Revert "jtag_scan: Rework chain detection"

This reverts commit 2d4a503135.

src/Makefile

@@ -31,6 +31,7 @@ SRC =			\
 	gdb_hostio.c	\
 	gdb_packet.c	\
 	hex_utils.c	\
+	jtag_devs.c	\
 	jtag_scan.c	\
 	lmi.c		\
 	lpc_common.c	\

src/platforms/hosted/Makefile.inc

@@ -73,7 +73,7 @@ ifneq ($(HOSTED_BMP_ONLY), 1)
 endif
 
 VPATH += platforms/pc
-SRC += timing.c cl_utils.c utils.c jtag_devs.c
+SRC += timing.c cl_utils.c utils.c
 SRC += bmp_remote.c remote_swdptap.c remote_jtagtap.c
 ifneq ($(HOSTED_BMP_ONLY), 1)
 SRC += bmp_libusb.c stlinkv2.c

src/target/adiv5.h

@@ -89,23 +89,19 @@
 #define ADIV5_AP_BASE		ADIV5_AP_REG(0xF8)
 #define ADIV5_AP_IDR		ADIV5_AP_REG(0xFC)
 
-/* Known designers seen in SYSROM-PIDR and JTAG IDCode.
+/* Known designers seen in SYSROM-PIDR. Ignore Bit 0 from
- * Ignore Bit 0 from the designer bits to get JEDEC Ids.
+ * the designer bits to get JEDEC Ids with bit 7 ignored.*/
- * Should get it's one file as not only related to Adiv5!
- */
 #define AP_DESIGNER_FREESCALE    0x00e
 #define AP_DESIGNER_TEXAS        0x017
 #define AP_DESIGNER_ATMEL        0x01f
 #define AP_DESIGNER_STM          0x020
 #define AP_DESIGNER_CYPRESS      0x034
 #define AP_DESIGNER_INFINEON     0x041
-#define DESIGNER_XILINX          0x049
 #define AP_DESIGNER_NORDIC       0x244
 #define AP_DESIGNER_ARM          0x43b
 /*LPC845 with designer 501. Strange!? */
 #define AP_DESIGNER_SPECULAR     0x501
 #define AP_DESIGNER_CS           0x555
-#define DESIGNER_XAMBALA         0x61e
 #define AP_DESIGNER_ENERGY_MICRO 0x673
 #define AP_DESIGNER_GIGADEVICE   0x751
 #define AP_DESIGNER_RASPBERRY    0x927

src/target/jtag_scan.c

@@ -3,7 +3,6 @@
  *
  * Copyright (C) 2011  Black Sphere Technologies Ltd.
  * Written by Gareth McMullin <gareth@blacksphere.co.nz>
- * Copyright (C) 2021 Uwe Bonnes(bon@elektron.ikp.physik.tu-darmstadt.de)
  *
  * This program is free software: you can redistribute it and/or modify
  * it under the terms of the GNU General Public License as published by
@@ -26,14 +25,16 @@
 
 #include "general.h"
 #include "jtagtap.h"
+#include "jtag_scan.h"
 #include "target.h"
 #include "adiv5.h"
+#include "jtag_devs.h"
 
 jtag_dev_t jtag_devs[JTAG_MAX_DEVS+1];
 int jtag_dev_count;
 
 /* bucket of ones for don't care TDI */
-static const uint8_t ones[] = {0xff, 0xFF, 0xFF, 0xFF};
+static const uint8_t ones[] = "\xFF\xFF\xFF\xFF\xFF\xFF\xFF\xFF";
 
 #if PC_HOSTED == 0
 void jtag_add_device(const int dev_index, const jtag_dev_t *jtag_dev)
@@ -46,32 +47,36 @@ void jtag_add_device(const int dev_index, const jtag_dev_t *jtag_dev)
 #endif
 
