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remote_bitbang: Add SWD support 

This adds new command characters to make SWD work with the new split
jtag and swd operations of bitbang.

The command characters are as follows:
    O - SWDIO drive 1
    o - SWDIO drive 0
    c - SWDIO read request
    d - SWD write 0 0
    e - SWD write 0 1
    f - SWD write 1 0
    g - SWD write 1 1

Documentation has been updated accordingly. The new commands will be
used by an adapted version of the jtag-openocd applet of the "Glasgow
Debug Tool" (https://github.com/glasgowEmbedded/Glasgow). It has been
tested against an stm32f103 and an at91samd21 target.

contrib/remote/bitbang/remote_bitbang_sysfsgpio.c has also been adapted
to support SWD via the new command set. Some limited testing has been
done using a Raspberry Pi 2 with an stm32f103 and an at91samd21 target
attached.

Change-Id: I8e998a2cb36905142cb16e534483094cd99e8fa7
Signed-off-by: Manuel Wick <manuel@matronix.de>
Signed-off-by: David Ryskalczyk <david.rysk@gmail.com>
Reviewed-on: https://review.openocd.org/c/openocd/+/6044
Tested-by: jenkins
Reviewed-by: Tomas Vanek <vanekt@fbl.cz>
Reviewed-by: Antonio Borneo <borneo.antonio@gmail.com>
This commit is contained in:
Manuel Wick 2021-01-30 22:46:50 +01:00 committed by Tomas Vanek
parent 119a533862
commit 0f70c6c325
5 changed files with 230 additions and 60 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

6
configure.ac
View File

@ -382,7 +382,7 @@ AC_ARG_ENABLE([internal-libjaylink],
[use_internal_libjaylink=$enableval], [use_internal_libjaylink=no]) [use_internal_libjaylink=$enableval], [use_internal_libjaylink=no])
AC_ARG_ENABLE([remote-bitbang], AC_ARG_ENABLE([remote-bitbang],
AS_HELP_STRING([--enable-remote-bitbang], [Enable building support for the Remote Bitbang jtag driver]), AS_HELP_STRING([--enable-remote-bitbang], [Enable building support for the Remote Bitbang driver]),
[build_remote_bitbang=$enableval], [build_remote_bitbang=no]) [build_remote_bitbang=$enableval], [build_remote_bitbang=no])
AS_CASE(["${host_cpu}"], AS_CASE(["${host_cpu}"],
@ -598,9 +598,9 @@ AS_IF([test "x$use_internal_jimtcl" = "xyes"], [
AS_IF([test "x$build_remote_bitbang" = "xyes"], [ AS_IF([test "x$build_remote_bitbang" = "xyes"], [
build_bitbang=yes build_bitbang=yes
AC_DEFINE([BUILD_REMOTE_BITBANG], [1], [1 if you want the Remote Bitbang JTAG driver.]) AC_DEFINE([BUILD_REMOTE_BITBANG], [1], [1 if you want the Remote Bitbang driver.])
], [ ], [
AC_DEFINE([BUILD_REMOTE_BITBANG], [0], [0 if you don't want the Remote Bitbang JTAG driver.]) AC_DEFINE([BUILD_REMOTE_BITBANG], [0], [0 if you don't want the Remote Bitbang driver.])
]) ])
AS_IF([test "x$build_sysfsgpio" = "xyes"], [ AS_IF([test "x$build_sysfsgpio" = "xyes"], [

