Cortex-M3: report lockup, and recover

ARMv7-M defines a "lockup" state that's entered in certain double
fault sequences which can't be recovered from without external help.
OpenOCD has previously ignored this.

Issue a diagnostic saying the chip has locked up, and force exit
from this state by halting the core.  It's not clear this is the
best way to handle lockup; but there should now be less confusion.

Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
This commit is contained in:
David Brownell 2010-01-27 13:47:48 -08:00
parent d44f1aaeff
commit 3172be80a3
1 changed files with 15 additions and 0 deletions

View File

@ -416,6 +416,21 @@ static int cortex_m3_poll(struct target *target)
return retval;
}
/* Recover from lockup. See ARMv7-M architecture spec,
* section B1.5.15 "Unrecoverable exception cases".
*
* REVISIT Is there a better way to report and handle this?
*/
if (cortex_m3->dcb_dhcsr & S_LOCKUP) {
LOG_WARNING("%s -- clearing lockup after double fault",
target_name(target));
cortex_m3_write_debug_halt_mask(target, C_HALT, 0);
target->debug_reason = DBG_REASON_DBGRQ;
/* refresh status bits */
mem_ap_read_atomic_u32(swjdp, DCB_DHCSR, &cortex_m3->dcb_dhcsr);
}
if (cortex_m3->dcb_dhcsr & S_RESET_ST)
{
/* check if still in reset */