canboot_main: Add support for entering the bootloader on a button press

Signed-off-by: Kevin O'Connor <kevin@koconnor.net>

scripts/buildcommands.py

@@ -183,6 +183,47 @@ uint32_t led_gpio = %d, led_gpio_high = %d; // "%s"
 
 Handlers.append(HandleStatusLED())
 
+######################################################################
+# Button entry functionality
+######################################################################
+
+class HandleButton:
+    def __init__(self):
+        self.pin = None
+        self.ctr_dispatch = { 'DECL_BUTTON': self.decl_button }
+    def decl_button(self, req):
+        pin = req.split(None, 1)[1].strip()
+        if pin.startswith('"') and pin.endswith('"'):
+            pin = pin[1:-1].strip()
+        self.pin = pin
+    def generate_code(self, options):
+        button_gpio = button_high = button_pullup = 0
+        pin = self.pin
+        if pin:
+            if pin[0] in "^~":
+                button_pullup = 1
+                if pin[0] == "~":
+                    button_pullup = -1
+                pin = pin[1:].strip()
+            button_high = 1
+            if pin[0] == "!":
+                button_high = 0
+                pin = pin[1:].strip()
+            avail_pins = HandlerEnumerations.get_available_pins()
+            reserved_pins = HandlerConstants.get_reserved_pins()
+            button_gpio = avail_pins.get(pin)
+            if button_gpio is None:
+                error("Pin %s is not available for this build" % pin)
+            if pin in reserved_pins:
+                error("Pin %s is reserved by an active MCU peripheral" % pin)
+        fmt = """
+int32_t button_gpio = %d, button_high = %d, button_pullup = %d; // "%s"
+"""
+        return fmt % (button_gpio, button_high, button_pullup, self.pin)
+
+
+Handlers.append(HandleButton())
+
 ######################################################################
 # Main code
 ######################################################################

src/Kconfig

@@ -20,6 +20,14 @@ config ENABLE_DOUBLE_RESET
     bool "Support bootloader entry on rapid double click of reset button"
     default y
 
+config ENABLE_BUTTON
+    bool "Enable bootloader entry on button (or gpio) state"
+    default n
+
+config BUTTON_PIN
+    string "Button GPIO Pin"
+    depends on ENABLE_BUTTON
+
 config ENABLE_LED
     bool "Enable Status LED"
     default n

src/canboot_main.c

@@ -9,7 +9,9 @@
 #include "board/misc.h"     // delay_ms
 #include "board/canbus.h"   // canbus_send
 #include "board/flash.h"    // write_page
+#include "board/gpio.h"     // gpio_in_setup
 #include "canboot_main.h"   // canboot_main
+#include "ctr.h"            // DECL_CTR
 #include "led.h"            // check_blink_time
 
 
@@ -219,6 +221,21 @@ check_application_code(void)
     return 0;
 }
 
+// Generated by buildcommands.py
+DECL_CTR("DECL_BUTTON " __stringify(CONFIG_BUTTON_PIN));
+extern int32_t button_gpio, button_high, button_pullup;
+
+// Check for a bootloader request via double tap of reset button
+static int
+check_button_pressed(void)
+{
+    if (!CONFIG_ENABLE_BUTTON)
+        return 0;
+    struct gpio_in button = gpio_in_setup(button_gpio, button_pullup);
+    udelay(10);
+    return gpio_in_read(button) == button_high;
+}
+
 // Check for a bootloader request via double tap of reset button
 static void
 check_double_reset(void)
@@ -265,7 +282,8 @@ canboot_main(void)
     // - The request signature is set in memory (request from app)
     // - No application code is present
     uint64_t bootup_code = get_bootup_code();
-    if (bootup_code == REQUEST_SIG || !check_application_code()) {
+    if (bootup_code == REQUEST_SIG || !check_application_code()
+        || check_button_pressed()) {
         set_bootup_code(0);
         enter_bootloader();
     }