From: Ahmad Fatoum <a.fatoum@pengutronix.de>
Date: Mon, 15 Jul 2024 20:23:09 +0000 (+0200)
Subject: rtc: export RTC_Linux_{SwitchInterrupt,CheckInterrupt}
X-Git-Tag: 4.7-pre1~56
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=8028984f34963898b59617c1e46a3ef02f2c78ea;p=thirdparty%2Fchrony.git

rtc: export RTC_Linux_{SwitchInterrupt,CheckInterrupt}

We have code to enable and disable the RTC's UIE interrupt, as well as
check whether it occurred and skip the first interrupt as it may be
bogus.
This is currently used as part of maintaining the correction file.

In a later commit, we will need the same functionality for using the RTC
as reference clock, so export the functions and give them descriptive
names appropriate for globally visible functions.
---

diff --git a/rtc_linux.c b/rtc_linux.c
index 11e2baa4..06e19308 100644
--- a/rtc_linux.c
+++ b/rtc_linux.c
@@ -497,8 +497,8 @@ write_coefs_to_file(int valid,time_t ref_time,double offset,double rate)
 
 /* ================================================== */
 
-static int
-switch_interrupts(int on_off)
+int
+RTC_Linux_SwitchInterrupt(int fd, int on_off)
 {
   if (ioctl(fd, on_off ? RTC_UIE_ON : RTC_UIE_OFF, 0) < 0) {
     LOG(LOGS_ERR, "Could not %s RTC interrupt : %s",
@@ -529,7 +529,7 @@ RTC_Linux_Initialise(void)
   }
 
   /* Make sure the RTC supports interrupts */
-  if (!switch_interrupts(1) || !switch_interrupts(0)) {
+  if (!RTC_Linux_SwitchInterrupt(fd, 1) || !RTC_Linux_SwitchInterrupt(fd, 0)) {
     close(fd);
     return 0;
   }
@@ -578,7 +578,7 @@ RTC_Linux_Finalise(void)
   /* Remove input file handler */
   if (fd >= 0) {
     SCH_RemoveFileHandler(fd);
-    switch_interrupts(0);
+    RTC_Linux_SwitchInterrupt(fd, 0);
     close(fd);
 
     /* Save the RTC data */
@@ -599,7 +599,7 @@ static void
 measurement_timeout(void *any)
 {
   timeout_id = 0;
-  switch_interrupts(1);
+  RTC_Linux_SwitchInterrupt(fd, 1);
 }
 
 /* ================================================== */
@@ -760,15 +760,11 @@ process_reading(time_t rtc_time, struct timespec *system_time)
 
 /* ================================================== */
 
-static void
-read_from_device(int fd_, int event, void *any)
+int
+RTC_Linux_CheckInterrupt(int fd)
 {
   int status;
   unsigned long data;
-  struct timespec sys_time;
-  struct rtc_time rtc_raw;
-  time_t rtc_t;
-  int error = 0;
 
   status = read(fd, &data, sizeof(data));
 
@@ -776,56 +772,67 @@ read_from_device(int fd_, int event, void *any)
     /* This looks like a bad error : the file descriptor was indicating it was
      * ready to read but we couldn't read anything.  Give up. */
     LOG(LOGS_ERR, "Could not read flags %s : %s", CNF_GetRtcDevice(), strerror(errno));
-    SCH_RemoveFileHandler(fd);
-    switch_interrupts(0); /* Likely to raise error too, but just to be sure... */
-    close(fd);
-    fd = -1;
-    return;
-  }    
+    return -1;
+  }
 
   if (skip_interrupts > 0) {
     /* Wait for the next interrupt, this one may be bogus */
     skip_interrupts--;
+    return 0;
+  }
+
+  /* Update interrupt detected? */
+  return (data & RTC_UF) == RTC_UF;
+}
+
+static void
+read_from_device(int fd_, int event, void *any)
+{
+  struct timespec sys_time;
+  struct rtc_time rtc_raw;
+  int status, error = 0;
+  time_t rtc_t;
+
+  status = RTC_Linux_CheckInterrupt(fd);
+  if (status < 0) {
+    SCH_RemoveFileHandler(fd);
+    RTC_Linux_SwitchInterrupt(fd, 0); /* Likely to raise error too, but just to be sure... */
+    close(fd);
+    fd = -1;
+    return;
+  } else if (status == 0) {
     return;
   }
 
-  if ((data & RTC_UF) == RTC_UF) {
-    /* Update interrupt detected */
-    
-    /* Read RTC time, sandwiched between two polls of the system clock
-       so we can bound any error. */
+  SCH_GetLastEventTime(&sys_time, NULL, NULL);
 
