static unsigned int regmap_debugfs_get_dump_start()

in regmap/regmap-debugfs.c [95:179]

• 61 lines of code
• 11 McCabe index (conditional complexity)

static unsigned int regmap_debugfs_get_dump_start(struct regmap *map,
						  unsigned int base,
						  loff_t from,
						  loff_t *pos)
{
	struct regmap_debugfs_off_cache *c = NULL;
	loff_t p = 0;
	unsigned int i, ret;
	unsigned int fpos_offset;
	unsigned int reg_offset;

	/* Suppress the cache if we're using a subrange */
	if (base)
		return base;

	/*
	 * If we don't have a cache build one so we don't have to do a
	 * linear scan each time.
	 */
	mutex_lock(&map->cache_lock);
	i = base;
	if (list_empty(&map->debugfs_off_cache)) {
		for (; i <= map->max_register; i += map->reg_stride) {
			/* Skip unprinted registers, closing off cache entry */
			if (!regmap_printable(map, i)) {
				if (c) {
					c->max = p - 1;
					c->max_reg = i - map->reg_stride;
					list_add_tail(&c->list,
						      &map->debugfs_off_cache);
					c = NULL;
				}

				continue;
			}

			/* No cache entry?  Start a new one */
			if (!c) {
				c = kzalloc(sizeof(*c), GFP_KERNEL);
				if (!c) {
					regmap_debugfs_free_dump_cache(map);
					mutex_unlock(&map->cache_lock);
					return base;
				}
				c->min = p;
				c->base_reg = i;
			}

			p += map->debugfs_tot_len;
		}
	}

	/* Close the last entry off if we didn't scan beyond it */
	if (c) {
		c->max = p - 1;
		c->max_reg = i - map->reg_stride;
		list_add_tail(&c->list,
			      &map->debugfs_off_cache);
	}

	/*
	 * This should never happen; we return above if we fail to
	 * allocate and we should never be in this code if there are
	 * no registers at all.
	 */
	WARN_ON(list_empty(&map->debugfs_off_cache));
	ret = base;

	/* Find the relevant block:offset */
	list_for_each_entry(c, &map->debugfs_off_cache, list) {
		if (from >= c->min && from <= c->max) {
			fpos_offset = from - c->min;
			reg_offset = fpos_offset / map->debugfs_tot_len;
			*pos = c->min + (reg_offset * map->debugfs_tot_len);
			mutex_unlock(&map->cache_lock);
			return c->base_reg + (reg_offset * map->reg_stride);
		}

		*pos = c->max;
		ret = c->max_reg;
	}
	mutex_unlock(&map->cache_lock);

	return ret;
}