Add a delay after rtc_set_datetime (#2156)

If you call rtc_get_datetime immediately after rtc_set_datetime you get
junk back. According to the datasheet "Writing to the RTC will take
2 clk_rtc clock periods to arrive". So add a delay after calling
rtc_set_datetime in aon_timer_set_time_calendar.

Fixes #2148

Author: peterharperuk

src/rp2_common/pico_aon_timer/BUILD.bazel

@@ -6,10 +6,14 @@ cc_library(
     name = "pico_aon_timer",
     srcs = ["aon_timer.c"],
     hdrs = ["include/pico/aon_timer.h"],
+    defines = [
+        "LIB_PICO_AON_TIMER=1",
+    ],
     includes = ["include"],
     target_compatible_with = compatible_with_rp2(),
     deps = [
         "//src/common/pico_util",
+        "//src/common/pico_time",
         "//src/rp2_common:hardware_regs",
         "//src/rp2_common:pico_platform",
         "//src/rp2_common/hardware_irq",

src/rp2_common/pico_aon_timer/CMakeLists.txt

@@ -12,6 +12,7 @@ pico_mirrored_target_link_libraries(pico_aon_timer INTERFACE pico_util)
 
 if (TARGET hardware_rtc)
     pico_mirrored_target_link_libraries(pico_aon_timer INTERFACE hardware_rtc)
+    target_link_libraries(pico_aon_timer_headers INTERFACE pico_time_headers)
 endif()
 
 if (TARGET hardware_powman)

src/rp2_common/pico_aon_timer/aon_timer.c

@@ -13,6 +13,8 @@ static aon_timer_alarm_handler_t aon_timer_alarm_handler;
 #if HAS_RP2040_RTC
 #include "hardware/rtc.h"
 #include "pico/util/datetime.h"
+#include "pico/time.h"
+#include "hardware/clocks.h"
 
 #elif HAS_POWMAN_TIMER
 #include "hardware/powman.h"
@@ -56,6 +58,10 @@ bool aon_timer_set_time_calendar(const struct tm *tm) {
     datetime_t dt;
     tm_to_datetime(tm, &dt);
     rtc_set_datetime(&dt);
+
+    // Writing to the RTC will take 2 clk_rtc clock periods to arrive
+    uint rtc_freq = clock_get_hz(clk_rtc);
+    busy_wait_us(((1000000 + rtc_freq - 1) / rtc_freq) * 2);
     return true;
 #elif HAS_POWMAN_TIMER
     struct timespec ts;

test/pico_time_test/BUILD.bazel

@@ -12,6 +12,7 @@ cc_binary(
     target_compatible_with = compatible_with_rp2(),
     deps = [
         "//src/rp2_common/pico_stdlib",
+        "//src/rp2_common/pico_aon_timer",
         "//test/pico_test",
     ],
 )

test/pico_time_test/CMakeLists.txt

@@ -4,5 +4,8 @@ if (NOT PICO_TIME_NO_ALARM_SUPPORT)
             PICO_TIME_DEFAULT_ALARM_POOL_MAX_TIMERS=250
     )
     target_link_libraries(pico_time_test PRIVATE pico_test)
+    if (PICO_RP2040)
+        target_link_libraries(pico_time_test PRIVATE pico_aon_timer)
+    endif()
     pico_add_extra_outputs(pico_time_test)
 endif()

test/pico_time_test/pico_time_test.c

@@ -13,6 +13,11 @@
 #endif
 #include "pico/stdlib.h"
 #include "pico/test.h"
+
+#if LIB_PICO_AON_TIMER
+#include "pico/aon_timer.h"
+#endif
+
 // Include sys/types.h before inttypes.h to work around issue with
 // certain versions of GCC and newlib which causes omission of PRIi64
 #include <sys/types.h>
@@ -74,11 +79,12 @@ static bool repeating_timer_callback(struct repeating_timer *t) {
 #define RESOLUTION_ALLOWANCE PICO_HARDWARE_TIMER_RESOLUTION_US
 #endif
 
