mips: support connecting under reset

Some targets support connecting while the target's srst is asserted.
Tested on pic32 family.

Change-Id: I0d20c40af6d031d1306043893e95e61f484c0a87
Signed-off-by: Spencer Oliver <spen@spen-soft.co.uk>
Reviewed-on: http://openocd.zylin.com/608
Tested-by: jenkins

diff --git a/src/target/mips_m4k.c b/src/target/mips_m4k.c
index c64d5cf6093c35d67416714c3f225dee755dcc73..1a10d5a979160a3fbd77c954db61105c83de569d 100644 (file)
--- a/src/target/mips_m4k.c
+++ b/src/target/mips_m4k.c
@@ -222,15 +222,22 @@ static int mips_m4k_assert_reset(struct target *target)
 {
        struct mips_m4k_common *mips_m4k = target_to_m4k(target);
        struct mips_ejtag *ejtag_info = &mips_m4k->mips32.ejtag_info;
-       int assert_srst = 1;
 
        LOG_DEBUG("target->state: %s",
                target_state_name(target));
 
        enum reset_types jtag_reset_config = jtag_get_reset_config();
 
-       if (!(jtag_reset_config & RESET_HAS_SRST))
-               assert_srst = 0;
+       /* some cores support connecting while srst is asserted
+        * use that mode is it has been configured */
+
+       bool srst_asserted = false;
+
+       if (!(jtag_reset_config & RESET_SRST_PULLS_TRST) &&
+                       (jtag_reset_config & RESET_SRST_NO_GATING)) {
+               jtag_add_reset(0, 1);
+               srst_asserted = true;
+       }
 
        if (target->reset_halt) {
                /* use hardware to catch reset */
@@ -238,11 +245,11 @@ static int mips_m4k_assert_reset(struct target *target)
        } else
                mips_ejtag_set_instr(ejtag_info, EJTAG_INST_NORMALBOOT);
 
-       if (assert_srst) {
+       if (jtag_reset_config & RESET_HAS_SRST) {
                /* here we should issue a srst only, but we may have to assert trst as well */
                if (jtag_reset_config & RESET_SRST_PULLS_TRST)
                        jtag_add_reset(1, 1);
-               else
+               else if (!srst_asserted)
                        jtag_add_reset(0, 1);
        } else {
                if (mips_m4k->is_pic32mx) {