target/riscv: Add support for external triggers

doc/openocd.texi

@@ -11673,6 +11673,20 @@ The second argument configures how OpenOCD should use the selected trigger featu
 With no parameters, prints current trigger features configuration.
 @end deffn
 
+@deffn {Command} {riscv set_group} grouptype group ['trigger' triggernum]
+OpenOCD assigns a hart or a given external trigger into a RISC-V halt group.
+This command associates current target or supplied external trigger(s) with this halt group.
+
+@option{trigger} and @var{triggernum} Specify the index of the external trigger.
+When an external input trigger fires, the harts in the halt group will get halted.
+Similarly, all external output triggers will be notified when a hart in the halt group halts.
+
+The only supported value of @var{grouptype} is @option{halt_group}. RISC-V resume groups
+are not allowed because the concept of a target resuming due to a different reason than
+user's resume request is not supported by OpenOCD and GDB.
+@end deffn
+
+
 @subsection RISC-V Authentication Commands
 
 The following commands can be used to authenticate to a RISC-V system. Eg.  a

src/target/riscv/riscv-013.c

@@ -68,12 +68,8 @@ static int riscv013_access_memory(struct target *target, const riscv_mem_access_
 static bool riscv013_get_impebreak(const struct target *target);
 static unsigned int riscv013_get_progbufsize(const struct target *target);
 
-typedef enum {
-	HALT_GROUP,
-	RESUME_GROUP
-} grouptype_t;
 static int set_group(struct target *target, bool *supported, unsigned int group,
-		grouptype_t grouptype);
+		enum grouptype grouptype, bool is_trigger, unsigned int trigger_num);
 
 /**
  * Since almost everything can be accomplish by scanning the dbus register, all
@@ -138,6 +134,8 @@ typedef struct {
 	 * abstractcs.busy may have remained set. In that case we may need to
 	 * re-check the busy state before executing these operations. */
 	bool abstract_cmd_maybe_busy;
+
+	struct riscv_ext_trigger external_triggers[RISCV_MAX_EXTTRIGGERS];
 } dm013_info_t;
 
 typedef struct {
@@ -1732,7 +1730,7 @@ static int halt_set_dcsr_ebreak(struct target *target)
 
 	if (info->haltgroup_supported) {
 		bool supported;
-		if (set_group(target, &supported, 0, HALT_GROUP) != ERROR_OK)
+		if (set_group(target, &supported, 0, HALT_GROUP, false, 0) != ERROR_OK)
 			return ERROR_FAIL;
 		if (!supported)
 			LOG_TARGET_ERROR(target, "Couldn't place hart in halt group 0. "
@@ -1754,7 +1752,7 @@ static int halt_set_dcsr_ebreak(struct target *target)
 	/* Add it back to the halt group. */
 	if (info->haltgroup_supported) {
 		bool supported;
-		if (set_group(target, &supported, target->smp, HALT_GROUP) != ERROR_OK)
+		if (set_group(target, &supported, target->smp, HALT_GROUP, false, 0) != ERROR_OK)
 			return ERROR_FAIL;
 		if (!supported)
 			LOG_TARGET_ERROR(target, "Couldn't place hart back in halt group %d. "
@@ -1785,19 +1783,46 @@ static void deinit_target(struct target *target)
 }
 
