arm11: add etmr/etmw registers to access ETM via DBGTAP scan chain

First cut of these commands. Øyvind tinkered a bit with
the number parsing to bring it up to speed + rebased it.
Ready for testing.

Signed-off-by: Øyvind Harboe <oyvind.harboe@zylin.com>

src/target/arm11.c

@@ -2143,6 +2143,59 @@ static int arm11_mcr(target_t *target, int cpnum,
 	return arm11_mrc_inner(target, cpnum, op1, op2, CRn, CRm, &value, false);
 }
 
+static int arm11_handle_etm_read_write(struct command_context_s *cmd_ctx, char *cmd, char **args, int argc, bool read)
+{
+	if (argc != (read ? 2 : 3))
+	{
+		LOG_ERROR("Invalid number of arguments.");
+		return ERROR_COMMAND_SYNTAX_ERROR;
+	}
+
+	arm11_common_t * arm11 = arm11_find_target(args[0]);
+
+	if (!arm11)
+	{
+		LOG_ERROR("Parameter 1 is not the target name of an ARM11 device.");
+		return ERROR_COMMAND_SYNTAX_ERROR;
+	}
+
+	uint32_t address;
+	COMMAND_PARSE_NUMBER(u32, args[1], address);
+
+	if (!read)
+	{
+		uint32_t value;
+		COMMAND_PARSE_NUMBER(u32, args[2], value);
+
+		LOG_INFO("ETM write register 0x%02" PRIx32 " (%" PRId32 ") = 0x%08" PRIx32 " (%" PRId32 ")",
+		  address, address, value, value);
+
+		CHECK_RETVAL(arm11_write_etm(arm11, address, value));
+	}
+	else
+	{
+		uint32_t value;
+
+		CHECK_RETVAL(arm11_read_etm(arm11, address, &value));
+
+	    LOG_INFO("ETM read register 0x%02" PRIx32 " (%" PRId32 ") = 0x%08" PRIx32 " (%" PRId32 ")",
+		  address, address, value, value);
+	}
+
+	return ERROR_OK;
+}
+
+int arm11_handle_etmr(struct command_context_s *cmd_ctx, char *cmd, char **args, int argc)
+{
+	return arm11_handle_etm_read_write(cmd_ctx, cmd, args, argc, true);
+}
+
+int arm11_handle_etmw(struct command_context_s *cmd_ctx, char *cmd, char **args, int argc)
+{
+	return arm11_handle_etm_read_write(cmd_ctx, cmd, args, argc, false);
+}
+
+
 #define ARM11_HANDLER(x)	.x = arm11_##x
 
 target_type_t arm11_target = {
@@ -2196,6 +2249,14 @@ int arm11_register_commands(struct command_context_s *cmd_ctx)
 	top_cmd = register_command(cmd_ctx, NULL, "arm11",
 			NULL, COMMAND_ANY, NULL);
 
+	register_command(cmd_ctx, top_cmd, "etmr",
+			arm11_handle_etmr, COMMAND_ANY,
+			"Read Embedded Trace Macrocell (ETM) register. etmr <jtag_target> <ETM register address>");
+
+	register_command(cmd_ctx, top_cmd, "etmw",
+			arm11_handle_etmw, COMMAND_ANY,
+			"Write Embedded Trace Macrocell (ETM) register. etmr <jtag_target> <ETM register address> <value>");
+
 	/* "hardware_step" is only here to check if the default
 	 * simulate + breakpoint implementation is broken.
 	 * TEMPORARY! NOT DOCUMENTED!

src/target/arm11.h

@@ -184,4 +184,9 @@ typedef struct arm11_reg_state_s
 
 int arm11_register_commands(struct command_context_s *cmd_ctx);
 
+int arm11_read_etm(arm11_common_t * arm11, uint8_t address, uint32_t *value);
+int arm11_write_etm(arm11_common_t * arm11, uint8_t address, uint32_t value);
+
+
+
 #endif /* ARM11_H */

src/target/arm11_dbgtap.c

@@ -940,3 +940,79 @@ int arm11_read_memory_word(arm11_common_t * arm11, uint32_t address, uint32_t *
 }
 
 
+/** Write Embedded Trace Macrocell (ETM) via Scan chain 6
+ *
+ * http://infocenter.arm.com/help/topic/com.arm.doc.ddi0318e/Bcfddjeh.html#Bcfggcbe
+ *
+ * \param arm11		Target state variable.
+ * \param address	7 bit ETM register address
+ * \param value		Value to be written
+ *					
+ * \return			Error status
+ *
+ * \remarks			This is a stand-alone function that executes the JTAG command queue.
+ */
+int arm11_write_etm(arm11_common_t * arm11, uint8_t address, uint32_t value)
+{
+	CHECK_RETVAL(arm11_add_debug_SCAN_N(arm11, 0x06, ARM11_TAP_DEFAULT));
+
+	/* Uses INTEST for read and write */
+	arm11_add_IR(arm11, ARM11_INTEST, ARM11_TAP_DEFAULT);
+
+	scan_field_t		chain6_fields[3];
+
+	uint8_t				nRW			= 1;
+
+	arm11_setup_field(arm11, 32, &value,		NULL,		chain6_fields + 0);
+	arm11_setup_field(arm11,  7, &address,		NULL,		chain6_fields + 1);
+	arm11_setup_field(arm11,  1, &nRW,			NULL,		chain6_fields + 2);
+
+	arm11_add_dr_scan_vc(asizeof(chain6_fields), chain6_fields, TAP_IDLE);
+
+	CHECK_RETVAL(jtag_execute_queue());
+
+	return ERROR_OK;
+}
+
+/** Read Embedded Trace Macrocell (ETM) via Scan chain 6
+ *
+ * http://infocenter.arm.com/help/topic/com.arm.doc.ddi0318e/Bcfddjeh.html#Bcfggcbe
+ *
+ * \param arm11		Target state variable.
+ * \param address	7 bit ETM register address
+ * \param value		Pointer that receives value that was read
+ *					
+ * \return			Error status
+ *
+ * \remarks			This is a stand-alone function that executes the JTAG command queue.
+ */
+int arm11_read_etm(arm11_common_t * arm11, uint8_t address, uint32_t * value)
+{
+	CHECK_RETVAL(arm11_add_debug_SCAN_N(arm11, 0x06, ARM11_TAP_DEFAULT));
+
+	/* Uses INTEST for read and write */
+	arm11_add_IR(arm11, ARM11_INTEST, ARM11_TAP_DEFAULT);
+
+	scan_field_t		chain6_fields[3];
+
+	uint8_t				nRW			= 0;
+
+	arm11_setup_field(arm11, 32, NULL,			NULL,		chain6_fields + 0);
+	arm11_setup_field(arm11,  7, &address,		NULL,		chain6_fields + 1);
+	arm11_setup_field(arm11,  1, &nRW,			NULL,		chain6_fields + 2);
+
+	arm11_add_dr_scan_vc(asizeof(chain6_fields), chain6_fields, TAP_IDLE);
+
+	/* Data is made available in Capture-DR and shifted out on the next access */
+
+	arm11_setup_field(arm11, 32, NULL,			value,		chain6_fields + 0);
+	arm11_setup_field(arm11,  7, &address,		NULL,		chain6_fields + 1);
+	arm11_setup_field(arm11,  1, &nRW,			NULL,		chain6_fields + 2);
+
+	arm11_add_dr_scan_vc(asizeof(chain6_fields), chain6_fields, TAP_IDLE);
+
+	CHECK_RETVAL(jtag_execute_queue());
+
+	return ERROR_OK;
+}
+