drivers: hwspinlock: add OMAP implementation (70ba4cc2) · Commits · 戴 / test

drivers/hwspinlock/Kconfig

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Original line number	Diff line number	Diff line
		@@ -11,3 +11,12 @@ config HWSPINLOCK
		coprocessors).

		If unsure, say N.

		config HWSPINLOCK_OMAP
		tristate "OMAP Hardware Spinlock device"
		depends on HWSPINLOCK && ARCH_OMAP4
		help
		Say y here to support the OMAP Hardware Spinlock device (firstly
		introduced in OMAP4).

		If unsure, say N.

drivers/hwspinlock/Makefile

+1 −0

Original line number	Diff line number	Diff line
		@@ -3,3 +3,4 @@
		#

		obj-$(CONFIG_HWSPINLOCK) += hwspinlock_core.o
		obj-$(CONFIG_HWSPINLOCK_OMAP) += omap_hwspinlock.o

drivers/hwspinlock/omap_hwspinlock.c

0 → 100644

+231 −0

Original line number	Diff line number	Diff line
		/*
		* OMAP hardware spinlock driver
		*
		* Copyright (C) 2010 Texas Instruments Incorporated - http://www.ti.com
		*
		* Contact: Simon Que <sque@ti.com>
		* Hari Kanigeri <h-kanigeri2@ti.com>
		* Ohad Ben-Cohen <ohad@wizery.com>
		*
		* This program is free software; you can redistribute it and/or
		* modify it under the terms of the GNU General Public License
		* version 2 as published by the Free Software Foundation.
		*
		* This program is distributed in the hope that it will be useful, but
		* WITHOUT ANY WARRANTY; without even the implied warranty of
		* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
		* General Public License for more details.
		*/

		#include <linux/kernel.h>
		#include <linux/module.h>
		#include <linux/device.h>
		#include <linux/delay.h>
		#include <linux/io.h>
		#include <linux/bitops.h>
		#include <linux/pm_runtime.h>
		#include <linux/slab.h>
		#include <linux/spinlock.h>
		#include <linux/hwspinlock.h>
		#include <linux/platform_device.h>

		#include "hwspinlock_internal.h"

		/* Spinlock register offsets */
		#define SYSSTATUS_OFFSET 0x0014
		#define LOCK_BASE_OFFSET 0x0800

		#define SPINLOCK_NUMLOCKS_BIT_OFFSET (24)

		/* Possible values of SPINLOCK_LOCK_REG */
		#define SPINLOCK_NOTTAKEN (0) /* free */
		#define SPINLOCK_TAKEN (1) /* locked */

		#define to_omap_hwspinlock(lock) \
		container_of(lock, struct omap_hwspinlock, lock)

		struct omap_hwspinlock {
		struct hwspinlock lock;
		void __iomem *addr;
		};

		struct omap_hwspinlock_state {
		int num_locks; /* Total number of locks in system */
		void __iomem io_base; / Mapped base address */
		};

		static int omap_hwspinlock_trylock(struct hwspinlock *lock)
		{
		struct omap_hwspinlock *omap_lock = to_omap_hwspinlock(lock);

		/* attempt to acquire the lock by reading its value */
		return (SPINLOCK_NOTTAKEN == readl(omap_lock->addr));
		}

		static void omap_hwspinlock_unlock(struct hwspinlock *lock)
		{
		struct omap_hwspinlock *omap_lock = to_omap_hwspinlock(lock);

		/* release the lock by writing 0 to it */
		writel(SPINLOCK_NOTTAKEN, omap_lock->addr);
		}

