zephyr: Move IO functions out of main to separate file

Moves IO functions into a separate file to allow reuse

Signed-off-by: Jamie McCrae <jamie.mccrae@nordicsemi.no>
diff --git a/boot/zephyr/io.c b/boot/zephyr/io.c
new file mode 100644
index 0000000..6d3b01e
--- /dev/null
+++ b/boot/zephyr/io.c
@@ -0,0 +1,190 @@
+/*
+ * Copyright (c) 2012-2014 Wind River Systems, Inc.
+ * Copyright (c) 2020 Arm Limited
+ * Copyright (c) 2021-2023 Nordic Semiconductor ASA
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include <assert.h>
+#include <zephyr/kernel.h>
+#include <zephyr/devicetree.h>
+#include <zephyr/drivers/gpio.h>
+#include <zephyr/sys/__assert.h>
+#include <zephyr/drivers/flash.h>
+#include <zephyr/drivers/timer/system_timer.h>
+#include <zephyr/usb/usb_device.h>
+#include <soc.h>
+#include <zephyr/linker/linker-defs.h>
+
+#include "target.h"
+
+#if defined(CONFIG_BOOT_SERIAL_PIN_RESET)
+#include <zephyr/drivers/hwinfo.h>
+#endif
+
+#if defined(CONFIG_BOOT_SERIAL_BOOT_MODE)
+#include <zephyr/retention/bootmode.h>
+#endif
+
+/* Validate serial recovery configuration */
+#ifdef CONFIG_MCUBOOT_SERIAL
+#if !defined(CONFIG_BOOT_SERIAL_ENTRANCE_GPIO) && \
+    !defined(CONFIG_BOOT_SERIAL_WAIT_FOR_DFU) && \
+    !defined(CONFIG_BOOT_SERIAL_BOOT_MODE) && \
+    !defined(CONFIG_BOOT_SERIAL_NO_APPLICATION) && \
+    !defined(CONFIG_BOOT_SERIAL_PIN_RESET)
+#error "Serial recovery selected without an entrance mode set"
+#endif
+#endif
+
+#ifdef CONFIG_MCUBOOT_INDICATION_LED
+
+/*
+ * The led0 devicetree alias is optional. If present, we'll use it
+ * to turn on the LED whenever the button is pressed.
+ */
+#if DT_NODE_EXISTS(DT_ALIAS(mcuboot_led0))
+#define LED0_NODE DT_ALIAS(mcuboot_led0)
+#elif DT_NODE_EXISTS(DT_ALIAS(bootloader_led0))
+#warning "bootloader-led0 alias is deprecated; use mcuboot-led0 instead"
+#define LED0_NODE DT_ALIAS(bootloader_led0)
+#endif
+
+#if DT_NODE_HAS_STATUS(LED0_NODE, okay) && DT_NODE_HAS_PROP(LED0_NODE, gpios)
+static const struct gpio_dt_spec led0 = GPIO_DT_SPEC_GET(LED0_NODE, gpios);
+#else
+/* A build error here means your board isn't set up to drive an LED. */
+#error "Unsupported board: led0 devicetree alias is not defined"
+#endif
+
+void io_led_init(void)
+{
+    if (!device_is_ready(led0.port)) {
+        BOOT_LOG_ERR("Didn't find LED device referred by the LED0_NODE\n");
+        return;
+    }
+
+    gpio_pin_configure_dt(&led0, GPIO_OUTPUT);
+    gpio_pin_set_dt(&led0, 0);
+}
+#endif /* CONFIG_MCUBOOT_INDICATION_LED */
+
+#if defined(CONFIG_BOOT_SERIAL_ENTRANCE_GPIO) || defined(CONFIG_BOOT_USB_DFU_GPIO)
+
+#if defined(CONFIG_MCUBOOT_SERIAL)
+#define BUTTON_0_DETECT_DELAY CONFIG_BOOT_SERIAL_DETECT_DELAY
+#else
+#define BUTTON_0_DETECT_DELAY CONFIG_BOOT_USB_DFU_DETECT_DELAY
+#endif
+
+#define BUTTON_0_NODE DT_ALIAS(mcuboot_button0)
+
+#if DT_NODE_EXISTS(BUTTON_0_NODE) && DT_NODE_HAS_PROP(BUTTON_0_NODE, gpios)
+static const struct gpio_dt_spec button0 = GPIO_DT_SPEC_GET(BUTTON_0_NODE, gpios);
+#else
+#error "Serial recovery/USB DFU button must be declared in device tree as 'mcuboot_button0'"
+#endif
+
+bool io_detect_pin(void)
+{
+    int rc;
+    int pin_active;
+
+    if (!device_is_ready(button0.port)) {
+        __ASSERT(false, "GPIO device is not ready.\n");
+        return false;
+    }
+
+    rc = gpio_pin_configure_dt(&button0, GPIO_INPUT);
+    __ASSERT(rc == 0, "Failed to initialize boot detect pin.\n");
+
+    rc = gpio_pin_get_dt(&button0);
+    pin_active = rc;
+
+    __ASSERT(rc >= 0, "Failed to read boot detect pin.\n");
+
+    if (pin_active) {
+        if (BUTTON_0_DETECT_DELAY > 0) {
+#ifdef CONFIG_MULTITHREADING
+            k_sleep(K_MSEC(50));
+#else
+            k_busy_wait(50000);
+#endif
+
+            /* Get the uptime for debounce purposes. */
+            int64_t timestamp = k_uptime_get();
+
+            for(;;) {
+                rc = gpio_pin_get_dt(&button0);
+                pin_active = rc;
+                __ASSERT(rc >= 0, "Failed to read boot detect pin.\n");
+
+                /* Get delta from when this started */
+                uint32_t delta = k_uptime_get() -  timestamp;
+
+                /* If not pressed OR if pressed > debounce period, stop. */
+                if (delta >= BUTTON_0_DETECT_DELAY || !pin_active) {
+                    break;
+                }
+
+                /* Delay 1 ms */
+#ifdef CONFIG_MULTITHREADING
+                k_sleep(K_MSEC(1));
+#else
+                k_busy_wait(1000);
+#endif
+            }
+        }
+    }
+
+    return (bool)pin_active;
+}
+#endif
+
+#if defined(CONFIG_BOOT_SERIAL_PIN_RESET)
+bool io_detect_pin_reset(void)
+{
+    uint32_t reset_cause;
+    int rc;
+
+    rc = hwinfo_get_reset_cause(&reset_cause);
+
+    if (rc == 0 && reset_cause == RESET_PIN) {
+        (void)hwinfo_clear_reset_cause();
+        return true;
+    }
+
+    return false;
+}
+#endif
+
+#if defined(CONFIG_BOOT_SERIAL_BOOT_MODE)
+bool io_detect_boot_mode(void)
+{
+    int32_t boot_mode;
+
+    boot_mode = bootmode_check(BOOT_MODE_TYPE_BOOTLOADER);
+
+    if (boot_mode == 1) {
+        /* Boot mode to stay in bootloader, clear status and enter serial
+         * recovery mode
+         */
+        bootmode_clear();
+
+        return true;
+    }
+
+    return false;
+}
+#endif