From 3a415ab870655b443012c87de4a591d33702952b Mon Sep 17 00:00:00 2001
From: Jessy Diamond Exum <jessy.diamondman@gmail.com>
Date: Fri, 14 Jul 2017 20:25:13 -0700
Subject: [PATCH] Can loopback now runtime configurable. Useful for board
 tests, customer troubleshooting, and linux driver loopback support.

---
 board/can.h       |  4 ++--
 board/config.h    |  1 -
 board/main.c      | 10 +++++++++-
 panda/__init__.py |  3 +++
 4 files changed, 14 insertions(+), 4 deletions(-)

diff --git a/board/can.h b/board/can.h
index f8387db1..3a2daa4e 100644
--- a/board/can.h
+++ b/board/can.h
@@ -17,9 +17,9 @@ void can_init(CAN_TypeDef *CAN, int silent) {
     CAN_BTR_TS2_0 | (prescaler - 1);
 
   // silent loopback mode for debugging
-  #ifdef CAN_LOOPBACK_MODE
+  if (can_loopback) {
     CAN->BTR |= CAN_BTR_SILM | CAN_BTR_LBKM;
-  #endif
+  }
 
   if (silent) {
     CAN->BTR |= CAN_BTR_SILM;
diff --git a/board/config.h b/board/config.h
index d9304bd8..523ac8bc 100644
--- a/board/config.h
+++ b/board/config.h
@@ -3,7 +3,6 @@
 
 //#define DEBUG
 //#define DEBUG_USB
-//#define CAN_LOOPBACK_MODE
 
 #ifdef STM32F4
   #define PANDA
diff --git a/board/main.c b/board/main.c
index e36ebb61..dff891bc 100644
--- a/board/main.c
+++ b/board/main.c
@@ -24,7 +24,7 @@ int can_forwarding[] = {-1,-1,-1};
 // debug safety check: is controls allowed?
 int controls_allowed = 0;
 int started = 0;
-int can_live = 0, pending_can_live = 0;
+int can_live = 0, pending_can_live = 0, can_loopback = 0;
 
 // optional features
 int gas_interceptor_detected = 0;
@@ -715,6 +715,14 @@ int usb_cb_control_msg(USB_Setup_TypeDef *setup, uint8_t *resp, int hardwired) {
       if (!ur) break;
       uart_set_baud(ur->uart, (int)setup->b.wIndex.w*300);
       break;
+    case 0xe5: // Set CAN loopback (for testing)
+      can_loopback = (setup->b.wValue.w > 0);
+      can_init(CAN1, 0);
+      can_init(CAN2, 0);
+      #ifdef CAN3
+        can_init(CAN3, 0);
+      #endif
+      break;
     case 0xf0: // k-line wValue pulse on uart2
       if (setup->b.wValue.w == 1) {
         GPIOC->ODR &= ~(1 << 10);
diff --git a/panda/__init__.py b/panda/__init__.py
index ad690143..aa3c3b8f 100644
--- a/panda/__init__.py
+++ b/panda/__init__.py
@@ -152,6 +152,9 @@ class Panda(object):
   def set_gmlan(self, on, bus=2):
     self._handle.controlWrite(Panda.REQUEST_TYPE, 0xdb, 1, bus, b'')
 
+  def set_can_loopback(self, enable):
+    self._handle.controlWrite(Panda.REQUEST_TYPE, 0xe5, bool(enable), 0, b'')
+
   def set_uart_baud(self, uart, rate):
     self._handle.controlWrite(Panda.REQUEST_TYPE, 0xe1, uart, rate, b'')