This is an automated email from Gerrit.
Tim Newsome (t...@sifive.com) just uploaded a new patch set to Gerrit, which
you can find at http://openocd.zylin.com/6283
-- gerrit
commit df5d2ecc1f268b5b2c17fcc05bbdf63c0e4c6a94
Author: Tim Newsome <t...@sifive.com>
Date: Fri May 28 13:38:50 2021 -0700
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.
Signed-off-by: Tim Newsome <t...@sifive.com>
Change-Id: I72ff4912cbbf316a30ef065e5b8f461a555f06cc
diff --git a/src/jtag/drivers/remote_bitbang.c
b/src/jtag/drivers/remote_bitbang.c
index f7b8830..b9ea7e4 100644
--- a/src/jtag/drivers/remote_bitbang.c
+++ b/src/jtag/drivers/remote_bitbang.c
@@ -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 remote_bitbang_recv_buf_start;
+static unsigned remote_bitbang_recv_buf_end;
static int 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. */
@@ -55,22 +57,22 @@ 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)
+ 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 +92,37 @@ 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;
+}
+
+static int remote_bitbang_queue(int c, bool flush)
+{
+ remote_bitbang_send_buf[remote_bitbang_send_buf_used++] = c;
+ if (flush || 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', true) == ERROR_FAIL)
return ERROR_FAIL;
if (close_socket(remote_bitbang_fd) != 0) {
@@ -135,6 +154,9 @@ 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 +176,19 @@ 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', false);
}
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 +197,25 @@ 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, false);
}
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, true);
}
static int remote_bitbang_blink(int on)
{
char c = on ? 'B' : 'b';
- return remote_bitbang_putc(c);
+ return remote_bitbang_queue(c, true);
}
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 +296,8 @@ 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 +354,23 @@ 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 = {
--
