Files
bs_explorer/modules/bscan/bscan.h
François 37efccaf50 bscan: rename from bscan_spi, add TAP primitives for the SVF player
The module outgrew its "SPI bridge" name — it's mostly generic
single-device JTAG TAP primitives now. Rename modules/bscan_spi ->
modules/bscan (dir, files, library target, includes, doc paths);
bscan_* function names and bscan_spi_xfer() kept.

Add the two primitives the SVF player needs beyond shift_dr:
- bscan_shift_ir: general IR scan with TDO capture (bscan_set_ir is
  opcode-only, no readback)
- bscan_tap_reset: force Test-Logic-Reset, land in Run-Test/Idle

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>
2026-05-24 12:00:38 +02:00

70 lines
2.9 KiB
C

#ifndef _BSCAN_H
#define _BSCAN_H
/*
* Single-device JTAG primitives and BSCAN-proxy operations.
*
* Provides:
* - low-level JTAG TAP primitives (set_ir, shift_ir, shift_dr,
* idle_cycles, tap_reset) that operate directly on jc->io_functions,
* leaving jtag_core untouched. These are the building blocks the SVF
* player and the proxy paths share;
* - bitstream loading via CFG_IN to install a BSCAN proxy in the FPGA
* fabric (Xilinx);
* - a fast SPI transfer routine via USER1 once the proxy is loaded.
*
* (Was modules/bscan_spi/ — renamed once it grew past the SPI bridge
* into general TAP primitives.)
*
* Current assumption: single device on the JTAG chain. Multi-device
* support requires knowing the IR length of bypassed devices; defer.
*/
#include <stddef.h>
#include <stdint.h>
#include "jtag_core/jtag_core.h"
#include "fpga/fpga.h"
/* --- Low-level primitives (single-device chain) -------------------- */
/* Shift `opcode` into IR. `ir_length` is the IR width in bits. */
int bscan_set_ir(jtag_core *jc, unsigned int opcode, int ir_length);
/* Shift `nbits` through DR. `tdi` may be NULL (shifts zeros).
* `tdo` may be NULL (write only). Both buffers are LSB-first per byte. */
int bscan_shift_dr(jtag_core *jc, const uint8_t *tdi, uint8_t *tdo, int nbits);
/* Like bscan_shift_dr but through Shift-IR — a general IR scan with TDO
* capture (bscan_set_ir is opcode-only). Single-device chain; buffers
* LSB-first per byte. Both ends in Run-Test/Idle. */
int bscan_shift_ir(jtag_core *jc, const uint8_t *tdi, uint8_t *tdo, int nbits);
/* Emit `ncycles` TCK cycles while staying in Run-Test/Idle. */
int bscan_idle_cycles(jtag_core *jc, int ncycles);
/* --- High-level operations ---------------------------------------- */
/* Load a raw bitstream payload (no .bit container header) into the
* FPGA via JPROGRAM -> CFG_IN -> shift -> JSTART. Bit-reverses each
* byte before shifting (Xilinx convention). */
int bscan_load_bitstream(jtag_core *jc, const fpga_target *t,
const uint8_t *data, size_t nbytes);
/* Convenience wrapper: read a file and load it. Detects the Xilinx
* .bit header and skips it; otherwise treats the file as raw payload. */
int bscan_load_bitstream_file(jtag_core *jc, const fpga_target *t,
const char *path);
/* One CS-framed SPI transaction through the BSCAN proxy (USER1 DR):
* clock out `txlen` MOSI bytes (e.g. command + address + write data),
* then read `rxlen` MISO bytes into `rx`. Either length may be 0.
* Bytes are MSB-first on the wire; bit-order juggling is internal.
* Follows the quartiq/OpenOCD jtagspi proxy framing. Single-device
* chain only. Requires a proxy bitstream already loaded (USER1 live). */
int bscan_spi_xfer(jtag_core *jc, const fpga_target *t,
const uint8_t *tx, size_t txlen,
uint8_t *rx, size_t rxlen);
#endif