Created driver for OMAP hardware spinlock.
- 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/hwspinlocks.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.
The device driver file is:
arch/arm/plat-omap/hwspinlock.c
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).
Signed-off-by: Simon Que <sque@xxxxxx>
Signed-off-by: Hari Kanigeri <h-kanigeri2@xxxxxx>
Signed-off-by: Krishnamoorthy, Balaji T <balajitk@xxxxxx>
---
arch/arm/mach-omap2/hwspinlocks.c | 65 +++++
arch/arm/plat-omap/hwspinlock.c | 353 ++++++++++++++++++++++++++
arch/arm/plat-omap/include/plat/hwspinlock.h | 47 ++++
3 files changed, 465 insertions(+), 0 deletions(-)
create mode 100644 arch/arm/mach-omap2/hwspinlocks.c
create mode 100644 arch/arm/plat-omap/hwspinlock.c
create mode 100644 arch/arm/plat-omap/include/plat/hwspinlock.h
diff --git a/arch/arm/mach-omap2/hwspinlocks.c b/arch/arm/mach-omap2/hwspinlocks.c
new file mode 100644
index 0000000..154fc40
--- /dev/null
+++ b/arch/arm/mach-omap2/hwspinlocks.c
@@ -0,0 +1,65 @@
+/*
+ * OMAP hardware spinlock device initialization
+ *
+ * Copyright (C) 2010 Texas Instruments. All rights reserved.
+ *
+ * Contact: Simon Que <sque@xxxxxx>
+ *
+ * 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);
diff --git a/arch/arm/plat-omap/hwspinlock.c b/arch/arm/plat-omap/hwspinlock.c
new file mode 100644
index 0000000..6f78658
--- /dev/null
+++ b/arch/arm/plat-omap/hwspinlock.c
@@ -0,0 +1,353 @@
+/*
+ * OMAP hardware spinlock driver
+ *
+ * Copyright (C) 2010 Texas Instruments. All rights reserved.
+ *
+ * Contact: Simon Que <sque@xxxxxx>
+ *
+ * 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");
diff --git a/arch/arm/plat-omap/include/plat/hwspinlock.h b/arch/arm/plat-omap/include/plat/hwspinlock.h
new file mode 100644
index 0000000..ea64c48
--- /dev/null
+++ b/arch/arm/plat-omap/include/plat/hwspinlock.h
@@ -0,0 +1,47 @@
+/*
+ * OMAP hardware spinlock driver header
+ *
+ * Copyright (C) 2010 Texas Instruments. All rights reserved.
+ *
+ * Contact: Simon Que <sque@xxxxxx>
+ *
+ * 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 */
--
1.7.0
Attachment:
0003-omap-hwspinlock-Created-driver-for-OMAP-hardware-spinlock.patch
Description: 0003-omap-hwspinlock-Created-driver-for-OMAP-hardware-spinlock.patch
