Modified: trunk/drivers/char/Kconfig (9152 => 9153)
--- trunk/drivers/char/Kconfig 2010-09-20 06:43:09 UTC (rev 9152)
+++ trunk/drivers/char/Kconfig 2010-09-20 07:26:56 UTC (rev 9153)
@@ -34,6 +34,14 @@
provides an interface to the above Blackfin General Purpose timers
hardware. See drivers/char/bfin_simple_timer.c for details.
+config BFIN_LATENCYTEST
+ tristate "Blackfin preempt latency test char device interface"
+ select BFIN_GPTIMERS
+ default n
+ help
+ If you say Y here, you will get the latency test char-device driver
+ that provides an interface for preempt kernel latency test.
+
config BFIN_SPI_ADC
tristate "Blackfin ADSP SPI ADC support"
depends on BLACKFIN
Modified: trunk/drivers/char/Makefile (9152 => 9153)
--- trunk/drivers/char/Makefile 2010-09-20 06:43:09 UTC (rev 9152)
+++ trunk/drivers/char/Makefile 2010-09-20 07:26:56 UTC (rev 9153)
@@ -67,6 +67,7 @@
obj-$(CONFIG_BFIN_DMA_INTERFACE) += bfin-dma.o
obj-$(CONFIG_BFIN_PPI) += bfin_ppi.o
obj-$(CONFIG_BFIN_SIMPLE_TIMER) += bfin_simple_timer.o
+obj-$(CONFIG_BFIN_LATENCYTEST) += bfin_latencytest.o
obj-$(CONFIG_BFIN_SPI_ADC) += bfin_spi_adc.o
obj-$(CONFIG_BFIN_SPORT) += bfin_sport.o
obj-$(CONFIG_BFIN_TWI_LCD) += bfin_twi_lcd.o
Added: trunk/drivers/char/bfin_latencytest.c (0 => 9153)
--- trunk/drivers/char/bfin_latencytest.c (rev 0)
+++ trunk/drivers/char/bfin_latencytest.c 2010-09-20 07:26:56 UTC (rev 9153)
@@ -0,0 +1,159 @@
+/*
+ * Preempt kernel latency tset driver
+ *
+ * Author: (C) 2010 by Bob Liu ([email protected])
+ *
+ * This is a simple char-device interface driver for gptimer TIMER2.
+ * It primarily serves for the preempt kernel latency test application
+ * in userspace to test the preempt kernel (CONFIG_PREEMPT is on)
+ * latency on blackfin.
+ *
+ * Behaviour
+ * This driver config the gptimer2 sendout interrupt every second, the
+ * isr handle record the time and send SIGIO to userapp preempt_test.
+ * preempt_test will read the recorded time when scheduled and compare
+ * with the actual time to calculate the latency.
+ *
+ * Licensed under the GPL-2 or later.
+ */
+
+#include <linux/kernel.h>
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/interrupt.h>
+#include <linux/fs.h>
+#include <linux/device.h>
+#include <linux/time.h>
+#include <linux/ioctl.h>
+#include <linux/uaccess.h>
+#include <linux/miscdevice.h>
+#include <linux/delay.h>
+#include <asm/gptimers.h>
+#include <asm/irq.h>
+#include <asm/bfin-global.h>
+
+#define BFIN_LATENCYTEST_IOCTL_MAGIC 'r'
+#define BFIN_LATENCYTEST_START _IO(BFIN_LATENCYTEST_IOCTL_MAGIC, \
+ 6)
+#define BFIN_LATENCYTEST_STOP _IO(BFIN_LATENCYTEST_IOCTL_MAGIC, \
+ 8)
+#define TIMER_MAJOR 0
+#define DRV_NAME "bfin_latencytest"
+
+static struct timeval interrupt_time;
+static struct fasync_struct *bfin_async_queue;
+
+static int timer_ioctl(struct inode *inode, struct file *filp, uint cmd,
+ unsigned long arg)
+{
+ unsigned long n;
+ switch (cmd) {
+ case BFIN_LATENCYTEST_START:
+ set_gptimer_config(TIMER2_id, OUT_DIS | PWM_OUT |
+ PERIOD_CNT | IRQ_ENA);
+ n = get_sclk();
+ set_gptimer_period(TIMER2_id, n); /* one second */
+ enable_gptimers(TIMER2bit);
+ break;
+ case BFIN_LATENCYTEST_STOP:
+ disable_gptimers(TIMER2bit);
+ break;
+ default:
+ return -EINVAL;
+ }
+ return 0;
+}
+
+static irqreturn_t timer_isr(int irq, void *dev_id)
+{
+ unsigned long state = get_gptimer_status(0);
+ if (state & TIMER_STATUS_TIMIL2) {
+ do_gettimeofday(&interrupt_time);
+ set_gptimer_status(0, TIMER_STATUS_TIMIL2);
+ kill_fasync(&bfin_async_queue, SIGIO, POLL_IN);
+ }
+ return IRQ_HANDLED;
+}
+
+static ssize_t timer_read(struct file *file, char *buf, size_t count,
+ loff_t *ppos)
+{
+ ssize_t retval;
+
+ if (count != sizeof(struct timeval))
+ return -EINVAL;
+ retval = -EIO;
+ if (copy_to_user(buf, &interrupt_time, sizeof(struct timeval)) == 0)
+ retval = sizeof(struct timeval);
+ return retval;
+}
+
+static int timer_open(struct inode *inode, struct file *filp)
+{
+ int minor = MINOR(inode->i_rdev);
+ int err = 0;
+ unsigned long n;
+
+ err = request_irq(IRQ_TIMER2, timer_isr, IRQF_DISABLED, DRV_NAME,
+ (void *)minor);
+ if (err < 0) {
+ printk(KERN_ERR "request_irq(%d) failed\n", IRQ_TIMER2);
+ return err;
+ }
+ pr_debug(DRV_NAME ": device(%d) opened\n", minor);
+ return 0;
+}
+
+static int timer_fasync(int fd, struct file *file, int on)
+{
+ return fasync_helper(fd, file, on, &bfin_async_queue);
+}
+
+static int timer_close(struct inode *inode, struct file *filp)
+{
+ int minor = MINOR(inode->i_rdev);
+ disable_gptimers(TIMER2bit);
+ free_irq(IRQ_TIMER2, (void *)minor);
+ pr_debug(DRV_NAME ": device closed\n");
+ return 0;
+}
+
+static const struct file_operations fops = {
+ .owner = THIS_MODULE,
+ .ioctl = timer_ioctl,
+ .read = timer_read,
+ .fasync = timer_fasync,
+ .open = timer_open,
+ .release = timer_close,
+};
+
+static struct miscdevice bfin_latencytest_misc_device = {
+ .minor = MISC_DYNAMIC_MINOR,
+ .name = DRV_NAME,
+ .fops = &fops,
+};
+
+static int __init timer_initialize(void)
+{
+ int ret;
+ ret = misc_register(&bfin_latencytest_misc_device);
+ if (ret) {
+ pr_debug(KERN_ERR "unable to register a misc device\n");
+ return ret;
+ }
+
+ pr_debug(KERN_INFO "initialized\n");
+ return 0;
+}
+module_init(timer_initialize);
+
+static void __exit timer_cleanup(void)
+{
+ misc_deregister(&bfin_latencytest_misc_device);
+ pr_debug(DRV_NAME ": module unloaded\n");
+}
+module_exit(timer_cleanup);
+
+MODULE_AUTHOR("Bob Liu <[email protected]>");
+MODULE_DESCRIPTION("latencytest char-device interface for preempt test");
+MODULE_LICENSE("GPL");
