diff mbox

[3/5] omap:hwspinlock-added hwspinlock driver

Message ID 1279558221-14954-4-git-send-email-h-kanigeri2@ti.com (mailing list archive)
State New, archived
Headers show

Commit Message

Kanigeri, Hari July 19, 2010, 4:50 p.m. UTC
None
diff mbox

Patch

diff --git a/arch/arm/mach-omap2/hwspinlocks.c b/arch/arm/mach-omap2/hwspinlocks.c
new file mode 100644
index 0000000..f0f05e1
--- /dev/null
+++ b/arch/arm/mach-omap2/hwspinlocks.c
@@ -0,0 +1,70 @@ 
+/*
+ * 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>
+
+/* Spinlock register offsets */
+#define REVISION_OFFSET			0x0000
+#define SYSCONFIG_OFFSET		0x0010
+#define SYSSTATUS_OFFSET		0x0014
+#define LOCK_BASE_OFFSET		0x0800
+#define LOCK_OFFSET(i)			(LOCK_BASE_OFFSET + 0x4 * (i))
+
+/* Initialization function */
+int __init hwspinlocks_init(void)
+{
+	int retval = 0;
+
+	struct hwspinlock_plat_info *pdata;
+	struct omap_hwmod *oh;
+	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 */
+	pdata = kzalloc(sizeof(struct hwspinlock_plat_info), GFP_KERNEL);
+	if (WARN_ON(pdata == NULL))
+		return -ENOMEM;
+	pdata->sysstatus_offset = SYSSTATUS_OFFSET;
+	pdata->lock_base_offset = LOCK_BASE_OFFSET;
+
+	omap_device_build(pdev_name, 0, oh, pdata,
+			sizeof(struct hwspinlock_plat_info), NULL, 0, false);
+
+	return retval;
+}
+module_init(hwspinlocks_init);
diff --git a/arch/arm/plat-omap/hwspinlock.c b/arch/arm/plat-omap/hwspinlock.c
new file mode 100644
index 0000000..1883add
--- /dev/null
+++ b/arch/arm/plat-omap/hwspinlock.c
@@ -0,0 +1,335 @@ 
+/*
+ * 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/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.
+ *
+ * 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 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_OFFSET	24
+
+/* for managing a hardware spinlock module */
+struct hwspinlock_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_state hwspinlock_state;
+static struct hwspinlock_state *hwspinlock_module = &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 *hwspinlocks;
+
+/* API functions */
+
+/* Busy loop to acquire a spinlock */
+int hwspinlock_lock(struct hwspinlock *handle)
+{
+	int retval;
+
+	if (WARN_ON(handle == NULL))
+		return -EINVAL;
+
+	if (WARN_ON(in_irq()))
+		return -EPERM;
+
+	if (pm_runtime_get(&handle->pdev->dev) < 0)
+		return -ENODEV;
+
+	/* Attempt to acquire the lock by reading from it */
+	do {
+		retval = readl(handle->lock_reg);
+	} while (retval == HWSPINLOCK_BUSY);
+
+	return 0;
+}
+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;
+
+	if (WARN_ON(in_irq()))
+		return -EPERM;
+
+	if (pm_runtime_get(&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(&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(&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_module->local_lock, flags);
+	/* Search for an unclaimed, unreserved lock */
+	for (i = 0; i < hwspinlock_module->num_locks && !found; i++) {
+		if (!hwspinlocks[i].is_allocated) {
+			found = true;
+			handle = &hwspinlocks[i];
+		}
+	}
+	spin_unlock_irqrestore(&hwspinlock_module->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_module->local_lock, flags);
+
+	if (WARN_ON(hwspinlocks[id].is_allocated))
+		goto exit;
+
+	handle = &hwspinlocks[id];
+	handle->is_allocated = true;
+
+exit:
+	spin_unlock_irqrestore(&hwspinlock_module->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 hwspinlock_plat_info *pdata = pdev->dev.platform_data;
+	struct resource *res;
+	void __iomem *io_base;
+	int id;
+
+	void __iomem *sysstatus_reg;
+
+	/* Determine number of locks */
+	sysstatus_reg = ioremap(OMAP44XX_SPINLOCK_BASE +
+					pdata->sysstatus_offset, sizeof(u32));
+	switch (readl(sysstatus_reg) >> SPINLOCK_NUMLOCKS_OFFSET) {
+	case SPINLOCK_32_REGS:
+		hwspinlock_module->num_locks = 32;
+		break;
+	case SPINLOCK_64_REGS:
+		hwspinlock_module->num_locks = 64;
+		break;
+	case SPINLOCK_128_REGS:
+		hwspinlock_module->num_locks = 128;
+		break;
+	case SPINLOCK_256_REGS:
+		hwspinlock_module->num_locks = 256;
+		break;
+	default:
+		return -EINVAL;	/* Invalid spinlock count code */
+	}
+	iounmap(sysstatus_reg);
+
+	/* Allocate spinlock device objects */
+	hwspinlocks = kmalloc(sizeof(struct hwspinlock) *
+			hwspinlock_module->num_locks, GFP_KERNEL);
+	if (WARN_ON(hwspinlocks == NULL))
+		return -ENOMEM;
+
+	/* Initialize local lock */
+	spin_lock_init(&hwspinlock_module->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_module->io_base = io_base;
+
+	/* Set up each individual lock handle */
+	for (id = 0; id < hwspinlock_module->num_locks; id++) {
+		hwspinlocks[id].id		= id;
+		hwspinlocks[id].pdev		= pdev;
+
+		hwspinlocks[id].is_init		= true;
+		hwspinlocks[id].is_allocated	= false;
+
+		hwspinlocks[id].lock_reg	= io_base + pdata->
+					lock_base_offset + sizeof(u32) * id;
+	}
+
+	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;
+}
+
+/* Cleanup function */
+static void __exit hwspinlock_exit(void)
+{
+	int id;
+
+	platform_driver_unregister(&hwspinlock_driver);
+
+	for (id = 0; id < hwspinlock_module->num_locks; id++)
+		hwspinlocks[id].is_init = false;
+	iounmap(hwspinlock_module->io_base);
+
+	/* Free spinlock device objects */
+	if (hwspinlock_module->is_init)
+		kfree(hwspinlocks);
+}
+
+module_init(hwspinlock_init);
+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..8c69ca5
--- /dev/null
+++ b/arch/arm/plat-omap/include/plat/hwspinlock.h
@@ -0,0 +1,29 @@ 
+/* hwspinlock.h */
+
+#ifndef HWSPINLOCK_H
+#define HWSPINLOCK_H
+
+#include <linux/platform_device.h>
+#include <plat/omap44xx.h>
+
+/* Read values from the spinlock register */
+#define HWSPINLOCK_ACQUIRED 0
+#define HWSPINLOCK_BUSY 1
+
+/* Device data */
+struct hwspinlock_plat_info {
+	u32 sysstatus_offset;		/* System status register offset */
+	u32 lock_base_offset;		/* Offset of spinlock registers */
+};
+
+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 */