From: Simon Que <sque@xxxxxx> Add hwspinlock support for the OMAP4 Hardware Spinlock device. The Hardware Spinlock device on OMAP4 provides hardware assistance for synchronization between the multiple processors in the system (dual Cortex-A9, dual Cortex-M3 and a C64x+ DSP). [ohad@xxxxxxxxxx: adapt to generic hwspinlock api, tidy up] Signed-off-by: Simon Que <sque@xxxxxx> Signed-off-by: Hari Kanigeri <h-kanigeri2@xxxxxx> Signed-off-by: Krishnamoorthy, Balaji T <balajitk@xxxxxx> Signed-off-by: Ohad Ben-Cohen <ohad@xxxxxxxxxx> Cc: Benoit Cousson <b-cousson@xxxxxx> Cc: Kevin Hilman <khilman@xxxxxxxxxxxxxxxxxxx> Cc: Grant Likely <grant.likely@xxxxxxxxxxxx> Cc: Tony Lindgren <tony@xxxxxxxxxxx> --- drivers/hwspinlock/Kconfig | 9 ++ drivers/hwspinlock/Makefile | 1 + drivers/hwspinlock/omap_hwspinlock.c | 231 ++++++++++++++++++++++++++++++++++ 3 files changed, 241 insertions(+), 0 deletions(-) create mode 100644 drivers/hwspinlock/omap_hwspinlock.c diff --git a/drivers/hwspinlock/Kconfig b/drivers/hwspinlock/Kconfig index 9dd8db4..eb4af28 100644 --- a/drivers/hwspinlock/Kconfig +++ b/drivers/hwspinlock/Kconfig @@ -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. diff --git a/drivers/hwspinlock/Makefile b/drivers/hwspinlock/Makefile index b9d2b9f..5729a3f 100644 --- a/drivers/hwspinlock/Makefile +++ b/drivers/hwspinlock/Makefile @@ -3,3 +3,4 @@ # obj-$(CONFIG_HWSPINLOCK) += hwspinlock_core.o +obj-$(CONFIG_HWSPINLOCK_OMAP) += omap_hwspinlock.o diff --git a/drivers/hwspinlock/omap_hwspinlock.c b/drivers/hwspinlock/omap_hwspinlock.c new file mode 100644 index 0000000..0525d59 --- /dev/null +++ b/drivers/hwspinlock/omap_hwspinlock.c @@ -0,0 +1,231 @@ +/* + * OMAP hardware spinlock driver + * + * Copyright (C) 2010 Texas Instruments Incorporated - http://www.ti.com + * + * Contact: Simon Que <sque@xxxxxx> + * Hari Kanigeri <h-kanigeri2@xxxxxx> + * Ohad Ben-Cohen <ohad@xxxxxxxxxx> + * + * 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/log2.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.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; + + /* exactly one of the four least significant bits must be 1 */ + if (!i || !is_power_of_2(i) || 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 = hwspinlock_register(&omap_lock->lock); + if (ret) { + kfree(omap_lock); + goto free_locks; + } + } + + return 0; + +free_locks: + while (--i >= 0) { + lock = hwspinlock_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(state->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 = hwspinlock_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@xxxxxx>"); +MODULE_AUTHOR("Hari Kanigeri <h-kanigeri2@xxxxxx>"); +MODULE_AUTHOR("Ohad Ben-Cohen <ohad@xxxxxxxxxx>"); -- 1.7.0.4 -- To unsubscribe from this list: send the line "unsubscribe linux-omap" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
