src/rp2_common/pico_stdio_usb/reset_interface.c

/**
 * Copyright (c) 2021 Raspberry Pi (Trading) Ltd.
 *
 * SPDX-License-Identifier: BSD-3-Clause
 */
#include "tusb.h"

#include "pico/bootrom.h"

#if PICO_STDIO_USB_ENABLE_RESET_VIA_VENDOR_INTERFACE && !(PICO_STDIO_USB_RESET_INTERFACE_SUPPORT_RESET_TO_BOOTSEL || PICO_STDIO_USB_RESET_INTERFACE_SUPPORT_RESET_TO_FLASH_BOOT)
#warning PICO_STDIO_USB_ENABLE_RESET_VIA_VENDOR_INTERFACE has been selected but neither PICO_STDIO_USB_RESET_INTERFACE_SUPPORT_RESET_TO_BOOTSEL nor PICO_STDIO_USB_RESET_INTERFACE_SUPPORT_RESET_TO_FLASH_BOOT have been selected.
#endif

#if PICO_STDIO_USB_ENABLE_RESET_VIA_VENDOR_INTERFACE
#include "pico/stdio_usb/reset_interface.h"
#include "hardware/watchdog.h"
#include "device/usbd_pvt.h"

static uint8_t itf_num;

static void resetd_init(void) {
}

static void resetd_reset(uint8_t __unused rhport) {
    itf_num = 0;
}

static uint16_t resetd_open(uint8_t __unused rhport, tusb_desc_interface_t const *itf_desc, uint16_t max_len) {
    TU_VERIFY(TUSB_CLASS_VENDOR_SPECIFIC == itf_desc->bInterfaceClass &&
              RESET_INTERFACE_SUBCLASS == itf_desc->bInterfaceSubClass &&
              RESET_INTERFACE_PROTOCOL == itf_desc->bInterfaceProtocol, 0);

    uint16_t const drv_len = sizeof(tusb_desc_interface_t);
    TU_VERIFY(max_len >= drv_len, 0);

    itf_num = itf_desc->bInterfaceNumber;
    return drv_len;
}

// Support for parameterized reset via vendor interface control request
static bool resetd_control_xfer_cb(uint8_t __unused rhport, uint8_t stage, tusb_control_request_t const * request) {
    // nothing to do with DATA & ACK stage
    if (stage != CONTROL_STAGE_SETUP) return true;

    if (request->wIndex == itf_num) {

#if PICO_STDIO_USB_RESET_INTERFACE_SUPPORT_RESET_TO_BOOTSEL
        if (request->bRequest == RESET_REQUEST_BOOTSEL) {
#ifdef PICO_STDIO_USB_RESET_BOOTSEL_ACTIVITY_LED
            uint gpio_mask = 1u << PICO_STDIO_USB_RESET_BOOTSEL_ACTIVITY_LED;
#else
            uint gpio_mask = 0u;
#endif
#if !PICO_STDIO_USB_RESET_BOOTSEL_FIXED_ACTIVITY_LED
            if (request->wValue & 0x100) {
                gpio_mask = 1u << (request->wValue >> 9u);
            }
#endif
            reset_usb_boot(gpio_mask, (request->wValue & 0x7f) | PICO_STDIO_USB_RESET_BOOTSEL_INTERFACE_DISABLE_MASK);
            // does not return, otherwise we'd return true
        }
#endif

#if PICO_STDIO_USB_RESET_INTERFACE_SUPPORT_RESET_TO_FLASH_BOOT
        if (request->bRequest == RESET_REQUEST_FLASH) {
            watchdog_reboot(0, 0, PICO_STDIO_USB_RESET_RESET_TO_FLASH_DELAY_MS);
            return true;
        }
#endif

    }
    return false;
}

static bool resetd_xfer_cb(uint8_t __unused rhport, uint8_t __unused ep_addr, xfer_result_t __unused result, uint32_t __unused xferred_bytes) {
    return true;
}

static usbd_class_driver_t const _resetd_driver =
{
#if CFG_TUSB_DEBUG >= 2
    .name = "RESET",
#endif
    .init             = resetd_init,
    .reset            = resetd_reset,
    .open             = resetd_open,
    .control_xfer_cb  = resetd_control_xfer_cb,
    .xfer_cb          = resetd_xfer_cb,
    .sof              = NULL
};

// Implement callback to add our custom driver
usbd_class_driver_t const *usbd_app_driver_get_cb(uint8_t *driver_count) {
    *driver_count = 1;
    return &_resetd_driver;
}
#endif

#if PICO_STDIO_USB_ENABLE_RESET_VIA_BAUD_RATE
// Support for default BOOTSEL reset by changing baud rate
void tud_cdc_line_coding_cb(__unused uint8_t itf, cdc_line_coding_t const* p_line_coding) {
    if (p_line_coding->bit_rate == PICO_STDIO_USB_RESET_MAGIC_BAUD_RATE) {
#ifdef PICO_STDIO_USB_RESET_BOOTSEL_ACTIVITY_LED
        const uint gpio_mask = 1u << PICO_STDIO_USB_RESET_BOOTSEL_ACTIVITY_LED;
#else
        const uint gpio_mask = 0u;
#endif
        reset_usb_boot(gpio_mask, PICO_STDIO_USB_RESET_BOOTSEL_INTERFACE_DISABLE_MASK);
    }
}
#endif