Commit dd56376d authored by Jaroslav Kysela's avatar Jaroslav Kysela Committed by Linus Torvalds

[PATCH] Patch - sharing RTC timer between kernel and user space (2nd)

This patch to allow using of RTC timer inside the kernel space.  We can
use the RTC timer as timing source for ALSA sequencer. Patch by Takashi.

The patch adds these three functions and one structure to rtc.h and
rtc.c:

typedef struct rtc_task {
       void (*func)(void *private_data);
       void *private_data;
} rtc_task_t;

int rtc_register(rtc_task_t *task);
int rtc_unregister(rtc_task_t *task);
int rtc_control(rtc_task_t *t, unsigned int cmd, unsigned long arg);

					Jaroslav
parent 7d06adb8
...@@ -23,7 +23,7 @@ obj-y += mem.o tty_io.o n_tty.o tty_ioctl.o raw.o pty.o misc.o random.o ...@@ -23,7 +23,7 @@ obj-y += mem.o tty_io.o n_tty.o tty_ioctl.o raw.o pty.o misc.o random.o
export-objs := busmouse.o console.o keyboard.o sysrq.o \ export-objs := busmouse.o console.o keyboard.o sysrq.o \
misc.o pty.o random.o selection.o serial.o \ misc.o pty.o random.o selection.o serial.o \
sonypi.o tty_io.o tty_ioctl.o generic_serial.o sonypi.o tty_io.o tty_ioctl.o generic_serial.o rtc.o
mod-subdirs := ftape drm pcmcia mod-subdirs := ftape drm pcmcia
......
...@@ -41,9 +41,11 @@ ...@@ -41,9 +41,11 @@
* 1.10c Cesar Barros: SMP locking fixes and cleanup * 1.10c Cesar Barros: SMP locking fixes and cleanup
* 1.10d Paul Gortmaker: delete paranoia check in rtc_exit * 1.10d Paul Gortmaker: delete paranoia check in rtc_exit
* 1.10e Maciej W. Rozycki: Handle DECstation's year weirdness. * 1.10e Maciej W. Rozycki: Handle DECstation's year weirdness.
* 1.11 Takashi Iwai: Kernel access functions
* rtc_register/rtc_unregister/rtc_control
*/ */
#define RTC_VERSION "1.10e" #define RTC_VERSION "1.11"
#define RTC_IO_EXTENT 0x10 /* Only really two ports, but... */ #define RTC_IO_EXTENT 0x10 /* Only really two ports, but... */
...@@ -139,6 +141,11 @@ static unsigned long rtc_status = 0; /* bitmapped status byte. */ ...@@ -139,6 +141,11 @@ static unsigned long rtc_status = 0; /* bitmapped status byte. */
static unsigned long rtc_freq = 0; /* Current periodic IRQ rate */ static unsigned long rtc_freq = 0; /* Current periodic IRQ rate */
static unsigned long rtc_irq_data = 0; /* our output to the world */ static unsigned long rtc_irq_data = 0; /* our output to the world */
#if RTC_IRQ
static spinlock_t rtc_task_lock = SPIN_LOCK_UNLOCKED;
static rtc_task_t *rtc_callback = NULL;
#endif
/* /*
* If this driver ever becomes modularised, it will be really nice * If this driver ever becomes modularised, it will be really nice
* to make the epoch retain its value across module reload... * to make the epoch retain its value across module reload...
...@@ -180,6 +187,10 @@ static void rtc_interrupt(int irq, void *dev_id, struct pt_regs *regs) ...@@ -180,6 +187,10 @@ static void rtc_interrupt(int irq, void *dev_id, struct pt_regs *regs)
spin_unlock (&rtc_lock); spin_unlock (&rtc_lock);
/* Now do the rest of the actions */ /* Now do the rest of the actions */