 /* Scan JTAG chain for devices, store IR length and IDCODE (if present).
+ * Reset TAP state machine.
+ * Select Shift-IR state.
+ * Each device is assumed to shift out IR at 0x01. (this may not always be true)
+ * Shift in ones until we read two consecutive ones, then we have shifted out the
+ * 	IRs of all devices.
  *
- * https://www.fpga4fun.com/JTAG3.html
+ * After this process all the IRs are loaded with the BYPASS command.
- * Count the number of devices in the JTAG chain
+ * Select Shift-DR state.
- *
+ * Shift in ones and count zeros shifted out. Should be one for each device.
- * shift enough ones in IR
+ * Check this against device count obtained by IR scan above.
- * shift enough zeros in DR
- * Now shift out ones and stop if first '1' is seen. This gets the number
- * of devices
- *
- * Assume max 32 devices with max IR len 16 = 512 bits = 16 loops * 32 bit
  *
  * Reset the TAP state machine again. This should load all IRs with IDCODE.
- * Read 32 bit IDCODE for all devices.
+ * For each device, shift out one bit. If this is zero IDCODE isn't present,
+ *	continue to next device. If this is one shift out the remaining 31 bits
+ *	of the IDCODE register.
  */
-
 int jtag_scan(const uint8_t *irlens)
 {
 	int i;
-	void (*jd_handlers[JTAG_MAX_DEVS])(jtag_dev_t *jd);
+	uint32_t j;
+
 	target_list_free();
 
-	memset(jd_handlers, 0, sizeof(jd_handlers));
+	jtag_dev_count = 0;
+	memset(&jtag_devs, 0, sizeof(jtag_devs));
 
