jtag: drivers: Add JTAP VPI client driver

This patch adds a driver for the jtag_vpi server [1]. This server is
now part of the ORPSoC version 3 (OpenRISC Reference Platform SoC).
The jtag_vpi server provides an interface between OpenOCD and a simulated
core.

[1] http://github.com/fjullien/jtag_vpi

Change-Id: I717b72cace4845f66c878581345074f99002e21a
Signed-off-by: Franck Jullien <franck.jullien@gmail.com>
Reviewed-on: http://openocd.zylin.com/1609
Tested-by: jenkins
Reviewed-by: Spencer Oliver <spen@spen-soft.co.uk>

3 files changed, 449 insertions, 0 deletions

diff --git a/src/jtag/drivers/Makefile.am b/src/jtag/drivers/Makefile.am
index e242cc6..e3ed219 100644
--- a/src/jtag/drivers/Makefile.am
+++ b/src/jtag/drivers/Makefile.am
@@ -42,6 +42,9 @@ endif
 if FTDI_DRIVER
 DRIVERFILES += ftdi.c mpsse.c
 endif
+if JTAG_VPI
+DRIVERFILES += jtag_vpi.c
+endif
 if USB_BLASTER_DRIVER
 SUBDIRS += usb_blaster
 libocdjtagdrivers_la_LIBADD += $(top_builddir)/src/jtag/drivers/usb_blaster/libocdusbblaster.la
diff --git a/src/jtag/drivers/jtag_vpi.c b/src/jtag/drivers/jtag_vpi.c
new file mode 100644
index 0000000..84cd947
--- /dev/null
+++ b/src/jtag/drivers/jtag_vpi.c
@@ -0,0 +1,440 @@
+/*
+ * JTAG to VPI driver
+ *
+ * Copyright (C) 2013 Franck Jullien, <elec4fun@gmail.com>
+ *
+ * See file CREDITS for list of people who contributed to this
+ * project.
+ *
+ * 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 the Free Software Foundation; either version 2 of
+ * the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ */
+
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#include <jtag/interface.h>
+#include <arpa/inet.h>
+
+#define NO_TAP_SHIFT	0
+#define TAP_SHIFT	1
+
+#define SERVER_ADDRESS	"127.0.0.1"
+#define SERVER_PORT	5555
+
+#define	XFERT_MAX_SIZE		512
+
+#define CMD_RESET		0
+#define CMD_TMS_SEQ		1
+#define CMD_SCAN_CHAIN		2
+#define CMD_SCAN_CHAIN_FLIP_TMS	3
+#define CMD_STOP_SIMU		4
+
+int server_port = SERVER_PORT;
+
+int sockfd;
+struct sockaddr_in serv_addr;
+
+struct vpi_cmd {
+	int cmd;
+	unsigned char buffer_out[XFERT_MAX_SIZE];
+	unsigned char buffer_in[XFERT_MAX_SIZE];
+	int length;
+	int nb_bits;
+};
+
+static int jtag_vpi_send_cmd(struct vpi_cmd *vpi)
+{
+	int retval = write(sockfd, vpi, sizeof(struct vpi_cmd));
+	if (retval <= 0)
+		return ERROR_FAIL;
+
+	return ERROR_OK;
+}
+
+static int jtag_vpi_receive_cmd(struct vpi_cmd *vpi)
+{
+	int retval = read(sockfd, vpi, sizeof(struct vpi_cmd));
+	if (retval < (int)sizeof(struct vpi_cmd))
+		return ERROR_FAIL;
+
+	return ERROR_OK;
+}
+
+/**
+ * jtag_vpi_reset - ask to reset the JTAG device
+ * @trst: 1 if TRST is to be asserted
+ * @srst: 1 if SRST is to be asserted
+ */
+static int jtag_vpi_reset(int trst, int srst)
+{
+	struct vpi_cmd vpi;
+
+	vpi.cmd = CMD_RESET;
+	vpi.length = 0;
+	return jtag_vpi_send_cmd(&vpi);
+}
+
+/**
+ * jtag_vpi_tms_seq - ask a TMS sequence transition to JTAG
+ * @bits: TMS bits to be written (bit0, bit1 .. bitN)
+ * @nb_bits: number of TMS bits (between 1 and 8)
+ *
+ * Write a serie of TMS transitions, where each transition consists in :
+ *  - writing out TCK=0, TMS=<new_state>, TDI=<???>
+ *  - writing out TCK=1, TMS=<new_state>, TDI=<???> which triggers the transition
+ * The function ensures that at the end of the sequence, the clock (TCK) is put
+ * low.
