tinyusb/dfu: Add option to enter booloader on reset pin

For device that don't have any button to use to enter bootloader
this adds possibility to enter bootloader after number of
pin resets. Number of resets is kept in NVReg of user choice.

Additionally if user application enters correct value into NVReg
and calls hal_system_reset it can directly start bootloader
with dfu capabilities.

Signed-off-by: Jerzy Kasenberg <jerzy@apache.org>

hw/usb/tinyusb/dfu/src/dfu.c

@@ -19,12 +19,15 @@
 
 #include <os/mynewt.h>
 
+#include <sysflash/sysflash.h>
 #include <class/dfu/dfu_device.h>
 
 #include <bsp/bsp.h>
 #include <img_mgmt/img_mgmt.h>
 #include <tinyusb/tinyusb.h>
 #include <hal/hal_gpio.h>
+#include <hal/hal_nvreg.h>
+#include <tusb.h>
 
 /*
  * If DFU is activated from bootloader it writes to SLOT0.
@@ -182,6 +185,22 @@ boot_preboot(void)
  tinyusb_start();
  }
  hal_gpio_deinit(MYNEWT_VAL(USBD_DFU_BOOT_PIN));
+#elif MYNEWT_VAL(USBD_DFU_BOOT_RESET_COUNT_NVREG) >= 0
+ uint32_t counter = hal_nvreg_read(MYNEWT_VAL(USBD_DFU_BOOT_RESET_COUNT_NVREG));
+ /* If special value is stored in counter register or counter due to reset pin was done number of times start dfu */
+ if (counter == MYNEWT_VAL(USBD_DFU_BOOT_RESET_COUNT_NVREG) ||
+ ((MYNEWT_VAL(USBD_DFU_BOOT_RESET_COUNT) > 0) && counter >= MYNEWT_VAL(USBD_DFU_BOOT_RESET_COUNT))) {
+ hal_nvreg_write(MYNEWT_VAL(USBD_DFU_BOOT_RESET_COUNT_NVREG), 0);
+ tinyusb_start();
+ } else {
+ if (hal_reset_cause() == HAL_RESET_PIN) {
+ /* Reset pin count increment */
+ hal_nvreg_write(MYNEWT_VAL(USBD_DFU_BOOT_RESET_COUNT_NVREG), counter + 1);
+ } else if (counter) {
+ /* Write 0 if not already there */
+ hal_nvreg_write(MYNEWT_VAL(USBD_DFU_BOOT_RESET_COUNT_NVREG), 0);
+ }
+ }
 #endif
 }
 

hw/usb/tinyusb/dfu/syscfg.yml

@@ -93,6 +93,22 @@ syscfg.defs:
  Set to 2 if boto pin needs internal pull-down resistor.
  value: 0
 
+ USBD_DFU_BOOT_RESET_COUNT:
+ description: >
+ Number of time bootloader must detects reset cause by reset pin before
+ starting dfu bootloader.
+ value: 0
+ USBD_DFU_BOOT_RESET_COUNT_NVREG:
+ description: >
+ NVReg number to use for reset counting.
+ value: -1
+ USBD_DFU_BOOT_RESET_COUNT_MAGIC:
+ description: >
+ Value stored in NVReg (indexed by USBD_DFU_BOOT_RESET_COUNT_NVREG)
+ to start DFU. This can be used by application that does not have
+ DFU support to request DFU in bootloader.
+ value: 0xDF00AE01
+
  USBD_DFU_SYSINIT_STAGE:
  description: >
  Sysinit stage for DFU functionality.