zephyr: Switch to interrupt-driven pull-style console.

While this console API improves handling on real hardware boards
(e.g. clipboard paste is much more reliable, as well as programmatic
communication), it vice-versa poses problems under QEMU, apparently
because it doesn't emulate UART interrupt handling faithfully. That
leads to inability to run the testsuite on QEMU at all. To work that
around, we have to suuport both old and new console routines, and use
the old ones under QEMU.

ports/zephyr/prj_base.conf

@@ -4,6 +4,12 @@ CONFIG_REBOOT=y
 CONFIG_STDOUT_CONSOLE=y
 CONFIG_CONSOLE_HANDLER=y
 CONFIG_UART_CONSOLE_DEBUG_SERVER_HOOKS=y
+
+CONFIG_CONSOLE_PULL=y
+CONFIG_CONSOLE_GETCHAR=y
+CONFIG_CONSOLE_GETCHAR_BUFSIZE=128
+CONFIG_CONSOLE_PUTCHAR_BUFSIZE=128
+
 CONFIG_NEWLIB_LIBC=y
 CONFIG_FLOAT=y
 CONFIG_MAIN_STACK_SIZE=4096

ports/zephyr/prj_qemu_cortex_m3.conf

@@ -1,3 +1,7 @@
+# Interrupt-driven UART console has emulation artifacts under QEMU,
+# disable it
+CONFIG_CONSOLE_PULL=n
+
 # Networking drivers
 # SLIP driver for QEMU
 CONFIG_NET_SLIP_TAP=y

ports/zephyr/prj_qemu_x86.conf

@@ -1,3 +1,7 @@
+# Interrupt-driven UART console has emulation artifacts under QEMU,
+# disable it
+CONFIG_CONSOLE_PULL=n
+
 # Networking drivers
 # SLIP driver for QEMU
 CONFIG_NET_SLIP_TAP=y

ports/zephyr/src/zephyr_start.c

@@ -24,11 +24,16 @@
  * THE SOFTWARE.
  */
 #include <zephyr.h>
+#include <console.h>
 #include "zephyr_getchar.h"
 
 int real_main(void);
 
 void main(void) {
+#ifdef CONFIG_CONSOLE_PULL
+    console_init();
+#else
     zephyr_getchar_init();
+#endif
     real_main();
 }

ports/zephyr/uart_core.c

@@ -28,6 +28,7 @@
 #include "src/zephyr_getchar.h"
 // Zephyr headers
 #include <uart.h>
+#include <console.h>
 
 /*
  * Core UART functions to implement for a port
@@ -35,11 +36,23 @@
 
 // Receive single character
 int mp_hal_stdin_rx_chr(void) {
+#ifdef CONFIG_CONSOLE_PULL
+    return console_getchar();
+#else
     return zephyr_getchar();
+#endif
 }
 
 // Send string of given length
 void mp_hal_stdout_tx_strn(const char *str, mp_uint_t len) {
+#ifdef CONFIG_CONSOLE_PULL
+    while (len--) {
+        char c = *str++;
+        while (console_putchar(c) == -1) {
+            k_sleep(1);
+        }
+    }
+#else
     static struct device *uart_console_dev;
     if (uart_console_dev == NULL) {
         uart_console_dev = device_get_binding(CONFIG_UART_CONSOLE_ON_DEV_NAME);
@@ -48,4 +61,5 @@ void mp_hal_stdout_tx_strn(const char *str, mp_uint_t len) {
     while (len--) {
         uart_poll_out(uart_console_dev, *str++);
     }
+#endif
 }