FPC: got RX working, got client over usart somehow working..., see detailed commit msg

* using WITH_FPC:
  * activate basic usart
  * no double buffer for now, no interrupt
  * usart_dataavailable/usart_readbuffer/usart_writebuffer, to demo it:
    * pm3 client over USB, minicom over usart
    * analyse a d 414243
* using WITH_FPC_HOST:
  * it implies WITH_FPC as it's based on it
  * control pm3 with client over usart
  * EXPERIMENTAL! still some frame desync issues
  * you can connect both from usart & USB with two pm3 clients
    * actually you *have* to connect USB for the moment because
      it's used to send debug messages about buggy usart... See Dbprintf_usb below
  * "sessions": msgs are directed to the latest client to have sent a cmd
  * Dbprintf_usb macro to send msgs to USB client to help debugging usart...
  * We now have an option to run client at different speed as usart is 115200:
    client/proxmark3 /dev/ttyUSB0 -b 115200
  * Consequently, argc,argv handling is a bit revamped, it was so messy...
  * USB and flashing are still at 460800, don't try flashing over usart yet ^^

uart/uart.h

@@ -71,7 +71,7 @@ typedef void *serial_port;
  *
  * On errors, this method returns INVALID_SERIAL_PORT or CLAIMED_SERIAL_PORT.
  */
-serial_port uart_open(const char *pcPortName);
+serial_port uart_open(const char *pcPortName, uint32_t speed);
 
 /* Closes the given port.
  */

uart/uart_posix.c

@@ -73,7 +73,7 @@ struct timeval timeout = {
     .tv_usec = 30000  // 30 000 micro seconds
 };
 
-serial_port uart_open(const char *pcPortName) {
+serial_port uart_open(const char *pcPortName, uint32_t speed) {
     serial_port_unix *sp = calloc(sizeof(serial_port_unix), sizeof(uint8_t));
     if (sp == 0) return INVALID_SERIAL_PORT;
 
@@ -194,14 +194,19 @@ serial_port uart_open(const char *pcPortName) {
     // Flush all lingering data that may exist
     tcflush(sp->fd, TCIOFLUSH);
 
-    // set speed, works for UBUNTU 14.04
-    bool success = uart_set_speed(sp, 460800);
-    if (success) {
-        printf("[=] UART Setting serial baudrate 460800\n");
-    } else {
-        uart_set_speed(sp, 115200);
-        printf("[=] UART Setting serial baudrate 115200\n");
+    if (!uart_set_speed(sp, speed)) {
+        // trying some fallbacks automatically
+        speed = 115200;
+        if (!uart_set_speed(sp, speed)) {
+            speed = 9600;
+            if (!uart_set_speed(sp, speed)) {
+                uart_close(sp);
+                printf("[!] UART error while setting baudrate\n");
+                return INVALID_SERIAL_PORT;
+            }
+        }
     }
+    printf("[=] UART Setting serial baudrate %i\n", speed);
     return sp;
 }
 

uart/uart_win32.c

@@ -48,7 +48,7 @@ typedef struct {
     COMMTIMEOUTS ct;  // Serial port time-out configuration
 } serial_port_windows;
 
-serial_port uart_open(const char *pcPortName) {
+serial_port uart_open(const char *pcPortName, uint32_t speed) {
     char acPortName[255];
     serial_port_windows *sp = calloc(sizeof(serial_port_windows), sizeof(uint8_t));
 
@@ -87,6 +87,7 @@ serial_port uart_open(const char *pcPortName) {
     // all zero's configure: no timeout for read/write used.
     // took settings from libnfc/buses/uart.c
 #ifdef WITH_FPC
+    // Still relevant?
     sp->ct.ReadIntervalTimeout         = 1000;
     sp->ct.ReadTotalTimeoutMultiplier  = 0;
     sp->ct.ReadTotalTimeoutConstant    = 1500;
@@ -108,22 +109,19 @@ serial_port uart_open(const char *pcPortName) {
 
     PurgeComm(sp->hPort, PURGE_RXABORT | PURGE_RXCLEAR);
 
-#ifdef WITH_FPC
-    if (uart_set_speed(sp, 115200)) {
-        printf("[=] UART Setting serial baudrate 115200 [FPC enabled]\n");
-    } else {
-        uart_set_speed(sp, 9600);
-        printf("[=] UART Setting serial baudrate 9600 [FPC enabled]\n");
+    if (!uart_set_speed(sp, speed)) {
+        // trying some fallbacks automatically
+        speed = 115200;
+        if (!uart_set_speed(sp, speed)) {
+            speed = 9600;
+            if (!uart_set_speed(sp, speed)) {
+                uart_close(sp);
+                printf("[!] UART error while setting baudrate\n");
+                return INVALID_SERIAL_PORT;
+            }
+        }
     }
-#else
-    bool success = uart_set_speed(sp, 460800);
-    if (success) {
-        printf("[=] UART Setting serial baudrate 460800\n");
-    } else {
-        uart_set_speed(sp, 115200);
-        printf("[=] UART Setting serial baudrate 115200\n");
-    }
-#endif
+    printf("[=] UART Setting serial baudrate %i\n", speed);
     return sp;
 }