zephyr/soc/arm/atmel_sam0/common/bossa.c

61 lines
1.3 KiB
C

/*
* Copyright (c) 2020 Google LLC.
*
* SPDX-License-Identifier: Apache-2.0
*/
#include <soc.h>
#include <drivers/uart/cdc_acm.h>
#include <drivers/usb/usb_dc.h>
#include <usb/class/usb_cdc.h>
/*
* Magic value that causes the bootloader to stay in bootloader mode instead of
* starting the application.
*/
#if CONFIG_BOOTLOADER_BOSSA_ADAFRUIT_UF2
#define DOUBLE_TAP_MAGIC 0xf01669ef
#elif CONFIG_BOOTLOADER_BOSSA_ARDUINO
#define DOUBLE_TAP_MAGIC 0x07738135
#else
#error Unsupported BOSSA bootloader variant
#endif
#if defined(CONFIG_BOOTLOADER_BOSSA_DEVICE_NAME)
static void bossa_reset(const struct device *dev, uint32_t rate)
{
uint32_t *top;
if (rate != 1200) {
return;
}
/* The programmer set the baud rate to 1200 baud. Reset into the
* bootloader.
*/
usb_dc_detach();
top = (uint32_t *)(DT_REG_ADDR(DT_NODELABEL(sram0)) +
DT_REG_SIZE(DT_NODELABEL(sram0)));
top[-1] = DOUBLE_TAP_MAGIC;
NVIC_SystemReset();
}
static int bossa_init(const struct device *unused)
{
const struct device *dev =
device_get_binding(CONFIG_BOOTLOADER_BOSSA_DEVICE_NAME);
if (dev == NULL) {
return -ENODEV;
}
return cdc_acm_dte_rate_callback_set(dev, bossa_reset);
}
SYS_INIT(bossa_init, APPLICATION, 0);
#endif /* CONFIG_BOOTLOADER_BOSSA_DEVICE_NAME */