ports: Implement simple write polling for stdout.

This is a best-effort implementation of write polling. It's difficult to do correctly because if there are multiple output streams (eg UART and USB CDC) then some may not be writeable while others are. A full solution should also have a return value from mp_hal_stdout_tx_strn(), returning the number of bytes written to the stream(s). That's also hard to define. The renesas-ra and stm32 ports already implement a similar best-effort mechanism for write polling. Fixes issue micropython#11026. Signed-off-by: Damien George <[email protected]>
Darkpecas · Mar 23, 2023 · 38e7b84 · 38e7b84
1 parent 6c76248
commit 38e7b84
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diff --git a/ports/esp32/mphalport.c b/ports/esp32/mphalport.c
@@ -88,6 +88,9 @@ uintptr_t mp_hal_stdio_poll(uintptr_t poll_flags) {
     if ((poll_flags & MP_STREAM_POLL_RD) && stdin_ringbuf.iget != stdin_ringbuf.iput) {
         ret |= MP_STREAM_POLL_RD;
     }
+    if (poll_flags & MP_STREAM_POLL_WR) {
+        ret |= MP_STREAM_POLL_WR;
+    }
     return ret;
 }
 

diff --git a/ports/esp8266/esp_mphal.c b/ports/esp8266/esp_mphal.c
@@ -62,6 +62,9 @@ uintptr_t mp_hal_stdio_poll(uintptr_t poll_flags) {
     if ((poll_flags & MP_STREAM_POLL_RD) && stdin_ringbuf.iget != stdin_ringbuf.iput) {
         ret |= MP_STREAM_POLL_RD;
     }
+    if (poll_flags & MP_STREAM_POLL_WR) {
+        ret |= mp_uos_dupterm_poll(poll_flags);
+    }
     return ret;
 }
 

diff --git a/ports/mimxrt/mphalport.c b/ports/mimxrt/mphalport.c
@@ -86,6 +86,9 @@ uintptr_t mp_hal_stdio_poll(uintptr_t poll_flags) {
     if ((poll_flags & MP_STREAM_POLL_RD) && ringbuf_peek(&stdin_ringbuf) != -1) {
         ret |= MP_STREAM_POLL_RD;
     }
+    if ((poll_flags & MP_STREAM_POLL_WR) && tud_cdc_connected() && tud_cdc_write_available() > 0) {
+        ret |= MP_STREAM_POLL_WR;
+    }
     #if MICROPY_PY_OS_DUPTERM
     ret |= mp_uos_dupterm_poll(poll_flags);
     #endif

diff --git a/ports/nrf/drivers/bluetooth/ble_uart.c b/ports/nrf/drivers/bluetooth/ble_uart.c
@@ -164,6 +164,9 @@ uintptr_t mp_hal_stdio_poll(uintptr_t poll_flags) {
         && !isBufferEmpty(mp_rx_ring_buffer)) {
         ret |= MP_STREAM_POLL_RD;
     }
+    if ((poll_flags & MP_STREAM_POLL_WR) && ble_uart_enabled()) {
+        ret |= MP_STREAM_POLL_WR;
+    }
     return ret;
 }
 #endif

diff --git a/ports/nrf/drivers/usb/usb_cdc.c b/ports/nrf/drivers/usb/usb_cdc.c
@@ -213,6 +213,9 @@ uintptr_t mp_hal_stdio_poll(uintptr_t poll_flags) {
             ret |= MP_STREAM_POLL_RD;
         }
     }
+    if (poll_flags & MP_STREAM_POLL_WR) {
+        ret |= MP_STREAM_POLL_WR;
+    }
     return ret;
 }
 

diff --git a/ports/nrf/mphalport.c b/ports/nrf/mphalport.c
@@ -179,6 +179,9 @@ uintptr_t mp_hal_stdio_poll(uintptr_t poll_flags) {
         && uart_rx_any(MP_STATE_PORT(board_stdio_uart))) {
         ret |= MP_STREAM_POLL_RD;
     }
+    if ((poll_flags & MP_STREAM_POLL_WR) && MP_STATE_PORT(board_stdio_uart) != NULL) {
+        ret |= MP_STREAM_POLL_WR;
+    }
     return ret;
 }
 

diff --git a/ports/pic16bit/pic16bit_mphal.c b/ports/pic16bit/pic16bit_mphal.c
@@ -57,6 +57,9 @@ uintptr_t mp_hal_stdio_poll(uintptr_t poll_flags) {
     if ((poll_flags & MP_STREAM_POLL_RD) && uart_rx_any()) {
         ret |= MP_STREAM_POLL_RD;
     }
+    if (poll_flags & MP_STREAM_POLL_WR) {
+        ret |= MP_STREAM_POLL_WR;
+    }
     return ret;
 }
 

diff --git a/ports/rp2/mphalport.c b/ports/rp2/mphalport.c
@@ -98,6 +98,15 @@ uintptr_t mp_hal_stdio_poll(uintptr_t poll_flags) {
     if ((poll_flags & MP_STREAM_POLL_RD) && ringbuf_peek(&stdin_ringbuf) != -1) {
         ret |= MP_STREAM_POLL_RD;
     }
+    if (poll_flags & MP_STREAM_POLL_WR) {
+        #if MICROPY_HW_ENABLE_UART_REPL
+        ret |= MP_STREAM_POLL_WR;
+        #else
+        if (tud_cdc_connected() && tud_cdc_write_available() > 0) {
+            ret |= MP_STREAM_POLL_WR;
+        }
+        #endif
+    }
     #endif
     #if MICROPY_PY_OS_DUPTERM
     ret |= mp_uos_dupterm_poll(poll_flags);

diff --git a/ports/samd/mphalport.c b/ports/samd/mphalport.c
@@ -162,6 +162,10 @@ uintptr_t mp_hal_stdio_poll(uintptr_t poll_flags) {
         ret |= MP_STREAM_POLL_RD;
     }
 
+    if ((poll_flags & MP_STREAM_POLL_WR) && tud_cdc_connected() && tud_cdc_write_available() > 0) {
+        ret |= MP_STREAM_POLL_WR;
+    }
+
     #if MICROPY_PY_OS_DUPTERM
     ret |= mp_uos_dupterm_poll(poll_flags);
     #endif

diff --git a/ports/teensy/teensy_hal.c b/ports/teensy/teensy_hal.c
@@ -32,6 +32,11 @@ uintptr_t mp_hal_stdio_poll(uintptr_t poll_flags) {
             ret |= MP_STREAM_POLL_RD;
         }
     }
+    if (poll_flags & MP_STREAM_POLL_WR) {
+        if (MP_STATE_PORT(pyb_stdio_uart) != NULL || usb_vcp_is_enabled()) {
+            ret |= MP_STREAM_POLL_WR;
+        }
+    }
     return ret;
 }