DNM: add zms_get_num_cycles()

...which calculates the maximum number of times a single
ZMS sector has been recycled. This is to enable estimation
of an RRAM lifetime based on a set of tests.

Signed-off-by: Damian Krolik <[email protected]>

Author: Damian-Nordic

include/zephyr/fs/zms.h

@@ -235,6 +235,7 @@ size_t zms_active_sector_free_space(struct zms_fs *fs);
  */
 int zms_sector_use_next(struct zms_fs *fs);
 
+uint32_t zms_get_num_cycles(struct zms_fs *fs);
 /**
  * @}
  */

subsys/fs/zms/zms.c

@@ -20,6 +20,7 @@ LOG_MODULE_REGISTER(fs_zms, CONFIG_ZMS_LOG_LEVEL);
 
 static int zms_prev_ate(struct zms_fs *fs, uint64_t *addr, struct zms_ate *ate);
 static int zms_ate_valid(struct zms_fs *fs, const struct zms_ate *entry);
+static int zms_get_full_sector_cycle(struct zms_fs *fs, uint64_t addr, uint32_t *cycle_cnt);
 static int zms_get_sector_cycle(struct zms_fs *fs, uint64_t addr, uint8_t *cycle_cnt);
 static int zms_get_sector_header(struct zms_fs *fs, uint64_t addr, struct zms_ate *empty_ate,
 				 struct zms_ate *close_ate);
@@ -754,7 +755,7 @@ static int zms_add_gc_done_ate(struct zms_fs *fs)
 static int zms_add_empty_ate(struct zms_fs *fs, uint64_t addr)
 {
 	struct zms_ate empty_ate;
-	uint8_t cycle_cnt;
+	uint32_t cycle_cnt;
 	int rc = 0;
 	uint64_t previous_ate_wra;
 
@@ -763,11 +764,10 @@ static int zms_add_empty_ate(struct zms_fs *fs, uint64_t addr)
 	LOG_DBG("Adding empty ate at %llx", (uint64_t)(addr + fs->sector_size - fs->ate_size));
 	empty_ate.id = ZMS_HEAD_ID;
 	empty_ate.len = 0xffff;
-	empty_ate.offset = 0U;
 	empty_ate.metadata =
 		FIELD_PREP(ZMS_MAGIC_NUMBER_MASK, ZMS_MAGIC_NUMBER) | ZMS_DEFAULT_VERSION;
 
-	rc = zms_get_sector_cycle(fs, addr, &cycle_cnt);
+	rc = zms_get_full_sector_cycle(fs, addr, &cycle_cnt);
 	if (rc == -ENOENT) {
 		/* sector never used */
 		cycle_cnt = 0;
@@ -777,7 +777,8 @@ static int zms_add_empty_ate(struct zms_fs *fs, uint64_t addr)
 	}
 
 	/* increase cycle counter */
-	empty_ate.cycle_cnt = (cycle_cnt + 1) % BIT(8);
+	empty_ate.full_cycle_cnt = cycle_cnt + 1;
+	empty_ate.cycle_cnt = (uint8_t)empty_ate.full_cycle_cnt;
 	zms_ate_crc8_update(&empty_ate);
 
 	/* Adding empty ate to this sector changes fs->ate_wra value
@@ -818,6 +819,30 @@ static int zms_get_sector_cycle(struct zms_fs *fs, uint64_t addr, uint8_t *cycle
 	return -ENOENT;
 }
 
+static int zms_get_full_sector_cycle(struct zms_fs *fs, uint64_t addr, uint32_t *cycle_cnt)
+{
+	int rc;
+	struct zms_ate empty_ate;
+	uint64_t empty_addr;
+
+	empty_addr = zms_empty_ate_addr(fs, addr);
+
+	/* read the cycle counter of the current sector */
+	rc = zms_flash_ate_rd(fs, empty_addr, &empty_ate);
+	if (rc < 0) {
+		/* flash error */
+		return rc;
+	}
+
+	if (zms_empty_ate_valid(fs, &empty_ate)) {
+		*cycle_cnt = empty_ate.full_cycle_cnt;
+		return 0;
+	}
+
+	/* there is no empty ATE in this sector */
+	return -ENOENT;
+}
+
 static int zms_get_sector_header(struct zms_fs *fs, uint64_t addr, struct zms_ate *empty_ate,
 				 struct zms_ate *close_ate)
 {
@@ -1828,3 +1853,26 @@ int zms_sector_use_next(struct zms_fs *fs)
 	k_mutex_unlock(&fs->zms_lock);
 	return ret;
 }
+
+uint32_t zms_get_num_cycles(struct zms_fs *fs)
+{
+	uint32_t max_cycle_cnt = 0;
+	uint32_t cycle_cnt;
+	int rc;
+
+	k_mutex_lock(&fs->zms_lock, K_FOREVER);
+
+	for (uint32_t i = 0; i < fs->sector_count; i++) {
+		rc = zms_get_full_sector_cycle(fs, (uint64_t)i << ADDR_SECT_SHIFT, &cycle_cnt);
+
+		if (rc) {
+			continue;
+		}
+
+		max_cycle_cnt = MAX(max_cycle_cnt, cycle_cnt);
+	}
+
+	k_mutex_unlock(&fs->zms_lock);
+
+	return max_cycle_cnt;
+}

subsys/fs/zms/zms_priv.h

@@ -57,8 +57,12 @@ struct zms_ate {
 		/** data field used to store small sized data */
 		uint8_t data[8];
 		struct {
-			/** data offset within sector */
-			uint32_t offset;
+			union {
+				/** data offset within sector */
+				uint32_t offset;
+				/** full cycle count (for empty ATE) */
+				uint32_t full_cycle_cnt;
+			};
 			union {
 				/**
 				 * crc for data: The data CRC is checked only when the whole data