211
contrib/remote_bitbang/remote_bitbang_sysfsgpio.c
View File

@ -1,30 +1,31 @@
// SPDX-License-Identifier: GPL-2.0-or-later // SPDX-License-Identifier: GPL-2.0-or-later
/*************************************************************************** /***************************************************************************
* Copyright (C) 2021 by Manuel Wick <manuel@matronix.de> *
* Copyright (C) 2013 Paul Fertser <fercerpav@gmail.com> * * Copyright (C) 2013 Paul Fertser <fercerpav@gmail.com> *
* Copyright (C) 2012 by Creative Product Design, marc @ cpdesign.com.au * * Copyright (C) 2012 by Creative Product Design, marc @ cpdesign.com.au *
***************************************************************************/ ***************************************************************************/
/* /*
This is a test application to be used as a remote bitbang server for * This is a test application to be used as a remote bitbang server for
the OpenOCD remote_bitbang interface driver. * the OpenOCD remote_bitbang interface driver.
*
To compile run: * To compile run:
gcc -Wall -ansi -pedantic -std=c99 -o remote_bitbang_sysfsgpio remote_bitbang_sysfsgpio.c * gcc -Wall -ansi -pedantic -std=c99 -o remote_bitbang_sysfsgpio remote_bitbang_sysfsgpio.c
*
*
Usage example: * Usage example:
*
On Raspberry Pi run: * On Raspberry Pi run:
socat TCP6-LISTEN:7777,fork EXEC:"sudo ./remote_bitbang_sysfsgpio tck 11 tms 25 tdo 9 tdi 10" * socat TCP6-LISTEN:7777,fork EXEC:"sudo ./remote_bitbang_sysfsgpio tck 11 tms 25 tdo 9 tdi 10"
*
On host run: * On host run:
openocd -c "interface remote_bitbang; remote_bitbang host raspberrypi; remote_bitbang port 7777" \ * openocd -c "adapter driver remote_bitbang; remote_bitbang host raspberrypi; remote_bitbang port 7777" \
-f target/stm32f1x.cfg * -f target/stm32f1x.cfg
*
Or if you want to test UNIX sockets, run both on Raspberry Pi: * Or if you want to test UNIX sockets, run both on Raspberry Pi:
socat UNIX-LISTEN:/tmp/remotebitbang-socket,fork EXEC:"sudo ./remote_bitbang_sysfsgpio tck 11 tms 25 tdo 9 tdi 10" * socat UNIX-LISTEN:/tmp/remotebitbang-socket,fork EXEC:"sudo ./remote_bitbang_sysfsgpio tck 11 tms 25 tdo 9 tdi 10"
openocd -c "interface remote_bitbang; remote_bitbang host /tmp/remotebitbang-socket" -f target/stm32f1x.cfg * openocd -c "adapter driver remote_bitbang; remote_bitbang host /tmp/remotebitbang-socket" -f target/stm32f1x.cfg
*/ */
#include <sys/types.h> #include <sys/types.h>
@ -97,11 +98,14 @@ static void unexport_sysfs_gpio(int gpio)
* If the gpio is an output, it is initialized according to init_high, * If the gpio is an output, it is initialized according to init_high,
* otherwise it is ignored. * otherwise it is ignored.
* *
* When open_rw is set, the file descriptor will be open as read and write,
* e.g. for SWDIO (TMS) that is used as input and output.
*
* If the gpio is already exported we just show a warning and continue; if * If the gpio is already exported we just show a warning and continue; if
* openocd happened to crash (or was killed by user) then the gpios will not * openocd happened to crash (or was killed by user) then the gpios will not
* have been cleaned up. * have been cleaned up.
*/ */
static int setup_sysfs_gpio(int gpio, int is_output, int init_high) static int setup_sysfs_gpio(int gpio, int is_output, int init_high, int open_rw)
{ {
char buf[40]; char buf[40];
char gpiostr[4]; char gpiostr[4];
@ -132,7 +136,9 @@ static int setup_sysfs_gpio(int gpio, int is_output, int init_high)
} }
snprintf(buf, sizeof(buf), "/sys/class/gpio/gpio%d/value", gpio); snprintf(buf, sizeof(buf), "/sys/class/gpio/gpio%d/value", gpio);
if (is_output) if (open_rw)
ret = open(buf, O_RDWR | O_NONBLOCK | O_SYNC);
else if (is_output)
ret = open(buf, O_WRONLY | O_NONBLOCK | O_SYNC); ret = open(buf, O_WRONLY | O_NONBLOCK | O_SYNC);
else else
