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+/*
+ * OMAP hardware spinlock device initialization
+ *
+ * Copyright (C) 2010 Texas Instruments. All rights reserved.
+ *
+ * Contact: Simon Que <sque@ti.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.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
+ * 02110-1301 USA
+ *
+ */
+
+#include <linux/module.h>
+#include <linux/interrupt.h>
+#include <linux/device.h>
+#include <linux/delay.h>
+#include <linux/io.h>
+#include <linux/slab.h>
+
+#include <plat/hwspinlock.h>
+#include <plat/omap_device.h>
+#include <plat/omap_hwmod.h>
+
+
+struct omap_device_pm_latency omap_spinlock_latency[] = {
+ {
+ .deactivate_func = omap_device_idle_hwmods,
+ .activate_func = omap_device_enable_hwmods,
+ .flags = OMAP_DEVICE_LATENCY_AUTO_ADJUST,
+ }
+};
+
+/* Initialization function */
+int __init hwspinlocks_init(void)
+{
+ int retval = 0;
+
+ struct omap_hwmod *oh;
+ const char *oh_name, *pdev_name;
+
+ oh_name = "spinlock";
+ oh = omap_hwmod_lookup(oh_name);
+ if (WARN_ON(oh == NULL))
+ return -EINVAL;
+
+ pdev_name = "hwspinlock";
+
+ /* Pass data to device initialization */
+ omap_device_build(pdev_name, 0, oh, NULL, 0, omap_spinlock_latency,
+ ARRAY_SIZE(omap_spinlock_latency), false);
+
+ return retval;
+}
+postcore_initcall(hwspinlocks_init);
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+/*
+ * OMAP hardware spinlock driver
+ *
+ * Copyright (C) 2010 Texas Instruments. All rights reserved.
+ *
+ * Contact: Simon Que <sque@ti.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.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
+ * 02110-1301 USA
+ *
+ * This driver supports:
+ * - Reserved spinlocks for internal use
+ * - Dynamic allocation of unreserved locks
+ * - Lock, unlock, and trylock functions, with or without disabling irqs/preempt
+ * - Registered as a platform device driver
+ *
+ * The device initialization uses hwmod to configure the devices. One device
+ * will be created for each IP. It will pass spinlock register offset info to
+ * the driver. The device initialization file is:
+ * arch/arm/mach-omap2/hwspinlock_array.c
+ *
+ * The driver takes in register offset info passed in device initialization.
+ * It uses hwmod to obtain the base address of the hardware spinlock module.
+ * Then it reads info from the registers. The function hwspinlock_probe()
+ * initializes the array of spinlock structures, each containing a spinlock
+ * register address calculated from the base address and lock offsets.
+ *
+ * Here's an API summary:
+ *
+ * int hwspinlock_lock(struct hwspinlock *);
+ * Attempt to lock a hardware spinlock. If it is busy, the function will
+ * keep trying until it succeeds. This is a blocking function.
+ * int hwspinlock_trylock(struct hwspinlock *);
+ * Attempt to lock a hardware spinlock. If it is busy, the function will
+ * return BUSY. If it succeeds in locking, the function will return
+ * ACQUIRED. This is a non-blocking function
+ * int hwspinlock_unlock(struct hwspinlock *);
+ * Unlock a hardware spinlock.
+ *
+ * struct hwspinlock *hwspinlock_request(void);
+ * Provides for "dynamic allocation" of a hardware spinlock. It returns
+ * the handle to the next available (unallocated) spinlock. If no more
+ * locks are available, it returns NULL.
+ * struct hwspinlock *hwspinlock_request_specific(unsigned int);
+ * Provides for "static allocation" of a specific hardware spinlock. This
+ * allows the system to use a specific spinlock, identified by an ID. If
+ * the ID is invalid or if the desired lock is already allocated, this
+ * will return NULL. Otherwise it returns a spinlock handle.
+ * int hwspinlock_free(struct hwspinlock *);
+ * Frees an allocated hardware spinlock (either reserved or unreserved).