+ */
+static int jtag_vpi_tms_seq(const uint8_t *bits, int nb_bits)
+{
+	struct vpi_cmd vpi;
+	int nb_bytes;
+
+	nb_bytes = (nb_bits / 8) + !!(nb_bits % 8);
+
+	vpi.cmd = CMD_TMS_SEQ;
+	memcpy(vpi.buffer_out, bits, nb_bytes);
+	vpi.length = nb_bytes;
+	vpi.nb_bits = nb_bits;
+
+	return jtag_vpi_send_cmd(&vpi);
+}
+
+/**
+ * jtag_vpi_path_move - ask a TMS sequence transition to JTAG
+ * @cmd: path transition
+ *
+ * Write a serie of TMS transitions, where each transition consists in :
+ *  - writing out TCK=0, TMS=<new_state>, TDI=<???>
+ *  - writing out TCK=1, TMS=<new_state>, TDI=<???> which triggers the transition
+ * The function ensures that at the end of the sequence, the clock (TCK) is put
+ * low.
+ */
+
+static int jtag_vpi_path_move(struct pathmove_command *cmd)
+{
+	uint16_t trans = 0;
+	int retval;
+	int i;
+
+	for (i = 0; i < cmd->num_states; i++) {
+		if (tap_state_transition(tap_get_state(), true) == cmd->path[i])
+			trans = trans | 1;
+		trans = trans << 1;
+	}
+
+	retval = jtag_vpi_tms_seq((uint8_t *)&trans, 1);
+	if (retval != ERROR_OK)
+		return retval;
+
+	tap_set_state(cmd->path[i]);
+
+	return ERROR_OK;
+}
+
+/**
+ * jtag_vpi_tms - ask a tms command
+ * @cmd: tms command
+ */
+static int jtag_vpi_tms(struct tms_command *cmd)
+{
+	return jtag_vpi_tms_seq(cmd->bits, cmd->num_bits);
+}
+
+static int jtag_vpi_state_move(tap_state_t state)
+{
+	if (tap_get_state() == state)
+		return ERROR_OK;
+
+	uint8_t tms_scan = tap_get_tms_path(tap_get_state(), state);
+	int tms_len = tap_get_tms_path_len(tap_get_state(), state);
+
+	int retval = jtag_vpi_tms_seq(&tms_scan, tms_len);
+	if (retval != ERROR_OK)
+		return retval;
+
+	tap_set_state(state);
+
+	return ERROR_OK;
+}
+
+static int jtag_vpi_queue_tdi_xfer(uint8_t *bits, int nb_bits, int tap_shift)
+{
+	struct vpi_cmd vpi;
+	int nb_bytes = (nb_bits / 8) + !!(nb_bits % 8);
+
+	vpi.cmd = tap_shift ? CMD_SCAN_CHAIN_FLIP_TMS : CMD_SCAN_CHAIN;
+
+	if (bits)
+		memcpy(vpi.buffer_out, bits, nb_bytes);
+	else
+		memset(vpi.buffer_out, 0xff, nb_bytes);
+
+	vpi.length = nb_bytes;
+	vpi.nb_bits = nb_bits;
+
+	int retval = jtag_vpi_send_cmd(&vpi);
+	if (retval != ERROR_OK)
+		return retval;
+
+	retval = jtag_vpi_receive_cmd(&vpi);
+	if (retval != ERROR_OK)
+		return retval;
+
+	if (bits)
+		memcpy(bits, vpi.buffer_in, nb_bytes);
+
+	return ERROR_OK;
+}
+
+/**
+ * jtag_vpi_queue_tdi - short description
+ * @bits: bits to be queued on TDI (or NULL if 0 are to be queued)
+ * @nb_bits: number of bits
+ */
+static int jtag_vpi_queue_tdi(uint8_t *bits, int nb_bits, int tap_shift)
+{
+	int nb_xfer = (nb_bits / (XFERT_MAX_SIZE * 8)) + !!(nb_bits % (XFERT_MAX_SIZE * 8));
+	uint8_t *xmit_buffer = bits;
+	int xmit_nb_bits = nb_bits;
+	int i = 0;
+	int retval;
+
+	while (nb_xfer) {
+
+		if (nb_xfer ==  1) {
+			retval = jtag_vpi_queue_tdi_xfer(&xmit_buffer[i], xmit_nb_bits, tap_shift);
+			if (retval != ERROR_OK)
+				return retval;
+		} else {
+			retval = jtag_vpi_queue_tdi_xfer(&xmit_buffer[i], XFERT_MAX_SIZE * 8, NO_TAP_SHIFT);
+			if (retval != ERROR_OK)
+				return retval;
+			xmit_nb_bits -= XFERT_MAX_SIZE * 8;
+			i += XFERT_MAX_SIZE;
+		}
+
+		nb_xfer--;
+	}
+
+	return ERROR_OK;
+}
+
+/**
+ * jtag_vpi_clock_tms - clock a TMS transition
+ * @tms: the TMS to be sent
+ *
+ * Triggers a TMS transition (ie. one JTAG TAP state move).