ret = open(buf, O_RDONLY | O_NONBLOCK | O_SYNC); ret = open(buf, O_RDONLY | O_NONBLOCK | O_SYNC);
@ -143,6 +149,37 @@ static int setup_sysfs_gpio(int gpio, int is_output, int init_high)
return ret; return ret;
} }
/*
* Change direction for gpio.
*/
static int change_dir_sysfs_gpio(int gpio, int is_output, int init_high)
{
char buf[40];
int ret;
if (!is_gpio_valid(gpio))
return ERROR_OK;
snprintf(buf, sizeof(buf), "/sys/class/gpio/gpio%d/direction", gpio);
ret = open_write_close(buf, is_output ? (init_high ? "high" : "low") : "in");
if (ret < 0) {
LOG_ERROR("Couldn't set direction for gpio %d", gpio);
perror("sysfsgpio: ");
unexport_sysfs_gpio(gpio);
return ERROR_FAIL;
}
return ERROR_OK;
}
/* gpio numbers for each gpio. Negative values are invalid */
static int tck_gpio = -1;
static int tms_gpio = -1;
static int tdi_gpio = -1;
static int tdo_gpio = -1;
static int trst_gpio = -1;
static int srst_gpio = -1;
/* /*
* file descriptors for /sys/class/gpio/gpioXX/value * file descriptors for /sys/class/gpio/gpioXX/value
* Set up during init. * Set up during init.
@ -154,6 +191,15 @@ static int tdo_fd = -1;
static int trst_fd = -1; static int trst_fd = -1;
static int srst_fd = -1; static int srst_fd = -1;
/*
* GPIO state of /sys/class/gpio/gpioXX/value
*/
static int last_tck = -1;
static int last_tms = -1;
static int last_tms_drive = -1;
static int last_tdi = -1;
static int last_initialized = -1;
/* /*
* Bitbang interface read of TDO * Bitbang interface read of TDO
* *
@ -179,26 +225,22 @@ static int sysfsgpio_read(void)
/* /*
* Bitbang interface write of TCK, TMS, TDI * Bitbang interface write of TCK, TMS, TDI
* *
* Seeing as this is the only function where the outputs are changed, * Output states are changed here and in sysfsgpio_write_swd,
* we can cache the old value to avoid needlessly writing it. * which are not used simultaneously, so we can cache the old
* value to avoid needlessly writing it.
*/ */
static void sysfsgpio_write(int tck, int tms, int tdi) static void sysfsgpio_write(int tck, int tms, int tdi)
{ {
const char one[] = "1"; const char one[] = "1";
const char zero[] = "0"; const char zero[] = "0";
static int last_tck;
static int last_tms;
static int last_tdi;
static int first_time;
size_t bytes_written; size_t bytes_written;
if (!first_time) { if (!last_initialized) {
last_tck = !tck; last_tck = !tck;
last_tms = !tms; last_tms = !tms;
last_tdi = !tdi; last_tdi = !tdi;
first_time = 1; last_initialized = 1;
} }
if (tdi != last_tdi) { if (tdi != last_tdi) {
@ -251,13 +293,81 @@ static void sysfsgpio_reset(int trst, int srst)
} }
} }
/* gpio numbers for each gpio. Negative values are invalid */ /*
static int tck_gpio = -1; * Bitbang interface set direction of SWDIO (TMS)
static int tms_gpio = -1; */
static int tdi_gpio = -1; static void sysfsgpio_swdio_drive(int is_output)
static int tdo_gpio = -1; {
static int trst_gpio = -1; int ret;
static int srst_gpio = -1;
if (is_output != 0 && last_tms == -1)
last_tms = 0;
ret = change_dir_sysfs_gpio(tms_gpio, (is_output != 0) ? 1 : 0, last_tms);
if (ret != ERROR_OK)
LOG_WARNING("Failed to change SWDIO (TMS) direction to output");
else
last_tms_drive = (is_output != 0) ? 1 : 0;
}
/*
* Bitbang interface read of SWDIO (TMS)
*
* The sysfs value will read back either '0' or '1'. The trick here is to call
* lseek to bypass buffering in the sysfs kernel driver.
*/
static int sysfsgpio_swdio_read(void)
{
char buf[1];
/* important to seek to signal sysfs of new read */
lseek(tms_fd, 0, SEEK_SET);
int ret = read(tms_fd, &buf, sizeof(buf));
if (ret < 0) {
LOG_WARNING("reading swdio (tms) failed");
return 0;
}
return buf[0];
}
/*
* Bitbang interface write of SWCLK (TCK) and SWDIO (TMS)
*
* Output states are changed here and in sysfsgpio_write, which
* are not used simultaneously, so we can cache the old value
* to avoid needlessly writing it.
*/