-int issue_195_test(void);
-int issue_1812_test(void);
-int issue_1953_test(void);
-int issue_2118_test(void);
-int issue_2186_test(void);
+static int issue_195_test(void);
+static int issue_1812_test(void);
+static int issue_1953_test(void);
+static int issue_2118_test(void);
+static int issue_2148_test(void);
+static int issue_2186_test(void);
 
 int main() {
     setup_default_uart();
@@ -253,6 +259,8 @@ int main() {
 
     issue_2118_test();
 
+    issue_2148_test();
+    
     issue_2186_test();
 
     PICOTEST_END_TEST();
@@ -265,7 +273,7 @@ int64_t issue_195_callback(alarm_id_t id, void *user_data) {
     return -ISSUE_195_TIMER_DELAY;
 }
 
-int issue_195_test(void) {
+static int issue_195_test(void) {
     PICOTEST_START_SECTION("Issue #195 race condition - without fix may hang on gcc 10.2.1 release builds");
     absolute_time_t t1 = get_absolute_time();
     int id = add_alarm_in_us(ISSUE_195_TIMER_DELAY, issue_195_callback, NULL, true);
@@ -284,7 +292,7 @@ int issue_195_test(void) {
 }
 
 // Setting an alarm should not swallow a sev
-int issue_1812_test(void) {
+static int issue_1812_test(void) {
     PICOTEST_START_SECTION("Issue #1812 defect - Setting an alarm should not ignore a sev");
 
     __sev(); // Make sure the call below does not ignore this
@@ -308,7 +316,7 @@ static void alarm_pool_stuck_issue_1953(uint alarm) {
     hard_assert(false);
 }
 
-int issue_1953_test(void) {
+static int issue_1953_test(void) {
     PICOTEST_START_SECTION("Issue #1953 defect - Alarm can be set in the past");
     int alarm = hardware_alarm_claim_unused(true);
     hardware_alarm_set_callback(alarm, alarm_pool_stuck_issue_1953);
@@ -341,7 +349,7 @@ static bool timer_callback_issue_2118(repeating_timer_t *rt) {
     return true;
 }
 
-int issue_2118_test(void) {
+static int issue_2118_test(void) {
     PICOTEST_START_SECTION("Issue #2118 defect - failure to set an alarm");
 
 #if PICO_ON_DEVICE
@@ -373,7 +381,7 @@ int issue_2118_test(void) {
     return 0;
 }
 
-int issue_2186_test(void) {
+static int issue_2186_test(void) {
     PICOTEST_START_SECTION("Issue #2186 defect - ta_wakes_up_on_or_before");
 
     hard_assert(best_effort_wfe_or_timeout(get_absolute_time() - 1));
@@ -382,3 +390,34 @@ int issue_2186_test(void) {
     PICOTEST_END_SECTION();
     return 0;
 }
+
+static int issue_2148_test(void) {
+#if HAS_RP2040_RTC
+    PICOTEST_START_SECTION("Issue #2148 defect - get time after rtc start");
+    struct tm tm = { 0 };
+    struct tm tm_check = { 0 };
+
+    tm.tm_sec = 55;
+    tm.tm_min = 36;
+    tm.tm_hour = 20;
+    tm.tm_mday = 21;
+    tm.tm_mon = 10;
+    tm.tm_year = 124;
+    tm.tm_wday = 4;
+    tm.tm_yday = 325;
+    tm.tm_isdst = 0;
+    hard_assert(aon_timer_start_calendar(&tm));
+    hard_assert(aon_timer_get_time_calendar(&tm_check));
+
+    PICOTEST_CHECK(tm.tm_sec == tm_check.tm_sec || tm.tm_sec == tm_check.tm_sec - 1, "failed to get seconds");
+    PICOTEST_CHECK(tm.tm_min == tm_check.tm_min, "failed to get minutes");
+    PICOTEST_CHECK(tm.tm_hour == tm_check.tm_hour, "failed to get hour");
+    PICOTEST_CHECK(tm.tm_mday == tm_check.tm_mday, "failed to get day");
+    PICOTEST_CHECK(tm.tm_mon == tm_check.tm_mon, "failed to get month");
+    PICOTEST_CHECK(tm.tm_year == tm_check.tm_year, "failed to get year");
+
+    aon_timer_stop();
+    PICOTEST_END_SECTION();
+#endif
+    return 0;
+}