drv/clock: move clock driver out of contiki

This refactors the code base to use pbdrv_clock_* instead of clock_*
from contiki. This is a step towards eliminating contiki from the
public API, which will be nice if we ever have PBIO as a stand-alone
C library.

It also simplifies the code a bit since it gets rid of clock_from_msec()
and clock_to_msec() which were NOPs in the PBIO library anyway.

clock_delay_usec() is moved into the MicroPython code (as
mp_hal_delay_us()) since we want to avoid any blocking functions
in PBIO.

bricks/cityhub/mphalport.h

@@ -1,10 +1,9 @@
 // SPDX-License-Identifier: MIT
-// Copyright (c) 2018-2020 The Pybricks Authors
+// Copyright (c) 2018-2021 The Pybricks Authors
 
-#include <contiki.h>
+#include <pbdrv/clock.h>
 
 void mp_hal_set_interrupt_char(int c);
-#define mp_hal_ticks_ms clock_time
-#define mp_hal_ticks_us clock_usecs
-#define mp_hal_delay_us clock_delay_usec
+#define mp_hal_ticks_ms pbdrv_clock_get_ms
+#define mp_hal_ticks_us pbdrv_clock_get_us
 #define mp_hal_ticks_cpu() 0

bricks/debug/mphalport.h

@@ -1,10 +1,9 @@
 // SPDX-License-Identifier: MIT
-// Copyright (c) 2018-2020 The Pybricks Authors
+// Copyright (c) 2018-2021 The Pybricks Authors
 
-#include <contiki.h>
+#include <pbdrv/clock.h>
 
 void mp_hal_set_interrupt_char(int c);
-#define mp_hal_ticks_ms clock_time
-#define mp_hal_ticks_us clock_usecs
-#define mp_hal_delay_us clock_delay_usec
+#define mp_hal_ticks_ms pbdrv_clock_get_ms
+#define mp_hal_ticks_us pbdrv_clock_get_us
 #define mp_hal_ticks_cpu() 0

bricks/essentialhub/mphalport.h

@@ -1,10 +1,9 @@
 // SPDX-License-Identifier: MIT
-// Copyright (c) 2018-2020 The Pybricks Authors
+// Copyright (c) 2018-2021 The Pybricks Authors
 
-#include "sys/clock.h"
+#include <pbdrv/clock.h>
 
 void mp_hal_set_interrupt_char(int c);
-#define mp_hal_ticks_ms clock_time
-#define mp_hal_ticks_us clock_usecs
-#define mp_hal_delay_us clock_delay_usec
+#define mp_hal_ticks_ms pbdrv_clock_get_ms
+#define mp_hal_ticks_us pbdrv_clock_get_us
 #define mp_hal_ticks_cpu() 0

bricks/ev3dev/ev3dev_mphal.c

@@ -33,7 +33,7 @@
 #include <unistd.h>
 #include <sys/time.h>
 
-#include <contiki.h>
+#include <pbdrv/clock.h>
 
 #include "py/mphal.h"
 #include "py/runtime.h"
@@ -125,11 +125,11 @@ void mp_hal_stdout_tx_str(const char *str) {
 }
 
 mp_uint_t mp_hal_ticks_ms(void) {
-    return clock_to_msec(clock_time());
+    return pbdrv_clock_get_ms();
 }
 
 mp_uint_t mp_hal_ticks_us(void) {
-    return clock_usecs();
+    return pbdrv_clock_get_us();
 }
 
 uint64_t mp_hal_time_ns(void) {

bricks/movehub/mphalport.h

@@ -1,10 +1,9 @@
 // SPDX-License-Identifier: MIT
-// Copyright (c) 2018-2020 The Pybricks Authors
+// Copyright (c) 2018-2021 The Pybricks Authors
 
-#include <contiki.h>
+#include <pbdrv/clock.h>
 
 void mp_hal_set_interrupt_char(int c);
-#define mp_hal_ticks_ms clock_time
-#define mp_hal_ticks_us clock_usecs
-#define mp_hal_delay_us clock_delay_usec
+#define mp_hal_ticks_ms pbdrv_clock_get_ms
+#define mp_hal_ticks_us pbdrv_clock_get_us
 #define mp_hal_ticks_cpu() 0

bricks/nxt/mphalport.h

@@ -1,10 +1,9 @@
 // SPDX-License-Identifier: MIT
-// Copyright (c) 2018-2020 The Pybricks Authors
+// Copyright (c) 2018-2021 The Pybricks Authors
 
