Hello,
Thanks for all your comments and feedback. I've updated the patch with changes based on the feedback I've received:
- Switched to using hwmod. I enabled the hwmod entry for spinlock in omap_hwmod_44xx_data.
- Removed reserved/unreserved distinction. Removed CONFIG option for number of reserved locks as well. The reservation will be done at runtime as Kevin and Benoit have suggested. The new API simply provides for reservation of spinlock w/ specific ID or the next available spinlock.
- Simplified #define names -- removed the HWSPINLOCK prefix.
- Added OMAP4 conditional to Makefiles for building hwspinlock.
- Moved base address definition of spinlock register to omap44xx.h
- Base addresses are mapped using ioremap and accessed using readl/writel.
- Removed the irqsave/restore functions. Now there are only lock/trylock/unlock, without the irq and preempt disable/enable. This keeps it simple, and we can add the irq/preempt disable/enable as a future enhancement.
Regarding reserving locks: how do we use the board code to reserve locks? This is not familiar to us.
Please see attached patch, or inline patch contents below.
Thanks,
Simon
============================================================================
>From a1aa1f5a85814bdf924d140b664a3305224392b2 Mon Sep 17 00:00:00 2001
From: Simon Que <sque@xxxxxx>
Date: Wed, 23 Jun 2010 18:40:30 -0500
Subject: [PATCH] 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 hardware spinlock. It will pass spinlock register
addresses to the driver. The device initialization file is:
arch/arm/mach-omap2/hwspinlocks.c
The driver takes in data passed in device initialization. The function
hwspinlock_probe() initializes the array of spinlock structures, each
containing a spinlock register address provided by the device initialization.
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>
---
arch/arm/mach-omap2/Makefile | 2 +
arch/arm/mach-omap2/hwspinlocks.c | 122 +++++++++++++
arch/arm/mach-omap2/omap_hwmod_44xx_data.c | 2 +-
arch/arm/plat-omap/Makefile | 3 +-
arch/arm/plat-omap/hwspinlock.c | 250 ++++++++++++++++++++++++++
arch/arm/plat-omap/include/plat/hwspinlock.h | 30 +++
arch/arm/plat-omap/include/plat/omap44xx.h | 2 +
7 files changed, 409 insertions(+), 2 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/Makefile b/arch/arm/mach-omap2/Makefile
index 6725b3a..5f5c87b 100644
--- a/arch/arm/mach-omap2/Makefile
+++ b/arch/arm/mach-omap2/Makefile
@@ -170,3 +170,5 @@ obj-y += $(nand-m) $(nand-y)
smc91x-$(CONFIG_SMC91X) := gpmc-smc91x.o
obj-y += $(smc91x-m) $(smc91x-y)
+
+obj-$(CONFIG_ARCH_OMAP4) += hwspinlocks.o
\ No newline at end of file
diff --git a/arch/arm/mach-omap2/hwspinlocks.c b/arch/arm/mach-omap2/hwspinlocks.c
new file mode 100644
index 0000000..868edea
--- /dev/null
+++ b/arch/arm/mach-omap2/hwspinlocks.c
@@ -0,0 +1,122 @@
+/*
+ * 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
+ *
+ */
+
+#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>
+
+#define SPINLOCK_REGADDR(reg) (OMAP44XX_SPINLOCK_BASE + (reg))
+
+/* Spinlock register offsets */
+#define REVISION_OFFSET 0x0000
+#define SYSCONFIG_OFFSET 0x0010
+#define SYSSTATUS_OFFSET 0x0014
+#define LOCK_BASE_OFFSET 0x0800
+
+/* Spinlock register addresses */
+#define SPINLOCK_REVISION_REG \
+ SPINLOCK_REGADDR(REVISION_OFFSET)
+#define SPINLOCK_SYSCONFIG_REG \
+ SPINLOCK_REGADDR(SYSCONFIG_OFFSET)
+#define SPINLOCK_SYSSTATUS_REG \
+ SPINLOCK_REGADDR(SYSSTATUS_OFFSET)
+#define SPINLOCK_LOCK_REG(i) \
+ SPINLOCK_REGADDR(LOCK_BASE_OFFSET + 0x4 * (i))
+
+/* 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
+
+/* Initialization function */
+int __init hwspinlocks_init(void)
+{
+ int i;
+ int retval = 0;
+
+ struct hwspinlock_plat_info *pdata;
+ void __iomem *base;
+ int num_locks;
+
+ void __iomem *sysstatus_reg = ioremap(SPINLOCK_SYSSTATUS_REG,
+ sizeof(u32));
+
+ struct omap_hwmod *oh;
+ char *oh_name, *pdev_name;
+
+ /* Determine number of locks */
+ switch (readl(sysstatus_reg) >> SPINLOCK_NUMLOCKS_OFFSET) {
+ case SPINLOCK_32_REGS:
+ num_locks = 32;
+ break;
+ case SPINLOCK_64_REGS:
+ num_locks = 64;
+ break;
+ case SPINLOCK_128_REGS:
+ num_locks = 128;
+ break;
+ case SPINLOCK_256_REGS:
+ num_locks = 256;
+ break;
+ default:
+ return -EINVAL; /* Invalid spinlock count code */
+ }
+
+ iounmap(sysstatus_reg);
+