+ */
+
+#include <linux/module.h>
+#include <linux/interrupt.h>
+#include <linux/device.h>
+#include <linux/delay.h>
+#include <linux/io.h>
+#include <linux/pm_runtime.h>
+#include <linux/slab.h>
+#include <linux/spinlock.h>
+
+#include <plat/hwspinlock.h>
+
+/* Spinlock register offsets */
+#define SYSSTATUS_OFFSET 0x0014
+#define LOCK_BASE_OFFSET 0x0800
+
+/* Spinlock count code */
+#define SPINLOCK_32_REGS 1
+#define SPINLOCK_64_REGS 2
+#define SPINLOCK_128_REGS 4
+#define SPINLOCK_256_REGS 8
+#define SPINLOCK_NUMLOCKS_BIT_OFFSET 24
+
+/* Number of attempts to try locking */
+#define MAX_LOCK_ATTEMPTS 1000
+
+/* for managing a hardware spinlock module */
+struct hwspinlock_module_state {
+ bool is_init; /* For first-time initialization */
+ int num_locks; /* Total number of locks in system */
+ spinlock_t local_lock; /* Local protection */
+ void __iomem *io_base; /* Mapped base address */
+};
+
+/* Points to the hardware spinlock module */
+static struct hwspinlock_module_state hwspinlock_state;
+
+/* Spinlock object */
+struct hwspinlock {
+ bool is_init;
+ int id;
+ void __iomem *lock_reg;
+ bool is_allocated;
+ struct platform_device *pdev;
+};
+
+/* Array of spinlocks */
+static struct hwspinlock *hwspinlock_array;
+
+/* API functions */
+
+/* Busy loop to acquire a spinlock */
+int hwspinlock_lock(struct hwspinlock *handle)
+{
+ int retval;
+ int num_attempts = 0;
+
+ if (WARN_ON(handle == NULL))
+ return -EINVAL;
+
+ /* This is not permitted in IRQ because we do not want a context */
+ /* switch while the lock is being held */
+ if (WARN_ON(in_irq()))
+ return -EPERM;
+
+ if (pm_runtime_get_sync(&handle->pdev->dev) < 0)
+ return -ENODEV;
+
+ /* Attempt to acquire the lock by reading from it */
+ do {
+ retval = readl(handle->lock_reg);
+ num_attempts++; /* Increment the timeout counter */
+ } while (retval == HWSPINLOCK_BUSY &&
+ num_attempts < MAX_LOCK_ATTEMPTS);
+
+ /* If there was a timeout, put the device back */
+ if (num_attempts >= MAX_LOCK_ATTEMPTS)
+ pm_runtime_put_sync(&handle->pdev->dev);
+
+ return retval;
+}
+EXPORT_SYMBOL(hwspinlock_lock);
+
+/* Attempt to acquire a spinlock once */
+int hwspinlock_trylock(struct hwspinlock *handle)
+{
+ int retval = 0;
+
+ if (WARN_ON(handle == NULL))
+ return -EINVAL;
+
+ /* This is not permitted in IRQ because we do not want a context */
+ /* switch while the lock is being held */
+ if (WARN_ON(in_irq()))
+ return -EPERM;
+
+ if ((retval = pm_runtime_get_sync(&handle->pdev->dev)) < 0)
+ return -ENODEV;
+
+ /* Attempt to acquire the lock by reading from it */
+ retval = readl(handle->lock_reg);
+
+ if (retval == HWSPINLOCK_BUSY)
+ pm_runtime_put_sync(&handle->pdev->dev);
+
+ return retval;
+}
+EXPORT_SYMBOL(hwspinlock_trylock);
+
+/* Release a spinlock */
+int hwspinlock_unlock(struct hwspinlock *handle)
+{
+ if (WARN_ON(handle == NULL))
+ return -EINVAL;
+
+ /* Release it by writing 0 to it */
+ writel(0, handle->lock_reg);
+
+ pm_runtime_put_sync(&handle->pdev->dev);
+
+ return 0;
+}
+EXPORT_SYMBOL(hwspinlock_unlock);
+
+/* Request an unclaimed spinlock */
+struct hwspinlock *hwspinlock_request(void)
+{
+ int i;
+ bool found = false;
+ struct hwspinlock *handle = NULL;
+ unsigned long flags;
+
+ spin_lock_irqsave(&hwspinlock_state.local_lock, flags);
+ /* Search for an unclaimed, unreserved lock */
+ for (i = 0; i < hwspinlock_state.num_locks && !found; i++) {
+ if (!hwspinlock_array[i].is_allocated) {
+ found = true;
+ handle = &hwspinlock_array[i];
+ }
+ }
+ spin_unlock_irqrestore(&hwspinlock_state.local_lock, flags);
+
+ /* Return error if no more locks available */
+ if (!found)
+ return NULL;
+
+ handle->is_allocated = true;
+
+ return handle;
+}
+EXPORT_SYMBOL(hwspinlock_request);
+
+/* Request an unclaimed spinlock by ID */
+struct hwspinlock *hwspinlock_request_specific(unsigned int id)
+{
+ struct hwspinlock *handle = NULL;
+ unsigned long flags;
+
+ spin_lock_irqsave(&hwspinlock_state.local_lock, flags);
+
+ if (WARN_ON(hwspinlock_array[id].is_allocated))
+ goto exit;
+
+ handle = &hwspinlock_array[id];
+ handle->is_allocated = true;
+
+exit:
+ spin_unlock_irqrestore(&hwspinlock_state.local_lock, flags);