static void sysfsgpio_swd_write(int swclk, int swdio)
{
static const char one[] = "1";
static const char zero[] = "0";
size_t bytes_written;
if (!last_initialized) {
last_tck = !swclk;
last_tms = !swdio;
last_initialized = 1;
}
if (last_tms_drive == 1 && swdio != last_tms) {
bytes_written = write(tms_fd, swdio ? &one : &zero, 1);
if (bytes_written != 1)
LOG_WARNING("writing swdio (tms) failed");
}
/* write clk last */
if (swclk != last_tck) {
bytes_written = write(tck_fd, swclk ? &one : &zero, 1);
if (bytes_written != 1)
LOG_WARNING("writing swclk (tck) failed");
}
last_tms = swdio;
last_tck = swclk;
}
/* helper func to close and cleanup files only if they were valid/ used */ /* helper func to close and cleanup files only if they were valid/ used */
static void cleanup_fd(int fd, int gpio) static void cleanup_fd(int fd, int gpio)
@ -293,13 +403,21 @@ static void process_remote_protocol(void)
char d = c - 'r'; char d = c - 'r';
sysfsgpio_reset(!!(d & 2), sysfsgpio_reset(!!(d & 2),
(d & 1)); (d & 1));
} else if (c >= '0' && c <= '0' + 7) {/* Write */ } else if (c >= '0' && c <= '0' + 7) { /* Write */
char d = c - '0'; char d = c - '0';
sysfsgpio_write(!!(d & 4), sysfsgpio_write(!!(d & 4),
!!(d & 2), !!(d & 2),
(d & 1)); (d & 1));
} else if (c == 'R') } else if (c == 'R')
putchar(sysfsgpio_read()); putchar(sysfsgpio_read());
else if (c == 'c') /* SWDIO read */
putchar(sysfsgpio_swdio_read());
else if (c == 'o' || c == 'O') /* SWDIO drive */
sysfsgpio_swdio_drive(c == 'o' ? 0 : 1);
else if (c >= 'd' && c <= 'g') { /* SWD write */
char d = c - 'd';
sysfsgpio_swd_write((d & 2), (d & 1));
}
else else
LOG_ERROR("Unknown command '%c' received", c); LOG_ERROR("Unknown command '%c' received", c);
} }
@ -307,7 +425,7 @@ static void process_remote_protocol(void)
int main(int argc, char *argv[]) int main(int argc, char *argv[])
{ {
LOG_WARNING("SysfsGPIO remote_bitbang JTAG driver\n"); LOG_WARNING("SysfsGPIO remote_bitbang JTAG+SWD driver\n");
for (int i = 1; i < argc; i++) { for (int i = 1; i < argc; i++) {
if (!strcmp(argv[i], "tck")) if (!strcmp(argv[i], "tck"))
@ -349,36 +467,39 @@ int main(int argc, char *argv[])
* Configure TDO as an input, and TDI, TCK, TMS, TRST, SRST * Configure TDO as an input, and TDI, TCK, TMS, TRST, SRST
* as outputs. Drive TDI and TCK low, and TMS/TRST/SRST high. * as outputs. Drive TDI and TCK low, and TMS/TRST/SRST high.
*/ */
tck_fd = setup_sysfs_gpio(tck_gpio, 1, 0); tck_fd = setup_sysfs_gpio(tck_gpio, 1, 0, 0);
if (tck_fd < 0) if (tck_fd < 0)
goto out_error; goto out_error;
tms_fd = setup_sysfs_gpio(tms_gpio, 1, 1); tms_fd = setup_sysfs_gpio(tms_gpio, 1, 1, 1);
if (tms_fd < 0) if (tms_fd < 0)
goto out_error; goto out_error;
last_tms_drive = 0;
tdi_fd = setup_sysfs_gpio(tdi_gpio, 1, 0); tdi_fd = setup_sysfs_gpio(tdi_gpio, 1, 0, 0);
if (tdi_fd < 0) if (tdi_fd < 0)
goto out_error; goto out_error;
tdo_fd = setup_sysfs_gpio(tdo_gpio, 0, 0); tdo_fd = setup_sysfs_gpio(tdo_gpio, 0, 0, 0);
if (tdo_fd < 0) if (tdo_fd < 0)
goto out_error; goto out_error;
/* assume active low */ /* assume active low */
if (trst_gpio > 0) { if (trst_gpio > 0) {
trst_fd = setup_sysfs_gpio(trst_gpio, 1, 1); trst_fd = setup_sysfs_gpio(trst_gpio, 1, 1, 0);
if (trst_fd < 0) if (trst_fd < 0)
goto out_error; goto out_error;
} }
/* assume active low */ /* assume active low */
if (srst_gpio > 0) { if (srst_gpio > 0) {
srst_fd = setup_sysfs_gpio(srst_gpio, 1, 1); srst_fd = setup_sysfs_gpio(srst_gpio, 1, 1, 0);
if (srst_fd < 0) if (srst_fd < 0)
goto out_error; goto out_error;
} }
last_initialized = 0;
LOG_WARNING("SysfsGPIO nums: tck = %d, tms = %d, tdi = %d, tdo = %d", LOG_WARNING("SysfsGPIO nums: tck = %d, tms = %d, tdi = %d, tdo = %d",
tck_gpio, tms_gpio, tdi_gpio, tdo_gpio); tck_gpio, tms_gpio, tdi_gpio, tdo_gpio);
LOG_WARNING("SysfsGPIO num: srst = %d", srst_gpio); LOG_WARNING("SysfsGPIO num: srst = %d", srst_gpio);