spin_lock(&rtc_task_lock);
if (rtc_callback)
rtc_callback->func(rtc_callback->private_data);
spin_unlock(&rtc_task_lock);
wake_up_interruptible(&rtc_wait); wake_up_interruptible(&rtc_wait);
kill_fasync (&rtc_async_queue, SIGIO, POLL_IN); kill_fasync (&rtc_async_queue, SIGIO, POLL_IN);
...@@ -244,8 +255,7 @@ static ssize_t rtc_read(struct file *file, char *buf, ...@@ -244,8 +255,7 @@ static ssize_t rtc_read(struct file *file, char *buf,
#endif #endif
} }
static int rtc_ioctl(struct inode *inode, struct file *file, unsigned int cmd, static int rtc_do_ioctl(unsigned int cmd, unsigned long arg, int kernel)
unsigned long arg)
{ {
struct rtc_time wtime; struct rtc_time wtime;
...@@ -295,7 +305,7 @@ static int rtc_ioctl(struct inode *inode, struct file *file, unsigned int cmd, ...@@ -295,7 +305,7 @@ static int rtc_ioctl(struct inode *inode, struct file *file, unsigned int cmd,
* We don't really want Joe User enabling more * We don't really want Joe User enabling more
* than 64Hz of interrupts on a multi-user machine. * than 64Hz of interrupts on a multi-user machine.
*/ */
if ((rtc_freq > 64) && (!capable(CAP_SYS_RESOURCE))) if (!kernel && (rtc_freq > 64) && (!capable(CAP_SYS_RESOURCE)))
return -EACCES; return -EACCES;
if (!(rtc_status & RTC_TIMER_ON)) { if (!(rtc_status & RTC_TIMER_ON)) {
...@@ -493,7 +503,7 @@ static int rtc_ioctl(struct inode *inode, struct file *file, unsigned int cmd, ...@@ -493,7 +503,7 @@ static int rtc_ioctl(struct inode *inode, struct file *file, unsigned int cmd,
* We don't really want Joe User generating more * We don't really want Joe User generating more
* than 64Hz of interrupts on a multi-user machine. * than 64Hz of interrupts on a multi-user machine.
*/ */
if ((arg > 64) && (!capable(CAP_SYS_RESOURCE))) if (!kernel && (arg > 64) && (!capable(CAP_SYS_RESOURCE)))
return -EACCES; return -EACCES;
while (arg > (1<<tmp)) while (arg > (1<<tmp))
...@@ -539,6 +549,12 @@ static int rtc_ioctl(struct inode *inode, struct file *file, unsigned int cmd, ...@@ -539,6 +549,12 @@ static int rtc_ioctl(struct inode *inode, struct file *file, unsigned int cmd,
return copy_to_user((void *)arg, &wtime, sizeof wtime) ? -EFAULT : 0; return copy_to_user((void *)arg, &wtime, sizeof wtime) ? -EFAULT : 0;
} }
static int rtc_ioctl(struct inode *inode, struct file *file, unsigned int cmd,
unsigned long arg)
{
return rtc_do_ioctl(cmd, arg, 0);
}
/* /*
* We enforce only one user at a time here with the open/close. * We enforce only one user at a time here with the open/close.
* Also clear the previous interrupt data on an open, and clean * Also clear the previous interrupt data on an open, and clean
...@@ -606,11 +622,8 @@ static int rtc_release(struct inode *inode, struct file *file) ...@@ -606,11 +622,8 @@ static int rtc_release(struct inode *inode, struct file *file)
spin_lock_irq (&rtc_lock); spin_lock_irq (&rtc_lock);
rtc_irq_data = 0; rtc_irq_data = 0;
spin_unlock_irq (&rtc_lock);