-    SCH_GetLastEventTime(&sys_time, NULL, NULL);
+  status = ioctl(fd, RTC_RD_TIME, &rtc_raw);
+  if (status < 0) {
+    LOG(LOGS_ERR, "Could not read time from %s : %s", CNF_GetRtcDevice(), strerror(errno));
+    error = 1;
+    goto turn_off_interrupt;
+  }
 
-    status = ioctl(fd, RTC_RD_TIME, &rtc_raw);
-    if (status < 0) {
-      LOG(LOGS_ERR, "Could not read time from %s : %s", CNF_GetRtcDevice(), strerror(errno));
-      error = 1;
-      goto turn_off_interrupt;
-    }
+  /* Convert RTC time into a struct timespec */
+  rtc_t = t_from_rtc(&rtc_raw, rtc_on_utc);
 
-    /* Convert RTC time into a struct timespec */
-    rtc_t = t_from_rtc(&rtc_raw, rtc_on_utc);
+  if (rtc_t == (time_t)(-1)) {
+    error = 1;
+    goto turn_off_interrupt;
+  }
 
-    if (rtc_t == (time_t)(-1)) {
-      error = 1;
-      goto turn_off_interrupt;
-    }      
-
-    process_reading(rtc_t, &sys_time);
-
-    if (n_samples < 4) {
-      measurement_period = LOWEST_MEASUREMENT_PERIOD;
-    } else if (n_samples < 6) {
-      measurement_period = LOWEST_MEASUREMENT_PERIOD << 1;
-    } else if (n_samples < 10) {
-      measurement_period = LOWEST_MEASUREMENT_PERIOD << 2;
-    } else if (n_samples < 14) {
-      measurement_period = LOWEST_MEASUREMENT_PERIOD << 3;
-    } else {
-      measurement_period = LOWEST_MEASUREMENT_PERIOD << 4;
-    }
+  process_reading(rtc_t, &sys_time);
 
+  if (n_samples < 4) {
+    measurement_period = LOWEST_MEASUREMENT_PERIOD;
+  } else if (n_samples < 6) {
+    measurement_period = LOWEST_MEASUREMENT_PERIOD << 1;
+  } else if (n_samples < 10) {
+    measurement_period = LOWEST_MEASUREMENT_PERIOD << 2;
+  } else if (n_samples < 14) {
+    measurement_period = LOWEST_MEASUREMENT_PERIOD << 3;
+  } else {
+    measurement_period = LOWEST_MEASUREMENT_PERIOD << 4;
   }
 
 turn_off_interrupt:
@@ -837,7 +844,7 @@ turn_off_interrupt:
         operating_mode = OM_NORMAL;
         (after_init_hook)(after_init_hook_arg);
 
-        switch_interrupts(0);
+        RTC_Linux_SwitchInterrupt(fd, 0);
     
         timeout_id = SCH_AddTimeoutByDelay((double) measurement_period, measurement_timeout, NULL);
       }
@@ -849,7 +856,7 @@ turn_off_interrupt:
         DEBUG_LOG("Could not complete after trim relock due to errors");
         operating_mode = OM_NORMAL;
 
-        switch_interrupts(0);
+        RTC_Linux_SwitchInterrupt(fd, 0);
     
         timeout_id = SCH_AddTimeoutByDelay((double) measurement_period, measurement_timeout, NULL);
       }
@@ -857,7 +864,7 @@ turn_off_interrupt:
       break;
 
     case OM_NORMAL:
-      switch_interrupts(0);
+      RTC_Linux_SwitchInterrupt(fd, 0);
     
       timeout_id = SCH_AddTimeoutByDelay((double) measurement_period, measurement_timeout, NULL);
 
@@ -879,7 +886,7 @@ RTC_Linux_TimeInit(void (*after_hook)(void *), void *anything)
 
   operating_mode = OM_INITIAL;
   timeout_id = 0;
-  switch_interrupts(1);
+  RTC_Linux_SwitchInterrupt(fd, 1);
 }
 
 /* ================================================== */
@@ -1058,7 +1065,7 @@ RTC_Linux_Trim(void)
     /* And start rapid sampling, interrupts on now */
     SCH_RemoveTimeout(timeout_id);
     timeout_id = 0;
-    switch_interrupts(1);
+    RTC_Linux_SwitchInterrupt(fd, 1);
   }
 
   return 1;
diff --git a/rtc_linux.h b/rtc_linux.h
index fa33ef16..1f67ba80 100644
--- a/rtc_linux.h
+++ b/rtc_linux.h
@@ -42,4 +42,7 @@ extern int RTC_Linux_Trim(void);
 
 extern void RTC_Linux_CycleLogFile(void);
 
+extern int RTC_Linux_SwitchInterrupt(int fd, int on_off);
+extern int RTC_Linux_CheckInterrupt(int fd);
+
 #endif /* _GOT_RTC_LINUX_H */