-	/* Run throught the SWD to JTAG sequence for the case where an
+	/* Run throught the SWD to JTAG sequence for the case where an attached SWJ-DP is
-	 * attached SWJ-DP is in SW-DP mode.
+	 * in SW-DP mode.
 	 */
+	DEBUG_INFO("Resetting TAP\n");
 #if PC_HOSTED == 1
 	if (platform_jtagtap_init()) {
 		DEBUG_WARN("JTAG not available\n");
@@ -81,146 +86,139 @@ int jtag_scan(const uint8_t *irlens)
 	jtagtap_init();
 #endif
 	jtag_proc.jtagtap_reset();
-#define LOOPS 16
+
+	if (irlens) {
+		DEBUG_WARN("Given list of IR lengths, skipping probe\n");
+		DEBUG_INFO("Change state to Shift-IR\n");
 		jtagtap_shift_ir();
-	i = LOOPS;
+		j = 0;
-	uint8_t ir_chain[64], *din = ir_chain;
+		while((jtag_dev_count <= JTAG_MAX_DEVS) &&
-	while (i--) {
+		      (jtag_devs[jtag_dev_count].ir_len <= JTAG_MAX_IR_LEN)) {
-		jtag_proc.jtagtap_tdi_tdo_seq(din, (i == 0) ? 1 : 0, ones,
+			uint32_t irout;
-									  sizeof(ones) * 8);
+			if(*irlens == 0)
-		din += sizeof(ones);
+				break;
+			jtag_proc.jtagtap_tdi_tdo_seq((uint8_t*)&irout, 0, ones, *irlens);
+			if (!(irout & 1)) {
+				DEBUG_WARN("check failed: IR[0] != 1\n");
+				return -1;
 			}
-	if (!(ir_chain[0] & 1)) {
+			jtag_devs[jtag_dev_count].ir_len = *irlens;
-		DEBUG_WARN("Unexpected IR chain!\n");
+			jtag_devs[jtag_dev_count].ir_prescan = j;
-		return 0;
+			jtag_devs[jtag_dev_count].jd_dev = jtag_dev_count;
+			j += *irlens;
+			irlens++;
+			jtag_dev_count++;
 		}
+	} else {
+		DEBUG_INFO("Change state to Shift-IR\n");
+		jtagtap_shift_ir();
+
+		DEBUG_INFO("Scanning out IRs\n");
+		if(!jtag_proc.jtagtap_next(0, 1)) {
+			DEBUG_WARN("jtag_scan: Sanity check failed: IR[0] shifted out "
+					   "as 0\n");
+			jtag_dev_count = -1;
+			return -1; /* must be 1 */
+		}
+		jtag_devs[0].ir_len = 1; j = 1;
+		while((jtag_dev_count <= JTAG_MAX_DEVS) &&
+		      (jtag_devs[jtag_dev_count].ir_len <= JTAG_MAX_IR_LEN)) {
+			if(jtag_proc.jtagtap_next(0, 1)) {
+				if(jtag_devs[jtag_dev_count].ir_len == 1) break;
+				jtag_devs[++jtag_dev_count].ir_len = 1;
+				jtag_devs[jtag_dev_count].ir_prescan = j;
+				jtag_devs[jtag_dev_count].jd_dev = jtag_dev_count;
+			} else jtag_devs[jtag_dev_count].ir_len++;
+			j++;
+		}
+		if(jtag_dev_count > JTAG_MAX_DEVS) {
+			DEBUG_WARN("jtag_scan: Maximum device count exceeded\n");
+			jtag_dev_count = -1;
+			return -1;
+		}
+		if(jtag_devs[jtag_dev_count].ir_len > JTAG_MAX_IR_LEN) {
+			DEBUG_WARN("jtag_scan: Maximum IR length exceeded\n");
+			jtag_dev_count = -1;
+			return -1;
+		}
+	}
+
+	DEBUG_INFO("Return to Run-Test/Idle\n");
+	jtag_proc.jtagtap_next(1, 1);
 	jtagtap_return_idle();
+
+	/* All devices should be in BYPASS now */
+
+	/* Count device on chain */
+	DEBUG_INFO("Change state to Shift-DR\n");
 	jtagtap_shift_dr();
-	i = LOOPS;
+	for(i = 0; (jtag_proc.jtagtap_next(0, 1) == 0) && (i <= jtag_dev_count); i++)
-	uint8_t zeros[] = {0, 0, 0, 0};
-	while(i--) {
-		jtag_proc.jtagtap_tdi_seq(0, zeros, sizeof(zeros) * 8);
-	}
-	int num_devices = 0;
-	while (!jtag_proc.jtagtap_next(0,1) && (i++ < 6))
-			num_devices++;
-	jtag_proc.jtagtap_reset();
-	jtagtap_shift_dr();
-	jtag_dev_count = num_devices;
-	if (!num_devices)
-		return 0;
-	DEBUG_TARGET("Found %d devices\n", num_devices);
-	int irbit = 1;
-	int j = 0;
-	for (i = 0; i < num_devices; i++) {
-		uint8_t id[4];
-		jtag_proc.jtagtap_tdi_tdo_seq(id, 0, ones, 32);
-		if (!(id[0] & 1)) {
-			DEBUG_WARN("Invalid IDCode!\n");
-			return 0;
-		}
-		uint32_t idcode = id[3] << 24 | id[2] << 16 |  id[1] << 8 | id[0];
-		unsigned int designer = ((id[1] & 0xf) << 8) | (id[0] >> 1);
-		unsigned int product = id[2] | ((id[3] & 0xf) << 8);
-		unsigned int expected_irlen = 0;
-		switch (designer) {
-		case AP_DESIGNER_ARM:
-			switch (product) {
-			case 0xba0:
-				jtag_devs[i].jd_descr = "ADIv5 JTAG-DP port";
-				jd_handlers[i] = adiv5_jtag_dp_handler;
-				expected_irlen = 4;
-				break;
-			default:
-				jtag_devs[i].jd_descr = "ARM";
-			}
-			break;
-		case AP_DESIGNER_STM:
-			expected_irlen = 5;
-			jtag_devs[i].jd_descr = "STM32 BSD";
-			break;
-		case AP_DESIGNER_ATMEL:
-			if ((product >= 0x940) & (product < 0x990)) {
