electronics/bs_explorer
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

digilent: heap-allocate shift buffers, drop the size cap

Browse Source 
The TX/TXRX functions used fixed ~1-2 KB stack buffers and rejected
anything larger, so any big shift failed: bscan_idle_cycles(10000) and
above all the ~19 Mbit bitstream load for the BSCAN proxy. Size the
pack/capture buffers to the shift on the heap instead.

This is what unblocked the proxy load — see next commit.
This commit is contained in:
Foué
2026-05-24 00:04:31 +02:00
parent 1814c4cf0c
commit 4d0637e997
1 changed files with 37 additions and 42 deletions
Download Patch File Download Diff File Expand all files Collapse all files

77
modules/drivers/digilent_jtag/digilent_jtag_drv.c
View File

@@ -285,26 +285,26 @@ static int drv_Digilent_DeInit(jtag_core *jc)
static int drv_Digilent_TMS_xfer(jtag_core *jc, unsigned char *str_out, int size)
{
DJ_BYTE buf_snd[1024];
DJ_BYTE *buf_snd;
int nbytes = (size + 7) / 8;
int i;
int i, ok;
if (!g_dj_open) return JTAG_CORE_BAD_PARAMETER;
if (size <= 0) return JTAG_CORE_NO_ERROR;
if (nbytes > (int)sizeof(buf_snd)) {
jtagcore_logs_printf(jc, MSG_ERROR,
"drv_Digilent_TMS_xfer : size %d > %d bits\r\n",
size, (int)sizeof(buf_snd) * 8);
return JTAG_CORE_BAD_PARAMETER;
}
memset(buf_snd, 0, nbytes);
/* Heap-allocated and sized to the shift: a bitstream load shifts
* millions of bits in one call, far past any fixed buffer. */
buf_snd = calloc(1, (size_t)nbytes);
if (!buf_snd) return JTAG_CORE_BAD_PARAMETER;
for (i = 0; i < size; i++) {
if (str_out[i] & JTAG_STR_TMS)
buf_snd[i >> 3] |= (DJ_BYTE)(1u << (i & 7));
}
if (!g_dj.PutTmsBits(g_dj_hif, /*fTdi=*/0, buf_snd, NULL, (DJ_DWORD)size, /*fOverlap=*/0)) {
ok = g_dj.PutTmsBits(g_dj_hif, /*fTdi=*/0, buf_snd, NULL, (DJ_DWORD)size, /*fOverlap=*/0);
free(buf_snd);
if (!ok) {
jtagcore_logs_printf(jc, MSG_ERROR,
"drv_Digilent_TMS_xfer : DjtgPutTmsBits failed\r\n");
return JTAG_CORE_BAD_PARAMETER;
@@ -317,10 +317,9 @@ static int drv_Digilent_TDOTDI_xfer(jtag_core *jc,
unsigned char *str_in,
int size)
{
DJ_BYTE buf_snd[2048];
DJ_BYTE buf_rcv[1024];
DJ_BYTE *buf_snd, *buf_rcv = NULL;
int has_tms = 0;
int i;
int i, ok, snd_bytes;
if (!g_dj_open) return JTAG_CORE_BAD_PARAMETER;
if (size <= 0) return JTAG_CORE_NO_ERROR;
@@ -329,54 +328,50 @@ static int drv_Digilent_TDOTDI_xfer(jtag_core *jc,
if (str_out[i] & JTAG_STR_TMS) { has_tms = 1; break; }
}
if (has_tms) {
/* Mixed TMS+TDI shift: 2 bits per clock (TDI low, TMS high), LSB-first. */
