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| author | N S <nlshipp@yahoo.com> | 2024-01-22 21:47:34 -0800 |
|---|---|---|
| committer | Antonio Borneo <borneo.antonio@gmail.com> | 2024-02-11 23:11:00 +0000 |
| commit | c6e7e48b053c281ef4a9dd50f2d94fa12184a956 (patch) | |
| tree | bc14b688e59106b954432e9b8e11fbdd5654e66d /src/jtag | |
| parent | 7295ddc15c0516a64c9996d2b351accb50175803 (diff) | |
| download | riscv-openocd-c6e7e48b053c281ef4a9dd50f2d94fa12184a956.zip riscv-openocd-c6e7e48b053c281ef4a9dd50f2d94fa12184a956.tar.gz riscv-openocd-c6e7e48b053c281ef4a9dd50f2d94fa12184a956.tar.bz2 | |
jtag/drivers: fix reset logic handling in OpenJTAG
The OpenJTAG driver behaviour always forces a system reset on jtag_init.
The driver was incorrectly assuming that when execute_reset is called
with trst set to 1 - perform a software TAP reset, otherwise perform a
system reset when trst is 0.
The set_state call assumes the that OpenJTAG hardware will perform a
software TLR reset if the target state is TAP_RESET. This is not the
case: the published VHDL will simply find the shortest path to TLR and
not perform a fixed 5 cycle operation with TMS held high.
Fix the code to only perform system resets when srst is 1 in
execute_reset and to force a software TAP reset operation in set_state
when the target state is TAP_RESET.
Change-Id: I7e0f76f8491efefff1ccaeb4b1ae16e722d76df4
Signed-off-by: N S <nlshipp@yahoo.com>
Reviewed-on: https://review.openocd.org/c/openocd/+/8121
Reviewed-by: Antonio Borneo <borneo.antonio@gmail.com>
Tested-by: jenkins
Diffstat (limited to 'src/jtag')
| -rw-r--r-- | src/jtag/drivers/openjtag.c | 18 |
1 files changed, 11 insertions, 7 deletions
diff --git a/src/jtag/drivers/openjtag.c b/src/jtag/drivers/openjtag.c index 1c79a2c..086a411 100644 --- a/src/jtag/drivers/openjtag.c +++ b/src/jtag/drivers/openjtag.c @@ -671,14 +671,12 @@ static void openjtag_execute_reset(struct jtag_command *cmd) uint8_t buf = 0x00; - if (cmd->cmd.reset->trst) { - buf = 0x03; - } else { + /* Pull SRST low for 5 TCLK cycles */ + if (cmd->cmd.reset->srst) { buf |= 0x04; buf |= 0x05 << 4; + openjtag_add_byte(buf); } - - openjtag_add_byte(buf); } static void openjtag_execute_sleep(struct jtag_command *cmd) @@ -691,8 +689,14 @@ static void openjtag_set_state(uint8_t openocd_state) uint8_t state = openjtag_get_tap_state(openocd_state); uint8_t buf = 0; - buf = 0x01; - buf |= state << 4; + + if (state != OPENJTAG_TAP_RESET) { + buf = 0x01; + buf |= state << 4; + } else { + /* Force software TLR */ + buf = 0x03; + } openjtag_add_byte(buf); } |