py: Overhaul and simplify printf/pfenv mechanism.

Previous to this patch the printing mechanism was a bit of a tangled
mess.  This patch attempts to consolidate printing into one interface.

All (non-debug) printing now uses the mp_print* family of functions,
mainly mp_printf.  All these functions take an mp_print_t structure as
their first argument, and this structure defines the printing backend
through the "print_strn" function of said structure.

Printing from the uPy core can reach the platform-defined print code via
two paths: either through mp_sys_stdout_obj (defined pert port) in
conjunction with mp_stream_write; or through the mp_plat_print structure
which uses the MP_PLAT_PRINT_STRN macro to define how string are printed
on the platform.  The former is only used when MICROPY_PY_IO is defined.

With this new scheme printing is generally more efficient (less layers
to go through, less arguments to pass), and, given an mp_print_t*
structure, one can call mp_print_str for efficiency instead of
mp_printf("%s", ...).  Code size is also reduced by around 200 bytes on
Thumb2 archs.

4 files changed, 16 insertions, 14 deletions

diff --git a/teensy/led.c b/teensy/led.c
index fc60167b98..500900ffce 100644
--- a/teensy/led.c
+++ b/teensy/led.c
@@ -83,10 +83,10 @@ void led_toggle(pyb_led_t led) {
 /******************************************************************************/
 /* Micro Python bindings                                                      */
 
-void led_obj_print(void (*print)(void *env, const char *fmt, ...), void *env, mp_obj_t self_in, mp_print_kind_t kind) {
+void led_obj_print(const mp_print_t *print, mp_obj_t self_in, mp_print_kind_t kind) {
     pyb_led_obj_t *self = self_in;
     (void)kind;
-    print(env, "<LED %lu>", self->led_id);
+    mp_printf(print, "<LED %lu>", self->led_id);
 }
 
 STATIC mp_obj_t led_obj_make_new(mp_obj_t type_in, uint n_args, uint n_kw, const mp_obj_t *args) {
diff --git a/teensy/mpconfigport.h b/teensy/mpconfigport.h
index 57e4c36b08..d4bfd1cd3b 100644
--- a/teensy/mpconfigport.h
+++ b/teensy/mpconfigport.h
@@ -66,6 +66,9 @@ typedef void *machine_ptr_t; // must be of pointer size
 typedef const void *machine_const_ptr_t; // must be of pointer size
 typedef long mp_off_t;
 
+void mp_hal_stdout_tx_strn_cooked(const char *str, uint32_t len);
+#define MP_PLAT_PRINT_STRN(str, len) mp_hal_stdout_tx_strn_cooked(str, len)
+
 // We have inlined IRQ functions for efficiency (they are generally
 // 1 machine instruction).
 //
diff --git a/teensy/timer.c b/teensy/timer.c
index e048f61d8a..5d6237d006 100644
--- a/teensy/timer.c
+++ b/teensy/timer.c
@@ -31,7 +31,6 @@
 
 #include "py/nlr.h"
 #include "py/runtime.h"
-#include "py/pfenv.h"
 #include "py/gc.h"
 #include MICROPY_HAL_H
 #include "pin.h"
@@ -188,13 +187,13 @@ STATIC mp_obj_t compute_percent_from_pwm_value(uint32_t period, uint32_t cmp) {
     #endif
 }
 
-STATIC void pyb_timer_print(void (*print)(void *env, const char *fmt, ...), void *env, mp_obj_t self_in, mp_print_kind_t kind) {
+STATIC void pyb_timer_print(const mp_print_t *print, mp_obj_t self_in, mp_print_kind_t kind) {
     pyb_timer_obj_t *self = self_in;
 
     if (self->ftm.State == HAL_FTM_STATE_RESET) {
-        print(env, "Timer(%u)", self->tim_id);
+        mp_printf(print, "Timer(%u)", self->tim_id);
     } else {
-        print(env, "Timer(%u, prescaler=%u, period=%u, mode=%s)",
+        mp_printf(print, "Timer(%u, prescaler=%u, period=%u, mode=%s)",
             self->tim_id,
             1 << (self->ftm.Instance->SC & 7),
             self->ftm.Instance->MOD & 0xffff,
@@ -752,10 +751,10 @@ const mp_obj_type_t pyb_timer_type = {
 /// Timer channels are used to generate/capture a signal using a timer.
 ///
 /// TimerChannel objects are created using the Timer.channel() method.
-STATIC void pyb_timer_channel_print(void (*print)(void *env, const char *fmt, ...), void *env, mp_obj_t self_in, mp_print_kind_t kind) {
+STATIC void pyb_timer_channel_print(const mp_print_t *print, mp_obj_t self_in, mp_print_kind_t kind) {
     pyb_timer_channel_obj_t *self = self_in;
 
-    print(env, "TimerChannel(timer=%u, channel=%u, mode=%s)",
+    mp_printf(print, "TimerChannel(timer=%u, channel=%u, mode=%s)",
           self->timer->tim_id,
           self->channel,
           qstr_str(channel_mode_info[self->mode].name));
@@ -913,7 +912,7 @@ STATIC bool ftm_handle_irq_callback(pyb_timer_obj_t *self, mp_uint_t channel, mp
             printf("Uncaught exception in Timer(" UINT_FMT ") channel "
                    UINT_FMT " interrupt handler\n", self->tim_id, channel);
         }
-        mp_obj_print_exception(printf_wrapper, NULL, (mp_obj_t)nlr.ret_val);
+        mp_obj_print_exception(&mp_plat_print, (mp_obj_t)nlr.ret_val);
     }
     gc_unlock();
     return handled;
diff --git a/teensy/uart.c b/teensy/uart.c
index 7e08366b2e..1a04bb0d69 100644
--- a/teensy/uart.c
+++ b/teensy/uart.c
@@ -224,20 +224,20 @@ void uart_tx_strn_cooked(pyb_uart_obj_t *uart_obj, const char *str, uint len) {
 /******************************************************************************/
 /* Micro Python bindings                                                      */
 
-STATIC void pyb_uart_print(void (*print)(void *env, const char *fmt, ...), void *env, mp_obj_t self_in, mp_print_kind_t kind) {
+STATIC void pyb_uart_print(const mp_print_t *print, mp_obj_t self_in, mp_print_kind_t kind) {
     pyb_uart_obj_t *self = self_in;
     if (!self->is_enabled) {
-        print(env, "UART(%lu)", self->uart_id);
+        mp_printf(print, "UART(%lu)", self->uart_id);
     } else {
 #if 0
-        print(env, "UART(%lu, baudrate=%u, bits=%u, stop=%u",
+        mp_printf(print, "UART(%lu, baudrate=%u, bits=%u, stop=%u",
             self->uart_id, self->uart.Init.BaudRate,
             self->uart.Init.WordLength == UART_WORDLENGTH_8B ? 8 : 9,
             self->uart.Init.StopBits == UART_STOPBITS_1 ? 1 : 2);
         if (self->uart.Init.Parity == UART_PARITY_NONE) {
-            print(env, ", parity=None)");
+            mp_print_str(print, ", parity=None)");
         } else {
-            print(env, ", parity=%u)", self->uart.Init.Parity == UART_PARITY_EVEN ? 0 : 1);
+            mp_printf(print, ", parity=%u)", self->uart.Init.Parity == UART_PARITY_EVEN ? 0 : 1);
         }
 #endif
     }