36
doc/manual/jtag/drivers/remote_bitbang.txt
View File

@ -1,15 +1,19 @@
/** @remote_bitbangpage OpenOCD Developer's Guide /** @remote_bitbangpage OpenOCD Developer's Guide
The remote_bitbang JTAG driver is used to drive JTAG from a remote process. The The remote_bitbang JTAG+SWD driver is used to drive JTAG and/or SWD from a
remote_bitbang driver communicates via TCP or UNIX sockets with some remote remote process. The remote_bitbang driver communicates via TCP or UNIX
process using an ASCII encoding of the bitbang interface. The remote process sockets with some remote process using an ASCII encoding of the bitbang
presumably then drives the JTAG however it pleases. The remote process should interface. The remote process presumably then drives the JTAG/SWD however
act as a server, listening for connections from the openocd remote_bitbang it pleases. The remote process should act as a server, listening for
driver. connections from the openocd remote_bitbang driver.
The remote bitbang driver is useful for debugging software running on The remote bitbang driver is useful for debugging software running on
processors which are being simulated. processors which are being simulated.
There also is an implementation of the server-side protocol for the
Glasgow Debug Tool (https://github.com/glasgowEmbedded/Glasgow) through
the jtag-openocd applet.
The bitbang interface consists of the following functions. The bitbang interface consists of the following functions.
blink on blink on
@ -24,11 +28,20 @@ write tck tms tdi
reset trst srst reset trst srst
Set the value of trst, srst. Set the value of trst, srst.
swdio_drive
Set the output enable of the bidirectional swdio (tms) pin
swdio_read
Sample the value of swdio (tms).
swd_write
Set the value of swclk (tck) and swdio (tms).
An additional function, quit, is added to the remote_bitbang interface to An additional function, quit, is added to the remote_bitbang interface to
indicate there will be no more requests and the connection with the remote indicate there will be no more requests and the connection with the remote
driver should be closed. driver should be closed.
These five functions are encoded in ASCII by assigning a single character to These eight functions are encoded in ASCII by assigning a single character to
each possible request. The assignments are: each possible request. The assignments are:
B - Blink on B - Blink on
@ -47,7 +60,14 @@ each possible request. The assignments are:
s - Reset 0 1 s - Reset 0 1
t - Reset 1 0 t - Reset 1 0
u - Reset 1 1 u - Reset 1 1
O - SWDIO drive 1
o - SWDIO drive 0
c - SWDIO read request
d - SWD write 0 0
e - SWD write 0 1
f - SWD write 1 0
g - SWD write 1 1
The read response is encoded in ASCII as either digit 0 or 1. The read responses are encoded in ASCII as either digit 0 or 1.
*/ */

6
doc/openocd.texi
View File

@ -2810,9 +2810,9 @@ If not specified, default 0xFFFF is used.
@end deffn @end deffn
@deffn {Interface Driver} {remote_bitbang} @deffn {Interface Driver} {remote_bitbang}
Drive JTAG from a remote process. This sets up a UNIX or TCP socket connection Drive JTAG and SWD from a remote process. This sets up a UNIX or TCP socket
with a remote process and sends ASCII encoded bitbang requests to that process connection with a remote process and sends ASCII encoded bitbang requests to
instead of directly driving JTAG. that process instead of directly driving JTAG and SWD.
The remote_bitbang driver is useful for debugging software running on The remote_bitbang driver is useful for debugging software running on
processors which are being simulated. processors which are being simulated.

