split "interface" commands from "jtag" ones

We'll need to be able to work with debug adapter interfaces (drivers)
even when they're not used for JTAG ... for example, while there are
multi-transport drivers which support JTAG *and* several other
transports (or just one more, like SWD) there are also adapters
with more limited goals (and no JTAG support at all).

Start decoupling the two concepts ("debug adapter driver", "jtag")
by having two command groups, which initialize separately.

This will help us support OpenOCD sessions using only non-JTAG
transports, in which JTAG commands should not be registered.
Update docs to mention that the JTAG, SVF, and XSVF commands
won't work without a JTAG transport.

Note that at least commands working with SRST are still inappropriately
coupled  to JTAG ... inappropriate because (a) SRST is not part of the
JTAG standard, for all that many platforms (like ARM) expect it; and also
(b) because they're used with non-JTAG debug and programming interfaces,
too.  They should perhaps become generic "interface" operations at some
point.  (Similarly with the clock rate to be used by a given adapter.)

Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>

4 files changed, 31 insertions, 5 deletions

diff --git a/doc/openocd.texi b/doc/openocd.texi
index f9f9b68e..33c442f6 100644
--- a/doc/openocd.texi
+++ b/doc/openocd.texi
@@ -6641,6 +6641,8 @@ the order of TAP state transitions.
 If you're not debugging OpenOCD internals, or bringing up a
 new JTAG adapter or a new type of TAP device (like a CPU or
 JTAG router), you probably won't need to use these commands.
+In a debug session that doesn't use JTAG for its transport protocol,
+these commands are not available.
 
 @deffn Command {drscan} tap [numbits value]+ [@option{-endstate} tap_state]
 Loads the data register of @var{tap} with a series of bit fields
@@ -6831,6 +6833,7 @@ OpenOCD also includes some boundary scan commands.
 
 The Serial Vector Format, better known as @dfn{SVF}, is a
 way to represent JTAG test patterns in text files.
+In a debug session using JTAG for its transport protocol,
 OpenOCD supports running such test files.
 
 @deffn Command {svf} filename [@option{quiet}]
@@ -6847,6 +6850,7 @@ each command is logged before it is executed.
 The Xilinx Serial Vector Format, better known as @dfn{XSVF}, is a
 binary representation of SVF which is optimized for use with
 Xilinx devices.
+In a debug session using JTAG for its transport protocol,
 OpenOCD supports running such test files.
 
 @quotation Important
diff --git a/src/jtag/driver.h b/src/jtag/driver.h
new file mode 100644
index 00000000..62cda414
--- /dev/null
+++ b/src/jtag/driver.h
@@ -0,0 +1,4 @@
+struct command_context;
+
+int interface_register_commands(struct command_context *ctx);
+
diff --git a/src/jtag/tcl.c b/src/jtag/tcl.c
index 1073abc0..3ffa930d 100644
--- a/src/jtag/tcl.c
+++ b/src/jtag/tcl.c
@@ -985,7 +985,7 @@ COMMAND_HANDLER(handle_interface_list_command)
 	if (strcmp(CMD_NAME, "interface_list") == 0 && CMD_ARGC > 0)
 		return ERROR_COMMAND_SYNTAX_ERROR;
 
-	command_print(CMD_CTX, "The following JTAG interfaces are available:");
+	command_print(CMD_CTX, "The following debug interfaces are available:");
 	for (unsigned i = 0; NULL != jtag_interfaces[i]; i++)
 	{
 		const char *name = jtag_interfaces[i]->name;
@@ -1038,7 +1038,7 @@ COMMAND_HANDLER(handle_interface_command)
 	/* no valid interface was found (i.e. the configuration option,
 	 * didn't match one of the compiled-in interfaces
 	 */
-	LOG_ERROR("The specified JTAG interface was not found (%s)", CMD_ARGV[0]);
+	LOG_ERROR("The specified debug interface was not found (%s)", CMD_ARGV[0]);
 	CALL_COMMAND_HANDLER(handle_interface_list_command);
 	return ERROR_JTAG_INVALID_INTERFACE;
 }
@@ -1607,20 +1607,35 @@ COMMAND_HANDLER(handle_tms_sequence_command)
 	return ERROR_OK;
 }
 
-static const struct command_registration jtag_command_handlers[] = {
+static const struct command_registration interface_command_handlers[] = {
 	{
 		.name = "interface",
 		.handler = handle_interface_command,
 		.mode = COMMAND_CONFIG,
-		.help = "Select a JTAG interface",
+		.help = "Select a debug adapter interface (driver)",
 		.usage = "driver_name",
 	},
 	{
 		.name = "interface_list",
 		.handler = handle_interface_list_command,
 		.mode = COMMAND_ANY,
-		.help = "List all built-in interfaces",
+		.help = "List all built-in debug adapter interfaces (drivers)",
 	},
+	COMMAND_REGISTRATION_DONE
+};
+
+/**
+ * Register the commands which deal with arbitrary debug adapter drivers.
+ *
+ * @todo Remove internal assumptions that all debug adapters use JTAG for
+ * transport.  Various types and data structures are not named generically.
+ */
+int interface_register_commands(struct command_context *ctx)
+{
+	return register_commands(ctx, NULL, interface_command_handlers);
+}
+
+static const struct command_registration jtag_command_handlers[] = {
 	{
 		.name = "jtag_khz",
 		.handler = handle_jtag_khz_command,
@@ -1746,6 +1761,7 @@ static const struct command_registration jtag_command_handlers[] = {
 	},
 	COMMAND_REGISTRATION_DONE
 };
+
 int jtag_register_commands(struct command_context *cmd_ctx)
 {
 	return register_commands(cmd_ctx, NULL, jtag_command_handlers);
diff --git a/src/openocd.c b/src/openocd.c
index 78336068..42504343 100644
--- a/src/openocd.c
+++ b/src/openocd.c
@@ -29,6 +29,7 @@
 #endif
 
 #include "openocd.h"
+#include <jtag/driver.h>
 #include <jtag/jtag.h>
 #include <helper/ioutil.h>
 #include <helper/configuration.h>
@@ -207,6 +208,7 @@ struct command_context *setup_command_handler(Jim_Interp *interp)
 		&server_register_commands,
 		&gdb_register_commands,
 		&log_register_commands,
+		&interface_register_commands,
 		&jtag_register_commands,
 		&xsvf_register_commands,
 		&svf_register_commands,