target/cortex_m: allow setting the type of a breakpoint

Cortex-M target used 'auto_bp_type' mode. The requested type
of breakpoint was ignored and hard (FPB) breakpoints were set in
'code memory area' 0x00000000-0x1fffffff, soft breakpoints were set above
0x20000000.

The code memory area of Cortex-M does not mean the memory is flash and
vice versa. External flash (parallel or QSPI) is usually mapped above
code memory area. Cortex-M7 ITCM RAM is mapped at 0. Kinetis
has a RAM block under 0x20000000 boundary.

Remove 'auto_bp_type' mode, set breakpoints to requested type.

Change 'cortex_m maskisr auto' handling to use a hard temporary
breakpoint everywhere: it can also workaround not working soft breakpoints
on Cortex-M7 with ICache enabled.

Change-Id: I7a9f9464c5e10bfd7f17cba1037ed07a064fa2e8
Signed-off-by: Tomas Vanek <vanekt@fbl.cz>
Reviewed-on: http://openocd.zylin.com/4429
Tested-by: jenkins
Reviewed-by: Matthias Welwarsky <matthias@welwarsky.de>

3 files changed, 5 insertions, 32 deletions

diff --git a/doc/openocd.texi b/doc/openocd.texi
index 1243438..a472446 100644
--- a/doc/openocd.texi
+++ b/doc/openocd.texi
@@ -8630,9 +8630,10 @@ the next instruction where the core was halted. After the step interrupts
 are enabled again. If the interrupt handlers don't complete within 500ms,
 the step command leaves with the core running.
 
-Note that a free breakpoint is required for the @option{auto} option. If no
-breakpoint is available at the time of the step, then the step is taken
-with interrupts enabled, i.e. the same way the @option{off} option does.
+Note that a free hardware (FPB) breakpoint is required for the @option{auto}
+option. If no breakpoint is available at the time of the step, then the step
+is taken with interrupts enabled, i.e. the same way the @option{off} option
+does.
 
 Default is @option{auto}.
 @end deffn
diff --git a/src/target/cortex_m.c b/src/target/cortex_m.c
index a356350..30439f4 100644
--- a/src/target/cortex_m.c
+++ b/src/target/cortex_m.c
@@ -51,11 +51,6 @@
  * any longer.
  */
 
-/**
- * Returns the type of a break point required by address location
- */
-#define BKPT_TYPE_BY_ADDR(addr) ((addr) < 0x20000000 ? BKPT_HARD : BKPT_SOFT)
-
 /* forward declarations */
 static int cortex_m_store_core_reg_u32(struct target *target,
 		uint32_t num, uint32_t value);
@@ -868,7 +863,7 @@ static int cortex_m_step(struct target *target, int current,
 				if (breakpoint)
 					retval = cortex_m_set_breakpoint(target, breakpoint);
 				else
-					retval = breakpoint_add(target, pc_value, 2, BKPT_TYPE_BY_ADDR(pc_value));
+					retval = breakpoint_add(target, pc_value, 2, BKPT_HARD);
 				bool tmp_bp_set = (retval == ERROR_OK);
 
 				/* No more breakpoints left, just do a step */
@@ -1131,9 +1126,6 @@ int cortex_m_set_breakpoint(struct target *target, struct breakpoint *breakpoint
 		return ERROR_OK;
 	}
 
-	if (cortex_m->auto_bp_type)
-		breakpoint->type = BKPT_TYPE_BY_ADDR(breakpoint->address);
-
 	if (breakpoint->type == BKPT_HARD) {
 		uint32_t fpcr_value;
 		while (comparator_list[fp_num].used && (fp_num < cortex_m->fp_num_code))
@@ -1253,21 +1245,6 @@ int cortex_m_add_breakpoint(struct target *target, struct breakpoint *breakpoint
 {
 	struct cortex_m_common *cortex_m = target_to_cm(target);
 
-	if (cortex_m->auto_bp_type)
-		breakpoint->type = BKPT_TYPE_BY_ADDR(breakpoint->address);
-
-	if (breakpoint->type != BKPT_TYPE_BY_ADDR(breakpoint->address)) {
-		if (breakpoint->type == BKPT_HARD) {
-			LOG_INFO("flash patch comparator requested outside code memory region");
-			return ERROR_TARGET_RESOURCE_NOT_AVAILABLE;
-		}
-
-		if (breakpoint->type == BKPT_SOFT) {
-			LOG_INFO("soft breakpoint requested in code (flash) memory region");
-			return ERROR_TARGET_RESOURCE_NOT_AVAILABLE;
-		}
-	}
-
 	if ((breakpoint->type == BKPT_HARD) && (cortex_m->fp_code_available < 1)) {
 		LOG_INFO("no flash patch comparator unit available for hardware breakpoint");
 		return ERROR_TARGET_RESOURCE_NOT_AVAILABLE;
@@ -1299,9 +1276,6 @@ int cortex_m_remove_breakpoint(struct target *target, struct breakpoint *breakpo
 		return ERROR_TARGET_NOT_HALTED;
 	}
 
-	if (cortex_m->auto_bp_type)
-		breakpoint->type = BKPT_TYPE_BY_ADDR(breakpoint->address);
-
 	if (breakpoint->set)
 		cortex_m_unset_breakpoint(target, breakpoint);
 
@@ -2111,7 +2085,6 @@ int cortex_m_examine(struct target *target)
 
 		/* Setup FPB */
 		target_read_u32(target, FP_CTRL, &fpcr);
-		cortex_m->auto_bp_type = 1;
 		/* bits [14:12] and [7:4] */
 		cortex_m->fp_num_code = ((fpcr >> 8) & 0x70) | ((fpcr >> 4) & 0xF);
 		cortex_m->fp_num_lit = (fpcr >> 8) & 0xF;
diff --git a/src/target/cortex_m.h b/src/target/cortex_m.h
index 9500acc..2daf4cb 100644
--- a/src/target/cortex_m.h
+++ b/src/target/cortex_m.h
@@ -175,7 +175,6 @@ struct cortex_m_common {
 	int fp_code_available;
 	int fp_rev;
 	int fpb_enabled;
-	int auto_bp_type;
 	struct cortex_m_fp_comparator *fp_comparator_list;
 
 	/* Data Watchpoint and Trace (DWT) */