Kinetis: suppress false alarms "MCU is secured"

Kinetis driver checks MDM STAT register to detect secured state of MCU.
An unsecured clean device typically triggered a huge fat alarm message.
Now when driver detects secured state it tries to halt MCU and then
re-reads status register.

Command "mdm mass_erase" used to deassert reset when finished
and MCU started looping in hard fault - WDOG reset cycle.
Now "reset halt" is issued. Clean flash is not run after mass_erase.

Change-Id: I23f393509fbd8751d44ffc744ff2d67f1074f74e
Signed-off-by: Tomas Vanek <vanekt@fbl.cz>
Reviewed-on: http://openocd.zylin.com/3010
Tested-by: jenkins
Reviewed-by: Thomas Schmid <thomas@rfranging.com>
Reviewed-by: Freddie Chopin <freddie.chopin@gmail.com>

diff --git a/src/flash/nor/kinetis.c b/src/flash/nor/kinetis.c
index 73ba586a0fc1d6c7be0aa927b3c694092d2c7f73..ce5807ffedf4bb449de39bf45b45086cb589dc20 100644 (file)
--- a/src/flash/nor/kinetis.c
+++ b/src/flash/nor/kinetis.c
@@ -34,6 +34,7 @@
 #include "jtag/interface.h"
 #include "imp.h"
 #include <helper/binarybuffer.h>
+#include <target/target_type.h>
 #include <target/algorithm.h>
 #include <target/armv7m.h>
 #include <target/cortex_m.h>
@@ -383,10 +384,15 @@ COMMAND_HANDLER(kinetis_mdm_mass_erase)
        if (retval != ERROR_OK)
                return retval;
 
-       if (jtag_get_reset_config() & RESET_HAS_SRST)
-               adapter_deassert_reset();
-
        dap_ap_select(dap, original_ap);
+
+       if (jtag_get_reset_config() & RESET_HAS_SRST) {
+               /* halt MCU otherwise it loops in hard fault - WDOG reset cycle */
+               target->reset_halt = true;
+               target->type->assert_reset(target);
+               target->type->deassert_reset(target);
+       }
+
        return ERROR_OK;
 }
 
@@ -464,6 +470,31 @@ COMMAND_HANDLER(kinetis_check_flash_security_status)
                goto fail;
        }
 
+       if ((val & (MDM_STAT_SYSSEC | MDM_STAT_CORE_HALTED)) == MDM_STAT_SYSSEC) {
+               LOG_WARNING("MDM: Secured MCU state detected however it may be a false alarm");
+               LOG_WARNING("MDM: Halting target to detect secured state reliably");
+
+               dap_ap_select(dap, origninal_ap);
+               retval = target_halt(target);
+               if (retval == ERROR_OK)
+                       retval = target_wait_state(target, TARGET_HALTED, 100);
+
+               if (retval != ERROR_OK) {
+                       LOG_WARNING("MDM: Target not halted, trying reset halt");
+                       target->reset_halt = true;
+                       target->type->assert_reset(target);
+                       target->type->deassert_reset(target);
+               }
+
+               /* re-read status */
+               dap_ap_select(dap, 1);
+               retval = kinetis_mdm_read_register(dap, MDM_REG_STAT, &val);
+               if (retval != ERROR_OK) {
+                       LOG_ERROR("MDM: failed to read MDM_REG_STAT");
+                       goto fail;
+               }
+       }
+
        if (val & MDM_STAT_SYSSEC) {
                jtag_poll_set_enabled(false);