Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755503Ab0KWPhy (ORCPT ); Tue, 23 Nov 2010 10:37:54 -0500 Received: from mail-bw0-f46.google.com ([209.85.214.46]:51462 "EHLO mail-bw0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753651Ab0KWPht (ORCPT ); Tue, 23 Nov 2010 10:37:49 -0500 From: Ohad Ben-Cohen To: , , Cc: , Greg KH , Tony Lindgren , Benoit Cousson , Grant Likely , Hari Kanigeri , Suman Anna , Kevin Hilman , Arnd Bergmann , Simon Que , "Krishnamoorthy, Balaji T" , Ohad Ben-Cohen Subject: [PATCH v2 2/4] drivers: hwspinlock: add OMAP implementation Date: Tue, 23 Nov 2010 17:38:58 +0200 Message-Id: <1290526740-27624-3-git-send-email-ohad@wizery.com> X-Mailer: git-send-email 1.7.0.4 In-Reply-To: <1290526740-27624-1-git-send-email-ohad@wizery.com> References: <1290526740-27624-1-git-send-email-ohad@wizery.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 8360 Lines: 295 From: Simon Que 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@wizery.com: adapt to generic hwspinlock api, tidy up] Signed-off-by: Simon Que Signed-off-by: Hari Kanigeri Signed-off-by: Krishnamoorthy, Balaji T Signed-off-by: Ohad Ben-Cohen Cc: Benoit Cousson Cc: Kevin Hilman Cc: Grant Likely Cc: Tony Lindgren --- 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 + * Hari Kanigeri + * Ohad Ben-Cohen + * + * 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 +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#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 "); +MODULE_AUTHOR("Hari Kanigeri "); +MODULE_AUTHOR("Ohad Ben-Cohen "); -- 1.7.0.4 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/