Squashed 'panda/' changes from c371fe6..2573d86

2573d86 docs say max is 4, respect the docs
864cd8f failing on some devices
54bcc67 Merge pull request #75 from gregjhogan/j2534-vs-2017-upgrade
1664270 Merge pull request #74 from gregjhogan/j2534-disconnect-fix
a7e3a8f bump panda version for serial bug
aa0cfad fix UART hang
09ab8f6 add sendaddr support to isotp
40a1883 fix up baud rate
65997ff add PandaSerial and location panda (aka pigeon) test
57d633c upgraded to VS 2017
35cc32a fixed pointer exception on disconnect

git-subtree-dir: panda
git-subtree-split: 2573d861e605a2dcf456a6421b31e83fdd9ca606

board/drivers/uart.h

@@ -5,16 +5,19 @@
 // esp = USART1
 uart_ring esp_ring = { .w_ptr_tx = 0, .r_ptr_tx = 0,
                        .w_ptr_rx = 0, .r_ptr_rx = 0,
-                       .uart = USART1 };
+                       .uart = USART1,
+                       .callback = NULL};
 
 // lin1, K-LINE = UART5
 // lin2, L-LINE = USART3
 uart_ring lin1_ring = { .w_ptr_tx = 0, .r_ptr_tx = 0,
                         .w_ptr_rx = 0, .r_ptr_rx = 0,
-                        .uart = UART5 };
+                        .uart = UART5,
+                        .callback = NULL};
 uart_ring lin2_ring = { .w_ptr_tx = 0, .r_ptr_tx = 0,
                         .w_ptr_rx = 0, .r_ptr_rx = 0,
-                        .uart = USART3 };
+                        .uart = USART3,
+                        .callback = NULL};
 
 // debug = USART2
 void debug_ring_callback(uart_ring *ring);
@@ -59,7 +62,7 @@ void uart_ring_process(uart_ring *q) {
     q->uart->CR1 &= ~USART_CR1_TXEIE;
   }
 
-  if (sr & USART_SR_RXNE) {
+  if (sr & USART_SR_RXNE || sr & USART_SR_ORE) {
     uint8_t c = q->uart->DR;  // TODO: can drop packets
     uint8_t next_w_ptr = q->w_ptr_rx + 1;
     if (next_w_ptr != q->r_ptr_rx) {
@@ -68,6 +71,11 @@ void uart_ring_process(uart_ring *q) {
       if (q->callback) q->callback(q);
     }
   }
+
+  if (sr & USART_SR_ORE) {
+    // set dropped packet flag?
+  }
+
   exit_critical_section();
 }