int nbytes_snd = (2 * size + 7) / 8;
if (nbytes_snd > (int)sizeof(buf_snd) || (size + 7) / 8 > (int)sizeof(buf_rcv)) {
jtagcore_logs_printf(jc, MSG_ERROR,
"drv_Digilent_TDOTDI_xfer : size %d too large\r\n", size);
return JTAG_CORE_BAD_PARAMETER;
if (str_in) {
buf_rcv = calloc(1, (size_t)((size + 7) / 8));
if (!buf_rcv) return JTAG_CORE_BAD_PARAMETER;
}
memset(buf_snd, 0, nbytes_snd);
/* PutTmsTdiBits packs 2 bits/clock, PutTdiBits 1 bit/clock. Buffers
* are heap-sized to the shift (bitstream loads run into MB). */
snd_bytes = has_tms ? (2 * size + 7) / 8 : (size + 7) / 8;
buf_snd = calloc(1, (size_t)snd_bytes);
if (!buf_snd) { free(buf_rcv); return JTAG_CORE_BAD_PARAMETER; }
if (has_tms) {
/* 2 bits per clock: TDI low, TMS high, LSB-first. */
for (i = 0; i < size; i++) {
int pos = 2 * i;
if (str_out[i] & JTAG_STR_DOUT)
buf_snd[pos >> 3] |= (DJ_BYTE)(1u << (pos & 7)); /* TDI = low bit */
buf_snd[pos >> 3] |= (DJ_BYTE)(1u << (pos & 7));
pos++;
if (str_out[i] & JTAG_STR_TMS)
buf_snd[pos >> 3] |= (DJ_BYTE)(1u << (pos & 7)); /* TMS = high bit */
}
if (!g_dj.PutTmsTdiBits(g_dj_hif, buf_snd, str_in ? buf_rcv : NULL,
(DJ_DWORD)size, /*fOverlap=*/0)) {
jtagcore_logs_printf(jc, MSG_ERROR,
"drv_Digilent_TDOTDI_xfer : DjtgPutTmsTdiBits failed\r\n");
return JTAG_CORE_BAD_PARAMETER;
buf_snd[pos >> 3] |= (DJ_BYTE)(1u << (pos & 7));
}
ok = g_dj.PutTmsTdiBits(g_dj_hif, buf_snd, buf_rcv, (DJ_DWORD)size, /*fOverlap=*/0);
} else {
/* Pure data shift: TMS held to 0, 1 bit per clock. */
int nbytes_snd = (size + 7) / 8;
if (nbytes_snd > (int)sizeof(buf_rcv)) {
jtagcore_logs_printf(jc, MSG_ERROR,
"drv_Digilent_TDOTDI_xfer : size %d too large\r\n", size);
return JTAG_CORE_BAD_PARAMETER;
}
memset(buf_snd, 0, nbytes_snd);
for (i = 0; i < size; i++) {
if (str_out[i] & JTAG_STR_DOUT)
buf_snd[i >> 3] |= (DJ_BYTE)(1u << (i & 7));
}
if (!g_dj.PutTdiBits(g_dj_hif, /*fTms=*/0, buf_snd, str_in ? buf_rcv : NULL,
(DJ_DWORD)size, /*fOverlap=*/0)) {
jtagcore_logs_printf(jc, MSG_ERROR,
"drv_Digilent_TDOTDI_xfer : DjtgPutTdiBits failed\r\n");
return JTAG_CORE_BAD_PARAMETER;
ok = g_dj.PutTdiBits(g_dj_hif, /*fTms=*/0, buf_snd, buf_rcv, (DJ_DWORD)size, /*fOverlap=*/0);
}
free(buf_snd);
if (!ok) {
free(buf_rcv);
jtagcore_logs_printf(jc, MSG_ERROR,
"drv_Digilent_TDOTDI_xfer : Djtg shift failed (size %d)\r\n", size);
return JTAG_CORE_BAD_PARAMETER;
}
if (str_in) {
for (i = 0; i < size; i++) {
str_in[i] = (buf_rcv[i >> 3] & (1u << (i & 7))) ? JTAG_STR_DOUT : 0;
}
free(buf_rcv);
}
return JTAG_CORE_NO_ERROR;
}