target/cortex_m: reduce duplication in profiling

The Cortex-M implementation of profiling contains a bunch of
conditionals and checks to handle both chips which have PCSR and chips
which do not. However, the net effect of the non-PCSR branches is
actually exactly the same as what target_profiling_default does. Rather
than duplicating this code, just detect the situation where PCSR isn’t
available and delegate to target_profiling_default.

Change-Id: I1be57ac77f983816ab6bf644a3cfca77b67d6f70
Signed-off-by: Christopher Head <chead@zaber.com>
Reviewed-on: http://openocd.zylin.com/5236
Tested-by: jenkins
Reviewed-by: Antonio Borneo <borneo.antonio@gmail.com>

3 files changed, 24 insertions, 47 deletions

diff --git a/src/target/cortex_m.c b/src/target/cortex_m.c
index abc377f..503995a 100644
--- a/src/target/cortex_m.c
+++ b/src/target/cortex_m.c
@@ -1835,28 +1835,23 @@ int cortex_m_profiling(struct target *target, uint32_t *samples,
 	struct timeval timeout, now;
 	struct armv7m_common *armv7m = target_to_armv7m(target);
 	uint32_t reg_value;
-	bool use_pcsr = false;
-	int retval = ERROR_OK;
-	struct reg *reg;
-
-	gettimeofday(&timeout, NULL);
-	timeval_add_time(&timeout, seconds, 0);
+	int retval;
 
 	retval = target_read_u32(target, DWT_PCSR, &reg_value);
 	if (retval != ERROR_OK) {
 		LOG_ERROR("Error while reading PCSR");
 		return retval;
 	}
-
-	if (reg_value != 0) {
-		use_pcsr = true;
-		LOG_INFO("Starting Cortex-M profiling. Sampling DWT_PCSR as fast as we can...");
-	} else {
-		LOG_INFO("Starting profiling. Halting and resuming the"
-			 " target as often as we can...");
-		reg = register_get_by_name(target->reg_cache, "pc", 1);
+	if (reg_value == 0) {
+		LOG_INFO("PCSR sampling not supported on this processor.");
+		return target_profiling_default(target, samples, max_num_samples, num_samples, seconds);
 	}
 
+	gettimeofday(&timeout, NULL);
+	timeval_add_time(&timeout, seconds, 0);
+
+	LOG_INFO("Starting Cortex-M profiling. Sampling DWT_PCSR as fast as we can...");
+
 	/* Make sure the target is running */
 	target_poll(target);
 	if (target->state == TARGET_HALTED)
@@ -1870,40 +1865,21 @@ int cortex_m_profiling(struct target *target, uint32_t *samples,
 	uint32_t sample_count = 0;
 
 	for (;;) {
-		if (use_pcsr) {
-			if (armv7m && armv7m->debug_ap) {
-				uint32_t read_count = max_num_samples - sample_count;
-				if (read_count > 1024)
-					read_count = 1024;
-
-				retval = mem_ap_read_buf_noincr(armv7m->debug_ap,
-							(void *)&samples[sample_count],
-							4, read_count, DWT_PCSR);
-				sample_count += read_count;
-			} else {
-				target_read_u32(target, DWT_PCSR, &samples[sample_count++]);
-			}
+		if (armv7m && armv7m->debug_ap) {
+			uint32_t read_count = max_num_samples - sample_count;
+			if (read_count > 1024)
+				read_count = 1024;
+
+			retval = mem_ap_read_buf_noincr(armv7m->debug_ap,
+						(void *)&samples[sample_count],
+						4, read_count, DWT_PCSR);
+			sample_count += read_count;
 		} else {
-			target_poll(target);
-			if (target->state == TARGET_HALTED) {
-				reg_value = buf_get_u32(reg->value, 0, 32);
-				/* current pc, addr = 0, do not handle breakpoints, not debugging */
-				retval = target_resume(target, 1, 0, 0, 0);
-				samples[sample_count++] = reg_value;
-				target_poll(target);
-				alive_sleep(10); /* sleep 10ms, i.e. <100 samples/second. */
-			} else if (target->state == TARGET_RUNNING) {
-				/* We want to quickly sample the PC. */
-				retval = target_halt(target);
-			} else {
-				LOG_INFO("Target not halted or running");
-				retval = ERROR_OK;
-				break;
-			}
+			target_read_u32(target, DWT_PCSR, &samples[sample_count++]);
 		}
 
 		if (retval != ERROR_OK) {
-			LOG_ERROR("Error while reading %s", use_pcsr ? "PCSR" : "target pc");
+			LOG_ERROR("Error while reading PCSR");
 			return retval;
 		}
 
diff --git a/src/target/target.c b/src/target/target.c
index d1399ed..e64004f 100644
--- a/src/target/target.c
+++ b/src/target/target.c
@@ -72,8 +72,6 @@ static int target_get_gdb_fileio_info_default(struct target *target,
 		struct gdb_fileio_info *fileio_info);
 static int target_gdb_fileio_end_default(struct target *target, int retcode,
 		int fileio_errno, bool ctrl_c);
-static int target_profiling_default(struct target *target, uint32_t *samples,
-		uint32_t max_num_samples, uint32_t *num_samples, uint32_t seconds);
 
 /* targets */
 extern struct target_type arm7tdmi_target;
@@ -2137,7 +2135,7 @@ static int target_gdb_fileio_end_default(struct target *target,
 	return ERROR_OK;
 }
 
-static int target_profiling_default(struct target *target, uint32_t *samples,
+int target_profiling_default(struct target *target, uint32_t *samples,
 		uint32_t max_num_samples, uint32_t *num_samples, uint32_t seconds)
 {
 	struct timeval timeout, now;
diff --git a/src/target/target.h b/src/target/target.h
index c69aa93..9589b53 100644
--- a/src/target/target.h
+++ b/src/target/target.h
@@ -748,6 +748,9 @@ void target_handle_md_output(struct command_invocation *cmd,
 	struct target *target, target_addr_t address, unsigned size,
 	unsigned count, const uint8_t *buffer);
 
+int target_profiling_default(struct target *target, uint32_t *samples, uint32_t
+		max_num_samples, uint32_t *num_samples, uint32_t seconds);
+
 #define ERROR_TARGET_INVALID	(-300)
 #define ERROR_TARGET_INIT_FAILED (-301)
 #define ERROR_TARGET_TIMEOUT	(-302)