Merge pull request riscv-collab#1087 from en-sc/en-sc/delay-types

 target/riscv: replace `info->*_delay` with `riscv_scan_delays`

Author: en-sc

src/target/riscv/batch.c

@@ -29,7 +29,7 @@ struct riscv_batch *riscv_batch_alloc(struct target *target, size_t scans)
 	out->allocated_scans = scans;
 	out->last_scan = RISCV_SCAN_TYPE_INVALID;
 	out->was_run = false;
-	out->used_delay = 0;
+	out->last_scan_delay = 0;
 
 	out->data_out = NULL;
 	out->data_in = NULL;
@@ -109,7 +109,7 @@ static bool riscv_batch_was_scan_busy(const struct riscv_batch *batch,
 }
 
 static void add_idle_before_batch(const struct riscv_batch *batch, size_t start_idx,
-		struct riscv_scan_delays delays)
+		const struct riscv_scan_delays *delays)
 {
 	if (!batch->was_run)
 		return;
@@ -121,29 +121,29 @@ static void add_idle_before_batch(const struct riscv_batch *batch, size_t start_
 		? batch->delay_classes[start_idx - 1]
 		: RISCV_DELAY_BASE;
 	const unsigned int new_delay = riscv_scan_get_delay(delays, delay_class);
-	if (new_delay <= batch->used_delay)
+	if (new_delay <= batch->last_scan_delay)
 		return;
-	const unsigned int idle_change = new_delay - batch->used_delay;
+	const unsigned int idle_change = new_delay - batch->last_scan_delay;
 	LOG_TARGET_DEBUG(batch->target, "Adding %u idle cycles before the batch.",
 			idle_change);
 	assert(idle_change <= INT_MAX);
 	jtag_add_runtest(idle_change, TAP_IDLE);
 }
 
 static int get_delay(const struct riscv_batch *batch, size_t scan_idx,
-		struct riscv_scan_delays delays)
+		const struct riscv_scan_delays *delays)
 {
 	assert(batch);
 	assert(scan_idx < batch->used_scans);
 	const enum riscv_scan_delay_class delay_class =
 		batch->delay_classes[scan_idx];
-	const unsigned int delay =  riscv_scan_get_delay(delays, delay_class);
+	const unsigned int delay = riscv_scan_get_delay(delays, delay_class);
 	assert(delay <= INT_MAX);
 	return delay;
 }
 
 int riscv_batch_run_from(struct riscv_batch *batch, size_t start_idx,
-		struct riscv_scan_delays delays, bool resets_delays,
+		const struct riscv_scan_delays *delays, bool resets_delays,
 		size_t reset_delays_after)
 {
 	assert(batch->used_scans);
@@ -195,7 +195,7 @@ int riscv_batch_run_from(struct riscv_batch *batch, size_t start_idx,
 	}
 
 	batch->was_run = true;
-	batch->used_delay = get_delay(batch, batch->used_scans - 1, delays);
+	batch->last_scan_delay = get_delay(batch, batch->used_scans - 1, delays);
 	return ERROR_OK;
 }
 

src/target/riscv/batch.h

@@ -25,40 +25,66 @@ enum riscv_scan_delay_class {
 	/* Delay for System Bus read operation: */
 	RISCV_DELAY_SYSBUS_READ,
 	/* Delay for System Bus write operation: */
-	RISCV_DELAY_SYSBUS_WRITE,
+	RISCV_DELAY_SYSBUS_WRITE
 };
 
