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Add remote bitbang write buffer. 

Change 7dd323b26 reduced remote bitbang performance a lot. This change
gets most of that performance back again, by reintroducing a write
buffer.

Performance numbers collected using DebugBreakpoint test from
riscv-tests/debug against a single 64-bit spike (RISC-V simulator)
instance. (Ubuntu 20.04.2, AMD Ryzen 5 3600)
Before Windows support was added: 3.09s
After Windows support was added: 12.67s
After this change: 4.69s

Signed-off-by: Tim Newsome <tim@sifive.com>
Change-Id: I72ff4912cbbf316a30ef065e5b8f461a555f06cc
Reviewed-on: http://openocd.zylin.com/6283
Tested-by: jenkins
Reviewed-by: Jan Matyas <matyas@codasip.com>
Reviewed-by: Tarek BOCHKATI <tarek.bouchkati@gmail.com>
Reviewed-by: Antonio Borneo <borneo.antonio@gmail.com>
This commit is contained in:
Tim Newsome 2021-05-28 13:38:50 -07:00 committed by Antonio Borneo
parent 076b4d708e
commit f2958fc04b
1 changed files with 86 additions and 37 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

123
src/jtag/drivers/remote_bitbang.c
View File

@ -36,17 +36,19 @@ static char *remote_bitbang_host;
static char *remote_bitbang_port;
static int remote_bitbang_fd;
static uint8_t remote_bitbang_send_buf[512];
static unsigned int remote_bitbang_send_buf_used;
/* Circular buffer. When start == end, the buffer is empty. */
static char remote_bitbang_buf[64];
static unsigned remote_bitbang_start;
static unsigned remote_bitbang_end;
static char remote_bitbang_recv_buf[64];
static unsigned int remote_bitbang_recv_buf_start;
static unsigned int remote_bitbang_recv_buf_end;
static int remote_bitbang_buf_full(void)
static bool remote_bitbang_buf_full(void)
{
return remote_bitbang_end ==
((remote_bitbang_start + sizeof(remote_bitbang_buf) - 1) %
sizeof(remote_bitbang_buf));
return remote_bitbang_recv_buf_end ==
((remote_bitbang_recv_buf_start + sizeof(remote_bitbang_recv_buf) - 1) %
sizeof(remote_bitbang_recv_buf));
}
/* Read any incoming data, placing it into the buffer. */
@ -54,23 +56,23 @@ static int remote_bitbang_fill_buf(void)
{
socket_nonblock(remote_bitbang_fd);
while (!remote_bitbang_buf_full()) {
unsigned contiguous_available_space;
if (remote_bitbang_end >= remote_bitbang_start) {
contiguous_available_space = sizeof(remote_bitbang_buf) -
remote_bitbang_end;
if (remote_bitbang_start == 0)
unsigned int contiguous_available_space;
if (remote_bitbang_recv_buf_end >= remote_bitbang_recv_buf_start) {
contiguous_available_space = sizeof(remote_bitbang_recv_buf) -
remote_bitbang_recv_buf_end;
if (remote_bitbang_recv_buf_start == 0)
contiguous_available_space -= 1;
} else {
contiguous_available_space = remote_bitbang_start -
remote_bitbang_end - 1;
contiguous_available_space = remote_bitbang_recv_buf_start -
remote_bitbang_recv_buf_end - 1;
}
ssize_t count = read_socket(remote_bitbang_fd,
remote_bitbang_buf + remote_bitbang_end,
remote_bitbang_recv_buf + remote_bitbang_recv_buf_end,
contiguous_available_space);
if (count > 0) {
remote_bitbang_end += count;
if (remote_bitbang_end == sizeof(remote_bitbang_buf))
remote_bitbang_end = 0;
remote_bitbang_recv_buf_end += count;
if (remote_bitbang_recv_buf_end == sizeof(remote_bitbang_recv_buf))
remote_bitbang_recv_buf_end = 0;
} else if (count == 0) {
return ERROR_OK;
} else if (count < 0) {
@ -90,20 +92,43 @@ static int remote_bitbang_fill_buf(void)
return ERROR_OK;
}
static int remote_bitbang_putc(int c)
static int remote_bitbang_flush(void)
{
char buf = c;
ssize_t count = write_socket(remote_bitbang_fd, &buf, sizeof(buf));
if (count < 0) {
log_socket_error("remote_bitbang_putc");
return ERROR_FAIL;
if (remote_bitbang_send_buf_used <= 0)
return ERROR_OK;
unsigned int offset = 0;
while (offset < remote_bitbang_send_buf_used) {
ssize_t written = write_socket(remote_bitbang_fd, remote_bitbang_send_buf + offset,
remote_bitbang_send_buf_used - offset);
