From d459a2d27df52643dc8932827a63467a14f7c162 Mon Sep 17 00:00:00 2001 From: Tomas Vanek Date: Fri, 1 Mar 2019 21:44:27 +0100 Subject: [PATCH] adi_v5_swd: wait for readable DPIDR, ABORT if stalled Reading of DPIDR is the very first operation after JTAG to SWD sequence. Without this change if DPIDR read fails then swd connect fails. Keep trying JTAG to SWD sequence and DPIDR read until success or timeout 0.5 sec. It makes setting of adapter srst delay on SWD transport mostly unnecessary. Also test for ERROR_WAIT (which should not occur according to IHI 0031E B4.3.2 but a quirk is known) and if bus is kept stalled then issue abort to make the next connect possible. Change-Id: Id8fe6618605bbeb4fed5061e987ed55de90a35f2 Signed-off-by: Tomas Vanek Reviewed-on: http://openocd.zylin.com/5730 Tested-by: jenkins Reviewed-by: Antonio Borneo Reviewed-by: Andreas Fritiofson --- src/target/adi_v5_swd.c | 69 +++++++++++++++++++++++++++++++++-------- 1 file changed, 56 insertions(+), 13 deletions(-) diff --git a/src/target/adi_v5_swd.c b/src/target/adi_v5_swd.c index ee30ff7ba4..b25181e21f 100644 --- a/src/target/adi_v5_swd.c +++ b/src/target/adi_v5_swd.c @@ -118,26 +118,69 @@ static int swd_connect(struct adiv5_dap *dap) } } - /* Note, debugport_init() does setup too */ - swd->switch_seq(JTAG_TO_SWD); - /* Clear link state, including the SELECT cache. */ - dap->do_reconnect = false; - dap_invalidate_cache(dap); + int64_t timeout = timeval_ms() + 500; - swd_queue_dp_read(dap, DP_DPIDR, &dpidr); + do { + /* Note, debugport_init() does setup too */ + swd->switch_seq(JTAG_TO_SWD); - /* force clear all sticky faults */ - swd_clear_sticky_errors(dap); + /* Clear link state, including the SELECT cache. */ + dap->do_reconnect = false; + dap_invalidate_cache(dap); + + status = swd_queue_dp_read(dap, DP_DPIDR, &dpidr); + if (status == ERROR_OK) { + status = swd_run_inner(dap); + if (status == ERROR_OK) + break; + } + + alive_sleep(1); + + } while (timeval_ms() < timeout); + + if (status != ERROR_OK) { + LOG_ERROR("Error connecting DP: cannot read IDR"); + return status; + } + + LOG_INFO("SWD DPIDR %#8.8" PRIx32, dpidr); + + do { + dap->do_reconnect = false; - status = swd_run_inner(dap); + /* force clear all sticky faults */ + swd_clear_sticky_errors(dap); + + status = swd_run_inner(dap); + if (status != ERROR_WAIT) + break; + + alive_sleep(10); + + } while (timeval_ms() < timeout); + + /* IHI 0031E B4.3.2: + * "A WAIT response must not be issued to the ... + * ... writes to the ABORT register" + * swd_clear_sticky_errors() writes to the ABORT register only. + * + * Unfortunately at least Microchip SAMD51/E53/E54 returns WAIT + * in a corner case. Just try if ABORT resolves the problem. + */ + if (status == ERROR_WAIT) { + LOG_WARNING("Connecting DP: stalled AP operation, issuing ABORT"); - if (status == ERROR_OK) { - LOG_INFO("SWD DPIDR %#8.8" PRIx32, dpidr); dap->do_reconnect = false; + + swd->write_reg(swd_cmd(false, false, DP_ABORT), + DAPABORT | STKCMPCLR | STKERRCLR | WDERRCLR | ORUNERRCLR, 0); + status = swd_run_inner(dap); + } + + if (status == ERROR_OK) status = dap_dp_init(dap); - } else - dap->do_reconnect = true; return status; } -- 2.30.2