From 88258042730260a763115d0718bd027a7708200d Mon Sep 17 00:00:00 2001 From: Tomas Vanek Date: Sun, 15 Mar 2015 19:09:15 +0100 Subject: target: improve robustness of reset command Before this change jim_target_reset() checked examined state of a target and failed without calling .assert_reset in particular target layer (and without comprehensible warning to user). Cortex-M target (which refuses access to DP under active SRST): If connection is lost then reset process fails before asserting SRST and connection with MCU is not restored. This resulted in: 1) A lot of Cortex-M MCUs required use of reset button or cycling power after firmware blocked SWD access somehow (sleep, misconfigured clock etc). If firmware blocks SWD access early during initialization, a MCU could become completely inaccessible by SWD. 2) If OpenOCD is (re)started and a MCU is in a broken state unresponsive to SWD, reset command does not work even if it could help to restore communication. Hopefully this scenario is not possible under full JTAG. jim_target_reset() in target.c now does not check examined state and delegates this task to a particular target. All targets have been checked and xx_assert_reset() (or xx_deassert_reset()) procedures were changed to check examined state if needed. Targets except arm11, cortex_a and cortex_m just fail if target is not examined although it may be possible to use at least hw reset. Left as TODO for developers familiar with these targets. cortex_m_assert_reset(): memory access errors are stored instead of immediate returning them to a higher level. Errors from less important reads/writes are ignored. Requested reset always leads to a configured action. arm11_assert_reset() just asserts hw reset in case of not examined target. cortex_a_assert_reset() works as usual in case of not examined target. Change-Id: I84fa869f4f58e2fa83b6ea75de84440d9dc3d929 Signed-off-by: Tomas Vanek Reviewed-on: http://openocd.zylin.com/2606 Tested-by: jenkins Reviewed-by: Matthias Welwarsky Reviewed-by: Paul Fertser --- src/target/xscale.c | 7 +++++++ 1 file changed, 7 insertions(+) (limited to 'src/target/xscale.c') diff --git a/src/target/xscale.c b/src/target/xscale.c index 8799e5c4..713a31e1 100644 --- a/src/target/xscale.c +++ b/src/target/xscale.c @@ -1446,6 +1446,13 @@ static int xscale_assert_reset(struct target *target) { struct xscale_common *xscale = target_to_xscale(target); + /* TODO: apply hw reset signal in not examined state */ + if (!(target_was_examined(target))) { + LOG_WARNING("Reset is not asserted because the target is not examined."); + LOG_WARNING("Use a reset button or power cycle the target."); + return ERROR_TARGET_NOT_EXAMINED; + } + LOG_DEBUG("target->state: %s", target_state_name(target)); -- cgit v1.2.3-18-g5258