diff options
| -rw-r--r-- | src/target/arm_adi_v5.c | 113 | ||||
| -rw-r--r-- | src/target/arm_adi_v5.h | 8 |
2 files changed, 121 insertions, 0 deletions
diff --git a/src/target/arm_adi_v5.c b/src/target/arm_adi_v5.c index 41f00ec0..6be60af3 100644 --- a/src/target/arm_adi_v5.c +++ b/src/target/arm_adi_v5.c @@ -1716,3 +1716,116 @@ DAP_COMMAND_HANDLER(dap_apid_command) return retval; } + +/* + * This represents the bits which must be sent out on TMS/SWDIO to + * switch a DAP implemented using an SWJ-DP module into SWD mode. + * These bits are stored (and transmitted) LSB-first. + * + * See the DAP-Lite specification, section 2.2.5 for information + * about making the debug link select SWD or JTAG. (Similar info + * is in a few other ARM documents.) + */ +static const uint8_t jtag2swd_bitseq[] = { + /* More than 50 TCK/SWCLK cycles with TMS/SWDIO high, + * putting both JTAG and SWD logic into reset state. + */ + 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, + /* Switching sequence enables SWD and disables JTAG + * NOTE: bits in the DP's IDCODE may expose the need for + * an old/deprecated sequence (0xb6 0xed). + */ + 0x9e, 0xe7, + /* More than 50 TCK/SWCLK cycles with TMS/SWDIO high, + * putting both JTAG and SWD logic into reset state. + */ + 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, +}; + +/** + * Put the debug link into SWD mode, if the target supports it. + * The link's initial mode may be either JTAG (for example, + * with SWJ-DP after reset) or SWD. + * + * @param target Enters SWD mode (if possible). + * + * Note that targets using the JTAG-DP do not support SWD, and that + * some targets which could otherwise support it may have have been + * configured to disable SWD signaling + * + * @return ERROR_OK or else a fault code. + */ +int dap_to_swd(struct target *target) +{ + int retval; + + LOG_DEBUG("Enter SWD mode"); + + /* REVISIT it's nasty to need to make calls to a "jtag" + * subsystem if the link isn't in JTAG mode... + */ + + retval = jtag_add_tms_seq(8 * sizeof(jtag2swd_bitseq), + jtag2swd_bitseq, TAP_INVALID); + if (retval == ERROR_OK) + retval = jtag_execute_queue(); + + /* REVISIT set up the DAP's ops vector for SWD mode. */ + + return retval; +} + +/** + * This represents the bits which must be sent out on TMS/SWDIO to + * switch a DAP implemented using an SWJ-DP module into JTAG mode. + * These bits are stored (and transmitted) LSB-first. + * + * These bits are stored (and transmitted) LSB-first. + */ +static const uint8_t swd2jtag_bitseq[] = { + /* More than 50 TCK/SWCLK cycles with TMS/SWDIO high, + * putting both JTAG and SWD logic into reset state. + */ + 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, + /* Switching equence disables SWD and enables JTAG + * NOTE: bits in the DP's IDCODE can expose the need for + * the old/deprecated sequence (0xae 0xde). + */ + 0x3c, 0xe7, + /* At least 50 TCK/SWCLK cycles with TMS/SWDIO high, + * putting both JTAG and SWD logic into reset state. + * NOTE: some docs say "at least 5". + */ + 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, +}; + +/** Put the debug link into JTAG mode, if the target supports it. + * The link's initial mode may be either SWD or JTAG. + * + * @param target Enters JTAG mode (if possible). + * + * Note that targets implemented with SW-DP do not support JTAG, and + * that some targets which could otherwise support it may have been + * configured to disable JTAG signaling + * + * @return ERROR_OK or else a fault code. + */ +int dap_to_jtag(struct target *target) +{ + int retval; + + LOG_DEBUG("Enter JTAG mode"); + + /* REVISIT it's nasty to need to make calls to a "jtag" + * subsystem if the link isn't in JTAG mode... + */ + + retval = jtag_add_tms_seq(8 * sizeof(swd2jtag_bitseq), + swd2jtag_bitseq, TAP_RESET); + if (retval == ERROR_OK) + retval = jtag_execute_queue(); + + /* REVISIT set up the DAP's ops vector for JTAG mode. */ + + return retval; +} diff --git a/src/target/arm_adi_v5.h b/src/target/arm_adi_v5.h index 316701e5..5c5ca4f0 100644 --- a/src/target/arm_adi_v5.h +++ b/src/target/arm_adi_v5.h @@ -235,4 +235,12 @@ DAP_COMMAND_HANDLER(dap_memaccess_command); DAP_COMMAND_HANDLER(dap_apsel_command); DAP_COMMAND_HANDLER(dap_apid_command); +struct target; + +/* Put debug link into SWD mode */ +int dap_to_swd(struct target *target); + +/* Put debug link into JTAG mode */ +int dap_to_jtag(struct target *target); + #endif |