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jtagremote: Implement ntrst pin 

ntrst pin is critical to some JTAG taps to put tap
into a known state.

Implement it in jtagremote testbench with corresponding
remote bitbang commands and hook it up in litex_sim.

Signed-off-by: Jiaxun Yang <jiaxun.yang@flygoat.com>
This commit is contained in:
Jiaxun Yang 2024-06-18 14:18:28 +01:00
parent a8b3f36592
commit 50c8ef07b6
No known key found for this signature in database
GPG Key ID: 43710C7DD77729C3
2 changed files with 31 additions and 16 deletions
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41
litex/build/sim/core/modules/jtagremote/jtagremote.c
View File

@ -15,6 +15,7 @@ struct session_s {
char *tdo;
char *tck;
char *tms;
char *ntrst;
char *sys_clk;
struct event *ev;
char databuf[2048];
@ -199,6 +200,7 @@ static int jtagremote_add_pads(void *sess, struct pad_list_s *plist)
litex_sim_module_pads_get(pads, "tdi", (void**)&s->tdi);
litex_sim_module_pads_get(pads, "tdo", (void**)&s->tdo);
litex_sim_module_pads_get(pads, "tms", (void**)&s->tms);
litex_sim_module_pads_get(pads, "ntrst", (void**)&s->ntrst);
}
if(!strcmp(plist->name, "sys_clk"))
@ -227,19 +229,34 @@ static int jtagremote_tick(void *sess, uint64_t time_ps)
{
c = s->databuf[s->data_start];
if((c >= '0') && (c <= '7')){
*s->tck = ((c - '0') >> 2) & 1;
*s->tms = ((c - '0') >> 1) & 1;
*s->tdi = (c - '0') & 1;
}
if(c == 'R'){
val = *s->tdo + '0';
if(-1 == write(s->fd, &val, 1)) {
eprintf("Error writing on socket\n");
ret = RC_ERROR;
goto out;
}
switch(c) {
case '0'...'7':
*s->tck = ((c - '0') >> 2) & 1;
*s->tms = ((c - '0') >> 1) & 1;
*s->tdi = (c - '0') & 1;
break;
case 'r':
case 's':
/* Deassert reset */
*s->ntrst = 1;
break;
case 't':
case 'u':
/* Assert reset */
*s->ntrst = 0;
break;
case 'R':
val = *s->tdo + '0';
if(write(s->fd, &val, 1) == -1) {
eprintf("Error writing on socket\n");
ret = RC_ERROR;
goto out;
}
break;
default:
break;
}
s->data_start = (s->data_start + 1) % 2048;
s->datalen--;
}

6
litex/tools/litex_sim.py
View File

@ -135,6 +135,7 @@ _io = [
Subsignal("tms", Pins(1)),
Subsignal("tdi", Pins(1)),
Subsignal("tdo", Pins(1)),
Subsignal("ntrst", Pins(1)),
),
# Video (VGA).
@ -277,10 +278,7 @@ class SimSoC(SoCCore):
# JTAG -------------------------------------------------------------------------------------
if with_jtag:
jtag_pads = platform.request("jtag")
self.comb += self.cpu.jtag_clk.eq(jtag_pads.tck)
self.comb += self.cpu.jtag_tms.eq(jtag_pads.tms)
self.comb += self.cpu.jtag_tdi.eq(jtag_pads.tdi)
self.comb += jtag_pads.tdo.eq(self.cpu.jtag_tdo)
self.cpu.add_jtag(jtag_pads)
# SDCard -----------------------------------------------------------------------------------
if with_sdcard: