esp32/usb_serial_jtag: Flush usb_serial_jtag TXFIFO from ISR.

This was necessary to un-wedge the USJ TX path on ESP32-P4, I think because
the bootloader prints a lot on this chip. I think it might be possible to
hit it on other chips, though.

The implementation is based on the ESP-IDF driver, which will always add an
extra flush when the TXFIFO is empty in case the host is expecting a ZLP.

This work was funded through GitHub Sponsors.

Signed-off-by: Angus Gratton <angus@redyak.com.au>
This commit is contained in:
Angus Gratton
2025-11-20 17:33:01 +11:00
committed by Damien George
parent 50a06b6404
commit eb5d89cd83

View File

@@ -71,23 +71,31 @@ static void usb_serial_jtag_handle_rx(void) {
static void usb_serial_jtag_isr_handler(void *arg) {
uint32_t flags = usb_serial_jtag_ll_get_intsts_mask();
if (flags & USB_SERIAL_JTAG_INTR_SOF) {
usb_serial_jtag_ll_clr_intsts_mask(USB_SERIAL_JTAG_INTR_SOF);
}
usb_serial_jtag_ll_clr_intsts_mask(flags);
if (flags & USB_SERIAL_JTAG_INTR_SERIAL_OUT_RECV_PKT) {
usb_serial_jtag_ll_clr_intsts_mask(USB_SERIAL_JTAG_INTR_SERIAL_OUT_RECV_PKT);
usb_serial_jtag_handle_rx();
mp_hal_wake_main_task_from_isr();
}
if (flags & USB_SERIAL_JTAG_INTR_SERIAL_IN_EMPTY) {
// As per the ESP-IDF driver, allow for the possibility the USJ just sent a full
// 64-bit endpoint to the host and now it's waiting for another ZLP to flush the result
// to the OS
usb_serial_jtag_ll_txfifo_flush();
// Disable this interrupt until next time we write into the FIFO
usb_serial_jtag_ll_disable_intr_mask(USB_SERIAL_JTAG_INTR_SERIAL_IN_EMPTY);
}
}
void usb_serial_jtag_init(void) {
// Note: Don't clear the SERIAL_IN_EMPTY interrupt, as it's possible the
// bootloader wrote enough data to the host that we need the interrupt to flush it.
usb_serial_jtag_ll_clr_intsts_mask(USB_SERIAL_JTAG_INTR_SERIAL_OUT_RECV_PKT |
USB_SERIAL_JTAG_INTR_SOF);
usb_serial_jtag_ll_ena_intr_mask(USB_SERIAL_JTAG_INTR_SERIAL_OUT_RECV_PKT |
USB_SERIAL_JTAG_INTR_SOF);
USB_SERIAL_JTAG_INTR_SOF | USB_SERIAL_JTAG_INTR_SERIAL_IN_EMPTY);
ESP_ERROR_CHECK(esp_intr_alloc(ETS_USB_SERIAL_JTAG_INTR_SOURCE, ESP_INTR_FLAG_LEVEL1,
usb_serial_jtag_isr_handler, NULL, NULL));
}
@@ -114,10 +122,11 @@ void usb_serial_jtag_tx_strn(const char *str, size_t len) {
}
terminal_connected = true;
l = usb_serial_jtag_ll_write_txfifo((const uint8_t *)str, l);
usb_serial_jtag_ll_txfifo_flush();
str += l;
len -= l;
usb_serial_jtag_ll_ena_intr_mask(USB_SERIAL_JTAG_INTR_SERIAL_IN_EMPTY);
}
usb_serial_jtag_ll_txfifo_flush();
}
#endif // MICROPY_HW_ESP_USB_SERIAL_JTAG