This is an automated email from Gerrit.
"Tomas Vanek <van...@fbl.cz>" just uploaded a new patch set to Gerrit, which
you can find at https://review.openocd.org/c/openocd/+/8746
-- gerrit
commit ee7b907d8d883269deb01c2dde1e5a9e23d57788
Author: Tomas Vanek <van...@fbl.cz>
Date: Sat Feb 8 22:40:43 2025 +0100
drivers/ch347: limit SWD packet size by processing time
CH347 chip firmware probably does not service USB poll/requests
from the host during processing of SWD packet. If the processing
lasts longer than approx 16 ms, USB host disconnects the adapter
from the bus as if it were dead.
To avoid disconnect, compute approximate processing time
of SWD transactions and flush the queue if the total time
gets over the limit.
The workaround works for me. Tested on a linux x64 PC and RPi 5.
Change-Id: Ibdcff4de52e3eb4d86ed83af81a1c64f1f9b5d24
Signed-off-by: Tomas Vanek <van...@fbl.cz>
diff --git a/src/jtag/drivers/ch347.c b/src/jtag/drivers/ch347.c
index ec3db226d7..4290f51c7e 100644
--- a/src/jtag/drivers/ch347.c
+++ b/src/jtag/drivers/ch347.c
@@ -115,9 +115,10 @@
#define CH347_CMD_SWD_REG_W 0xA0 // SWD Interface write reg
#define CH347_CMD_SWD_SEQ_W 0xA1 // SWD Interface write spec seq
#define CH347_CMD_SWD_REG_R 0xA2 // SWD Interface read reg
-#define CH347_MAX_SEND_CMD 19 // max send cmd number
-#define CH347_MAX_SEND_BUF 0X200
-#define CH347_MAX_RECV_BUF 0X200
+#define CH347_MAX_PROCESSING_US 17000 // max time in us for packet processing
+ // USB hosts disconnect the adapter if SWD processing
takes more!
+#define CH347_MAX_SEND_BUF USBC_PACKET_USBHS
+#define CH347_MAX_RECV_BUF USBC_PACKET_USBHS
#define CH347_MAX_CMD_BUF 128
#define CH347_EPOUT 0x06u // the usb endpoint number for writing
@@ -236,6 +237,8 @@ struct ch347_swd_context {
int need_recv_len;
int queued_retval;
int sent_cmd_count;
+ int clk_divisor;
+ int total_swd_clk;
struct list_head send_cmd_head;
struct list_head free_cmd_head;
struct ch347_swd_io ch347_cmd_buf[CH347_MAX_CMD_BUF];
@@ -1607,6 +1610,7 @@ static int ch347_swd_init_cmd(uint8_t clock_divisor)
uint8_t init_result = 0;
retval = ch347_single_read_get_byte(0, &init_result);
LOG_DEBUG("SWD init result %02" PRIx8, init_result);
+ ch347_swd_context.clk_divisor = clock_divisor ? clock_divisor : 10;
return retval;
}
@@ -1696,7 +1700,8 @@ static int ch347_speed_get_index(int khz, int *speed_idx)
}
if (swd_mode) {
- *speed_idx = MIN(DIV_ROUND_UP(1000, khz), 20);
+ // Don't allow too low clk speeds: packet processing is limited
to ~16 msec
+ *speed_idx = MIN(DIV_ROUND_UP(1000, khz), 50);
return ERROR_OK;
}
@@ -1956,6 +1961,7 @@ static void ch347_write_swd_reg(uint8_t cmd, const
uint32_t out)
ch347_swd_context.send_buf[ch347_swd_context.send_len++] =
parity_u32(out);
// 0xA0 + 1 byte(3bit ACK)
ch347_swd_context.need_recv_len += (1 + 1);
+ ch347_swd_context.total_swd_clk += 46;
}
static void ch347_write_spec_seq(const uint8_t *out, uint8_t out_len)
@@ -1967,6 +1973,7 @@ static void ch347_write_spec_seq(const uint8_t *out,
uint8_t out_len)
for (uint8_t i = 0; i < DIV_ROUND_UP(out_len, 8); i++)