-#include <contiki.h>
+#include <pbdrv/clock.h>
 
 void mp_hal_set_interrupt_char(int c);
-#define mp_hal_ticks_ms clock_time
-#define mp_hal_ticks_us clock_usecs
-#define mp_hal_delay_us clock_delay_usec
+#define mp_hal_ticks_ms pbdrv_clock_get_ms
+#define mp_hal_ticks_us pbdrv_clock_get_us
 #define mp_hal_ticks_cpu() 0

bricks/nxt/systick.c

@@ -9,6 +9,7 @@
 #include "py/mphal.h"
 #include "py/mpconfig.h"
 
+#include <nxt/at91sam7.h>
 #include <nxt/interrupts.h>
 #include <nxt/systick.h>
 
@@ -30,3 +31,17 @@ void mp_hal_delay_ms(mp_uint_t Delay) {
         systick_wait_ms(Delay);
     }
 }
+
+/* The inner loop takes 4 cycles. The outer 5+SPIN_COUNT*4. */
+
+#define SPIN_TIME 2 /* us */
+#define SPIN_COUNT (((CLOCK_FREQUENCY * SPIN_TIME / 1000000) - 5) / 4)
+
+void mp_hal_delay_us(mp_uint_t t) {
+    #ifdef __THUMBEL__
+    __asm volatile ("1: mov r1,%2\n2:\tsub r1,#1\n\tbne 2b\n\tsub %0,#1\n\tbne 1b\n"
+        : "=l" (t) : "0" (t), "l" (SPIN_COUNT));
+    #else
+    #error Must be compiled in thumb mode
+    #endif
+}

bricks/primehub/mphalport.h

@@ -1,10 +1,9 @@
 // SPDX-License-Identifier: MIT
-// Copyright (c) 2018-2020 The Pybricks Authors
+// Copyright (c) 2018-2021 The Pybricks Authors
 
-#include "sys/clock.h"
+#include <pbdrv/clock.h>
 
 void mp_hal_set_interrupt_char(int c);
-#define mp_hal_ticks_ms clock_time
-#define mp_hal_ticks_us clock_usecs
-#define mp_hal_delay_us clock_delay_usec
+#define mp_hal_ticks_ms pbdrv_clock_get_ms
+#define mp_hal_ticks_us pbdrv_clock_get_us
 #define mp_hal_ticks_cpu() 0

bricks/stm32/configport.h

@@ -69,7 +69,7 @@
 #define MICROPY_PY_SYS_STDIO_BUFFER         (PYBRICKS_STM32_OPT_EXTRA_MOD)
 #define MICROPY_PY_URANDOM                  (PYBRICKS_STM32_OPT_EXTRA_MOD)
 #define MICROPY_PY_URANDOM_EXTRA_FUNCS      (PYBRICKS_STM32_OPT_EXTRA_MOD)
-#define MICROPY_PY_URANDOM_SEED_INIT_FUNC   ({ extern unsigned long clock_usecs(void); clock_usecs(); })
+#define MICROPY_PY_URANDOM_SEED_INIT_FUNC   ({ extern uint32_t pbdrv_clock_get_us(void); pbdrv_clock_get_us(); })
 #define MICROPY_PY_USELECT                  (PYBRICKS_STM32_OPT_EXTRA_MOD)
 #define MICROPY_PY_UTIME_MP_HAL             (0)
 #define MICROPY_MODULE_BUILTIN_INIT         (1)

bricks/stm32/mphalport.c

@@ -13,21 +13,21 @@
 #include "py/stream.h"
 
 // using "internal" pbdrv variable
-extern volatile uint32_t clock_time_ticks;
+extern volatile uint32_t pbdrv_clock_ticks;
 
