From 4b4f88078503648b38444feee1fda322b65baa43 Mon Sep 17 00:00:00 2001
From: hathach <thach@tinyusb.org>
Date: Mon, 23 Nov 2020 23:40:13 +0700
Subject: [PATCH] add tud_ready() check in tud_cdc_n_write_flush()

other clean up
---
 examples/device/cdc_msc/src/main.c | 10 ----------
 src/class/cdc/cdc_device.c         | 19 +++++++++++++------
 src/common/tusb_fifo.c             |  2 +-
 src/common/tusb_fifo.h             |  2 +-
 4 files changed, 15 insertions(+), 18 deletions(-)

diff --git a/examples/device/cdc_msc/src/main.c b/examples/device/cdc_msc/src/main.c
index e4477927..cf2bfd7c 100644
--- a/examples/device/cdc_msc/src/main.c
+++ b/examples/device/cdc_msc/src/main.c
@@ -145,16 +145,6 @@ void tud_cdc_line_state_cb(uint8_t itf, bool dtr, bool rts)
 void tud_cdc_rx_cb(uint8_t itf)
 {
   (void) itf;
-  uint8_t const line_state = tud_cdc_get_line_state();
-
-  // Provide information that terminal did not set DTR bit
-  if( !(line_state & 0x01) )
-  {
-    tud_cdc_write_str("\r\nTinyUSB example: Your terminal did not set DTR bit\r\n");
-    tud_cdc_write_flush();
-    // Clear rx fifo since we do not read the data
-    tud_cdc_read_flush();
-  }
 }
 
 //--------------------------------------------------------------------+
diff --git a/src/class/cdc/cdc_device.c b/src/class/cdc/cdc_device.c
index bd1d9b0d..58f485a5 100644
--- a/src/class/cdc/cdc_device.c
+++ b/src/class/cdc/cdc_device.c
@@ -178,6 +178,9 @@ uint32_t tud_cdc_n_write_flush (uint8_t itf)
 {
   cdcd_interface_t* p_cdc = &_cdcd_itf[itf];
 
+  // Skip if usb is not ready yet
+  TU_VERIFY( tud_ready(), 0 );
+
   // No data to send
   if ( !tu_fifo_count(&p_cdc->tx_ff) ) return 0;
 
@@ -231,9 +234,10 @@ void cdcd_init(void)
     p_cdc->line_coding.parity    = 0;
     p_cdc->line_coding.data_bits = 8;
 
-    // config fifo
+    // Config RX fifo
     tu_fifo_config(&p_cdc->rx_ff, p_cdc->rx_ff_buf, TU_ARRAY_SIZE(p_cdc->rx_ff_buf), 1, false);
-    // tx fifo is set to overwritable at initialization and will be changed to not overwritable
+
+    // Config TX fifo as overwritable at initialization and will be changed to non-overwritable
     // if terminal supports DTR bit. Without DTR we do not know if data is actually polled by terminal.
     // In this way, the most current data is prioritized.
     tu_fifo_config(&p_cdc->tx_ff, p_cdc->tx_ff_buf, TU_ARRAY_SIZE(p_cdc->tx_ff_buf), 1, true);
@@ -251,9 +255,12 @@ void cdcd_reset(uint8_t rhport)
 
   for(uint8_t i=0; i<CFG_TUD_CDC; i++)
   {
-    tu_memclr(&_cdcd_itf[i], ITF_MEM_RESET_SIZE);
-    tu_fifo_clear(&_cdcd_itf[i].rx_ff);
-    tu_fifo_clear(&_cdcd_itf[i].tx_ff);
+    cdcd_interface_t* p_cdc = &_cdcd_itf[i];
+
+    tu_memclr(p_cdc, ITF_MEM_RESET_SIZE);
+    tu_fifo_clear(&p_cdc->rx_ff);
+    tu_fifo_clear(&p_cdc->tx_ff);
+    tu_fifo_set_overwritable(&p_cdc->tx_ff, true);
   }
 }
 
@@ -381,7 +388,7 @@ bool cdcd_control_xfer_cb(uint8_t rhport, uint8_t stage, tusb_control_request_t
         p_cdc->line_state = (uint8_t) request->wValue;
         
         // Disable fifo overwriting if DTR bit is set
-        tu_fifo_set_mode(&p_cdc->tx_ff, !dtr);
+        tu_fifo_set_overwritable(&p_cdc->tx_ff, !dtr);
 
         TU_LOG2("  Set Control Line State: DTR = %d, RTS = %d\r\n", dtr, rts);
 
diff --git a/src/common/tusb_fifo.c b/src/common/tusb_fifo.c
index 444c60f9..608bfd08 100644
--- a/src/common/tusb_fifo.c
+++ b/src/common/tusb_fifo.c
@@ -607,7 +607,7 @@ bool tu_fifo_clear(tu_fifo_t *f)
                 Overwritable mode the fifo is set to
 */
 /******************************************************************************/
-bool tu_fifo_set_mode(tu_fifo_t *f, bool overwritable)
+bool tu_fifo_set_overwritable(tu_fifo_t *f, bool overwritable)
 {
   tu_fifo_lock(f);
 
diff --git a/src/common/tusb_fifo.h b/src/common/tusb_fifo.h
index abb301b5..b965386a 100644
--- a/src/common/tusb_fifo.h
+++ b/src/common/tusb_fifo.h
@@ -89,7 +89,7 @@ typedef struct
         .non_used_index_space   = 0xFFFF - 2*_depth-1,                  \
     }
 
-bool tu_fifo_set_mode(tu_fifo_t *f, bool overwritable);
+bool tu_fifo_set_overwritable(tu_fifo_t *f, bool overwritable);
 bool tu_fifo_clear(tu_fifo_t *f);
 bool tu_fifo_config(tu_fifo_t *f, void* buffer, uint16_t depth, uint16_t item_size, bool overwritable);