+ return handle;
+}
+EXPORT_SYMBOL(hwspinlock_request_specific);
+
+/* Release a claimed spinlock */
+int hwspinlock_free(struct hwspinlock *handle)
+{
+ if (WARN_ON(handle == NULL))
+ return -EINVAL;
+
+ if (WARN_ON(!handle->is_allocated))
+ return -ENOMEM;
+
+ handle->is_allocated = false;
+
+ return 0;
+}
+EXPORT_SYMBOL(hwspinlock_free);
+
+/* Probe function */
+static int __devinit hwspinlock_probe(struct platform_device *pdev)
+{
+ struct resource *res;
+ void __iomem *io_base;
+ int id;
+
+ void __iomem *sysstatus_reg;
+
+ /* Determine number of locks */
+ sysstatus_reg = ioremap(OMAP44XX_SPINLOCK_BASE + SYSSTATUS_OFFSET,
+ sizeof(u32));
+ if (sysstatus_reg == NULL)
+ return -EFAULT;
+
+ switch (readl(sysstatus_reg) >> SPINLOCK_NUMLOCKS_BIT_OFFSET) {
+ case SPINLOCK_32_REGS:
+ hwspinlock_state.num_locks = 32;
+ break;
+ case SPINLOCK_64_REGS:
+ hwspinlock_state.num_locks = 64;
+ break;
+ case SPINLOCK_128_REGS:
+ hwspinlock_state.num_locks = 128;
+ break;
+ case SPINLOCK_256_REGS:
+ hwspinlock_state.num_locks = 256;
+ break;
+ default:
+ return -EINVAL; /* Invalid spinlock count code */
+ }
+ iounmap(sysstatus_reg);
+
+ /* Allocate spinlock device objects */
+ hwspinlock_array = kmalloc(sizeof(struct hwspinlock) *
+ hwspinlock_state.num_locks, GFP_KERNEL);
+ if (WARN_ON(hwspinlock_array == NULL))
+ return -ENOMEM;
+
+ /* Initialize local lock */
+ spin_lock_init(&hwspinlock_state.local_lock);
+
+ /* Get address info */
+ res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+
+ /* Map spinlock module address space */
+ io_base = ioremap(res->start, resource_size(res));
+ hwspinlock_state.io_base = io_base;
+
+ /* Set up each individual lock handle */
+ for (id = 0; id < hwspinlock_state.num_locks; id++) {
+ hwspinlock_array[id].id = id;
+ hwspinlock_array[id].pdev = pdev;
+ hwspinlock_array[id].is_init = true;
+ hwspinlock_array[id].is_allocated = false;
+
+ hwspinlock_array[id].lock_reg = io_base + LOCK_BASE_OFFSET +
+ sizeof(u32) * id;
+ }
+ pm_runtime_enable(&pdev->dev);
+
+ return 0;
+}
+
+static struct platform_driver hwspinlock_driver = {
+ .probe = hwspinlock_probe,
+ .driver = {
+ .name = "hwspinlock",
+ },
+};
+
+/* Initialization function */
+static int __init hwspinlock_init(void)
+{
+ int retval = 0;
+
+ /* Register spinlock driver */
+ retval = platform_driver_register(&hwspinlock_driver);
+
+ return retval;
+}
+postcore_initcall(hwspinlock_init);
+
+/* Cleanup function */
+static void __exit hwspinlock_exit(void)
+{
+ int id;
+
+ platform_driver_unregister(&hwspinlock_driver);
+
+ for (id = 0; id < hwspinlock_state.num_locks; id++)
+ hwspinlock_array[id].is_init = false;
+ iounmap(hwspinlock_state.io_base);
+
+ /* Free spinlock device objects */
+ if (hwspinlock_state.is_init)
+ kfree(hwspinlock_array);
+}
+module_exit(hwspinlock_exit);
+
+MODULE_LICENSE("GPL v2");
+MODULE_DESCRIPTION("Hardware spinlock driver");
+MODULE_AUTHOR("Simon Que");
+MODULE_AUTHOR("Hari Kanigeri");
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+/*
+ * OMAP hardware spinlock driver header
+ *
+ * Copyright (C) 2010 Texas Instruments. All rights reserved.
+ *
+ * Contact: Simon Que <sque@ti.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.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
+ * 02110-1301 USA
+ *
+ */
+
+#ifndef HWSPINLOCK_H
+#define HWSPINLOCK_H
+
+#include <linux/platform_device.h>
+#include <plat/omap44xx.h>
+
+/* Values that are read from the spinlock register */
+/* ACQUIRED means the lock was successfully acquired by the read operation */
+/* BUSY means the lock was already acquired before the read operation, and */
+/* thus the read operation was not successful */
+#define HWSPINLOCK_ACQUIRED 0
+#define HWSPINLOCK_BUSY 1
+
+struct hwspinlock;
+
+int hwspinlock_lock(struct hwspinlock *handle);
+int hwspinlock_trylock(struct hwspinlock *handle);
+int hwspinlock_unlock(struct hwspinlock *handle);
+
+struct hwspinlock *hwspinlock_request(void);
+struct hwspinlock *hwspinlock_request_specific(unsigned int id);
+int hwspinlock_free(struct hwspinlock *hwspinlock_ptr);
+
+#endif /* HWSPINLOCK_H */