Basic support for rebooting into the bootloader. (#10)

firmware/code/run.c

@@ -34,6 +34,7 @@
 #include "pico/stdlib.h"
 #include "pico/usb_device.h"
 #include "pico/multicore.h"
+#include "pico/bootrom.h"
 #include "AudioClassCommon.h"
 
 #include "run.h"
@@ -59,6 +60,10 @@ static struct {
     .freq = 48000,
 };
 
+enum vendor_cmds {
+    REBOOT_BOOTLOADER = 0
+};
+
 int main(void) {
     setup();
 
@@ -646,6 +651,20 @@ static bool do_set_current(struct usb_setup_packet *setup) {
     return false;
 }
 
+static bool ad_setup_request_handler(__unused struct usb_device *device, struct usb_setup_packet *setup) {
+    setup = __builtin_assume_aligned(setup, 4);
+    if (USB_REQ_TYPE_TYPE_VENDOR == (setup->bmRequestType & USB_REQ_TYPE_TYPE_MASK)) {
+        // To prevent badly behaving software from accidentally triggering a reboot, e expect
+        // the wValue to be equal to the Ploopy vendor id.
+        if (setup->bRequest == REBOOT_BOOTLOADER && setup->wValue == 0x2E8A) {
+            reset_usb_boot(0, 0);
+            // reset_usb_boot does not return, so we will not respond to this command.
+            return true;
+        }
+    }
+    return false;
+}
+
 static bool ac_setup_request_handler(__unused struct usb_interface *interface, struct usb_setup_packet *setup) {
     setup = __builtin_assume_aligned(setup, 4);
     if (USB_REQ_TYPE_TYPE_CLASS == (setup->bmRequestType & USB_REQ_TYPE_TYPE_MASK)) {
@@ -726,6 +745,8 @@ void usb_sound_card_init() {
         count_of(boot_device_interfaces), _get_descriptor_string);
 
     assert(device);
+
+    device->setup_request_handler = ad_setup_request_handler;
     audio_set_volume(DEFAULT_VOLUME);
     _audio_reconfigure();
 

firmware/tools/README.md

@@ -17,7 +17,21 @@ Run `filter_test` to process the PCM samples. The `filter_test` program takes tw
 You can listen to the PCM files using ffplay (which is usually included with ffmpeg):
 
 ```
-./ffplay -f s16le -ar 48000 -ac 2 output.pcm
+ffplay -f s16le -ar 48000 -ac 2 output.pcm
 ```
 
 If there are no obvious problems, go ahead and flash your firmware.
+
+## reboot_bootloader.py
+If your Ploopy Headphones firmware is new enough, it has support for a USB vendor command that will cause the RP2040 to reboot into the
+bootloader. This will enable you to update the firmware without having to remove the case and short the pins on the board.
+
+### Usage
+Connect the Ploopy headphones DAC and run:
+
+```
+./reboot_bootloader.py
+```
+
+You will need python3 and the pyusb module. If you get a permission denied error you may need to configure your udev rules, or run the
+script with administrator privileges.

firmware/tools/reboot_bootloader.py

@@ -0,0 +1,29 @@
+#!/usr/bin/python3
+import usb.core
+from usb.util import *
+
+REBOOT_BOOTLOADER = 0
+PLOOPY_VID = 0x2e8a
+PLOOPY_PID = 0xfedd
+
+device_count = 0
+
+# Find all connected Ploopy headphone devices
+for dev in usb.core.find(find_all=True, idVendor=PLOOPY_VID, idProduct=PLOOPY_PID):
+    device_count += 1
+
+    # The vendor command expects the wValue to be equal to the Ploopy vendor id. This
+    # will hopefully prevent badly behaved software from accidentally triggering bootloader
+    # mode.
+    try:
+        dev.ctrl_transfer(CTRL_RECIPIENT_DEVICE | CTRL_TYPE_VENDOR, REBOOT_BOOTLOADER, PLOOPY_VID)
+    except Exception as e:
+        # The headphones do not respond to the vendor command, as they have already rebooted,
+        # so for now, we always end up here.
+        if e.errno == 32:
+            # libusb pipe error, this is expected. OpenUSB doesnt report an error.
+            pass
+        else:
+            print(e)
+
+print(f"Sent a reboot command to {device_count} Ploopy devices.")