-				jtag_devs[i].jd_descr = "ATMEL AVR8";
-				expected_irlen = 4;
-				break;
-			}
-			jtag_devs[i].jd_descr = "ATMEL";
-			break;
-		case DESIGNER_XILINX:
-			if (!irlens) {
-				/* Guessed irlen for XILINX devices is wrong.
-				 * IR data contains status bits!
-				 */
-				DEBUG_WARN("Please provide irlens as chain contains XILINX devices!\n");
-				return 0;
-			}
-			jtag_devs[i].jd_descr = "XILINX";
-			break;
-		case DESIGNER_XAMBALA:
-			expected_irlen = 5;
-			jtag_devs[i].jd_descr = "RVDBG013";
-			break;
-		case AP_DESIGNER_GIGADEVICE:
-			expected_irlen = 5;
-			jtag_devs[i].jd_descr = "GIGADEVICE BSD";
-			break;
-		}
-		if (!jtag_devs[i].jd_descr) {
-			DEBUG_WARN("Unhandled designer %x\n", designer);
-			jtag_devs[i].jd_descr = "Unknow";
-		}
-		bool bit;
-		int guessed_irlen = 0;
-		int advance = irbit;
-		do {
-			/* Guess IR length from the IR scan after JTAG Reset
-			 * First bit should be '1', following bits are '0', if not used
-			 * for instruction capture, as for Xilinx parts.
-			 */
-			bit = (ir_chain[advance / 8] & (1 << (advance & 7)));
-			guessed_irlen++;
-			advance++;
-		} while (!bit && (advance < (JTAG_MAX_DEVS * 16)));
-		if (irlens) { /* Allow to overwrite from the command line!*/
-			if (*irlens != guessed_irlen) {
-				DEBUG_TARGET("Provides irlen %d vs guessed %d for device %d\n",
-							 *irlens, guessed_irlen, i + 1);
-			}
-			expected_irlen = *irlens++;
-		}
-		if (!expected_irlen) {
-			expected_irlen = guessed_irlen++;
-		}
-		jtag_devs[i].ir_len = expected_irlen;
-		jtag_devs[i].ir_prescan = j;
-		jtag_devs[i].jd_dev = i;
-		jtag_devs[i].jd_idcode = idcode;
 		jtag_devs[i].dr_postscan = jtag_dev_count - i - 1;
-		jtag_devs[i].current_ir = -1;
+
-		j += expected_irlen;
+	if(i != jtag_dev_count) {
-		irbit += expected_irlen;
+		DEBUG_WARN("jtag_scan: Sanity check failed: "
-		DEBUG_INFO("%2d: IDCODE: 0x%08" PRIx32 ", IR len %d %s%s\n", i + 1,
+			"BYPASS dev count doesn't match IR scan\n");
-				   idcode,jtag_devs[i].ir_len, jtag_devs[i].jd_descr,
+		jtag_dev_count = -1;
-				   (jd_handlers[i]) ? "" : " (Unhandled) ");
+		return -1;
 	}
-	jtag_proc.jtagtap_reset();
+
+	DEBUG_INFO("Return to Run-Test/Idle\n");
+	jtag_proc.jtagtap_next(1, 1);
+	jtagtap_return_idle();
+	if(!jtag_dev_count) {
+		return 0;
+	}
+
 	/* Fill in the ir_postscan fields */
-	for(i = jtag_dev_count - 1; i; i--) {
+	for(i = jtag_dev_count - 1; i; i--)
 		jtag_devs[i-1].ir_postscan = jtag_devs[i].ir_postscan +
 					jtag_devs[i].ir_len;
+
+	/* Reset jtagtap: should take all devs to IDCODE */
+	jtag_proc.jtagtap_reset();
+	jtagtap_shift_dr();
+	for(i = 0; i < jtag_dev_count; i++) {
+		if(!jtag_proc.jtagtap_next(0, 1)) continue;
+		jtag_devs[i].jd_idcode = 1;
+		for(j = 2; j; j <<= 1)
+			if(jtag_proc.jtagtap_next(0, 1)) jtag_devs[i].jd_idcode |= j;
+
 	}
+	DEBUG_INFO("Return to Run-Test/Idle\n");
+	jtag_proc.jtagtap_next(1, 1);
+	jtagtap_return_idle();
 #if PC_HOSTED == 1
 	/*Transfer needed device information to firmware jtag_devs*/
-	for(i = 0; i < jtag_dev_count; i++) {
+	for(i = 0; i < jtag_dev_count; i++)
 		platform_add_jtag_dev(i, &jtag_devs[i]);
+	for(i = 0; i < jtag_dev_count; i++) {
+		DEBUG_INFO("Idcode 0x%08" PRIx32, jtag_devs[i].jd_idcode);
+		for(j = 0; dev_descr[j].idcode; j++) {
+			if((jtag_devs[i].jd_idcode & dev_descr[j].idmask) ==
+			   dev_descr[j].idcode) {
+				DEBUG_INFO(": %s",
+						  (dev_descr[j].descr) ? dev_descr[j].descr : "unknown");
+				break;
+			}
+		}
+		DEBUG_INFO("\n");
 	}
 #endif
+
 	/* Check for known devices and handle accordingly */
 	for(i = 0; i < jtag_dev_count; i++)
+		for(j = 0; dev_descr[j].idcode; j++)
+			if((jtag_devs[i].jd_idcode & dev_descr[j].idmask) ==
+			   dev_descr[j].idcode) {
+				jtag_devs[i].current_ir = -1;
+				/* Save description in table */
+				jtag_devs[i].jd_descr = dev_descr[j].descr;
 				/* Call handler to initialise/probe device further */
-		if (jd_handlers[i])
+				if(dev_descr[j].handler)
-			jd_handlers[i](&jtag_devs[i]);
+					dev_descr[j].handler(i, jtag_devs[i].jd_idcode);
+				break;
+			}
+
 	return jtag_dev_count;
 }