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200 lines
5.0 KiB
200 lines
5.0 KiB
// SPDX-License-Identifier: GPL-2.0 |
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/* |
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* OMAP hardware spinlock driver |
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* |
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* Copyright (C) 2010-2021 Texas Instruments Incorporated - https://www.ti.com |
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* |
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* Contact: Simon Que <[email protected]> |
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* Hari Kanigeri <[email protected]> |
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* Ohad Ben-Cohen <[email protected]> |
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* Suman Anna <[email protected]> |
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*/ |
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#include <linux/kernel.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/of.h> |
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#include <linux/platform_device.h> |
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#include "hwspinlock_internal.h" |
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/* Spinlock register offsets */ |
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#define SYSSTATUS_OFFSET 0x0014 |
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#define LOCK_BASE_OFFSET 0x0800 |
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#define SPINLOCK_NUMLOCKS_BIT_OFFSET (24) |
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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 omap_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 omap_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 OMAP 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 omap_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 omap_hwspinlock_ops = { |
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.trylock = omap_hwspinlock_trylock, |
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.unlock = omap_hwspinlock_unlock, |
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.relax = omap_hwspinlock_relax, |
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}; |
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static int omap_hwspinlock_probe(struct platform_device *pdev) |
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{ |
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struct device_node *node = pdev->dev.of_node; |
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struct hwspinlock_device *bank; |
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struct hwspinlock *hwlock; |
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void __iomem *io_base; |
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int num_locks, i, ret; |
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/* Only a single hwspinlock block device is supported */ |
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int base_id = 0; |
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if (!node) |
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return -ENODEV; |
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io_base = devm_platform_ioremap_resource(pdev, 0); |
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if (IS_ERR(io_base)) |
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return PTR_ERR(io_base); |
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/* |
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* make sure the module is enabled and clocked before reading |
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* the module SYSSTATUS register |
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*/ |
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pm_runtime_enable(&pdev->dev); |
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ret = pm_runtime_get_sync(&pdev->dev); |
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if (ret < 0) { |
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pm_runtime_put_noidle(&pdev->dev); |
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goto runtime_err; |
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} |
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/* Determine number of locks */ |
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i = readl(io_base + SYSSTATUS_OFFSET); |
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i >>= SPINLOCK_NUMLOCKS_BIT_OFFSET; |
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/* |
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* runtime PM will make sure the clock of this module is |
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* enabled again iff at least one lock is requested |
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*/ |
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ret = pm_runtime_put(&pdev->dev); |
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if (ret < 0) |
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goto runtime_err; |
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/* one of the four lsb's must be set, and nothing else */ |
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if (hweight_long(i & 0xf) != 1 || i > 8) { |
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ret = -EINVAL; |
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goto runtime_err; |
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} |
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num_locks = i * 32; /* actual number of locks in this device */ |
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bank = devm_kzalloc(&pdev->dev, struct_size(bank, lock, num_locks), |
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GFP_KERNEL); |
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if (!bank) { |
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ret = -ENOMEM; |
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goto runtime_err; |
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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 = io_base + LOCK_BASE_OFFSET + sizeof(u32) * i; |
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ret = hwspin_lock_register(bank, &pdev->dev, &omap_hwspinlock_ops, |
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base_id, num_locks); |
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if (ret) |
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goto runtime_err; |
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dev_dbg(&pdev->dev, "Registered %d locks with HwSpinlock core\n", |
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num_locks); |
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return 0; |
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runtime_err: |
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pm_runtime_disable(&pdev->dev); |
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return ret; |
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} |
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static int omap_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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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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return 0; |
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} |
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static const struct of_device_id omap_hwspinlock_of_match[] = { |
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{ .compatible = "ti,omap4-hwspinlock", }, |
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{ .compatible = "ti,am64-hwspinlock", }, |
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{ .compatible = "ti,am654-hwspinlock", }, |
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{ /* end */ }, |
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}; |
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MODULE_DEVICE_TABLE(of, omap_hwspinlock_of_match); |
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static struct platform_driver omap_hwspinlock_driver = { |
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.probe = omap_hwspinlock_probe, |
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.remove = omap_hwspinlock_remove, |
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.driver = { |
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.name = "omap_hwspinlock", |
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.of_match_table = of_match_ptr(omap_hwspinlock_of_match), |
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}, |
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}; |
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static int __init omap_hwspinlock_init(void) |
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{ |
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return platform_driver_register(&omap_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(omap_hwspinlock_init); |
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static void __exit omap_hwspinlock_exit(void) |
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{ |
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platform_driver_unregister(&omap_hwspinlock_driver); |
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} |
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module_exit(omap_hwspinlock_exit); |
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MODULE_LICENSE("GPL v2"); |
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MODULE_DESCRIPTION("Hardware spinlock driver for OMAP"); |
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MODULE_AUTHOR("Simon Que <[email protected]>"); |
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MODULE_AUTHOR("Hari Kanigeri <[email protected]>"); |
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MODULE_AUTHOR("Ohad Ben-Cohen <[email protected]>");
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