ch347_swd_context.send_buf[ch347_swd_context.send_len++] = out
? out[i] : 0x00;
ch347_swd_context.need_recv_len += 1; // 0xA1
+ ch347_swd_context.total_swd_clk += out_len;
}
static void ch347_read_swd_reg(uint8_t cmd)
@@ -1977,6 +1984,7 @@ static void ch347_read_swd_reg(uint8_t cmd)
ch347_swd_context.send_buf[ch347_swd_context.send_len++] = cmd;
// 0xA2 + 1 byte(3bit ACK) + 4 byte(data) + 1 byte(1bit parity+1bit trn)
ch347_swd_context.need_recv_len += 1 + 1 + 4 + 1;
+ ch347_swd_context.total_swd_clk += 46;
}
static int ch347_swd_switch_out(enum swd_special_seq seq, const uint8_t *out,
unsigned int out_len)
@@ -2046,7 +2054,25 @@ static int ch347_swd_run_queue_inner(void);
static int ch347_swd_send_idle(uint32_t ap_delay_clk)
{
- struct ch347_swd_io *pswd_io = ch347_get_one_swd_io();
+ bool run_q = false;
+
+ if (ch347_swd_context.sent_cmd_count) {
+ unsigned int expected_total_clk =
ch347_swd_context.total_swd_clk + ap_delay_clk;
+ unsigned int expected_send_len = ch347_swd_context.send_len
+ + 1 + 1 + 1 +
DIV_ROUND_UP(ap_delay_clk, 8);
+ // 0xA1 + Len + rev + n byte(delay)
+ unsigned int expected_recv_len =
ch347_swd_context.need_recv_len + 1;
+ // 0xA1
+ if (expected_total_clk * ch347_swd_context.clk_divisor >
CH347_MAX_PROCESSING_US
+ || expected_send_len > CH347_MAX_SEND_BUF
+ || expected_recv_len > CH347_MAX_RECV_BUF)
+ run_q = true;
+ }
+
+ struct ch347_swd_io *pswd_io = NULL;
+ if (!run_q)
+ pswd_io = ch347_get_one_swd_io();
+
if (!pswd_io) {
int retval = ch347_swd_run_queue_inner();
if (retval != ERROR_OK)
@@ -2195,6 +2221,7 @@ skip:
ch347_swd_context.need_recv_len = CH347_CMD_HEADER;
ch347_swd_context.recv_len = 0;
ch347_swd_context.sent_cmd_count = 0;
+ ch347_swd_context.total_swd_clk = 0;
retval = ch347_swd_context.queued_retval;
ch347_swd_context.queued_retval = ERROR_OK;
@@ -2218,19 +2245,25 @@ static int ch347_swd_queue_cmd(uint8_t cmd, uint32_t
*dst, uint32_t data, uint32
if (ap_delay_clk > 255)
ap_delay_clk = 255; // limit imposed by spec. seq. size in
one byte
- if (ch347_swd_context.sent_cmd_count >= CH347_MAX_SEND_CMD) {
- retval = ch347_swd_run_queue_inner();
- if (retval != ERROR_OK)
- return retval;
+ bool run_q = false;
+ if (ch347_swd_context.sent_cmd_count) {
+ unsigned int expected_total_clk =
ch347_swd_context.total_swd_clk
+ + 46 // SWD transaction
+ + ap_delay_clk
+ + 8; // 8 idle cycles
at the end of queue
+ if (expected_total_clk * ch347_swd_context.clk_divisor >
CH347_MAX_PROCESSING_US) {
+ LOG_DEBUG_IO("Expected queue run %u cycles, with this
cmd %u",
+
ch347_swd_context.total_swd_clk, expected_total_clk);
+ run_q = true;
+ } else if (!ch347_chk_buf_size(cmd, ap_delay_clk)) {
+ run_q = true;
+ }
}
- if (!ch347_chk_buf_size(cmd, ap_delay_clk)) {
- retval = ch347_swd_run_queue_inner();
- if (retval != ERROR_OK)
- return retval;
- }
+ struct ch347_swd_io *pswd_io = NULL;
+ if (!run_q)
+ pswd_io = ch347_get_one_swd_io();
- struct ch347_swd_io *pswd_io = ch347_get_one_swd_io();
if (!pswd_io) {
retval = ch347_swd_run_queue_inner();
if (retval != ERROR_OK)
--
