Hi Simon,
On 6/25/2010 2:40 AM, Que, Simon wrote:
Hi,
We are introducing a kernel driver for hardware spinlock, called hwspinlock.
It is designed to interface with the OMAP4 hardware spinlock module. 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 will set aside some spinlocks as reserved for
special-purpose use. All other locks can be used by anyone. This is
configurable using a Kconfig option. The device initialization file is:
arch/arm/mach-omap2/hwspinlocks.c
Why using a Kconfig option in that case? You can reserve the locks at
run time based on other driver request. The goal of the hwspinlock is to
protect data shared between various processors inside OMAP4 like ipu,
iva, dsp and mpu. So in anycase the syslink driver can request the
needed locks at init time on behalf of the dsp or the ipu.
Since you don't even know the number of locks because it is determined
at init time, you cannot know at build time that information.
You should add an API to reserve some locks at run time instead of doing
that.
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.
int hwspinlock_lock_irqsave(struct hwspinlock *, unsigned long *);
Same as hwspinlock_lock, but disables interrupts and preemption
int hwspinlock_trylock_irqsave(struct hwspinlock *, unsigned long *);
Same as hwspinlock_trylock, but disables interrupts and preemption
int hwspinlock_unlock_irqrestore(struct hwspinlock *, unsigned long);
Same as hwspinlock_unlock, but restores interrupts and preemption
struct hwspinlock *hwspinlock_request(void);
Provides for "dynamic allocation" of an unreserved hardware spinlock.
If no more locks are available, returns NULL.
struct hwspinlock *hwspinlock_request_specific(unsigned int);
Provides for "static allocation" of a reserved hardware spinlock. This
allows the system to use a specific reserved lock, identified by an ID.
If the ID is invalid or if the desired lock is already allocated, this
will return NULL.
int hwspinlock_free(struct hwspinlock *);
Frees an allocated hardware spinlock (either reserved or unreserved).
Please see the below patch contents, or the attached patch, and provide
feedback.
Signed-off-by: Simon Que<s...@ti.com>
Cc: Hari Kanigeri<h-kanige...@ti.com>
=====================================================================
diff --git a/arch/arm/mach-omap2/Kconfig b/arch/arm/mach-omap2/Kconfig
index 9f73d79..a13c188 100644
--- a/arch/arm/mach-omap2/Kconfig
+++ b/arch/arm/mach-omap2/Kconfig
@@ -182,3 +182,13 @@ config OMAP3_SDRC_AC_TIMING
wish to say no. Selecting yes without understanding what is
going on could result in system crashes;
+config OMAP_HWSPINLOCK_NUM_RESERVED
+ int "Number of hardware spinlocks reserved for system use"
+ depends on ARCH_OMAP
+ default 8
+ range 0 32
+ help
+ Choose a number of hardware spinlocks to reserve for internal use.
+ The rest will be unreserved and availble for general use. Make
+ that the number of reserved locks does not exceed the total number
+ available locks.
diff --git a/arch/arm/mach-omap2/Makefile b/arch/arm/mach-omap2/Makefile
index 6725b3a..14af19a 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-y += 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..de813a0
--- /dev/null
+++ b/arch/arm/mach-omap2/hwspinlocks.c
@@ -0,0 +1,126 @@
+/*
+ * OMAP hardware spinlock driver
+ *
+ * Copyright (C) 2010 Texas Instruments. All rights reserved.
+ *
+ * Contact: Simon Que<s...@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>
+
+/* Base address of HW spinlock module */
+#define HWSPINLOCK_BASE (L4_44XX_BASE + 0xF6000)
It is a details, but why are you renaming the registers with the HW
prefix? The module name is spinlock not hwspinlock.
The names should be that:
#define SPINLOCK_REVISION 0x0000
#define SPINLOCK_SYSCONFIG 0x0010
#define SPINLOCK_SYSSTATUS 0x0014
#define SPINLOCK_LOCK_BASE 0x0800
or even that since you are not sharing these defines:
#define REVISION 0x0000
#define SYSCONFIG 0x0010
#define SYSSTATUS 0x0014
#define LOCK_BASE 0x0800
Every IPs are by definition an HW module, so that information is useless.
+#define HWSPINLOCK_REGADDR(reg) \
+ OMAP2_L4_IO_ADDRESS(HWSPINLOCK_BASE + (reg))
+
+/* Spinlock register offsets */
+#define HWSPINLOCK_REVISION 0x0000
+#define HWSPINLOCK_SYSCONFIG 0x0010
+#define HWSPINLOCK_SYSSTATUS 0x0014
+#define HWSPINLOCK_LOCK_BASE 0x0800
+
+/* Spinlock register addresses */
+#define HWSPINLOCK_REVISION_REG \
+ HWSPINLOCK_REGADDR(HWSPINLOCK_REVISION)
+#define HWSPINLOCK_SYSCONFIG_REG \
+ HWSPINLOCK_REGADDR(HWSPINLOCK_SYSCONFIG)
+#define HWSPINLOCK_SYSSTATUS_REG \
+ HWSPINLOCK_REGADDR(HWSPINLOCK_SYSSTATUS)
+#define HWSPINLOCK_LOCK_REG(i) \
+ HWSPINLOCK_REGADDR(HWSPINLOCK_LOCK_BASE + 0x4 * (i))
+
+/* Spinlock count code */
+#define HWSPINLOCK_32_REGS 1
+#define HWSPINLOCK_64_REGS 2
+#define HWSPINLOCK_128_REGS 4
+#define HWSPINLOCK_256_REGS 8
+#define HWSPINLOCK_NUMLOCKS_OFFSET 24
+
+
+/* Initialization function */
+int __init hwspinlocks_init(void)
+{
+ int i;
+ int retval = 0;
+
+ struct platform_device *pdev;
+ struct hwspinlock_plat_info *pdata;
+ void __iomem *base;
+ int num_locks;
+ bool is_reserved;
+
+ /* Determine number of locks */
+ switch (__raw_readl(HWSPINLOCK_SYSSTATUS_REG)>>
+ HWSPINLOCK_NUMLOCKS_OFFSET) {
+ case HWSPINLOCK_32_REGS:
+ num_locks = 32;
+ break;
+ case HWSPINLOCK_64_REGS:
+ num_locks = 64;
+ break;
+ case HWSPINLOCK_128_REGS:
+ num_locks = 128;
+ break;
+ case HWSPINLOCK_256_REGS:
+ num_locks = 256;
+ break;
+ default:
+ return -EINVAL; /* Invalid spinlock count code */
+ }
+
+ /* Device drivers */
+ for (i = 0; i< num_locks; i++) {
+ pdev = platform_device_alloc("hwspinlock", i);
Since it is a new driver for a new IP, why don't you use directly the
omap_device / omap_hwmod abstraction?
Regards,
Benoit
--
To unsubscribe from this list: send the line "unsubscribe linux-omap" in
the body of a message to majord...@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
