[PARISC] Convert soft power switch driver to kthread

And remove it's reference in time.c.
Allow lcd_print() to take a const char *.

Signed-off-by: Helge Deller <deller@gmx.de>
Signed-off-by: Kyle McMartin <kyle@parisc-linux.org>

4 files changed, 91 insertions, 118 deletions

diff --git a/arch/parisc/kernel/time.c b/arch/parisc/kernel/time.c
index c33b6e0f7c47..ccdce6ef67cc 100644
--- a/arch/parisc/kernel/time.c
+++ b/arch/parisc/kernel/time.c
@@ -148,10 +148,6 @@ irqreturn_t timer_interrupt(int irq, void *dev_id)
 		write_sequnlock(&xtime_lock);
 	}
 
-	/* check soft power switch status */
-	if (cpu == 0 && !atomic_read(&power_tasklet.count))
-		tasklet_schedule(&power_tasklet);
-
 	return IRQ_HANDLED;
 }
 
diff --git a/drivers/parisc/led.c b/drivers/parisc/led.c
index 6818c10c0c46..a415d9b1c715 100644
--- a/drivers/parisc/led.c
+++ b/drivers/parisc/led.c
@@ -631,7 +631,7 @@ void __init register_led_regions(void)
    ** avoid a race condition while writing the CMD/DATA register pair.
    **
  */
-int lcd_print( char *str )
+int lcd_print( const char *str )
 {
 	int i;
 
diff --git a/drivers/parisc/power.c b/drivers/parisc/power.c
index 9228e210c3bb..6dedbdef7106 100644
--- a/drivers/parisc/power.c
+++ b/drivers/parisc/power.c
@@ -2,7 +2,7 @@
  * linux/drivers/parisc/power.c
  * HP PARISC soft power switch support driver
  *
- * Copyright (c) 2001-2005 Helge Deller <deller@gmx.de>
+ * Copyright (c) 2001-2007 Helge Deller <deller@gmx.de>
  * All rights reserved.
  *
  *
@@ -29,7 +29,6 @@
  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  *
  *
- * 
  *  HINT:
  *  Support of the soft power switch button may be enabled or disabled at
  *  runtime through the "/proc/sys/kernel/power" procfs entry.
@@ -38,34 +37,28 @@
 #include <linux/module.h>
 #include <linux/init.h>
 #include <linux/kernel.h>
-#include <linux/string.h>
 #include <linux/notifier.h>
 #include <linux/reboot.h>
 #include <linux/sched.h>
-#include <linux/interrupt.h>
-#include <linux/workqueue.h>
+#include <linux/kthread.h>
 
 #include <asm/pdc.h>
 #include <asm/io.h>
 #include <asm/led.h>
-#include <asm/uaccess.h>
 
+#define DRIVER_NAME  "powersw"
+#define KTHREAD_NAME "kpowerswd"
 
-#ifdef DEBUG
-# define DPRINTK(x...) printk(x)
-#else
-# define DPRINTK(x...)
-#endif
-
-
-/* filename in /proc which can be used to enable/disable the power switch */
-#define SYSCTL_FILENAME		"sys/kernel/power"
+/* how often should the power button be polled ? */
+#define POWERSWITCH_POLL_PER_SEC 2
 
+/* how long does the power button needs to be down until we react ? */
+#define POWERSWITCH_DOWN_SEC 2
 
+/* assembly code to access special registers */
+/* taken from PCXL ERS page 82 */
 #define DIAG_CODE(code)		(0x14000000 + ((code)<<5))
 
-/* this will go to processor.h or any other place... */
-/* taken from PCXL ERS page 82 */
 #define MFCPU_X(rDiagReg, t_ch, t_th, code) \
 	(DIAG_CODE(code) + ((rDiagReg)<<21) + ((t_ch)<<16) + ((t_th)<<0) )
 	
@@ -76,111 +69,95 @@
 #define __getDIAG(dr) ( { 			\
         register unsigned long __res asm("r28");\
 	 __asm__ __volatile__ (			\
-		".word %1\n nop\n" : "=&r" (__res) : "i" (MFCPU_T(dr,28)) \
+		".word %1" : "=&r" (__res) : "i" (MFCPU_T(dr,28) ) \
 	);					\
 	__res;					\
 } )
 
