This patch makes the RTC emulation functions in arch/x86/kernel/hpet.c usable
for kernel modules. It

  - exports the functions (EXPORT_SYMBOL_GPL()),
  - adds an interface to register the interrupt callback function
    instead of using only a fixed callback function and
  - replaces the rtc_get_rtc_time() function which depends on
    CONFIG_RTC with a call to get_rtc_time() which is defined in
    include/asm-generic/rtc.h.

The only dependency to CONFIG_RTC is the call to rtc_interrupt() which is
removed by the next patch. After this, there's no (code) dependency of
this functions to CONFIG_RTC=y any more.


Signed-off-by: Bernhard Walle <[EMAIL PROTECTED]>

---
 arch/x86/kernel/hpet.c |   47 ++++++++++++++++++++++++++++++++++++++++++++++-
 include/asm-x86/hpet.h |    3 +++
 2 files changed, 49 insertions(+), 1 deletion(-)

--- a/arch/x86/kernel/hpet.c
+++ b/arch/x86/kernel/hpet.c
@@ -107,6 +107,7 @@ int is_hpet_enabled(void)
 {
        return is_hpet_capable() && hpet_legacy_int_enabled;
 }
+EXPORT_SYMBOL_GPL(is_hpet_enabled);
 
 /*
  * When the hpet driver (/dev/hpet) is enabled, we need to reserve
@@ -478,6 +479,7 @@ void hpet_disable(void)
  */
 #include <linux/mc146818rtc.h>
 #include <linux/rtc.h>
+#include <asm/rtc.h>
 
 #define DEFAULT_RTC_INT_FREQ   64
 #define DEFAULT_RTC_SHIFT      6
@@ -492,6 +494,38 @@ static unsigned long hpet_default_delta;
 static unsigned long hpet_pie_delta;
 static unsigned long hpet_pie_limit;
 
+static rtc_irq_handler irq_handler;
+
+/*
+ * Registers a IRQ handler.
+ */
+int hpet_register_irq_handler(rtc_irq_handler handler)
+{
+       if (!is_hpet_enabled())
+               return -ENODEV;
+       if (irq_handler)
+               return -EBUSY;
+
+       irq_handler = handler;
+
+       return 0;
+}
+EXPORT_SYMBOL_GPL(hpet_register_irq_handler);
+
+/*
+ * Deregisters the IRQ handler registered with hpet_register_irq_handler()
+ * and does cleanup.
+ */
+void hpet_unregister_irq_handler(rtc_irq_handler handler)
+{
+       if (!is_hpet_enabled())
+               return;
+
+       irq_handler = NULL;
+       hpet_rtc_flags = 0;
+}
+EXPORT_SYMBOL_GPL(hpet_unregister_irq_handler);
+
 /*
  * Timer 1 for RTC emulation. We use one shot mode, as periodic mode
  * is not supported by all HPET implementations for timer 1.
@@ -533,6 +567,7 @@ int hpet_rtc_timer_init(void)
 
        return 1;
 }
+EXPORT_SYMBOL_GPL(hpet_rtc_timer_init);
 
 /*
  * The functions below are called from rtc driver.
@@ -547,6 +582,7 @@ int hpet_mask_rtc_irq_bit(unsigned long 
        hpet_rtc_flags &= ~bit_mask;
        return 1;
 }
+EXPORT_SYMBOL_GPL(hpet_mask_rtc_irq_bit);
 
 int hpet_set_rtc_irq_bit(unsigned long bit_mask)
 {
@@ -562,6 +598,7 @@ int hpet_set_rtc_irq_bit(unsigned long b
 
        return 1;
 }
+EXPORT_SYMBOL_GPL(hpet_set_rtc_irq_bit);
 
 int hpet_set_alarm_time(unsigned char hrs, unsigned char min,
                        unsigned char sec)
@@ -575,6 +612,7 @@ int hpet_set_alarm_time(unsigned char hr
 
        return 1;
 }
+EXPORT_SYMBOL_GPL(hpet_set_alarm_time);
 
 int hpet_set_periodic_freq(unsigned long freq)
 {
@@ -593,11 +631,13 @@ int hpet_set_periodic_freq(unsigned long
        }
        return 1;
 }
+EXPORT_SYMBOL_GPL(hpet_set_periodic_freq);
 
 int hpet_rtc_dropped_irq(void)
 {
        return is_hpet_enabled();
 }
+EXPORT_SYMBOL_GPL(hpet_rtc_dropped_irq);
 
 static void hpet_rtc_timer_reinit(void)
 {
@@ -641,9 +681,10 @@ irqreturn_t hpet_rtc_interrupt(int irq, 
        unsigned long rtc_int_flag = 0;
 
        hpet_rtc_timer_reinit();
+       memset(&curr_time, 0, sizeof(struct rtc_time));
 
        if (hpet_rtc_flags & (RTC_UIE | RTC_AIE))
-               rtc_get_rtc_time(&curr_time);
+               get_rtc_time(&curr_time);
 
        if (hpet_rtc_flags & RTC_UIE &&
            curr_time.tm_sec != hpet_prev_update_sec) {
@@ -665,8 +706,12 @@ irqreturn_t hpet_rtc_interrupt(int irq, 
 
        if (rtc_int_flag) {
                rtc_int_flag |= (RTC_IRQF | (RTC_NUM_INTS << 8));
+               if (irq_handler)
+                       irq_handler(rtc_int_flag, dev_id);
+
                rtc_interrupt(rtc_int_flag, dev_id);
        }
        return IRQ_HANDLED;
 }
+EXPORT_SYMBOL_GPL(hpet_rtc_interrupt);
 #endif
--- a/include/asm-x86/hpet.h
+++ b/include/asm-x86/hpet.h
@@ -69,6 +69,7 @@ extern void force_hpet_resume(void);
 
 #include <linux/interrupt.h>
 
+typedef irqreturn_t (*rtc_irq_handler)(int interrupt, void *cookie);
 extern int hpet_mask_rtc_irq_bit(unsigned long bit_mask);
 extern int hpet_set_rtc_irq_bit(unsigned long bit_mask);
 extern int hpet_set_alarm_time(unsigned char hrs, unsigned char min,
@@ -77,6 +78,8 @@ extern int hpet_set_periodic_freq(unsign
 extern int hpet_rtc_dropped_irq(void);
 extern int hpet_rtc_timer_init(void);
 extern irqreturn_t hpet_rtc_interrupt(int irq, void *dev_id);
+extern int hpet_register_irq_handler(rtc_irq_handler handler);
+extern void hpet_unregister_irq_handler(rtc_irq_handler handler);
 
 #endif /* CONFIG_HPET_EMULATE_RTC */
 

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