 // Core delay function that does an efficient sleep and may switch thread context.
 // If IRQs are enabled then we must have the GIL.
 void mp_hal_delay_ms(mp_uint_t Delay) {
     if (__get_PRIMASK() == 0) {
         // IRQs enabled, so can use systick counter to do the delay
-        uint32_t start = clock_time_ticks;
+        uint32_t start = pbdrv_clock_ticks;
         // Wraparound of tick is taken care of by 2's complement arithmetic.
         do {
             // This macro will execute the necessary idle behaviour.  It may
             // raise an exception, switch threads or enter sleep mode (waiting for
             // (at least) the SysTick interrupt).
             MICROPY_EVENT_POLL_HOOK
-        } while (clock_time_ticks - start < Delay);
+        } while (pbdrv_clock_ticks - start < Delay);
     } else {
         // IRQs disabled, so need to use a busy loop for the delay.
         // To prevent possible overflow of the counter we use a double loop.
@@ -39,6 +39,22 @@ void mp_hal_delay_ms(mp_uint_t Delay) {
     }
 }
 
+// delay for given number of microseconds
+void mp_hal_delay_us(mp_uint_t usec) {
+    if (__get_PRIMASK() == 1) {
+        // IRQs enabled, so can use systick counter to do the delay
+        uint32_t start = pbdrv_clock_get_us();
+        while (pbdrv_clock_get_us() - start < usec) {
+        }
+    } else {
+        // IRQs disabled, so need to use a busy loop for the delay
+        // sys freq is always a multiple of 2MHz, so division here won't lose precision
+        const uint32_t ucount = PBDRV_CONFIG_SYS_CLOCK_RATE / 2000000 * usec / 2;
+        for (uint32_t count = 0; ++count <= ucount;) {
+        }
+    }
+}
+
 #if PYBRICKS_HUB_DEBUG
 
 #include "stm32f4xx.h"

bricks/technichub/mphalport.h

@@ -1,10 +1,9 @@
 // SPDX-License-Identifier: MIT
-// Copyright (c) 2018-2020 The Pybricks Authors
+// Copyright (c) 2018-2021 The Pybricks Authors
 
-#include <contiki.h>
+#include <pbdrv/clock.h>
 
 void mp_hal_set_interrupt_char(int c);
-#define mp_hal_ticks_ms clock_time
-#define mp_hal_ticks_us clock_usecs
-#define mp_hal_delay_us clock_delay_usec
+#define mp_hal_ticks_ms pbdrv_clock_get_ms
+#define mp_hal_ticks_us pbdrv_clock_get_us
 #define mp_hal_ticks_cpu() 0

lib/contiki-core/sys/clock.h

@@ -82,56 +82,14 @@
 #else
 #define CLOCK_SECOND (clock_time_t)32
 #endif
-
-/**
- * Converts milliseconds to clock ticks, rounding up so that the actual time
- * span will be >= *msec*.
- *
- * \param msec the time in milliseconds
- *
- * \return a ::clock_time_t value
- */
-static inline clock_time_t clock_from_msec(unsigned int msec) {
-#if CLOCK_SECOND == 1000
-  return msec;
-#else
-  return (msec * CLOCK_SECOND + 999) / 1000;
-#endif
-}
-
-/**
- * Converts clock ticks to milliseconds, rounding down so that the actual time
- * span will be <= *ticks*.
- *
- * \param ticks a ::clock_time_t value
- *
- * \return the time in milliseconds
- */
-static inline unsigned int clock_to_msec(clock_time_t ticks) {
-#if CLOCK_SECOND == 1000
-  return ticks;
-#else
-  return ticks * 1000 / CLOCK_SECOND;
-#endif
-}
-
-/**
- * Initialize the clock library.
- *
- * This function initializes the clock library and should be called
- * from the main() function of the system.
- *
- */
-void clock_init(void);
-
 /**
  * Get the current clock time.
  *
  * This function returns the current system clock time.
  *
  * \return The current clock time, measured in system ticks.
  */
-CCIF clock_time_t clock_time(void);
+clock_time_t clock_time(void);
 
 /**
  * Get the current value of the platform seconds.
@@ -141,36 +99,14 @@ CCIF clock_time_t clock_time(void);
  *
  * \return The value.
  */
-CCIF unsigned long clock_seconds(void);
+uint32_t clock_seconds(void);
 
