Feature: Initial RISC-V debug support (v0.13 spec)

src/Makefile

@@ -3,6 +3,7 @@ PLATFORM_DIR = platforms/$(PROBE_HOST)
 VPATH += $(PLATFORM_DIR) target
 ENABLE_DEBUG ?= 0
 ENABLE_CORTEXAR ?= 0
+ENABLE_RISCV ?= 0
 
 SYS = $(shell $(CC) -dumpmachine)
 
@@ -94,6 +95,15 @@ CFLAGS += -DENABLE_CORTEXAR
 SRC += cortexar.c
 endif
 
+ifeq ($(ENABLE_RISCV), 1)
+CFLAGS += -DENABLE_RISCV
+SRC +=               \
+	riscv32.c        \
+	riscv64.c        \
+	riscv_debug.c    \
+	riscv_jtag_dtm.c
+endif
+
 ifneq ($(PC_HOSTED),1)
 # Output memory usage information
 LDFLAGS += -Wl,--print-memory-usage

src/gdb_main.c

@@ -721,10 +721,13 @@ static void handle_z_packet(char *packet, const size_t plen)
 	else
 		ret = target_breakwatch_clear(cur_target, type, addr, len);
 
+	/* If the target handler was unable to set/clear the break/watch-point, return an error */
 	if (ret < 0)
 		gdb_putpacketz("E01");
+	/* If the handler does not support the kind requested, return empty string */
 	else if (ret > 0)
 		gdb_putpacketz("");
+	/* Otherwise let GDB know that everything went well */
 	else
 		gdb_putpacketz("OK");
 }

src/platforms/hosted/Makefile.inc

@@ -6,6 +6,7 @@ CFLAGS += -DENABLE_DEBUG -DPLATFORM_HAS_DEBUG
 CFLAGS +=-I ./target
 
 ENABLE_CORTEXAR := 1
+ENABLE_RISCV := 1
 
 # Clang requires some special handling here: -gnu means MinGW
 # while -msvc means Clang/CL. We don't currently support the latter

src/target/adiv5.h

@@ -207,6 +207,11 @@
 #define JTAG_IDCODE_PARTNO_MASK     (0xffffU << JTAG_IDCODE_PARTNO_OFFSET)
 #define JTAG_IDCODE_DESIGNER_OFFSET 1U
 #define JTAG_IDCODE_DESIGNER_MASK   (0x7ffU << JTAG_IDCODE_DESIGNER_OFFSET)
+/* Bits 10:7 - JEP-106 Continuation code */
+/* Bits 6:0 - JEP-106 Identity code */
+#define JTAG_IDCODE_DESIGNER_JEP106_CONT_OFFSET 7U
+#define JTAG_IDCODE_DESIGNER_JEP106_CONT_MASK   (0xfU << ADIV5_DP_DESIGNER_JEP106_CONT_OFFSET)
+#define JTAG_IDCODE_DESIGNER_JEP106_CODE_MASK   (0x7fU)
 
 #define JTAG_IDCODE_PARTNO_DPv0 0xba00U
 

src/target/jtag_devs.c

@@ -22,6 +22,7 @@
 #include "general.h"
 #include "jtag_scan.h"
 #include "adiv5.h"
+#include "riscv_debug.h"
 #include "jtag_devs.h"
 
 const jtag_dev_descr_s dev_descr[] = {
@@ -349,9 +350,10 @@ const jtag_dev_descr_s dev_descr[] = {
 	},
 #ifdef ENABLE_DEBUG
 	{
-		.idcode = 0x0000063dU,
-		.idmask = 0x00000fffU,
-		.descr = "Xambala: RVDBG013.",
+		.idcode = 0x0000563dU,
+		.idmask = 0x0fffffffU,
+		.descr = "RISC-V debug v0.13.",
+		.handler = riscv_jtag_dtm_handler,
 	},
 	{
 		.idcode = 0x000007a3U,