                                             regmap, field);
                if (IS_ERR(bank->lock[i].priv))
                        return PTR_ERR(bank->lock[i].priv);
        }

        return devm_hwspin_lock_register(&pdev->dev, bank, &qcom_hwspinlock_ops,
                                         0, QCOM_MUTEX_NUM_LOCKS);
}

static struct platform_driver qcom_hwspinlock_driver = {
        .probe          = qcom_hwspinlock_probe,
        .driver         = {
                .name   = "qcom_hwspinlock",
                .of_match_table = qcom_hwspinlock_of_match,
        },
};

static int __init qcom_hwspinlock_init(void)
{
        return platform_driver_register(&qcom_hwspinlock_driver);
}
/* board init code might need to reserve hwspinlocks for predefined purposes */
postcore_initcall(qcom_hwspinlock_init);

static void __exit qcom_hwspinlock_exit(void)
{
        platform_driver_unregister(&qcom_hwspinlock_driver);
}
module_exit(qcom_hwspinlock_exit);

MODULE_LICENSE("GPL v2");
MODULE_DESCRIPTION("Hardware spinlock driver for Qualcomm SoCs");