 /**
  * Get the current value of the platform microseconds.
  *
  * \return The value.
  */
-CCIF unsigned long clock_usecs(void);
-
-/**
- * Set the value of the platform seconds.
- * \param sec   The value to set.
- *
- */
-void clock_set_seconds(unsigned long sec);
-
-/**
- * Wait for a given number of ticks.
- * \param t   How many ticks.
- *
- */
-void clock_wait(clock_time_t t);
-
-/**
- * Delay a given number of microseconds.
- * \param dt   How many microseconds to delay.
- *
- * \note Interrupts could increase the delay by a variable amount.
- */
-void clock_delay_usec(uint16_t dt);
+uint32_t clock_usecs(void);
 
 #endif /* CLOCK_H_ */
 

lib/ev3dev/src/ev3dev_stretch/nxtcolor.c

@@ -11,6 +11,7 @@
 #include <ev3dev_stretch/lego_sensor.h>
 #include <ev3dev_stretch/sysfs.h>
 
+#include <pbdrv/clock.h>
 #include <pbio/color.h>
 #include <pbio/port.h>
 #include <pbio/iodev.h>
@@ -89,7 +90,7 @@ nxtcolor_t nxtcolorsensors[4];
 // Simplistic nonbusy wait. May be called only once per blocking operation.
 pbio_error_t nxtcolor_wait(nxtcolor_t *nxtcolor, uint32_t ms) {
 
-    uint32_t now = clock_usecs();
+    uint32_t now = pbdrv_clock_get_us();
 
     // Wait for existing wait to complete
     if (nxtcolor->waiting) {

lib/pbio/README.md

@@ -18,7 +18,7 @@ for the various platform-specific hardware.
 
 The `include/pbdrv` directory contains the public header files for the drivers
 (`drv` directory). Generally, these header files should not be used outside of
-this library.
+this library. One common exception is clocks.
 
 The `include/pbio` directory contains the public header files for the main
 library (`src` directory). This is the API for user programs.

lib/pbio/drv/bluetooth/bluetooth_btstack_run_loop_contiki.c

@@ -1,5 +1,5 @@
 // SPDX-License-Identifier: MIT
-// Copyright (c) 2020 The Pybricks Authors
+// Copyright (c) 2020-2021 The Pybricks Authors
 
 // Contiki run loop integration for BlueKitchen BTStack.
 
@@ -14,6 +14,8 @@
 #include <btstack.h>
 #include <contiki.h>
 
+_Static_assert(CLOCK_CONF_SECOND == 1000, "contiki clock must be configured for 1ms ticks");
+
 PROCESS(btstack_run_loop_contiki_process, "btstack");
 static struct etimer timer;
 static btstack_linked_list_t timers;
@@ -30,7 +32,7 @@ static void schedule_timer(void) {
     if (first_timer == NULL) {
         etimer_stop(&timer);
     } else {
-        etimer_set(&timer, clock_from_msec(first_timer->timeout - clock_to_msec(clock_time())));
+        etimer_set(&timer, first_timer->timeout - pbdrv_clock_get_ms());
     }
 
     PROCESS_CONTEXT_END();
@@ -57,7 +59,7 @@ static void btstack_run_loop_contiki_disable_data_source_callbacks(btstack_data_
 }
 
 static void btstack_run_loop_contiki_set_timer(btstack_timer_source_t *ts, uint32_t timeout_in_ms) {
-    ts->timeout = clock_to_msec(clock_time()) + timeout_in_ms;
+    ts->timeout = pbdrv_clock_get_ms() + timeout_in_ms;
 }
 
 static void btstack_run_loop_contiki_add_timer(btstack_timer_source_t *ts) {
@@ -100,7 +102,7 @@ static void btstack_run_loop_contiki_dump_timer(void) {
 }
 
 static uint32_t btstack_run_loop_contiki_get_time_ms(void) {
-    return clock_to_msec(clock_time());
+    return pbdrv_clock_get_ms();
 }
 
 static const btstack_run_loop_t btstack_run_loop_contiki = {
@@ -153,7 +155,7 @@ PROCESS_THREAD(btstack_run_loop_contiki_process, ev, data) {
         // process all BTStack timers in list that have expired
         while (timers) {
             btstack_timer_source_t *ts = (void *)timers;
-            int32_t delta = btstack_time_delta(ts->timeout, clock_to_msec(clock_time()));
+            int32_t delta = btstack_time_delta(ts->timeout, pbdrv_clock_get_ms());
             if (delta > 0) {
                 // we have reached unexpired timers
                 break;