From 79b51fedab9e8023a2e72551c4dcaf4373274287 Mon Sep 17 00:00:00 2001 From: =?utf8?q?J=2E=20Neusch=C3=A4fer?= Date: Sat, 30 Mar 2024 13:18:43 +0100 Subject: [PATCH] remote_bitbang: Change sleep commands to Zz to avoid conflict with SWD MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit It was noticed that the remote_bitbang protocol has a design issue: SWD and sleep commands cannot be implemented at the same time, because they overlap: - SWD uses d,e,f,g for setting pin state - sleep uses d,D for microsecond and millisecond sleep, respectively This has previously been reported by Marek Vrbka, but it wasn't fixed. This commit does the following to resolve the issue: - Change the sleep commands to 'Z' for 1 ms, 'z' for 1 µs - Document 'D' and 'd' as deprecated aliases - Switch the remote_bitbang driver in OpenOCD to 'Z' and 'z' Unfortunately that's a breaking change, because existing adapter-side implementations of the protocol will have to implement the new commands to keep working with future versions of OpenOCD. Fortunately, the remote sleep commands haven't been part of an OpenOCD release yet, which should limit the breakage somewhat. Reported-by: Marek Vrbka Link: https://sourceforge.net/p/openocd/mailman/openocd-devel/thread/670d28d2-75a1-45ec-afe5-541415701d7a%40codasip.com/ Fixes: e8e09b1b5 ("remote_bitbang: add use_remote_sleep option to send delays to remote") Change-Id: I04d2790a33bff9d47eb7f69b3275fd9a271625ae Signed-off-by: J. Neuschäfer Reviewed-on: https://review.openocd.org/c/openocd/+/8191 Reviewed-by: David Ryskalczyk Reviewed-by: Antonio Borneo Tested-by: jenkins Reviewed-by: Jeremy Herbert --- doc/manual/jtag/drivers/remote_bitbang.txt | 9 +++++++-- src/jtag/drivers/remote_bitbang.c | 4 ++-- 2 files changed, 9 insertions(+), 4 deletions(-) diff --git a/doc/manual/jtag/drivers/remote_bitbang.txt b/doc/manual/jtag/drivers/remote_bitbang.txt index 94d6038163..8316cb0dd5 100644 --- a/doc/manual/jtag/drivers/remote_bitbang.txt +++ b/doc/manual/jtag/drivers/remote_bitbang.txt @@ -77,7 +77,12 @@ The read responses are encoded in ASCII as either digit 0 or 1. If the use_remote_sleep option is set to 'yes', two additional requests may be sent: - D - Sleep for 1 millisecond - d - Sleep for 1 microsecond + Z - Sleep for 1 millisecond + z - Sleep for 1 microsecond + +NOTE: Previously these were specified as 'D' and 'd', which conflicts with the +"SWD write 0 0" command defined above. Adapters that implement Dd for remote +sleep must be updated to work with Zz. + */ diff --git a/src/jtag/drivers/remote_bitbang.c b/src/jtag/drivers/remote_bitbang.c index c97b6b6abe..53d2151fdc 100644 --- a/src/jtag/drivers/remote_bitbang.c +++ b/src/jtag/drivers/remote_bitbang.c @@ -230,13 +230,13 @@ static int remote_bitbang_sleep(unsigned int microseconds) unsigned int us = microseconds % 1000; for (unsigned int i = 0; i < ms; i++) { - tmp = remote_bitbang_queue('D', NO_FLUSH); + tmp = remote_bitbang_queue('Z', NO_FLUSH); if (tmp != ERROR_OK) return tmp; } for (unsigned int i = 0; i < us; i++) { - tmp = remote_bitbang_queue('d', NO_FLUSH); + tmp = remote_bitbang_queue('z', NO_FLUSH); if (tmp != ERROR_OK) return tmp; } -- 2.30.2