31
src/jtag/drivers/remote_bitbang.c
View File

@ -3,6 +3,8 @@
/*************************************************************************** /***************************************************************************
* Copyright (C) 2011 by Richard Uhler * * Copyright (C) 2011 by Richard Uhler *
* ruhler@mit.edu * * ruhler@mit.edu *
* *
* Copyright (C) 2021 by Manuel Wick <manuel@matronix.de> *
***************************************************************************/ ***************************************************************************/
#ifdef HAVE_CONFIG_H #ifdef HAVE_CONFIG_H
@ -220,11 +222,35 @@ static int remote_bitbang_blink(int on)
return remote_bitbang_queue(c, FLUSH_SEND_BUF); return remote_bitbang_queue(c, FLUSH_SEND_BUF);
} }
static void remote_bitbang_swdio_drive(bool is_output)
{
char c = is_output ? 'O' : 'o';
if (remote_bitbang_queue(c, FLUSH_SEND_BUF) == ERROR_FAIL)
LOG_ERROR("Error setting direction for swdio");
}
static int remote_bitbang_swdio_read(void)
{
if (remote_bitbang_queue('c', FLUSH_SEND_BUF) != ERROR_FAIL)
return remote_bitbang_read_sample();
else
return BB_ERROR;
}
static int remote_bitbang_swd_write(int swclk, int swdio)
{
char c = 'd' + ((swclk ? 0x2 : 0x0) | (swdio ? 0x1 : 0x0));
return remote_bitbang_queue(c, NO_FLUSH);
}
static struct bitbang_interface remote_bitbang_bitbang = { static struct bitbang_interface remote_bitbang_bitbang = {
.buf_size = sizeof(remote_bitbang_recv_buf) - 1, .buf_size = sizeof(remote_bitbang_recv_buf) - 1,
.sample = &remote_bitbang_sample, .sample = &remote_bitbang_sample,
.read_sample = &remote_bitbang_read_sample, .read_sample = &remote_bitbang_read_sample,
.write = &remote_bitbang_write, .write = &remote_bitbang_write,
.swdio_read = &remote_bitbang_swdio_read,
.swdio_drive = &remote_bitbang_swdio_drive,
.swd_write = &remote_bitbang_swd_write,
.blink = &remote_bitbang_blink, .blink = &remote_bitbang_blink,
}; };
@ -349,6 +375,8 @@ COMMAND_HANDLER(remote_bitbang_handle_remote_bitbang_host_command)
return ERROR_COMMAND_SYNTAX_ERROR; return ERROR_COMMAND_SYNTAX_ERROR;
} }
static const char * const remote_bitbang_transports[] = { "jtag", "swd", NULL };
static const struct command_registration remote_bitbang_subcommand_handlers[] = { static const struct command_registration remote_bitbang_subcommand_handlers[] = {
{ {
.name = "port", .name = "port",
@ -401,7 +429,7 @@ static struct jtag_interface remote_bitbang_interface = {
struct adapter_driver remote_bitbang_adapter_driver = { struct adapter_driver remote_bitbang_adapter_driver = {
.name = "remote_bitbang", .name = "remote_bitbang",
.transports = jtag_only, .transports = remote_bitbang_transports,
.commands = remote_bitbang_command_handlers, .commands = remote_bitbang_command_handlers,
.init = &remote_bitbang_init, .init = &remote_bitbang_init,
@ -409,4 +437,5 @@ struct adapter_driver remote_bitbang_adapter_driver = {
.reset = &remote_bitbang_reset, .reset = &remote_bitbang_reset,
.jtag_ops = &remote_bitbang_interface, .jtag_ops = &remote_bitbang_interface,
.swd_ops = &bitbang_swd,
}; };