digilent: add driver skeleton + CMake option BS_ENABLE_DIGILENT

Stub Digilent JTAG-SMT backend, off by default. Wiring only: option,
conditional sources, dl link, drivers_list registration. Detect()
returns 0 for now; dlopen + real implementation in follow-up commits.

CMakeLists.txt

@@ -2,6 +2,11 @@ cmake_minimum_required(VERSION 3.10)
 
 project(BoundaryScanExplorer)
 
+# Optional backends. Off by default: no proprietary runtime dependency.
+option(BS_ENABLE_DIGILENT
+       "Enable Digilent JTAG-SMT* backend (dlopen libdjtg.so / libdmgr.so at runtime; requires Adept Runtime installed)"
+       OFF)
+
 # script and jtag_core must be the last linked archive for the application to compile
 set(BS_MODULES script jtag_core)
 set(DIR_MODULES ${CMAKE_SOURCE_DIR}/modules)

modules/drivers/CMakeLists.txt

@@ -5,10 +5,20 @@ file(GLOB_RECURSE JLINK_SOURCES "jlink_jtag/*.c")
 file(GLOB_RECURSE FTDI_SOURCES "ftdi_jtag/*.c")
 file(GLOB_RECURSE GPIO_SOURCES "linux_gpio_jtag/*.c")
 
+set(DIGILENT_SOURCES "")
+if(BS_ENABLE_DIGILENT)
+    file(GLOB_RECURSE DIGILENT_SOURCES "digilent_jtag/*.c")
+    add_compile_definitions(BS_ENABLE_DIGILENT)
+endif()
+
 include_directories(${DIR_MODULES})
 include_directories(${DIR_LIBS})
 
 add_compile_definitions(FTD2XX_STATIC)
 add_compile_definitions(FTDILIB)
 
-add_library(drivers ${MAIN_SOURCES} ${FTDI_SOURCES} ${GPIO_SOURCES} ${JLINK_SOURCES})
+add_library(drivers ${MAIN_SOURCES} ${FTDI_SOURCES} ${GPIO_SOURCES} ${JLINK_SOURCES} ${DIGILENT_SOURCES})
+
+if(BS_ENABLE_DIGILENT)
+    target_link_libraries(drivers PUBLIC ${CMAKE_DL_LIBS})
+endif()