-
-static void deferred_poweroff(struct work_struct *unused)
-{
-	if (kill_cad_pid(SIGINT, 1)) {
-		/* just in case killing init process failed */
-		machine_power_off();
-	}
-}
-
-/*
- * This function gets called from interrupt context.
- * As it's called within an interrupt, it wouldn't sync if we don't
- * use schedule_work().
- */
-
-static DECLARE_WORK(poweroff_work, deferred_poweroff);
-
-static void poweroff(void)
-{
-	static int powering_off __read_mostly;
-
-	if (powering_off)
-		return;
-
-	powering_off++;
-	schedule_work(&poweroff_work);
-}
-
-
-/* local time-counter for shutdown */
+/* local shutdown counter */
 static int shutdown_timer __read_mostly;
 
 /* check, give feedback and start shutdown after one second */
 static void process_shutdown(void)
 {
 	if (shutdown_timer == 0)
-		DPRINTK(KERN_INFO "Shutdown requested...\n");
+		printk(KERN_ALERT KTHREAD_NAME ": Shutdown requested...\n");
 
 	shutdown_timer++;
 	
 	/* wait until the button was pressed for 1 second */
-	if (shutdown_timer == HZ) {
-#if defined (DEBUG) || defined(CONFIG_CHASSIS_LCD_LED)
-		static char msg[] = "Shutting down...";
-#endif
-		DPRINTK(KERN_INFO "%s\n", msg);
+	if (shutdown_timer == (POWERSWITCH_DOWN_SEC*POWERSWITCH_POLL_PER_SEC)) {
+		static const char msg[] = "Shutting down...";
+		printk(KERN_INFO KTHREAD_NAME ": %s\n", msg);
 		lcd_print(msg);
-		poweroff();
+
+		/* send kill signal */
+		if (kill_cad_pid(SIGINT, 1)) {
+			/* just in case killing init process failed */
+			if (pm_power_off)
+				pm_power_off();
+		}
 	}
 }
 
 
-/* main power switch tasklet struct (scheduled from time.c) */
-DECLARE_TASKLET_DISABLED(power_tasklet, NULL, 0);
+/* main power switch task struct */
+static struct task_struct *power_task;
+
+/* filename in /proc which can be used to enable/disable the power switch */
+#define SYSCTL_FILENAME	"sys/kernel/power"
 
 /* soft power switch enabled/disabled */
 int pwrsw_enabled __read_mostly = 1;
 
-/*
- * On gecko style machines (e.g. 712/xx and 715/xx) 
- * the power switch status is stored in Bit 0 ("the highest bit")
- * of CPU diagnose register 25.
- * 
- */
-static void gecko_tasklet_func(unsigned long unused)
+/* main kernel thread worker. It polls the button state */
+static int kpowerswd(void *param)
 {
-	if (unlikely(!pwrsw_enabled))
-		return;
-
-	if (__getDIAG(25) & 0x80000000) {
-		/* power switch button not pressed or released again */
-		/* Warning: Some machines do never reset this DIAG flag! */
-		shutdown_timer = 0;
-	} else {
-		process_shutdown();
-	}
-}
-
+	__set_current_state(TASK_RUNNING);
+
+	do {
+		int button_not_pressed;
+		unsigned long soft_power_reg = (unsigned long) param;
+
+		schedule_timeout_interruptible(pwrsw_enabled ? HZ : HZ/POWERSWITCH_POLL_PER_SEC);
+		__set_current_state(TASK_RUNNING);
+
+		if (unlikely(!pwrsw_enabled))
+			continue;
+
+		if (soft_power_reg) {
+			/*
+			 * Non-Gecko-style machines:
+			 * Check the power switch status which is read from the
+			 * real I/O location at soft_power_reg.
+			 * Bit 31 ("the lowest bit) is the status of the power switch.
+			 * This bit is "1" if the button is NOT pressed.
+			 */
+			button_not_pressed = (gsc_readl(soft_power_reg) & 0x1);
+		} else {
+			/*
+			 * On gecko style machines (e.g. 712/xx and 715/xx) 
+			 * the power switch status is stored in Bit 0 ("the highest bit")
+			 * of CPU diagnose register 25.
+			 * Warning: Some machines never reset the DIAG flag, even if
+			 * the button has been released again.
+			 */
+			button_not_pressed = (__getDIAG(25) & 0x80000000);
+		}
+
+		if (likely(button_not_pressed)) {
+			if (unlikely(shutdown_timer && /* avoid writing if not necessary */
+				shutdown_timer < (POWERSWITCH_DOWN_SEC*POWERSWITCH_POLL_PER_SEC))) {
+				shutdown_timer = 0;
+				printk(KERN_INFO KTHREAD_NAME ": Shutdown request aborted.\n");
+			}
+		} else
+			process_shutdown();
+
+
+	} while (!kthread_should_stop());
 
