From e0cd5850f9ab02ef6dbe924800cbfdda51505d6b Mon Sep 17 00:00:00 2001
From: Philippe Teuwen <phil@teuwen.org>
Date: Sun, 21 Apr 2019 12:02:30 +0200
Subject: [PATCH] usart: clean, doc, now uart_posix 60ms

---
 common/usart.c           | 22 +++++++---------------
 doc/new_frame_format.txt | 18 ++++++++++++++++--
 uart/uart_posix.c        |  7 ++++---
 3 files changed, 27 insertions(+), 20 deletions(-)

diff --git a/common/usart.c b/common/usart.c
index 56f6bb446..ecbd3a8e3 100644
--- a/common/usart.c
+++ b/common/usart.c
@@ -119,7 +119,7 @@ uint32_t usart_read_ng(uint8_t *data, size_t len) {
                 us_rxfifo_low = 0;
         }
         if (try++ == maxtry) {
-            Dbprintf_usb("Dbg USART TIMEOUT");
+//            Dbprintf_usb("Dbg USART TIMEOUT");
             break;
         }
     }
@@ -133,8 +133,6 @@ inline int16_t usart_writebuffer(uint8_t *data, size_t len) {
 
     // Wait for one free PDC bank
     while (pUS1->US_TCR && pUS1->US_TNCR) {};
-    // ? alternative to wait for end of transmissions?
-    // while (!(pUS1->US_CSR & AT91C_US_ENDTX)) {};
 
     // Check if the current PDC bank is free
     if (pUS1->US_TCR == 0) {
@@ -149,8 +147,6 @@ inline int16_t usart_writebuffer(uint8_t *data, size_t len) {
         // we shouldn't be here
         return 0;
     }
-    // Make sure TX transfer is enabled
-    pUS1->US_PTCR = AT91C_PDC_TXTEN;// | AT91C_PDC_RXTEN;
     //wait until finishing all transfers
     while (pUS1->US_TNCR || pUS1->US_TCR) {};
     return len;
@@ -202,19 +198,15 @@ void usart_init(void) {
     pUS1->US_TCR = 0;
     pUS1->US_TNPR = (uint32_t)0;
     pUS1->US_TNCR = 0;
-    pUS1->US_RPR = (uint32_t)0;
-    pUS1->US_RCR = 0;
-    pUS1->US_RNPR = (uint32_t)0;
-    pUS1->US_RNCR = 0;
-
-    // re-enable receiver / transmitter
-    pUS1->US_CR = (AT91C_US_RXEN | AT91C_US_TXEN);
-
-    // ready to receive
     pUS1->US_RPR = (uint32_t)us_inbuf1;
     pUS1->US_RCR = USART_BUFFLEN;
     usart_cur_inbuf = us_inbuf1;
     pUS1->US_RNPR = (uint32_t)us_inbuf2;
     pUS1->US_RNCR = USART_BUFFLEN;
-    pUS1->US_PTCR = AT91C_PDC_RXTEN;
+
+    // re-enable receiver / transmitter
+    pUS1->US_CR = (AT91C_US_RXEN | AT91C_US_TXEN);
+
+    // ready to receive and transmit
+    pUS1->US_PTCR = AT91C_PDC_RXTEN | AT91C_PDC_TXTEN;
 }
diff --git a/doc/new_frame_format.txt b/doc/new_frame_format.txt
index 3ca272be4..58aacc3d6 100644
--- a/doc/new_frame_format.txt
+++ b/doc/new_frame_format.txt
@@ -197,11 +197,25 @@ New bootrom might need to also still support old frame format, to ease flashing
 Timings
 =======
 
-Needed to increase client RX uart timeout: it was 30ms, we put arbitrarily 300ms as for TCP
+(common/usart.h)
+USART_BAUD_RATE defined
+
+     9600: #db#   USB Transfer Speed PM3 -> Client =    934 Bytes/s
+   115200: #db#   USB Transfer Speed PM3 -> Client =  11137 Bytes/s
+   460800: #db#   USB Transfer Speed PM3 -> Client =  43119 Bytes/s
+linux usb: #db#   USB Transfer Speed PM3 -> Client = 666624 Bytes/s (~7Mbaud)
+
+
+At some point, when still activating AT91C_PDC_TXTEN in usart_writebuffer, we needed to increase client uart timeout.
+We tried 300ms, but then USB flasher failed :
+[=] UART Setting serial baudrate 460800
+.Found
+Error: Unknown Proxmark3 mode
+Now we're at 60ms
 (uart/uart_posix.c)
 struct timeval timeout = {
     .tv_sec  =     0, // 0 second
-    .tv_usec = 300000  // 300 000 micro seconds
+    .tv_usec = 60000  // 60 000 micro seconds
 };
 
 Add automatically some communication delay in the WaitForResponseTimeout timeout
diff --git a/uart/uart_posix.c b/uart/uart_posix.c
index 41e4338b0..dac473379 100644
--- a/uart/uart_posix.c
+++ b/uart/uart_posix.c
@@ -70,11 +70,12 @@ typedef struct {
     term_info tiNew;  // Terminal info during the transaction
 } serial_port_unix;
 
-// Set time-out on 300 milliseconds
-// It was 30 ms for USB but we need more to receive from USART
+// To be checked, receiving from USART might need more than 30ms
+// if we get errors about partial packet reception
+// but e.g. extending to 300ms makes USB flasher failing
 struct timeval timeout = {
     .tv_sec  =     0, // 0 second
-    .tv_usec = 300000  // 300 000 micro seconds
+    .tv_usec = 60000  // 60 000 micro seconds
 };
 
 serial_port uart_open(const char *pcPortName, uint32_t speed) {