libflashrom,writeprotect: add flashrom_wp_get_available_ranges()

Generate list of available ranges by enumerating all possible values
that range bits (BPx, TB, ...) can take and using the chip's range
decoding function to get the range that is selected by each one.

BUG=b:195381327,b:153800563
BRANCH=none
TEST=flashrom --wp-list

Change-Id: Id51f038f03305c8536d80313e52f77d27835f34d
Signed-off-by: Nikolai Artemiev <nartemiev@google.com>
Reviewed-on: https://review.coreboot.org/c/flashrom/+/58481
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Nico Huber <nico.h@gmx.de>

1 files changed, 73 insertions, 0 deletions

diff --git a/libflashrom.c b/libflashrom.c
index f0b9cfda..f2288fef 100644
--- a/libflashrom.c
+++ b/libflashrom.c
@@ -747,4 +747,77 @@ enum flashrom_wp_result flashrom_wp_read_cfg(struct flashrom_wp_cfg *cfg, struct
 	return FLASHROM_WP_ERR_OTHER;
 }
 
+/**
+ * @brief Get a list of protection ranges supported by the flash chip.
+ *
+ * @param[out] ranges Points to a pointer of type struct flashrom_wp_ranges
+ *                    that will be set if available ranges are found. Finding
+ *                    available ranges may not always be possible, even if the
+ *                    chip's protection range can be read or modified. *ranges
+ *                    must be freed using @ref flashrom_wp_ranges_free.
+ * @param[in] flash   The flash context used to access the chip.
+ * @return  0 on success
+ *         >0 on failure
+ */
+enum flashrom_wp_result flashrom_wp_get_available_ranges(struct flashrom_wp_ranges **list, struct flashrom_flashctx *flash)
+{
+	/*
+	 * TODO: Call custom implementation if the programmer is opaque, as
+	 * direct WP operations require SPI access. We actually can't implement
+	 * this in linux_mtd right now, but we should adopt a proper generic
+	 * architechure to match the read and write functions anyway.
+	 */
+	if (flash->mst->buses_supported & BUS_SPI)
+		return wp_get_available_ranges(list, flash);
+
+	return FLASHROM_WP_ERR_OTHER;
+}
+
+/**
+ * @brief Get a number of protection ranges in a range list.
+ *
+ * @param[in]  ranges The range list to get the count from.
+ * @return Number of ranges in the list.
+ */
+size_t flashrom_wp_ranges_get_count(const struct flashrom_wp_ranges *list)
+{
+	return list->count;
+}
+
+/**
+ * @brief Get a protection range from a range list.
+ *
+ * @param[out] start  Points to a size_t to write the range's start to.
+ * @param[out] len    Points to a size_t to write the range's length to.
+ * @param[in]  ranges The range list to get the range from.
+ * @param[in]  index  Index of the range to get.
+ * @return  0 on success
+ *         >0 on failure
+ */
+enum flashrom_wp_result flashrom_wp_ranges_get_range(size_t *start, size_t *len, const struct flashrom_wp_ranges *list, unsigned int index)
+{
+	if (index >= list->count)
+		return FLASHROM_WP_ERR_OTHER;
+
+	*start = list->ranges[index].start;
+	*len = list->ranges[index].len;
+
+	return 0;
+}
+
+/**
+ * @brief Free a WP range list.
+ *
+ * @param[out] cfg Pointer to the flashrom_wp_ranges to free.
+ */
+void flashrom_wp_ranges_release(struct flashrom_wp_ranges *list)
+{
+	if (!list)
+		return;
+
+	free(list->ranges);
+	free(list);
+}
+
+
 /** @} */ /* end flashrom-wp */