+static inline const char *
+riscv_scan_delay_class_name(enum riscv_scan_delay_class delay_class)
+{
+	switch (delay_class) {
+	case RISCV_DELAY_BASE:
+		return "DM access";
+	case RISCV_DELAY_ABSTRACT_COMMAND:
+		return "Abstract Command";
+	case RISCV_DELAY_SYSBUS_READ:
+		return "System Bus read";
+	case RISCV_DELAY_SYSBUS_WRITE:
+		return "System Bus write";
+	}
+	assert(0);
+	return NULL;
+}
+
+/* The scan delay values are passed to "jtag_add_runtest()", which accepts an
+ * "int".  Therefore, the passed value should be no greater than "INT_MAX".
+ *
+ * Since the resulting delay value can be a sum of two individual delays,
+ * individual delays are limited to "INT_MAX / 2" to prevent overflow of the
+ * final sum.
+ */
+#define RISCV_SCAN_DELAY_MAX (INT_MAX / 2)
+
 struct riscv_scan_delays {
-	/* The purpose of these delays is to be passed to "jtag_add_runtest()",
-	 * which accepts an "int".
-	 * Therefore, they should be no greater then "INT_MAX".
-	 */
 	unsigned int base_delay;
 	unsigned int ac_delay;
 	unsigned int sb_read_delay;
 	unsigned int sb_write_delay;
 };
 
-static inline unsigned int riscv_scan_get_delay(struct riscv_scan_delays delays,
+static inline unsigned int
+riscv_scan_get_delay(const struct riscv_scan_delays *delays,
 		enum riscv_scan_delay_class delay_class)
 {
 	switch (delay_class) {
 	case RISCV_DELAY_BASE:
-		return delays.base_delay;
+		return delays->base_delay;
 	case RISCV_DELAY_ABSTRACT_COMMAND:
-		return delays.ac_delay;
+		return delays->base_delay + delays->ac_delay;
 	case RISCV_DELAY_SYSBUS_READ:
-		return delays.sb_read_delay;
+		return delays->base_delay + delays->sb_read_delay;
 	case RISCV_DELAY_SYSBUS_WRITE:
-		return delays.sb_write_delay;
+		return delays->base_delay + delays->sb_write_delay;
 	}
+	assert(0);
 	return 0;
 }
 
 static inline void riscv_scan_set_delay(struct riscv_scan_delays *delays,
 		enum riscv_scan_delay_class delay_class, unsigned int delay)
 {
-	assert(delay <= INT_MAX);
+	assert(delay <= RISCV_SCAN_DELAY_MAX);
+	LOG_DEBUG("%s delay is set to %u.",
+			riscv_scan_delay_class_name(delay_class), delay);
 	switch (delay_class) {
 	case RISCV_DELAY_BASE:
 		delays->base_delay = delay;
@@ -73,6 +99,25 @@ static inline void riscv_scan_set_delay(struct riscv_scan_delays *delays,
 		delays->sb_write_delay = delay;
 		return;
 	}
+	assert(0);
+}
+
+static inline int riscv_scan_increase_delay(struct riscv_scan_delays *delays,
+		enum riscv_scan_delay_class delay_class)
+{
+	const unsigned int delay = riscv_scan_get_delay(delays, delay_class);
+	const unsigned int delay_step = delay / 10 + 1;
+	if (delay > RISCV_SCAN_DELAY_MAX - delay_step) {
+		/* It's not clear if this issue actually occurs in real
+		 * use-cases, so stick with a simple solution until the
+		 * first bug report.
+		 */
+		LOG_ERROR("Delay for %s (%d) is not increased anymore (maximum was reached).",
+				riscv_scan_delay_class_name(delay_class), delay);
+		return ERROR_FAIL;
+	}
+	riscv_scan_set_delay(delays, delay_class, delay + delay_step);
+	return ERROR_OK;
 }
 
 /* A batch of multiple JTAG scans, which are grouped together to avoid the
@@ -113,7 +158,7 @@ struct riscv_batch {
 	/* Number of RTI cycles used by the last scan on the last run.
 	 * Only valid when `was_run` is set.
 	 */
-	unsigned int used_delay;
+	unsigned int last_scan_delay;
 };
 
 /* Allocates (or frees) a new scan set.  "scans" is the maximum number of JTAG
@@ -138,7 +183,7 @@ bool riscv_batch_full(struct riscv_batch *batch);
  * OpenOCD that are based on batches.
  */
 int riscv_batch_run_from(struct riscv_batch *batch, size_t start_idx,
-		struct riscv_scan_delays delays, bool resets_delays,
+		const struct riscv_scan_delays *delays, bool resets_delays,
 		size_t reset_delays_after);
 
 /* Get the number of scans successfully executed form this batch. */