omap:hwspinlock-added hwspinlock driver

Created driver for OMAP hardware spinlock.  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.  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 <[email protected]>
Signed-off-by: Hari Kanigeri <[email protected]>

Author: Simon Que

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 <[email protected]>
+ *
+ * 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);