-
-/*
- * Check the power switch status which is read from the
- * real I/O location at soft_power_reg.
- * Bit 31 ("the lowest bit) is the status of the power switch.
- */
-
-static void polling_tasklet_func(unsigned long soft_power_reg)
-{
-        unsigned long current_status;
-	
-	if (unlikely(!pwrsw_enabled))
-		return;
-
-	current_status = gsc_readl(soft_power_reg);
-	if (current_status & 0x1) {
-		/* power switch button not pressed */
-		shutdown_timer = 0;
-	} else {
-		process_shutdown();
-	}
+	return 0;
 }
 
 
@@ -220,7 +197,7 @@ static struct notifier_block parisc_panic_block = {
 static int __init power_init(void)
 {
 	unsigned long ret;
-	unsigned long soft_power_reg = 0;
+	unsigned long soft_power_reg;
 
 #if 0
 	request_irq( IRQ_FROM_REGION(CPU_IRQ_REGION)+2, &powerfail_interrupt,
@@ -235,44 +212,44 @@ static int __init power_init(void)
 		soft_power_reg = -1UL;
 	
 	switch (soft_power_reg) {
-	case 0:		printk(KERN_INFO "Gecko-style soft power switch enabled.\n");
-			power_tasklet.func = gecko_tasklet_func;
+	case 0:		printk(KERN_INFO DRIVER_NAME ": Gecko-style soft power switch enabled.\n");
 			break;
 			
-	case -1UL:	printk(KERN_INFO "Soft power switch support not available.\n");
+	case -1UL:	printk(KERN_INFO DRIVER_NAME ": Soft power switch support not available.\n");
 			return -ENODEV;
 	
-	default:	printk(KERN_INFO "Soft power switch enabled, polling @ 0x%08lx.\n",
+	default:	printk(KERN_INFO DRIVER_NAME ": Soft power switch at 0x%08lx enabled.\n",
 				soft_power_reg);
-			power_tasklet.data = soft_power_reg;
-			power_tasklet.func = polling_tasklet_func;
+	}
+
+	power_task = kthread_run(kpowerswd, (void*)soft_power_reg, KTHREAD_NAME);
+	if (IS_ERR(power_task)) {
+		printk(KERN_ERR DRIVER_NAME ": thread creation failed.  Driver not loaded.\n");
+		pdc_soft_power_button(0);
+		return -EIO;
 	}
 
 	/* Register a call for panic conditions. */
 	atomic_notifier_chain_register(&panic_notifier_list,
 			&parisc_panic_block);
 
-	tasklet_enable(&power_tasklet);
-
 	return 0;
 }
 
 static void __exit power_exit(void)
 {
-	if (!power_tasklet.func)
-		return;
+	kthread_stop(power_task);
 
-	tasklet_disable(&power_tasklet);
 	atomic_notifier_chain_unregister(&panic_notifier_list,
 			&parisc_panic_block);
-	power_tasklet.func = NULL;
+
 	pdc_soft_power_button(0);
 }
 
-module_init(power_init);
+arch_initcall(power_init);
 module_exit(power_exit);
 
 
-MODULE_AUTHOR("Helge Deller");
+MODULE_AUTHOR("Helge Deller <deller@gmx.de>");
 MODULE_DESCRIPTION("Soft power switch driver");
 MODULE_LICENSE("Dual BSD/GPL");
diff --git a/include/asm-parisc/led.h b/include/asm-parisc/led.h
index efadfd543ec6..c3405ab9d60a 100644
--- a/include/asm-parisc/led.h
+++ b/include/asm-parisc/led.h
@@ -31,7 +31,7 @@ void __init register_led_regions(void);
 
 #ifdef CONFIG_CHASSIS_LCD_LED
 /* writes a string to the LCD display (if possible on this h/w) */
-int lcd_print(char *str);
+int lcd_print(const char *str);
 #else
 #define lcd_print(str)
 #endif