if (written < 0) {
log_socket_error("remote_bitbang_putc");
remote_bitbang_send_buf_used = 0;
return ERROR_FAIL;
}
offset += written;
}
remote_bitbang_send_buf_used = 0;
return ERROR_OK;
}
typedef enum {
NO_FLUSH,
FLUSH_SEND_BUF
} flush_bool_t;
static int remote_bitbang_queue(int c, flush_bool_t flush)
{
remote_bitbang_send_buf[remote_bitbang_send_buf_used++] = c;
if (flush == FLUSH_SEND_BUF ||
remote_bitbang_send_buf_used >= ARRAY_SIZE(remote_bitbang_send_buf))
return remote_bitbang_flush();
return ERROR_OK;
}
static int remote_bitbang_quit(void)
{
if (remote_bitbang_putc('Q') == ERROR_FAIL)
if (remote_bitbang_queue('Q', FLUSH_SEND_BUF) == ERROR_FAIL)
return ERROR_FAIL;
if (close_socket(remote_bitbang_fd) != 0) {
@ -135,6 +160,9 @@ static bb_value_t char_to_int(int c)
/* Get the next read response. */
static bb_value_t remote_bitbang_rread(void)
{
if (remote_bitbang_flush() != ERROR_OK)
return ERROR_FAIL;
/* Enable blocking access. */
socket_block(remote_bitbang_fd);
char c;
@ -154,15 +182,19 @@ static int remote_bitbang_sample(void)
if (remote_bitbang_fill_buf() != ERROR_OK)
return ERROR_FAIL;
assert(!remote_bitbang_buf_full());
return remote_bitbang_putc('R');
return remote_bitbang_queue('R', NO_FLUSH);
}
static bb_value_t remote_bitbang_read_sample(void)
{
if (remote_bitbang_start != remote_bitbang_end) {
int c = remote_bitbang_buf[remote_bitbang_start];
remote_bitbang_start =
(remote_bitbang_start + 1) % sizeof(remote_bitbang_buf);
if (remote_bitbang_recv_buf_start == remote_bitbang_recv_buf_end) {
if (remote_bitbang_fill_buf() != ERROR_OK)
return ERROR_FAIL;
}
if (remote_bitbang_recv_buf_start != remote_bitbang_recv_buf_end) {
int c = remote_bitbang_recv_buf[remote_bitbang_recv_buf_start];
remote_bitbang_recv_buf_start =
(remote_bitbang_recv_buf_start + 1) % sizeof(remote_bitbang_recv_buf);
return char_to_int(c);
}
return remote_bitbang_rread();
@ -171,23 +203,25 @@ static bb_value_t remote_bitbang_read_sample(void)
static int remote_bitbang_write(int tck, int tms, int tdi)
{
char c = '0' + ((tck ? 0x4 : 0x0) | (tms ? 0x2 : 0x0) | (tdi ? 0x1 : 0x0));
return remote_bitbang_putc(c);
return remote_bitbang_queue(c, NO_FLUSH);
}
static int remote_bitbang_reset(int trst, int srst)
{
char c = 'r' + ((trst ? 0x2 : 0x0) | (srst ? 0x1 : 0x0));
return remote_bitbang_putc(c);
/* Always flush the send buffer on reset, because the reset call need not be
* followed by jtag_execute_queue(). */
return remote_bitbang_queue(c, FLUSH_SEND_BUF);
}
static int remote_bitbang_blink(int on)
{
char c = on ? 'B' : 'b';
return remote_bitbang_putc(c);
return remote_bitbang_queue(c, FLUSH_SEND_BUF);
}
static struct bitbang_interface remote_bitbang_bitbang = {
.buf_size = sizeof(remote_bitbang_buf) - 1,
.buf_size = sizeof(remote_bitbang_recv_buf) - 1,
.sample = &remote_bitbang_sample,
.read_sample = &remote_bitbang_read_sample,
.write = &remote_bitbang_write,
@ -268,8 +302,8 @@ static int remote_bitbang_init(void)
{
bitbang_interface = &remote_bitbang_bitbang;
remote_bitbang_start = 0;
remote_bitbang_end = 0;
remote_bitbang_recv_buf_start = 0;
remote_bitbang_recv_buf_end = 0;
LOG_INFO("Initializing remote_bitbang driver");
if (remote_bitbang_port == NULL)
@ -326,8 +360,23 @@ static const struct command_registration remote_bitbang_command_handlers[] = {
COMMAND_REGISTRATION_DONE,
};
static int remote_bitbang_execute_queue(void)
{
/* safety: the send buffer must be empty, no leftover characters from
* previous transactions */
assert(remote_bitbang_send_buf_used == 0);
/* process the JTAG command queue */
int ret = bitbang_execute_queue();
if (ret != ERROR_OK)
return ret;
/* flush not-yet-sent characters, if any */
return remote_bitbang_flush();
}
static struct jtag_interface remote_bitbang_interface = {
.execute_queue = &bitbang_execute_queue,
.execute_queue = &remote_bitbang_execute_queue,
};
struct adapter_driver remote_bitbang_adapter_driver = {