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drivers/jlink: Revert old workaround 

This workaround broke usage with at least the I.MX6Q.

The comment implies that talking to the J-Link dongle itself should
fail if the target isn't reset, which sounds really strange. I'm
guessing it just triggered another bug in OpenOCD or Segger FW which
might have been fixed since. Revert and wait and see if there are any
failure reports.

Tested with Kwikstik (J-Link + Kinetis K40), not with the mentioned
adapter.

Change-Id: I97f555efe079bd99c098bf483491d9509b2363ad
Signed-off-by: Roy Spliet <rspliet@mpi-sws.org>
Signed-off-by: Andreas Fritiofson <andreas.fritiofson@gmail.com>
Reviewed-on: http://openocd.zylin.com/2147
Tested-by: jenkins
Reviewed-by: Paul Fertser <fercerpav@gmail.com>
This commit is contained in:
Andreas Fritiofson 2014-07-24 23:14:03 +02:00
parent 66e20117e8
commit f75345b915
1 changed files with 0 additions and 22 deletions
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22
src/jtag/drivers/jlink.c
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@ -507,28 +507,6 @@ static int jlink_init(void)
return ERROR_JTAG_INIT_FAILED;
}
/*
* The next three instructions were added after discovering a problem
* while using an oscilloscope.
* For the V8 SAM-ICE dongle (and likely other j-link device variants),
* the reset line to the target microprocessor was found to cycle only
* intermittently during emulator startup (even after encountering the
* downstream reset instruction later in the code).
* This was found to create two issues:
* 1) In general it is a bad practice to not reset a CPU to a known
* state when starting an emulator and
* 2) something critical happens inside the dongle when it does the
* first read following a new USB session.
* Keeping the processor in reset during the first read collecting
* version information seems to prevent errant
* "J-Link command EMU_CMD_VERSION failed" issues.
*/
LOG_INFO("J-Link initialization started / target CPU reset initiated");
jlink_simple_command(EMU_CMD_HW_TRST0);
jlink_simple_command(EMU_CMD_HW_RESET0);
usleep(1000);
jlink_hw_jtag_version = 2;
if (jlink_get_version_info() == ERROR_OK) {