Hello,
I have updated my draft of the spinlock driver patch based on feedback from the Linux-OMAP community.
The changes I have made since RFC v.2:
- Only one device initialization per IP (in this case, OMAP4) -- this means the driver's probe func will only be called once.
- Spinlock address is obtained by calling platform_get_resource from driver, and ioremapped by driver. This makes better use of hwmod.
- Device initialization only provides spinlock register offsets, not mapped or raw addresses.
- Determining number of locks and lock register addresses is done in driver, not device init.
- Calling pm_runtime_get and pm_runtime_put when acquiring/releasing lock.
- Fixed file header comment: hwspinlocks.c should be called "device initialization" not "driver"
Please see attached patch or inline patch below, and provide feedback. I hope to submit the finalized patch on Tuesday July 6.
Thanks,
Simon
================================================================
>From 86223480bb46177b4c625b01122d0a4f40eb95c0 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 | 72 ++++++
arch/arm/mach-omap2/omap_hwmod_44xx_data.c | 2 +-
arch/arm/plat-omap/Makefile | 3 +-
arch/arm/plat-omap/hwspinlock.c | 298 ++++++++++++++++++++++++++
arch/arm/plat-omap/include/plat/hwspinlock.h | 29 +++
arch/arm/plat-omap/include/plat/omap44xx.h | 2 +
7 files changed, 406 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..f0b212b
--- /dev/null
+++ b/arch/arm/mach-omap2/hwspinlocks.c
@@ -0,0 +1,72 @@
+/*
+ * 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>
+
+/* 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/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..7cfd2c0
--- /dev/null
+++ b/arch/arm/plat-omap/hwspinlock.c
@@ -0,0 +1,298 @@
+/*
+ * 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/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_atomic() || 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);
+
+ if (retval == HWSPINLOCK_BUSY)
+ pm_runtime_put(&handle->pdev->dev);
+
+ 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;
+
+ 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 */
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