+ */
+static int jtag_vpi_clock_tms(int tms)
+{
+	const uint8_t tms_0 = 0;
+	const uint8_t tms_1 = 1;
+
+	return jtag_vpi_tms_seq(tms ? &tms_1 : &tms_0, 1);
+}
+
+/**
+ * jtag_vpi_scan - launches a DR-scan or IR-scan
+ * @cmd: the command to launch
+ *
+ * Launch a JTAG IR-scan or DR-scan
+ *
+ * Returns ERROR_OK if OK, ERROR_xxx if a read/write error occured.
+ */
+static int jtag_vpi_scan(struct scan_command *cmd)
+{
+	int scan_bits;
+	uint8_t *buf = NULL;
+	int retval = ERROR_OK;
+
+	scan_bits = jtag_build_buffer(cmd, &buf);
+
+	if (cmd->ir_scan) {
+		retval = jtag_vpi_state_move(TAP_IRSHIFT);
+		if (retval != ERROR_OK)
+			return retval;
+	} else {
+		retval = jtag_vpi_state_move(TAP_DRSHIFT);
+		if (retval != ERROR_OK)
+			return retval;
+	}
+
+	if (cmd->end_state == TAP_DRSHIFT) {
+		retval = jtag_vpi_queue_tdi(buf, scan_bits, NO_TAP_SHIFT);
+		if (retval != ERROR_OK)
+			return retval;
+	} else {
+		retval = jtag_vpi_queue_tdi(buf, scan_bits, TAP_SHIFT);
+		if (retval != ERROR_OK)
+			return retval;
+	}
+
+	if (cmd->end_state != TAP_DRSHIFT) {
+		/*
+		 * As our JTAG is in an unstable state (IREXIT1 or DREXIT1), move it
+		 * forward to a stable IRPAUSE or DRPAUSE.
+		 */
+		retval = jtag_vpi_clock_tms(0);
+		if (retval != ERROR_OK)
+			return retval;
+
+		if (cmd->ir_scan)
+			tap_set_state(TAP_IRPAUSE);
+		else
+			tap_set_state(TAP_DRPAUSE);
+	}
+
+	retval = jtag_read_buffer(buf, cmd);
+	if (retval != ERROR_OK)
+		return retval;
+
+	if (buf)
+		free(buf);
+
+	if (cmd->end_state != TAP_DRSHIFT) {
+		retval = jtag_vpi_state_move(cmd->end_state);
+		if (retval != ERROR_OK)
+			return retval;
+	}
+
+	return ERROR_OK;
+}
+
+static int jtag_vpi_runtest(int cycles, tap_state_t state)
+{
+	int retval;
+
+	retval = jtag_vpi_state_move(TAP_IDLE);
+	if (retval != ERROR_OK)
+		return retval;
+
+	retval = jtag_vpi_queue_tdi(NULL, cycles, TAP_SHIFT);
+	if (retval != ERROR_OK)
+		return retval;
+
+	return jtag_vpi_state_move(state);
+}
+
+static int jtag_vpi_stableclocks(int cycles)
+{
+	return jtag_vpi_queue_tdi(NULL, cycles, TAP_SHIFT);
+}
+
+static int jtag_vpi_execute_queue(void)
+{
+	struct jtag_command *cmd;
+	int retval = ERROR_OK;
+
+	for (cmd = jtag_command_queue; retval == ERROR_OK && cmd != NULL;
+	     cmd = cmd->next) {
+		switch (cmd->type) {
+		case JTAG_RESET:
+			retval = jtag_vpi_reset(cmd->cmd.reset->trst, cmd->cmd.reset->srst);
+			break;
+		case JTAG_RUNTEST:
+			retval = jtag_vpi_runtest(cmd->cmd.runtest->num_cycles,
+						  cmd->cmd.runtest->end_state);
+			break;
+		case JTAG_STABLECLOCKS:
+			retval = jtag_vpi_stableclocks(cmd->cmd.stableclocks->num_cycles);
+			break;
+		case JTAG_TLR_RESET:
+			retval = jtag_vpi_state_move(cmd->cmd.statemove->end_state);
+			break;