modules/drivers/digilent_jtag/digilent_jtag_drv.c

@@ -0,0 +1,92 @@
+/*
+ * Boundary-Scan Explorer - Digilent JTAG-SMT* driver (skeleton)
+ *
+ * Step 1: build wiring + driver registration only. Detect() returns 0,
+ * Init() returns an error. Real implementation lands in subsequent steps.
+ */
+
+#include <stdio.h>
+#include <string.h>
+
+#include "jtag_core/jtag_core.h"
+#include "jtag_core/dbg_logs.h"
+#include "config/bs_defines.h"
+
+#include "drivers/drv_loader.h"
+
+#include "digilent_jtag_drv.h"
+
+#define MAX_PROBES_DIGILENT 8
+
+typedef struct _digilent_drv_desc
+{
+    char drv_id[64];
+    char drv_desc[128];
+    int  sub_drv_id;
+} digilent_drv_desc;
+
+static digilent_drv_desc subdrv_list[MAX_PROBES_DIGILENT] = {
+    {"DIGILENT_SMT_PROBE", "DIGILENT JTAG-SMT PROBE", 0},
+    {"DIGILENT_SMT_PROBE", "DIGILENT JTAG-SMT PROBE", 0},
+    {"DIGILENT_SMT_PROBE", "DIGILENT JTAG-SMT PROBE", 0},
+    {"DIGILENT_SMT_PROBE", "DIGILENT JTAG-SMT PROBE", 0},
+    {"DIGILENT_SMT_PROBE", "DIGILENT JTAG-SMT PROBE", 0},
+    {"DIGILENT_SMT_PROBE", "DIGILENT JTAG-SMT PROBE", 0},
+    {"DIGILENT_SMT_PROBE", "DIGILENT JTAG-SMT PROBE", 0},
+    {"DIGILENT_SMT_PROBE", "DIGILENT JTAG-SMT PROBE", 0},
+};
+
+static int drv_Digilent_Detect(jtag_core * jc)
+{
+    /* Step 2 will populate subdrv_list via DmgrEnumDevices. */
+    return 0;
+}
+
+static int drv_Digilent_Init(jtag_core * jc, int sub_drv, char * params)
+{
+    jtagcore_logs_printf(jc, MSG_ERROR,
+        "drv_Digilent_Init : Digilent backend not yet implemented\r\n");
+    return -1;
+}
+
+static int drv_Digilent_DeInit(jtag_core * jc)
+{
+    return 0;
+}
+
+static int drv_Digilent_TMS_xfer(jtag_core * jc, unsigned char * str_out, int size)
+{
+    return -1;
+}
+
+static int drv_Digilent_TDOTDI_xfer(jtag_core * jc,
+                                    unsigned char * str_out,
+                                    unsigned char * str_in,
+                                    int size)
+{
+    return -1;
+}
+
+int drv_Digilent_libGetDrv(jtag_core * jc, int sub_drv, unsigned int infotype, void * returnvalue)
+{
+    drv_ptr drv_funcs = {
+        (DRV_DETECT)         drv_Digilent_Detect,
+        (DRV_INIT)           drv_Digilent_Init,
+        (DRV_DEINIT)         drv_Digilent_DeInit,
+        (DRV_TXTMS)          drv_Digilent_TMS_xfer,
+        (DRV_TXRXDATA)       drv_Digilent_TDOTDI_xfer,
+        (DRV_GETMODULEINFOS) drv_Digilent_libGetDrv,
+    };
+
+    if (sub_drv < 0 || sub_drv >= MAX_PROBES_DIGILENT)
+        return JTAG_CORE_BAD_PARAMETER;
+
+    return GetDrvInfo(
+        jc,
+        infotype,
+        returnvalue,
+        subdrv_list[sub_drv].drv_id,
+        subdrv_list[sub_drv].drv_desc,
+        &drv_funcs
+    );
+}

modules/drivers/digilent_jtag/digilent_jtag_drv.h

@@ -0,0 +1,18 @@
+#ifndef _DIGILENT_JTAG_DRV_H
+#define _DIGILENT_JTAG_DRV_H
+/*
+ * Boundary-Scan Explorer - Digilent JTAG-SMT* driver
+ *
+ * Talks to Digilent JTAG modules (SMT2, SMT2-NC, SMT3, ...) through
+ * dlopen of libdjtg.so / libdmgr.so at runtime. No Digilent binary or
+ * header is embedded in this repository; the typedefs in djtg_dlsym.h
+ * are hand-rolled from the public Adept API.
+ *
+ * Enabled with -DBS_ENABLE_DIGILENT=ON at CMake configure time.
+ */
+
+#include "jtag_core/jtag_core.h"
+
+int drv_Digilent_libGetDrv(jtag_core * jc, int sub_drv, unsigned int infotype, void * returnvalue);
+
+#endif

modules/drivers/drivers_list.c

@@ -40,6 +40,10 @@
 #include "./jlink_jtag/jlink_jtag_drv.h"
 #endif
 
+#ifdef BS_ENABLE_DIGILENT
+#include "./digilent_jtag/digilent_jtag_drv.h"
+#endif
+
 #include "drivers_list.h"
 
 const drv_entry staticdrvs[] =
@@ -57,6 +61,9 @@ const drv_entry staticdrvs[] =
 #endif
 #if defined(__linux__)
 	{(DRV_GETMODULEINFOS)drv_LinuxGPIO_libGetDrv,0},
+#endif
+#ifdef BS_ENABLE_DIGILENT
+	{(DRV_GETMODULEINFOS)drv_Digilent_libGetDrv,0},
 #endif
 	{(DRV_GETMODULEINFOS)-1,0}
 };