 static int set_group(struct target *target, bool *supported, unsigned int group,
-		grouptype_t grouptype)
+		enum grouptype grouptype, bool is_trigger, unsigned int trigger_num)
 {
-	uint32_t write_val = DM_DMCS2_HGWRITE;
 	assert(group <= 31);
+	assert(trigger_num < 16);
+
+	if (!is_trigger && dm013_select_target(target) != ERROR_OK)
+		return ERROR_FAIL;
+
+	dm013_info_t *dm = get_dm(target);
+	if (!dm)
+		return ERROR_FAIL;
+	if (is_trigger && dm->external_triggers[trigger_num].haltgroup_was_set &&
+			dm->external_triggers[trigger_num].haltgroup_num == group) {
+		LOG_TARGET_WARNING(target, "External trigger %d (at address dbgbase=0x%" PRIx32 ") "
+				"for halt group %d has been set.", trigger_num, dm->base, group);
+		return ERROR_OK;
+	}
+
+	uint32_t write_val = DM_DMCS2_HGWRITE;
 	write_val = set_field(write_val, DM_DMCS2_GROUP, group);
 	write_val = set_field(write_val, DM_DMCS2_GROUPTYPE, (grouptype == HALT_GROUP) ? 0 : 1);
+	write_val = set_field(write_val, DM_DMCS2_DMEXTTRIGGER, trigger_num);
+	write_val = set_field(write_val, DM_DMCS2_HGSELECT,
+			    is_trigger ? DM_DMCS2_HGSELECT_TRIGGERS : DM_DMCS2_HGSELECT_HARTS);
 	if (dm_write(target, DM_DMCS2, write_val) != ERROR_OK)
 		return ERROR_FAIL;
 	uint32_t read_val;
 	if (dm_read(target, &read_val, DM_DMCS2) != ERROR_OK)
 		return ERROR_FAIL;
 	if (supported)
-		*supported = (get_field(read_val, DM_DMCS2_GROUP) == group);
+		*supported = (get_field(read_val, DM_DMCS2_GROUP) == group &&
+			get_field(read_val, DM_DMCS2_GROUPTYPE) == ((grouptype == HALT_GROUP) ? 0 : 1) &&
+			get_field(read_val, DM_DMCS2_HGSELECT) ==
+				(is_trigger ? DM_DMCS2_HGSELECT_TRIGGERS : DM_DMCS2_HGSELECT_HARTS) &&
+			get_field(read_val, DM_DMCS2_DMEXTTRIGGER) == trigger_num);
+	if (is_trigger && *supported) {
+		dm->external_triggers[trigger_num].haltgroup_was_set = true;
+		dm->external_triggers[trigger_num].haltgroup_num = group;
+	}
+
 	return ERROR_OK;
 }
 
@@ -2145,8 +2170,9 @@ static int examine(struct target *target)
 	}
 
 	if (target->smp) {
-		if (set_group(target, &info->haltgroup_supported, target->smp, HALT_GROUP) != ERROR_OK)
+		if (set_group(target, &info->haltgroup_supported, target->smp, HALT_GROUP, false, 0) != ERROR_OK)
 			return ERROR_FAIL;
+
 		if (info->haltgroup_supported)
 			LOG_TARGET_INFO(target, "Core %d made part of halt group %d.", info->index,
 					target->smp);
@@ -2881,6 +2907,8 @@ static int init_target(struct command_context *cmd_ctx,
 	generic_info->handle_became_unavailable = &handle_became_unavailable;
 	generic_info->tick = &tick;
 
+	generic_info->set_group = &set_group;
+
 	if (!generic_info->version_specific) {
 		generic_info->version_specific = calloc(1, sizeof(riscv013_info_t));
 		if (!generic_info->version_specific)

src/target/riscv/riscv.c

@@ -5588,6 +5588,76 @@ COMMAND_HANDLER(handle_riscv_virt2phys_mode)
 	return ERROR_OK;
 }
 
