From 2a35f5648edeee8b829885c9e596ea4758cf4e95 Mon Sep 17 00:00:00 2001
From: John-Mark Gurney <jmg@funkthat.com>
Date: Tue, 6 Jul 2021 17:34:37 -0700
Subject: [PATCH] use funopen/stdio to buffer output, "fix" for FreeBSD...

convert to using stdio to line buffer usb output... This reduces
usb traffic like when doing hexdump...

The delay works, but could be a problem on slower systems...  It's
been reported, so hopefully a fix will happen..
---
 main.c                  | 14 +++++++-------
 misc.c                  |  2 +-
 stm32/usb/usb_device.c  |  2 +-
 stm32/usb/usbd_cdc_if.c | 36 ++++++++++++++++++++++--------------
 stm32/usb/usbd_cdc_if.h |  6 ++++--
 5 files changed, 35 insertions(+), 25 deletions(-)

diff --git a/main.c b/main.c
index b1bbdfc..a2c829c 100644
--- a/main.c
+++ b/main.c
@@ -184,6 +184,7 @@ process_line(char *start, char *end)
 		return;
 	}
 	usb_printf("line: %.*s", end - start, start);
+	fflush(vcp_usb);
 }
 
 int
@@ -199,16 +200,15 @@ main(void)
 	/* turn on LED */
 	HAL_GPIO_WritePin(GPIOB, GPIO_PIN_8, GPIO_PIN_SET);
 
+	setlinebuf(vcp_usb);
+
 #if 1
 	wait_for_vcp();
 
 	/*
-	 * This is required to use w/ FreeBSD.  Not sure why but if this
-	 * delay isn't here, the code will hang waiting for the output to
-	 * be sent, and it never does get sent.  I believe this is because
-	 * the packet to enable sending the data hasn't arrived yet, and
-	 * this code fails to handle that case, and drops the data on the
-	 * floor.
+	 * This is required to use w/ FreeBSD.  This is an issue w/ the
+	 * STM32 Core USB library:
+	 * https://github.com/STMicroelectronics/STM32CubeL1/issues/10
 	 */
 	DelayMs(50);
 	usb_printf("starting...\r\n");
@@ -227,7 +227,7 @@ main(void)
 	Radio.SetChannel(914350 * 1000);
 
 	v = Radio.Random();
-	usb_printf("rr: %#x\r\n", v);
+	usb_printf("rr: %#lx\r\n", v);
 
 	usb_printf("rssi: %#hx\r\n", Radio.Rssi(MODEM_LORA));
 
diff --git a/misc.c b/misc.c
index 0e9c847..7f8d6df 100644
--- a/misc.c
+++ b/misc.c
@@ -47,7 +47,7 @@ wait_for_vcp(void)
 {
 
 	for (;;) {
-		if (vcp_status(&hUsbDeviceFS.request))
+		if (vcp_status())
 			break;
 	}
 }
diff --git a/stm32/usb/usb_device.c b/stm32/usb/usb_device.c
index 7acc5c0..6ba479d 100755
--- a/stm32/usb/usb_device.c
+++ b/stm32/usb/usb_device.c
@@ -87,7 +87,7 @@ void MX_USB_DEVICE_Init(void)
   }
 
   /* USER CODE BEGIN USB_DEVICE_Init_PostTreatment */
-
+  vcp_usb = funopen(&vcp_usb, NULL, usb_write, NULL, NULL);
   /* USER CODE END USB_DEVICE_Init_PostTreatment */
 }
 
diff --git a/stm32/usb/usbd_cdc_if.c b/stm32/usb/usbd_cdc_if.c
index 35fd4d5..bb1daa9 100755
--- a/stm32/usb/usbd_cdc_if.c
+++ b/stm32/usb/usbd_cdc_if.c
@@ -25,6 +25,15 @@
 /* USER CODE BEGIN INCLUDE */
 uint8_t* CDC_RX_BUFFER = NULL ;
 uint16_t CDC_RX_LEN = 0;
+
+/*
+ * PSTN v1.20, § 6.3.12 SetControlLineState
+ *
+ * wValue:
+ *	D0	DTR
+ *	D1	RTS
+ */
+static uint16_t line_status;
 /* USER CODE END INCLUDE */
 
 /* Private typedef -----------------------------------------------------------*/
@@ -184,6 +193,10 @@ static int8_t CDC_DeInit_FS(void)
 static int8_t CDC_Control_FS(uint8_t cmd, uint8_t* pbuf, uint16_t length)
 {
   /* USER CODE BEGIN 5 */
+  USBD_SetupReqTypedef *req;
+
+  req = (USBD_SetupReqTypedef *)pbuf;
+
   switch(cmd)
   {
     case CDC_SEND_ENCAPSULATED_COMMAND:
@@ -232,7 +245,7 @@ static int8_t CDC_Control_FS(uint8_t cmd, uint8_t* pbuf, uint16_t length)
     break;
 
     case CDC_SET_CONTROL_LINE_STATE:
-
+        line_status = req->wValue;
     break;
 
     case CDC_SEND_BREAK:
@@ -300,23 +313,16 @@ uint8_t CDC_Transmit_FS(uint8_t* Buf, uint16_t Len)
 /* USER CODE BEGIN PRIVATE_FUNCTIONS_IMPLEMENTATION */
 #include <stdarg.h>
 
-uint16_t vcp_status( USBD_SetupReqTypedef  *req){
-	if(req->bRequest ==CDC_SET_CONTROL_LINE_STATE){
-		if(req->wValue){
-			return 1;
-		}
-	}
-	return 0;
+uint16_t vcp_status(){
+	return line_status & 0x1;
 }
 
-void usb_printf(const char *format, ...)
+int
+usb_write(void *cookie, const char *buf, int length)
 {
-    va_list args;
-    uint32_t length;
 
-    va_start(args, format);
-    length = vsnprintf((char *)UserTxBufferFS, APP_TX_DATA_SIZE, (char *)format, args);
-    va_end(args);
+	length = MIN(length, APP_TX_DATA_SIZE);
+	memcpy((char *)UserTxBufferFS, buf, length);
     for (;;) {
         if (CDC_Transmit_FS(UserTxBufferFS, length) == USBD_BUSY) {
             HAL_Delay(1);
@@ -324,6 +330,8 @@ void usb_printf(const char *format, ...)
         }
         break;
     }
+
+	return length;
 }
 /* USER CODE END PRIVATE_FUNCTIONS_IMPLEMENTATION */
 
diff --git a/stm32/usb/usbd_cdc_if.h b/stm32/usb/usbd_cdc_if.h
index 87da7a5..b46f64e 100755
--- a/stm32/usb/usbd_cdc_if.h
+++ b/stm32/usb/usbd_cdc_if.h
@@ -116,8 +116,10 @@ extern uint16_t CDC_RX_LEN;
 uint8_t CDC_Transmit_FS(uint8_t* Buf, uint16_t Len);
 
 /* USER CODE BEGIN EXPORTED_FUNCTIONS */
-void usb_printf(const char *format, ...);
-uint16_t vcp_status( USBD_SetupReqTypedef  *req);
+FILE *vcp_usb;
+int usb_write(void *cookie, const char *buf, int len);
+#define usb_printf(...)	fprintf(vcp_usb, __VA_ARGS__)
+uint16_t vcp_status(void);
 /* USER CODE END EXPORTED_FUNCTIONS */
 
 /**