		/*
		* relax the OMAP interconnect while spinning on it.
		*
		* The specs recommended that the retry delay time will be
		* just over half of the time that a requester would be
		* expected to hold the lock.
		*
		* The number below is taken from an hardware specs example,
		* obviously it is somewhat arbitrary.
		*/
		static void omap_hwspinlock_relax(struct hwspinlock *lock)
		{
		ndelay(50);
		}

		static const struct hwspinlock_ops omap_hwspinlock_ops = {
		.trylock = omap_hwspinlock_trylock,
		.unlock = omap_hwspinlock_unlock,
		.relax = omap_hwspinlock_relax,
		};

		static int __devinit omap_hwspinlock_probe(struct platform_device *pdev)
		{
		struct omap_hwspinlock *omap_lock;
		struct omap_hwspinlock_state *state;
		struct hwspinlock *lock;
		struct resource *res;
		void __iomem *io_base;
		int i, ret;

		res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
		if (!res)
		return -ENODEV;

		state = kzalloc(sizeof(*state), GFP_KERNEL);
		if (!state)
		return -ENOMEM;

		io_base = ioremap(res->start, resource_size(res));
		if (!io_base) {
		ret = -ENOMEM;
		goto free_state;
		}

		/* Determine number of locks */
		i = readl(io_base + SYSSTATUS_OFFSET);
		i >>= SPINLOCK_NUMLOCKS_BIT_OFFSET;

		/* one of the four lsb's must be set, and nothing else */
		if (hweight_long(i & 0xf) != 1 \|\| i > 8) {
		ret = -EINVAL;
		goto iounmap_base;
		}

		state->num_locks = i * 32;
		state->io_base = io_base;

		platform_set_drvdata(pdev, state);

		/*
		* runtime PM will make sure the clock of this module is
		* enabled iff at least one lock is requested
		*/
		pm_runtime_enable(&pdev->dev);

		for (i = 0; i < state->num_locks; i++) {
		omap_lock = kzalloc(sizeof(*omap_lock), GFP_KERNEL);
		if (!omap_lock) {
		ret = -ENOMEM;
		goto free_locks;
		}

		omap_lock->lock.dev = &pdev->dev;
		omap_lock->lock.owner = THIS_MODULE;
		omap_lock->lock.id = i;
		omap_lock->lock.ops = &omap_hwspinlock_ops;
		omap_lock->addr = io_base + LOCK_BASE_OFFSET + sizeof(u32) * i;

		ret = hwspin_lock_register(&omap_lock->lock);
		if (ret) {
		kfree(omap_lock);
		goto free_locks;
		}
		}

		return 0;

		free_locks:
		while (--i >= 0) {
		lock = hwspin_lock_unregister(i);
		/* this should't happen, but let's give our best effort */
		if (!lock) {
		dev_err(&pdev->dev, "%s: cleanups failed\n", __func__);
		continue;
		}
		omap_lock = to_omap_hwspinlock(lock);
		kfree(omap_lock);
		}
		pm_runtime_disable(&pdev->dev);
		iounmap_base:
		iounmap(io_base);
		free_state:
		kfree(state);
		return ret;
		}

		static int omap_hwspinlock_remove(struct platform_device *pdev)
		{
		struct omap_hwspinlock_state *state = platform_get_drvdata(pdev);
		struct hwspinlock *lock;
		struct omap_hwspinlock *omap_lock;
		int i;

		for (i = 0; i < state->num_locks; i++) {
		lock = hwspin_lock_unregister(i);
		/* this shouldn't happen at this point. if it does, at least
		* don't continue with the remove */
		if (!lock) {
		dev_err(&pdev->dev, "%s: failed on %d\n", __func__, i);
		return -EBUSY;
		}

		omap_lock = to_omap_hwspinlock(lock);
		kfree(omap_lock);
		}

		pm_runtime_disable(&pdev->dev);
		iounmap(state->io_base);
		kfree(state);

		return 0;
		}

		static struct platform_driver omap_hwspinlock_driver = {
		.probe = omap_hwspinlock_probe,
		.remove = omap_hwspinlock_remove,
		.driver = {
		.name = "omap_hwspinlock",
		},
		};

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

		static void __exit omap_hwspinlock_exit(void)
		{
		platform_driver_unregister(&omap_hwspinlock_driver);
		}
		module_exit(omap_hwspinlock_exit);

		MODULE_LICENSE("GPL v2");
		MODULE_DESCRIPTION("Hardware spinlock driver for OMAP");
		MODULE_AUTHOR("Simon Que <sque@ti.com>");
		MODULE_AUTHOR("Hari Kanigeri <h-kanigeri2@ti.com>");
		MODULE_AUTHOR("Ohad Ben-Cohen <ohad@wizery.com>");

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