/*
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* SUNXI hardware spinlock driver
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*
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* Copyright (C) 2015 Allwinnertech - http://www.allwinnertech.com
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*
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* Contact: Feng Xia <xiafeng@allwinnertech.com>
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* version 2 as published by the Free Software Foundation.
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*
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* This program is distributed in the hope that it will be useful, but
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* WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* General Public License for more details.
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*/
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#include <linux/kernel.h>
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#include <linux/platform_device.h>
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#include <linux/module.h>
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#include <linux/device.h>
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#include <linux/delay.h>
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#include <linux/io.h>
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#include <linux/bitops.h>
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#include <linux/pm_runtime.h>
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#include <linux/slab.h>
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#include <linux/spinlock.h>
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#include <linux/hwspinlock.h>
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#include <linux/clk.h>
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#include <linux/of.h>
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#include <linux/of_address.h>
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#include <linux/of_device.h>
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#include <linux/err.h>
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#include "hwspinlock_internal.h"
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/* hardware spinlock register list */
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#define LOCK_SYS_STATUS_REG (0x0000)
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#define LOCK_STATUS_REG (0x0010)
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#define LOCK_IRQ_EN_REG (0x0020)
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#define LOCK_IRQ_PEND_REG (0x0040)
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#define LOCK_BASE_OFFSET (0x0100)
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#define LOCK_BASE_ID (0)
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/* Possible values of SPINLOCK_LOCK_REG */
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#define SPINLOCK_NOTTAKEN (0) /* free */
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#define SPINLOCK_TAKEN (1) /* locked */
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static int sunxi_hwspinlock_trylock(struct hwspinlock *lock)
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{
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void __iomem *lock_addr = lock->priv;
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/* attempt to acquire the lock by reading its value */
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return (SPINLOCK_NOTTAKEN == readl(lock_addr));
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}
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static void sunxi_hwspinlock_unlock(struct hwspinlock *lock)
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{
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void __iomem *lock_addr = lock->priv;
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/* release the lock by writing 0 to it */
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writel(SPINLOCK_NOTTAKEN, lock_addr);
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}
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/*
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* relax the SUNXI interconnect while spinning on it.
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*
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* The specs recommended that the retry delay time will be
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* just over half of the time that a requester would be
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* expected to hold the lock.
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*
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* The number below is taken from an hardware specs example,
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* obviously it is somewhat arbitrary.
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*/
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static void sunxi_hwspinlock_relax(struct hwspinlock *lock)
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{
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ndelay(50);
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}
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static const struct hwspinlock_ops sunxi_hwspinlock_ops = {
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.trylock = sunxi_hwspinlock_trylock,
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.unlock = sunxi_hwspinlock_unlock,
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.relax = sunxi_hwspinlock_relax,
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};
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static int sunxi_hwspinlock_probe(struct platform_device *pdev)
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{
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struct hwspinlock_device *bank;
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struct hwspinlock *hwlock;
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void __iomem *iobase;
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int num_locks, i, ret;
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struct resource res;
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/*
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*struct clk *hwspinlock_rst, *hwspinlock_bus;
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*/
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struct device_node *node = pdev->dev.of_node;
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ret = of_address_to_resource(node, 0, &res);
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if (unlikely(ret || !res.start)) {
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pr_err("get spinlock pbase error\n");
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return -ENODEV;
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}
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iobase = of_iomap(node, 0);
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if (IS_ERR(iobase))
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return PTR_ERR(iobase);
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ret = of_property_read_u32(node, "num-locks", &num_locks);
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if (ret || (num_locks == 0))
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return -ENODEV;
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bank = devm_kzalloc(&pdev->dev, sizeof(*bank) + num_locks * sizeof(*hwlock), GFP_KERNEL);
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if (!bank) {
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ret = -ENOMEM;
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goto iounmap_base;
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}
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platform_set_drvdata(pdev, bank);
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for (i = 0, hwlock = &bank->lock[0]; i < num_locks; i++, hwlock++)
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hwlock->priv = iobase + LOCK_BASE_OFFSET + sizeof(u32) * i;
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/*
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* runtime PM will make sure the clock of this module is
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* enabled iff at least one lock is requested
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*/
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pm_runtime_enable(&pdev->dev);
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ret = hwspin_lock_register(bank, &pdev->dev, &sunxi_hwspinlock_ops,
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LOCK_BASE_ID, num_locks);
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if (ret)
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goto reg_fail;
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pr_info("sunxi hwspinlock vbase:0x%p\n", iobase);
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return 0;
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reg_fail:
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pm_runtime_disable(&pdev->dev);
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kfree(bank);
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iounmap_base:
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iounmap(iobase);
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return ret;
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}
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static int sunxi_hwspinlock_remove(struct platform_device *pdev)
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{
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struct hwspinlock_device *bank = platform_get_drvdata(pdev);
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void __iomem *iobase = bank->lock[0].priv - LOCK_BASE_OFFSET;
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int ret;
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ret = hwspin_lock_unregister(bank);
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if (ret) {
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dev_err(&pdev->dev, "%s failed: %d\n", __func__, ret);
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return ret;
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}
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pm_runtime_disable(&pdev->dev);
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iounmap(iobase);
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kfree(bank);
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return 0;
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}
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static const struct of_device_id sunxi_hwspinlock_of_match[] = {
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{ .compatible = "allwinner,sunxi-hwspinlock", },
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{ /* end */ },
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};
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MODULE_DEVICE_TABLE(of, sunxi_hwspinlock_of_match);
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static struct platform_driver sunxi_hwspinlock_driver = {
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.probe = sunxi_hwspinlock_probe,
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.remove = sunxi_hwspinlock_remove,
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.driver = {
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.name = "sunxi-hwspinlock",
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.owner = THIS_MODULE,
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.of_match_table = of_match_ptr(sunxi_hwspinlock_of_match),
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},
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};
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static int __init sunxi_hwspinlock_init(void)
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{
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return platform_driver_register(&sunxi_hwspinlock_driver);
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}
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/* board init code might need to reserve hwspinlocks for predefined purposes */
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postcore_initcall(sunxi_hwspinlock_init);
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static void __exit sunxi_hwspinlock_exit(void)
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{
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platform_driver_unregister(&sunxi_hwspinlock_driver);
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}
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module_exit(sunxi_hwspinlock_exit);
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MODULE_LICENSE("GPL v2");
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MODULE_DESCRIPTION("Hardware spinlock driver for SUNXI");
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MODULE_AUTHOR("Feng Xia <xiafeng@allwinnertech.com>");
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