Allow user to specify JTAG IR lengths.

This allows the use of devices that shift out values other than 0x01
from IR.

src/command.c

@@ -38,7 +38,7 @@
 static bool cmd_version(void);
 static bool cmd_help(target *t);
 
-static bool cmd_jtag_scan(void);
+static bool cmd_jtag_scan(target *t, int argc, char **argv);
 static bool cmd_swdp_scan(void);
 static bool cmd_targets(target *t);
 static bool cmd_morse(void);
@@ -128,11 +128,22 @@ bool cmd_help(target *t)
 	return true;
 }
 
-bool cmd_jtag_scan(void)
+static bool cmd_jtag_scan(target *t, int argc, char **argv)
 {
+	(void)t;
+	uint8_t *irlens = NULL;
+
 	gdb_outf("Target voltage: %s\n", platform_target_voltage());
 
-	int devs = jtag_scan();
+	if (argc > 1) {
+		/* Accept a list of IR lengths on command line */
+		irlens = alloca(argc);
+		for (int i = 1; i < argc; i++)
+			irlens[i-1] = atoi(argv[i]);
+		irlens[argc-1] = 0;
+	}
+
+	int devs = jtag_scan(irlens);
 
 	if(devs < 0) {
 		gdb_out("JTAG device scan failed!\n");

src/include/jtag_scan.h

@@ -47,7 +47,7 @@ typedef struct jtag_dev_s {
 extern struct jtag_dev_s jtag_devs[JTAG_MAX_DEVS+1];
 extern int jtag_dev_count;
 
-int jtag_scan(void);
+int jtag_scan(const uint8_t *lrlens);
 
 void jtag_dev_write_ir(jtag_dev_t *dev, uint32_t ir);
 void jtag_dev_shift_dr(jtag_dev_t *dev, uint8_t *dout, const uint8_t *din, int ticks);

src/jtag_scan.c

@@ -97,7 +97,7 @@ static const char ones[] = "\xFF\xFF\xFF\xFF\xFF\xFF\xFF\xFF";
  *	continue to next device. If this is one shift out the remaining 31 bits
  *	of the IDCODE register.
  */
-int jtag_scan(void)
+int jtag_scan(const uint8_t *irlens)
 {
 	int i;
 	uint32_t j;
@@ -117,6 +117,29 @@ int jtag_scan(void)
 	jtagtap_init();
 	jtagtap_reset();
 
+	if (irlens) {
+		DEBUG("Given list of IR lengths, skipping probe\n");
+		DEBUG("Change state to Shift-IR\n");
+		jtagtap_shift_ir();
+		j = 0;
+		while((jtag_dev_count <= JTAG_MAX_DEVS) && 
+		      (jtag_devs[jtag_dev_count].ir_len <= JTAG_MAX_IR_LEN)) {
+			uint32_t irout;
+			if(*irlens == 0) 
+				break;
+			jtagtap_tdi_tdo_seq((uint8_t*)&irout, 0, ones, *irlens);
+			if (!(irout & 1)) {
+				DEBUG("check failed: IR[0] != 1\n");
+				return -1;
+			}
+			jtag_devs[jtag_dev_count].ir_len = *irlens;
+			jtag_devs[jtag_dev_count].ir_prescan = j;
+			jtag_devs[jtag_dev_count].dev = jtag_dev_count;
+			j += *irlens;
+			irlens++;
+			jtag_dev_count++;
+		}
+	} else {
 		DEBUG("Change state to Shift-IR\n");
 		jtagtap_shift_ir();
 
@@ -147,6 +170,7 @@ int jtag_scan(void)
 			jtag_dev_count = -1;
 			return -1;
 		}
+	}
 	
 	DEBUG("Return to Run-Test/Idle\n");
 	jtagtap_next(1, 1);

src/platforms/libftdi/platform.c

@@ -79,7 +79,7 @@ int platform_init(void)
 
 	assert(gdb_if_init() == 0);
 
-	jtag_scan();
+	jtag_scan(NULL);
 	
 	return 0; 
 }

src/platforms/native/platform.c

@@ -120,7 +120,7 @@ int platform_init(void)
 
 	cdcacm_init();
 
-	jtag_scan();
+	jtag_scan(NULL);
 	
 	return 0;
 }

src/platforms/stlink/platform.c

@@ -68,7 +68,7 @@ int platform_init(void)
 
 	cdcacm_init();
 
-	jtag_scan();
+	jtag_scan(NULL);
 	
 	return 0;
 }