/* No need for locking -- nobody else can do anything until this rmw is
* committed, and no timer is running. */
rtc_status &= ~RTC_IS_OPEN; rtc_status &= ~RTC_IS_OPEN;
spin_unlock_irq (&rtc_lock);
return 0; return 0;
} }
...@@ -635,6 +648,88 @@ static unsigned int rtc_poll(struct file *file, poll_table *wait) ...@@ -635,6 +648,88 @@ static unsigned int rtc_poll(struct file *file, poll_table *wait)
} }
#endif #endif
/*
* exported stuffs
*/
EXPORT_SYMBOL(rtc_register);
EXPORT_SYMBOL(rtc_unregister);
EXPORT_SYMBOL(rtc_control);
int rtc_register(rtc_task_t *task)
{
#if !RTC_IRQ
return -EIO;
#else
if (task == NULL || task->func == NULL)
return -EINVAL;
spin_lock_irq(&rtc_lock);
if (rtc_status & RTC_IS_OPEN) {
spin_unlock_irq(&rtc_lock);
return -EBUSY;
}
spin_lock(&rtc_task_lock);
if (rtc_callback) {
spin_unlock(&rtc_task_lock);
spin_unlock_irq(&rtc_lock);
return -EBUSY;
}
rtc_status |= RTC_IS_OPEN;
rtc_callback = task;
spin_unlock(&rtc_task_lock);
spin_unlock_irq(&rtc_lock);
return 0;
#endif
}
int rtc_unregister(rtc_task_t *task)
{
#if !RTC_IRQ
return -EIO;
#else
unsigned char tmp;
spin_lock_irq(&rtc_task_lock);
if (rtc_callback != task) {
spin_unlock_irq(&rtc_task_lock);
return -ENXIO;
}
rtc_callback = NULL;
spin_lock(&rtc_lock);
/* disable controls */
tmp = CMOS_READ(RTC_CONTROL);
tmp &= ~RTC_PIE;
tmp &= ~RTC_AIE;
tmp &= ~RTC_UIE;
CMOS_WRITE(tmp, RTC_CONTROL);
CMOS_READ(RTC_INTR_FLAGS);
if (rtc_status & RTC_TIMER_ON) {
rtc_status &= ~RTC_TIMER_ON;
del_timer(&rtc_irq_timer);
}
rtc_status &= ~RTC_IS_OPEN;
spin_unlock(&rtc_lock);
spin_unlock_irq(&rtc_task_lock);
return 0;
#endif
}
int rtc_control(rtc_task_t *task, unsigned int cmd, unsigned long arg)
{
#if !RTC_IRQ
return -EIO;
#else
spin_lock_irq(&rtc_task_lock);
if (rtc_callback != task) {
spin_unlock_irq(&rtc_task_lock);
return -ENXIO;
}
spin_unlock_irq(&rtc_task_lock);
return rtc_do_ioctl(cmd, arg, 1);
#endif
}
/* /*
* The various file operations we support. * The various file operations we support.
*/ */
...@@ -822,7 +917,6 @@ static void __exit rtc_exit (void) ...@@ -822,7 +917,6 @@ static void __exit rtc_exit (void)
module_init(rtc_init); module_init(rtc_init);
module_exit(rtc_exit); module_exit(rtc_exit);
EXPORT_NO_SYMBOLS;
#if RTC_IRQ #if RTC_IRQ
/* /*
......
...@@ -66,4 +66,17 @@ struct rtc_wkalrm { ...@@ -66,4 +66,17 @@ struct rtc_wkalrm {
#define RTC_WKALM_SET _IOW('p', 0x0f, struct rtc_wkalrm)/* Set wakeup alarm*/ #define RTC_WKALM_SET _IOW('p', 0x0f, struct rtc_wkalrm)/* Set wakeup alarm*/
#define RTC_WKALM_RD _IOR('p', 0x10, struct rtc_wkalrm)/* Get wakeup alarm*/ #define RTC_WKALM_RD _IOR('p', 0x10, struct rtc_wkalrm)/* Get wakeup alarm*/
#ifdef __KERNEL__
typedef struct rtc_task {
void (*func)(void *private_data);
void *private_data;
} rtc_task_t;
int rtc_register(rtc_task_t *task);
int rtc_unregister(rtc_task_t *task);
int rtc_control(rtc_task_t *t, unsigned int cmd, unsigned long arg);
#endif /* __KERNEL__ */
#endif /* _LINUX_RTC_H_ */ #endif /* _LINUX_RTC_H_ */
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