Change MAX_NYET_RETRY to MAX_NOTREADY_RETRY

MAX_NYET_RETRY is an incorrect name, because URB_NOTREADY can have several different
causes that are unrelated to each other. Therefore, MAX_NOTREADY_RETRY is a better
name. This commit also changes a comment regarding the case where the max retries
limit has been reached, to better describe what happens.

Author: Alrik Vidstrom

src/targets/TARGET_STM/USBEndpoint_STM.cpp

@@ -181,7 +181,7 @@ USB_TYPE USBEndpoint::queueTransfer()
     state = USB_TYPE_PROCESSING;
     /*  one request */
     td_current->nextTD = (hcTd *)0;
-#if defined(MAX_NYET_RETRY)
+#if defined(MAX_NOTREADY_RETRY)
     td_current->retry = 0;
 #endif
     td_current->setup = setup;

src/targets/TARGET_STM/USBHALHost_STM.cpp

@@ -93,7 +93,7 @@ void HAL_HCD_HC_NotifyURBChange_Callback(HCD_HandleTypeDef *hhcd, uint8_t chnum,
         if ((type == EP_TYPE_BULK) || (type == EP_TYPE_CTRL)) {
             switch (urb_state) {
                 case URB_DONE:
-#if defined(MAX_NYET_RETRY)
+#if defined(MAX_NOTREADY_RETRY)
                     td->retry = 0;
 #endif
                     if (td->size >  max_size) {
@@ -110,18 +110,18 @@ void HAL_HCD_HC_NotifyURBChange_Callback(HCD_HandleTypeDef *hhcd, uint8_t chnum,
                     /*  try again  */
                     /*  abritary limit , to avoid dead lock if other error than
                      *  slow response is  */
-#if defined(MAX_NYET_RETRY)
-                    if (td->retry < MAX_NYET_RETRY) {
+#if defined(MAX_NOTREADY_RETRY)
+                    if (td->retry < MAX_NOTREADY_RETRY) {
                         /*  increment retry counter */
                         td->retry++;
 #endif
                         length = td->size <= max_size ? td->size : max_size;
                         HAL_HCD_HC_SubmitRequest(hhcd, chnum, dir, type, !td->setup, (uint8_t *) td->currBufPtr, length, 0);
                         HAL_HCD_EnableInt(hhcd, chnum);
                         return;
-#if defined(MAX_NYET_RETRY)
+#if defined(MAX_NOTREADY_RETRY)
                     } else {
-                        //USB_ERR("urb_state != URB_NOTREADY");
+                        // MAX_NOTREADY_RETRY reached, so stop trying to resend and instead wait for a timeout at a higher layer
                     }
 #endif
                     break;

src/targets/TARGET_STM/USBHALHost_STM.h

@@ -38,7 +38,7 @@
 
 #define TOTAL_SIZE (HCCA_SIZE + (MAX_ENDPOINT * ED_SIZE) + (MAX_TD * TD_SIZE))
 
-#define MAX_NYET_RETRY      5
+#define MAX_NOTREADY_RETRY      5
 
 /* STM device FS have 11 channels (definition is for 60 channels) */
 static volatile  uint8_t usb_buf[TOTAL_SIZE];