+COMMAND_HANDLER(riscv_set_group)
+{
+	struct target *target = get_current_target(CMD_CTX);
+	RISCV_INFO(r);
+
+	if (CMD_ARGC < 2)
+		return ERROR_COMMAND_SYNTAX_ERROR;
+
+	enum grouptype grouptype;
+	if (!strcmp("halt_group", CMD_ARGV[0])) {
+		grouptype = HALT_GROUP;
+	} else {
+		/* Ext. triggers for resume groups are not supported: neither OpenOCD nor GDB
+		 * have a concept of hart resuming on its own due to an external reason, without
+		 * an explicit resume request. */
+		LOG_ERROR("%s is not a valid argument. "
+			"The only supported group type is 'halt_group'.", CMD_ARGV[1]);
+		return ERROR_COMMAND_ARGUMENT_INVALID;
+	}
+
+	unsigned int group;
+	COMMAND_PARSE_NUMBER(uint, CMD_ARGV[1], group);
+	if (group > 31) {
+		LOG_ERROR("%d is not a valid group number - expecting a number in range 0..31.",
+			group);
+		return ERROR_COMMAND_ARGUMENT_INVALID;
+	}
+
+	if (!r->set_group) {
+		LOG_TARGET_ERROR(target, "set_group is not implemented for this target.");
+		return ERROR_FAIL;
+	}
+
+	bool is_trigger = false;
+	unsigned int trigger_num = 0;
+	switch (CMD_ARGC) {
+	case 2:
+		break;
+	case 4:
+		if (strcmp("trigger", CMD_ARGV[2]))
+			return ERROR_COMMAND_SYNTAX_ERROR;
+		is_trigger = true;
+		COMMAND_PARSE_NUMBER(uint, CMD_ARGV[3], trigger_num);
+		if (trigger_num > 15) {
+			LOG_ERROR("%d is not a valid external trigger number - expecting a number in range 0..15.",
+				trigger_num);
+			return ERROR_COMMAND_ARGUMENT_INVALID;
+		}
+		break;
+	default:
+		return ERROR_COMMAND_SYNTAX_ERROR;
+	}
+
+	bool supported;
+	if (r->set_group(target, &supported, group, grouptype, is_trigger, trigger_num) != ERROR_OK)
+		return ERROR_FAIL;
+
+	if (supported)
+		LOG_TARGET_INFO(target, "%s %d made part of halt group %d.",
+			(is_trigger ? "External trigger" : "Core"),
+			(is_trigger ? trigger_num : (unsigned int)target->coreid), group);
+	else
+		LOG_TARGET_WARNING(target, "%s %d could not be made part of halt group %d.",
+			(is_trigger ? "External trigger" : "Core"),
+			(is_trigger ? trigger_num : (unsigned int)target->coreid), group);
+
+	return ERROR_OK;
+}
+
+
 static const struct command_registration riscv_exec_command_handlers[] = {
 	{
 		.name = "dump_sample_buf",
@@ -5850,6 +5920,13 @@ static const struct command_registration riscv_exec_command_handlers[] = {
 			"When off, users need to take care of memory coherency themselves, for example by using "
 			"`riscv exec_progbuf` to execute fence or CMO instructions."
 	},
+	{
+		.name = "set_group",
+		.handler = riscv_set_group,
+		.mode = COMMAND_ANY,
+		.usage = "grouptype group ['trigger' triggernum]",
+		.help = "Set a hart or a given external trigger to the halt group."
+	},
 	COMMAND_REGISTRATION_DONE
 };
 

src/target/riscv/riscv.h

@@ -21,6 +21,7 @@ struct riscv_program;
 #define RISCV_MAX_TRIGGERS 32
 #define RISCV_MAX_HWBPS 16
 #define RISCV_MAX_DMS 100
+#define RISCV_MAX_EXTTRIGGERS 16
 
 #define DEFAULT_COMMAND_TIMEOUT_SEC 5
 
@@ -122,6 +123,11 @@ typedef struct {
 	char *name;
 } range_list_t;
 
+enum grouptype {
+	HALT_GROUP,
+	RESUME_GROUP
+};
+
 #define DTM_DTMCS_VERSION_UNKNOWN ((unsigned int)-1)
 #define RISCV_TINFO_VERSION_UNKNOWN (-1)
 
@@ -144,6 +150,17 @@ typedef struct riscv_mem_access_args {
 	uint32_t increment;
 } riscv_mem_access_args_t;
 
+struct riscv_ext_trigger {
+	bool haltgroup_was_set;
+	unsigned int haltgroup_num;
+	/*
+	In future, this can be added:
+
+	bool resumegroup_was_set;
+	unsigned int resumegroup_num;
+	 */
+};
+
 static inline bool
 riscv_mem_access_is_valid(const riscv_mem_access_args_t args)
 {
@@ -307,6 +324,9 @@ struct riscv_info {
 
 	unsigned int (*data_bits)(struct target *target);
 
+	int (*set_group)(struct target *target, bool *supported, unsigned int group,
+		enum grouptype grouptype, bool is_trigger, unsigned int trigger_num);
+
 	COMMAND_HELPER((*print_info), struct target *target);
 
 	/* Storage for arch_info of non-custom registers. */