From 803baf7fcd23011610b0e6b0db5d55e7a360c289 Mon Sep 17 00:00:00 2001
From: tychovrahe <brunam@seznam.cz>
Date: Fri, 16 May 2025 20:29:26 +0200
Subject: [PATCH] feat(core/unix): implement USB VCP emulation

[no changelog]
---
 core/embed/io/usb/unix/usb.c | 59 +++++++++++++++++++++++++++++++++++-
 core/src/usb.py              |  2 +-
 2 files changed, 59 insertions(+), 2 deletions(-)

diff --git a/core/embed/io/usb/unix/usb.c b/core/embed/io/usb/unix/usb.c
index d758ea72f8..e74b72a176 100644
--- a/core/embed/io/usb/unix/usb.c
+++ b/core/embed/io/usb/unix/usb.c
@@ -88,7 +88,8 @@ secbool usb_start(void) {
     usb_iface_t *iface = &usb_ifaces[i];
     // skip if not HID or WebUSB interface
     if (iface->type != USB_IFACE_TYPE_HID &&
-        iface->type != USB_IFACE_TYPE_WEBUSB) {
+        iface->type != USB_IFACE_TYPE_WEBUSB &&
+        iface->type != USB_IFACE_TYPE_VCP) {
       continue;
     }
 
@@ -328,6 +329,62 @@ int usb_webusb_write_blocking(uint8_t iface_num, const uint8_t *buf,
   return usb_webusb_write(iface_num, buf, len);
 }
 
+secbool usb_vcp_can_read(uint8_t iface_num) {
+  if (iface_num >= USBD_MAX_NUM_INTERFACES ||
+      usb_ifaces[iface_num].type != USB_IFACE_TYPE_VCP) {
+    return secfalse;
+  }
+  return usb_emulated_poll_read(&usb_ifaces[iface_num]);
+}
+
+secbool usb_vcp_can_write(uint8_t iface_num) {
+  if (iface_num >= USBD_MAX_NUM_INTERFACES ||
+      usb_ifaces[iface_num].type != USB_IFACE_TYPE_VCP) {
+    return secfalse;
+  }
+  return usb_emulated_poll_write(&usb_ifaces[iface_num]);
+}
+
+int usb_vcp_read(uint8_t iface_num, uint8_t *buf, uint32_t len) {
+  if (iface_num >= USBD_MAX_NUM_INTERFACES ||
+      usb_ifaces[iface_num].type != USB_IFACE_TYPE_VCP) {
+    return 0;
+  }
+  return usb_emulated_read(&usb_ifaces[iface_num], buf, len);
+}
+
+int usb_vcp_read_blocking(uint8_t iface_num, uint8_t *buf, uint32_t len,
+                          int timeout) {
+  const uint32_t start = clock();
+  while (sectrue != usb_vcp_can_read(iface_num)) {
+    if (timeout >= 0 &&
+        (1000 * (clock() - start)) / CLOCKS_PER_SEC >= timeout) {
+      return 0;  // Timeout
+    }
+  }
+  return usb_vcp_read(iface_num, buf, len);
+}
+
+int usb_vcp_write(uint8_t iface_num, const uint8_t *buf, uint32_t len) {
+  if (iface_num >= USBD_MAX_NUM_INTERFACES ||
+      usb_ifaces[iface_num].type != USB_IFACE_TYPE_VCP) {
+    return 0;
+  }
+  return usb_emulated_write(&usb_ifaces[iface_num], buf, len);
+}
+
+int usb_vcp_write_blocking(uint8_t iface_num, const uint8_t *buf, uint32_t len,
+                           int timeout) {
+  const uint32_t start = clock();
+  while (sectrue != usb_vcp_can_write(iface_num)) {
+    if (timeout >= 0 &&
+        (1000 * (clock() - start)) / CLOCKS_PER_SEC >= timeout) {
+      return 0;  // Timeout
+    }
+  }
+  return usb_vcp_write(iface_num, buf, len);
+}
+
 void mp_hal_set_vcp_iface(int iface_num) {}
 
 secbool usb_configured(void) {
diff --git a/core/src/usb.py b/core/src/usb.py
index 33d43f25ea..cd60dcb676 100644
--- a/core/src/usb.py
+++ b/core/src/usb.py
@@ -27,7 +27,7 @@ _iface_iter = iter(range(5))
 
 ENABLE_IFACE_DEBUG = __debug__
 ENABLE_IFACE_WEBAUTHN = not utils.BITCOIN_ONLY
-ENABLE_IFACE_VCP = __debug__
+ENABLE_IFACE_VCP = __debug__ and not utils.EMULATOR
 
 # interface used for trezor wire protocol
 id_wire = next(_iface_iter)