3 files changed, 241 insertions, 0 deletions

diff --git a/drivers/hwspinlock/Kconfig b/drivers/hwspinlock/Kconfig
index 9dd8db46606b..eb4af28f8567 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 b9d2b9f40491..5729a3f7ed3d 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 000000000000..a8f02734c026
--- /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@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>");