first approach at modding the reset scheme

now we reset from recv bytes. After receiving the DTR/RTS toggle the next byte in from usb is parsed as the program_delay. For now, this just delays the reset for a period to close the serial port gracefully. Later, this delay will perhaps inform the bootloader of how long to live for...

3 files changed, 47 insertions, 31 deletions

diff --git a/libmaple/usb/usb.c b/libmaple/usb/usb.c
index 6c144ba..09b51ea 100644
--- a/libmaple/usb/usb.c
+++ b/libmaple/usb/usb.c
@@ -332,40 +332,11 @@ if (wIstr & ISTR_CTR & wInterrupt_Mask)
   }
 #endif
 
-/* if we are about to reset from the DTR signal, then dont return
-   to user, instead return from the ISR into a wait slide */
- if (reset_state == RESET_NOW) {
-   reset_state = START;
-   unsigned int target = (unsigned int)usbWaitReset | 0x1;
-
-   asm volatile("mov r0, %[stack_top]      \n\t"             // Reset the stack
-		"mov sp, r0                \n\t"
-		"mov r0, #1                \n\t"
-		"mov r1, %[target_addr]    \n\t"
-		"mov r2, %[cpsr]           \n\t"
-		"push {r2}                 \n\t"             // Fake xPSR
-		"push {r1}                 \n\t"             // Target address for PC
-		"push {r0}                 \n\t"             // Fake LR
-		"push {r0}                 \n\t"             // Fake R12
-		"push {r0}                 \n\t"             // Fake R3
-		"push {r0}                 \n\t"             // Fake R2
-		"push {r0}                 \n\t"             // Fake R1
-		"push {r0}                 \n\t"             // Fake R0
-		"mov lr, %[exc_return]     \n\t"
-		"bx lr"
-		:
-		: [stack_top] "r" (STACK_TOP),
-		  [target_addr] "r" (target),
-		  [exc_return] "r" (EXC_RETURN),
-		  [cpsr] "r" (DEFAULT_CPSR)
-		: "r0", "r1", "r2");
-   // Should never get here.
- }
 }
 
 void usbWaitReset(void) {
-  static count=1000000;
-  while (count-- >0);
+  int count = program_delay*100000000;
+  delay(program_delay*10);
   systemHardReset();
 }
 
diff --git a/libmaple/usb/usb_callbacks.c b/libmaple/usb/usb_callbacks.c
index 5c4a386..cacfd02 100644
--- a/libmaple/usb/usb_callbacks.c
+++ b/libmaple/usb/usb_callbacks.c
@@ -5,6 +5,7 @@
 #include "descriptors.h"
 #include "usb_config.h"
 #include "usb.h"
+#include "usb_hardware.h"
 
 ONE_DESCRIPTOR Device_Descriptor = {
   (uint8*)&usbVcomDescriptor_Device,
@@ -38,6 +39,7 @@ volatile uint8 recvBufOut = 0;
 volatile uint8 maxNewBytes   = VCOM_RX_EPSIZE;
 
 RESET_STATE reset_state = START;
+uint8       program_delay = 1;
 
 void vcomDataTxCb(void) {
   /* do whatever after data has been sent to host */
@@ -61,6 +63,48 @@ void vcomDataRxCb(void) {
   uint8 newBytes = GetEPRxCount(VCOM_RX_ENDP);
   /* assert (newBytes <= maxNewBytes); */
 
+
+  if (reset_state == RESET_NOW) {
+    /* todo, check for magic bytes */
+    /* for now just grab the new byte as the delay argument */
+    /* if theres anything in the recv buffer clear it, 
+       then wait for the command byte and the delay argument. 
+       if we dont get it, then just reset. todo, if we dont 
+       get it, then revert back to user code */
+   
+
+    reset_state = START;
+    unsigned int target = (unsigned int)usbWaitReset | 0x1;
+
+    PMAToUserBufferCopy(&program_delay,VCOM_RX_ADDR,1);
+
+    asm volatile("mov r0, %[stack_top]      \n\t"             // Reset the stack
+		 "mov sp, r0                \n\t"
+		 "mov r0, #1                \n\t"
+		 "mov r1, %[target_addr]    \n\t"
+		 "mov r2, %[cpsr]           \n\t"
+		 "push {r2}                 \n\t"             // Fake xPSR
+		 "push {r1}                 \n\t"             // Target address for PC
+		 "push {r0}                 \n\t"             // Fake LR
+		 "push {r0}                 \n\t"             // Fake R12
+		 "push {r0}                 \n\t"             // Fake R3
+		 "push {r0}                 \n\t"             // Fake R2
+		 "push {r0}                 \n\t"             // Fake R1
+		 "push {r0}                 \n\t"             // Fake R0
+		 "mov lr, %[exc_return]     \n\t"
+		 "bx lr"
+		 :
+		 : [stack_top] "r" (STACK_TOP),
+		   [target_addr] "r" (target),
+		   [exc_return] "r" (EXC_RETURN),
+		   [cpsr] "r" (DEFAULT_CPSR)
+		 : "r0", "r1", "r2");
+    // Should never get here.
+
+  }
+
+
+
   if (recvBufIn + newBytes < VCOM_RX_EPSIZE) {
     PMAToUserBufferCopy(&vcomBufferRx[recvBufIn],VCOM_RX_ADDR,newBytes);
     recvBufIn += newBytes;
diff --git a/libmaple/usb/usb_callbacks.h b/libmaple/usb/usb_callbacks.h
index ed57fa1..d77a9fd 100644
--- a/libmaple/usb/usb_callbacks.h
+++ b/libmaple/usb/usb_callbacks.h
@@ -34,6 +34,7 @@ typedef enum {
 } RESET_STATE;
 
 extern RESET_STATE reset_state;  /* tracks DTR/RTS */
+extern uint8       program_delay;
 extern volatile uint8 countTx;
 extern uint8 vcomBufferRx[VCOM_RX_EPSIZE];  /* no reason this has to be VCOM_RX_EPSIZE, could be bigger */
 extern volatile uint8 recvBufIn;   /* the FIFO in index to the recvbuffer */