x86, rtc: make CONFIG_HPET_EMULATE_RTC usable from modules

enabled, then interrupts don't work for the rtc-cmos driver which results in
RTC_AIE*, RTC_PIE* and RTC_ALM being unusable.  This affects hwclock from
util-linux-ng at least on i386 since that uses RTC_PIE_ON.  (For x86-64, a
polling method is used for unknown reasons.)

This patch series now

  1. export the functions from arch/x86/kernel/hpet.c that the old char/rtc
     driver uses to work around that problem,

  2. makes it possible to compile the old rtc driver as module, while still
     having CONFIG_HPET_EMULATE_RTC enabled and

  3. makes use of the exported functions in (1) in the new rtc-cmos driver.

This patch:

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 <bwalle@suse.de>
Cc: Alessandro Zummo <a.zummo@towertech.it>
Cc: David Brownell <david-b@pacbell.net>
Cc: Andi Kleen <ak@suse.de>
Cc: john stultz <johnstul@us.ibm.com>
Cc: Robert Picco <Robert.Picco@hp.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

diff --git a/arch/x86/kernel/hpet.c b/arch/x86/kernel/hpet.c
index 5c1702789be400aac422acae49c1c33b4a4875cf..d65ced59a18fc14fefb07ce7d7c7bcc44896d125 100644 (file)
--- 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
@@ -475,6 +476,7 @@ 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
@@ -489,6 +491,38 @@ 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.
@@ -530,6 +564,7 @@ int hpet_rtc_timer_init(void)
 
        return 1;
 }
+EXPORT_SYMBOL_GPL(hpet_rtc_timer_init);
 
 /*
  * The functions below are called from rtc driver.
@@ -544,6 +579,7 @@ int hpet_mask_rtc_irq_bit(unsigned long bit_mask)
        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)
 {
@@ -559,6 +595,7 @@ int hpet_set_rtc_irq_bit(unsigned long bit_mask)
 
        return 1;
 }
+EXPORT_SYMBOL_GPL(hpet_set_rtc_irq_bit);
 
 int hpet_set_alarm_time(unsigned char hrs, unsigned char min,
                        unsigned char sec)
@@ -572,6 +609,7 @@ int hpet_set_alarm_time(unsigned char hrs, unsigned char min,
 
        return 1;
 }
+EXPORT_SYMBOL_GPL(hpet_set_alarm_time);
 
 int hpet_set_periodic_freq(unsigned long freq)
 {
@@ -590,11 +628,13 @@ int hpet_set_periodic_freq(unsigned long freq)
        }
        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)
 {
@@ -638,9 +678,10 @@ irqreturn_t hpet_rtc_interrupt(int irq, void *dev_id)
        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) {
@@ -662,8 +703,12 @@ irqreturn_t hpet_rtc_interrupt(int irq, void *dev_id)
 
        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

diff --git a/include/asm-x86/hpet.h b/include/asm-x86/hpet.h
index 624f600f716180a7340999d34bc73ef21f9dc2b2..6a9b4ac59bf717c321f6e10d8c74a9e2796e0c31 100644 (file)
--- 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(unsigned long freq);
 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 */