From: Robert Jordens <jordens@gmail.com>
Date: Fri, 3 Jul 2015 05:15:53 +0000 (-0600)
Subject: cpld/virtex2: allow JSTART to be disabled
X-Git-Tag: v0.10.0-rc1~463
X-Git-Url: https://review.openocd.org/gitweb?p=openocd.git;a=commitdiff_plain;h=2d99a0defa8fde13d4f421d54dbb6246b908303d

cpld/virtex2: allow JSTART to be disabled

This adds an option to disable the use of the JSTART instruction
when loading bitstreams to xilinx fpgas. JSTART apparently prevents
configuration if the startup clock is not set to the jtag clock in
the bitstream.

xc3sprog is omitting JSTART for all devices. Problems with loading a bitstream
that does not have StartupClk:JTAGClk are described here:
http://www.xilinx.com/support/answers/56151.html

Change-Id: I8137c0bae05a8c3c6f8e2611869f70a770d1651d
Signed-off-by: Robert Jordens <jordens@gmail.com>
Reviewed-on: http://openocd.zylin.com/2860
Tested-by: jenkins
Reviewed-by: Spencer Oliver <spen@spen-soft.co.uk>
---

diff --git a/doc/openocd.texi b/doc/openocd.texi
index 0208fcf835..140e86b406 100644
--- a/doc/openocd.texi
+++ b/doc/openocd.texi
@@ -6274,11 +6274,13 @@ Drivers may support PLD-specific options to the @command{pld device}
 definition command, and may also define commands usable only with
 that particular type of PLD.
 
-@deffn {FPGA Driver} virtex2
+@deffn {FPGA Driver} virtex2 [no_jstart]
 Virtex-II is a family of FPGAs sold by Xilinx.
 It supports the IEEE 1532 standard for In-System Configuration (ISC).
-No driver-specific PLD definition options are used,
-and one driver-specific command is defined.
+
+If @var{no_jstart} is non-zero, the JSTART instruction is not used after
+loading the bitstream. While required for Series2, Series3, and Series6, it
+breaks bitstream loading on Series7.
 
 @deffn {Command} {virtex2 read_stat} num
 Reads and displays the Virtex-II status register (STAT)
diff --git a/src/pld/virtex2.c b/src/pld/virtex2.c
index b600561588..82eb788f95 100644
--- a/src/pld/virtex2.c
+++ b/src/pld/virtex2.c
@@ -159,13 +159,15 @@ static int virtex2_load(struct pld_device *pld_device, const char *filename)
 
 	jtag_add_tlr();
 
-	virtex2_set_instr(virtex2_info->tap, 0xc);	/* JSTART */
+	if (!(virtex2_info->no_jstart))
+		virtex2_set_instr(virtex2_info->tap, 0xc);	/* JSTART */
 	jtag_add_runtest(13, TAP_IDLE);
-	virtex2_set_instr(virtex2_info->tap, 0x3f);	/* BYPASS */
-	virtex2_set_instr(virtex2_info->tap, 0x3f);	/* BYPASS */
-	virtex2_set_instr(virtex2_info->tap, 0xc);	/* JSTART */
+	virtex2_set_instr(virtex2_info->tap, 0x3f);		/* BYPASS */
+	virtex2_set_instr(virtex2_info->tap, 0x3f);		/* BYPASS */
+	if (!(virtex2_info->no_jstart))
+		virtex2_set_instr(virtex2_info->tap, 0xc);	/* JSTART */
 	jtag_add_runtest(13, TAP_IDLE);
-	virtex2_set_instr(virtex2_info->tap, 0x3f);	/* BYPASS */
+	virtex2_set_instr(virtex2_info->tap, 0x3f);		/* BYPASS */
 	jtag_execute_queue();
 
 	return ERROR_OK;
@@ -212,6 +214,10 @@ PLD_DEVICE_COMMAND_HANDLER(virtex2_pld_device_command)
 	virtex2_info = malloc(sizeof(struct virtex2_pld_device));
 	virtex2_info->tap = tap;
 
+	virtex2_info->no_jstart = 0;
+	if (CMD_ARGC >= 3)
+		COMMAND_PARSE_NUMBER(int, CMD_ARGV[2], virtex2_info->no_jstart);
+
 	pld->driver_priv = virtex2_info;
 
 	return ERROR_OK;
diff --git a/src/pld/virtex2.h b/src/pld/virtex2.h
index 94419ebf51..8ed1c1c77b 100644
--- a/src/pld/virtex2.h
+++ b/src/pld/virtex2.h
@@ -25,6 +25,7 @@
 
 struct virtex2_pld_device {
 	struct jtag_tap *tap;
+	int no_jstart;
 };
 
 #endif	/* VIRTEX2_H */