+		case JTAG_PATHMOVE:
+			retval = jtag_vpi_path_move(cmd->cmd.pathmove);
+			break;
+		case JTAG_TMS:
+			retval = jtag_vpi_tms(cmd->cmd.tms);
+			break;
+		case JTAG_SLEEP:
+			jtag_sleep(cmd->cmd.sleep->us);
+			break;
+		case JTAG_SCAN:
+			retval = jtag_vpi_scan(cmd->cmd.scan);
+			break;
+		}
+	}
+
+	return retval;
+}
+
+static int jtag_vpi_init(void)
+{
+	sockfd = socket(AF_INET, SOCK_STREAM, 0);
+	if (sockfd < 0) {
+		LOG_ERROR("Could not create socket");
+		return ERROR_FAIL;
+	}
+
+	memset(&serv_addr, 0, sizeof(serv_addr));
+
+	serv_addr.sin_family = AF_INET;
+	serv_addr.sin_port = htons(server_port);
+
+	if (inet_pton(AF_INET, SERVER_ADDRESS, &serv_addr.sin_addr) <= 0) {
+		LOG_ERROR("inet_pton error occured");
+		return ERROR_FAIL;
+	}
+
+	if (connect(sockfd, (struct sockaddr *)&serv_addr, sizeof(serv_addr)) < 0) {
+		close(sockfd);
+		LOG_ERROR("Can't connect to %s : %u", SERVER_ADDRESS, server_port);
+		return ERROR_COMMAND_CLOSE_CONNECTION;
+	}
+
+	LOG_INFO("Connection to %s : %u succeed", SERVER_ADDRESS, server_port);
+
+	return ERROR_OK;
+}
+
+static int jtag_vpi_quit(void)
+{
+	return close(sockfd);
+}
+
+COMMAND_HANDLER(jtag_vpi_set_port)
+{
+	if (CMD_ARGC == 0)
+		LOG_WARNING("You need to set a port number");
+	else
+		COMMAND_PARSE_NUMBER(int, CMD_ARGV[0], server_port);
+
+	LOG_INFO("Set server port to %u", server_port);
+
+	return ERROR_OK;
+}
+
+
+static const struct command_registration jtag_vpi_command_handlers[] = {
+	{
+		.name = "jtag_vpi_set_port",
+		.handler = &jtag_vpi_set_port,
+		.mode = COMMAND_CONFIG,
+		.help = "set the port of the VPI server",
+		.usage = "description_string",
+	},
+	COMMAND_REGISTRATION_DONE
+};
+
+struct jtag_interface jtag_vpi_interface = {
+	.name = "jtag_vpi",
+	.supported = DEBUG_CAP_TMS_SEQ,
+	.commands = jtag_vpi_command_handlers,
+	.transports = jtag_only,
+
+	.init = jtag_vpi_init,
+	.quit = jtag_vpi_quit,
+	.execute_queue = jtag_vpi_execute_queue,
+};
diff --git a/src/jtag/interfaces.c b/src/jtag/interfaces.c
index 579e9e7..eb447cd 100644
--- a/src/jtag/interfaces.c
+++ b/src/jtag/interfaces.c
@@ -65,6 +65,9 @@ extern struct jtag_interface ftdi_interface;
 #if BUILD_USB_BLASTER_LIBFTDI == 1 || BUILD_USB_BLASTER_FTD2XX == 1
 extern struct jtag_interface usb_blaster_interface;
 #endif
+#if BUILD_JTAG_VPI == 1
+extern struct jtag_interface jtag_vpi_interface;
+#endif
 #if BUILD_AMTJTAGACCEL == 1
 extern struct jtag_interface amt_jtagaccel_interface;
 #endif
@@ -158,6 +161,9 @@ struct jtag_interface *jtag_interfaces[] = {
 #if BUILD_USB_BLASTER_LIBFTDI == 1 || BUILD_USB_BLASTER_FTD2XX == 1
 		&usb_blaster_interface,
 #endif
+#if BUILD_JTAG_VPI == 1
+		&jtag_vpi_interface,
+#endif
 #if BUILD_AMTJTAGACCEL == 1
 		&amt_jtagaccel_interface,
 #endif