+ oh_name = "spinlock";
+ oh = omap_hwmod_lookup(oh_name);
+ if (WARN_ON(oh == NULL))
+ return -EINVAL;
+
+ pdev_name = "hwspinlock";
+
+ /* Device drivers */
+ for (i = 0; i < num_locks; i++) {
+ base = ioremap(SPINLOCK_LOCK_REG(i), sizeof(u32));
+
+ /* Pass data to device initialization */
+ pdata = kzalloc(sizeof(struct hwspinlock_plat_info),
+ GFP_KERNEL);
+ pdata->num_locks = num_locks;
+ pdata->io_base = base;
+
+ omap_device_build(pdev_name, i, oh, pdata,
+ sizeof(struct hwspinlock_plat_info),
+ NULL, 0, false);
+ }
+
+ return retval;
+}
+module_init(hwspinlocks_init);
+
diff --git a/arch/arm/mach-omap2/omap_hwmod_44xx_data.c b/arch/arm/mach-omap2/omap_hwmod_44xx_data.c
index d8d6d58..ce6c5ff 100644
--- a/arch/arm/mach-omap2/omap_hwmod_44xx_data.c
+++ b/arch/arm/mach-omap2/omap_hwmod_44xx_data.c
@@ -4875,7 +4875,7 @@ static __initdata struct omap_hwmod *omap44xx_hwmods[] = {
/* &omap44xx_smartreflex_iva_hwmod, */
/* &omap44xx_smartreflex_mpu_hwmod, */
/* spinlock class */
-/* &omap44xx_spinlock_hwmod, */
+ &omap44xx_spinlock_hwmod,
/* timer class */
&omap44xx_timer1_hwmod,
&omap44xx_timer2_hwmod,
diff --git a/arch/arm/plat-omap/Makefile b/arch/arm/plat-omap/Makefile
index a37abf5..f725afc 100644
--- a/arch/arm/plat-omap/Makefile
+++ b/arch/arm/plat-omap/Makefile
@@ -32,4 +32,5 @@ obj-y += $(i2c-omap-m) $(i2c-omap-y)
obj-$(CONFIG_OMAP_MBOX_FWK) += mailbox.o
obj-$(CONFIG_OMAP_REMOTE_PROC) += remoteproc.o
-obj-$(CONFIG_OMAP_PM_NOOP) += omap-pm-noop.o
\ No newline at end of file
+obj-$(CONFIG_OMAP_PM_NOOP) += omap-pm-noop.o
+obj-$(CONFIG_ARCH_OMAP4) += hwspinlock.o
\ No newline at end of file
diff --git a/arch/arm/plat-omap/hwspinlock.c b/arch/arm/plat-omap/hwspinlock.c
new file mode 100644
index 0000000..dbbf543
--- /dev/null
+++ b/arch/arm/plat-omap/hwspinlock.c
@@ -0,0 +1,250 @@
+/*
+ * 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
+ *
+ */
+
+#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 <linux/spinlock.h>
+
+#include <plat/hwspinlock.h>
+
+/* 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 */
+};
+
+/* 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;
+ void __iomem *io_base;
+ 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_atomic() || in_irq()))
+ return -EPERM;
+
+ /* Attempt to acquire the lock by reading from it */
+ do {
+ retval = readl(handle->io_base);
+ } 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_atomic() || in_irq()))
+ return -EPERM;
+
+ /* Attempt to acquire the lock by reading from it */
+ retval = readl(handle->io_base);
+
+ 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->io_base);
+
+ 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;
+ int id;
+
+ /* Set up the spinlock count and array */
+ if (!hwspinlock_module->is_init) {
+ hwspinlock_module->num_locks = pdata->num_locks;
+
+ /* 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);
+
+ /* Only do initialization once */
+ hwspinlock_module->is_init = true;
+
+ for (id = 0; id < pdata->num_locks; id++)
+ hwspinlocks[id].is_init = false;
+ }
+
+ id = pdev->id;
+
+ hwspinlocks[id].pdev = pdev;
+
+ hwspinlocks[id].is_allocated = false;
+ hwspinlocks[id].io_base = pdata->io_base;
+ hwspinlocks[id].is_init = true;
+
+ 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++) {
+ iounmap(hwspinlocks[id].io_base);
+ hwspinlocks[id].is_init = false;
+ }
+
+ /* 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..6de2cb9
--- /dev/null
+++ b/arch/arm/plat-omap/include/plat/hwspinlock.h
@@ -0,0 +1,30 @@
+/* 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 {
+ int num_locks; /* Number of locks (initialization) */
+ void __iomem *io_base; /* Address of spinlock register */
+ bool is_reserved; /* Reserved for system use? */
+};
+
+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 */
diff --git a/arch/arm/plat-omap/include/plat/omap44xx.h b/arch/arm/plat-omap/include/plat/omap44xx.h
index 8b3f12f..8016508 100644
--- a/arch/arm/plat-omap/include/plat/omap44xx.h
+++ b/arch/arm/plat-omap/include/plat/omap44xx.h
@@ -52,5 +52,7 @@
#define OMAP4_MMU1_BASE 0x55082000
#define OMAP4_MMU2_BASE 0x4A066000
+#define OMAP44XX_SPINLOCK_BASE (L4_44XX_BASE + 0xF6000)
+
#endif /* __ASM_ARCH_OMAP44XX_H */
--
1.7.0
Attachment:
0001-omap-hwspinlock-Added-hwspinlock-driver.patch
Description: 0001-omap-hwspinlock-Added-hwspinlock-driver.patch
