int (*register_commands)(struct command_context_s *cmd_ctx);
int (*init)(void);
int (*quit)(void);
+ /* returns JTAG maxium speed for KHz. 0=RTCK. The function returns
+ a failure if it can't support the KHz/RTCK. */
+ int (*khz)(int khz, int *jtag_speed);
} jtag_interface_t;
extern int jtag_init(struct command_context_s *cmd_ctx);
extern int jtag_register_commands(struct command_context_s *cmd_ctx);
-/* JTAG interface, can be implemented with a software or hardware fifo */
+/* JTAG interface, can be implemented with a software or hardware fifo
+ *
+ * TAP_SD and TAP_SI are illegal end states. TAP_SD/SI as end states
+ * can be emulated by using a larger scan.
+ *
+ * Code that is relatively insensitive to the path(as long
+ * as it is JTAG compliant) taken through state machine can use
+ * endstate for jtag_add_xxx_scan(). Otherwise the pause state must be
+ * specified as end state and a subsequent jtag_add_pathmove() must
+ * be issued.
+ *
+ */
extern void jtag_add_ir_scan(int num_fields, scan_field_t *fields, enum tap_state endstate);
extern int interface_jtag_add_ir_scan(int num_fields, scan_field_t *fields, enum tap_state endstate);
extern void jtag_add_dr_scan(int num_fields, scan_field_t *fields, enum tap_state endstate);
extern int interface_jtag_add_plain_ir_scan(int num_fields, scan_field_t *fields, enum tap_state endstate);
extern void jtag_add_plain_dr_scan(int num_fields, scan_field_t *fields, enum tap_state endstate);
extern int interface_jtag_add_plain_dr_scan(int num_fields, scan_field_t *fields, enum tap_state endstate);
-/* execute a state transition within the JTAG standard, but the exact path
- * path that is taken is undefined. Many implementations use precisely
- * 7 clocks to perform a transition, but it could be more or less
- * than that.
- *
- * The following assertions are made about certain common state moves:
- *
- * - A state move from Pause-[ID]R to Pause-[ID]R should always go through
- * Update-[ID]R and Capture-[ID]R before returning to Pause-[ID]R, otherwise
- * there's no way force a register update, if you can't go to Run-Test/Idle for
- * some reason.
+/* run a TAP_TLR reset. End state is TAP_TLR, regardless
+ * of start state.
+ */
+extern void jtag_add_tlr();
+extern int interface_jtag_add_tlr();
+/* Do not use jtag_add_pathmove() unless you need to, but do use it
+ * if you have to.
*
- * - A state move from Pause-[ID]R to Shift-[ID]R must not go through
- * Update-[ID]R.
+ * DANGER! If the target is dependent upon a particular sequence
+ * of transitions for things to work correctly(e.g. as a workaround
+ * for an errata that contradicts the JTAG standard), then pathmove
+ * must be used, even if some jtag interfaces happen to use the
+ * desired path. Worse, the jtag interface used for testing a
+ * particular implementation, could happen to use the "desired"
+ * path when transitioning to/from end
+ * state.
*
- * - Run-Test/Idle must not be entered unless requested, because R-T/I may have
- * side effects.
- *
- * NB! a jtag_add_statemove() to the current state is not
- * a no-operation.
- */
-extern void jtag_add_statemove(enum tap_state endstate);
-extern int interface_jtag_add_statemove(enum tap_state endstate);
-/* A list of unambigious single clock state transitions, not
+ * A list of unambigious single clock state transitions, not
* all drivers can support this, but it is required for e.g.
* XScale and Xilinx support
*
*
* Note that the first on the list must be reachable
* via a single transition from the current state.
+ *
+ * All drivers are required to implement jtag_add_pathmove().
+ * However, if the pathmove sequence can not be precisely
+ * executed, an interface_jtag_add_pathmove() or jtag_execute_queue()
+ * must return an error. It is legal, but not recommended, that
+ * a driver returns an error in all cases for a pathmove if it
+ * can only implement a few transitions and therefore
+ * a partial implementation of pathmove would have little practical
+ * application.
*/
extern void jtag_add_pathmove(int num_states, enum tap_state *path);
extern int interface_jtag_add_pathmove(int num_states, enum tap_state *path);
*/
extern void jtag_add_runtest(int num_cycles, enum tap_state endstate);
extern int interface_jtag_add_runtest(int num_cycles, enum tap_state endstate);
-/* If it fails and one of the error messages below are returned, nothing is
- * added to the queue and jtag_execute() won't return an error code.
+/* A reset of the TAP state machine can be requested.
+ *
+ * Whether tms or trst reset is used depends on the capabilities of
+ * the target and jtag interface(reset_config command configures this).
+ *
+ * srst can driver a reset of the TAP state machine and vice
+ * versa
*
- * ERROR_JTAG_RESET_WOULD_ASSERT_TRST
- * ERROR_JTAG_RESET_CANT_SRST
+ * Application code may need to examine value of jtag_reset_config
+ * to determine the proper codepath
+ *
+ * DANGER! Even though srst drives trst, trst might not be connected to
+ * the interface, and it might actually be *harmful* to assert trst in this case.
+ *
+ * This is why combinations such as "reset_config srst_only srst_pulls_trst"
+ * are supported.
+ *
+ */
+extern void jtag_add_reset(int req_tlr_or_trst, int srst);
+/* this drives the actual srst and trst pins. srst will always be 0
+ * if jtag_reset_config & RESET_SRST_PULLS_TRST != 0 and ditto for
+ * trst.
*
- * All other error codes will result in jtag_execute_queue() returning
- * an error.
+ * the higher level jtag_add_reset will invoke jtag_add_tlr() if
+ * approperiate
*/
-extern int jtag_add_reset(int trst, int srst);
extern int interface_jtag_add_reset(int trst, int srst);
extern void jtag_add_end_state(enum tap_state endstate);
extern int interface_jtag_add_end_state(enum tap_state endstate);
#define ERROR_JTAG_NOT_IMPLEMENTED (-102)
#define ERROR_JTAG_TRST_ASSERTED (-103)
#define ERROR_JTAG_QUEUE_FAILED (-104)
-#define ERROR_JTAG_RESET_WOULD_ASSERT_TRST (-105)
-#define ERROR_JTAG_RESET_CANT_SRST (-106)
#define ERROR_JTAG_DEVICE_ERROR (-107)
Code Review / openocd.git / blobdiff