FWU: Add helper functions for accessing FWU metadata

Add weak functions for getting the update index value and dfu
alternate number needed for FWU Multi Bank update
functionality.

The current implementation for getting the update index value is for
platforms with 2 banks. If a platform supports more than 2 banks, it
can implement it's own function. The function to get the dfu alternate
number has been added for platforms with GPT partitioned storage
devices. Platforms with other storage partition scheme need to
implement their own function.

Signed-off-by: Sughosh Ganu <sughosh.ganu@linaro.org>
Reviewed-by: Patrick Delaunay <patrick.delaunay@foss.st.com>
Acked-by: Etienne Carriere <etienne.carriere@linaro.org>
Reviewed-by: Ilias Apalodimas <ilias.apalodimas@linaro.org>

2 files changed, 150 insertions, 0 deletions

diff --git a/lib/fwu_updates/fwu.c b/lib/fwu_updates/fwu.c
index e92533ea65c..e73d5f11ff7 100644
--- a/lib/fwu_updates/fwu.c
+++ b/lib/fwu_updates/fwu.c
@@ -472,3 +472,30 @@ int fwu_clear_accept_image(efi_guid_t *img_type_id, u32 bank)
 	return fwu_clrset_image_accept(img_type_id, bank,
 				       IMAGE_ACCEPT_CLEAR);
 }
+
+/**
+ * fwu_plat_get_update_index() - Get the value of the update bank
+ * @update_idx: Bank number to which images are to be updated
+ *
+ * Get the value of the bank(partition) to which the update needs to be
+ * made.
+ *
+ * Note: This is a weak function and platforms can override this with
+ * their own implementation for selection of the update bank.
+ *
+ * Return: 0 if OK, -ve on error
+ *
+ */
+__weak int fwu_plat_get_update_index(uint *update_idx)
+{
+	int ret;
+	u32 active_idx;
+
+	ret = fwu_get_active_index(&active_idx);
+	if (ret < 0)
+		return -1;
+
+	*update_idx = (active_idx + 1) % CONFIG_FWU_NUM_BANKS;
+
+	return ret;
+}
diff --git a/lib/fwu_updates/fwu_gpt.c b/lib/fwu_updates/fwu_gpt.c
new file mode 100644
index 00000000000..21a573c9342
--- /dev/null
+++ b/lib/fwu_updates/fwu_gpt.c
@@ -0,0 +1,123 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright (c) 2022, Linaro Limited
+ */
+
+#include <blk.h>
+#include <dfu.h>
+#include <efi.h>
+#include <efi_loader.h>
+#include <fwu.h>
+#include <log.h>
+#include <part.h>
+
+#include <linux/errno.h>
+
+static int get_gpt_dfu_identifier(struct blk_desc *desc, efi_guid_t *image_guid)
+{
+	int i;
+	struct disk_partition info;
+	efi_guid_t unique_part_guid;
+
+	for (i = 1; i < MAX_SEARCH_PARTITIONS; i++) {
+		if (part_get_info(desc, i, &info))
+			continue;
+		uuid_str_to_bin(info.uuid, unique_part_guid.b,
+				UUID_STR_FORMAT_GUID);
+
+		if (!guidcmp(&unique_part_guid, image_guid))
+			return i;
+	}
+
+	log_err("No partition found with image_guid %pUs\n", image_guid);
+	return -ENOENT;
+}
+
+static int fwu_alt_num_for_dfu_dev(struct dfu_entity *dfu, int dev_num,
+				   int part, unsigned char dfu_dev,
+				   u8 *alt_num)
+{
+	int ret;
+
+	switch(dfu_dev) {
+	case DFU_DEV_MMC:
+		if (dfu->layout == DFU_RAW_ADDR &&
+		    dfu->data.mmc.dev_num == dev_num &&
+		    dfu->data.mmc.part == part) {
+			*alt_num = dfu->alt;
+			ret = 0;
+		} else {
+			ret = -ENOENT;
+		}
+		break;
+	default:
+		ret = -ENOENT;
+	}
+
+	return ret;
+}
+
+static int fwu_gpt_get_alt_num(struct blk_desc *desc, efi_guid_t *image_guid,
+			       u8 *alt_num, unsigned char dfu_dev)
+{
+	int ret = -1;
+	int i, part, dev_num;
+	struct dfu_entity *dfu;
+
+	dev_num = desc->devnum;
+	part = get_gpt_dfu_identifier(desc, image_guid);
+	if (part < 0)
+		return -ENOENT;
+
+	ret = dfu_init_env_entities(NULL, NULL);
+	if (ret)
+		goto out;
+
+	i = 0;
+	while (true) {
+		dfu = dfu_get_entity(i++);
+		if (!dfu) {
+			ret = -ENOENT;
+			break;
+		}
+
+		if (dfu->dev_type != dfu_dev)
+			continue;
+
+		ret = fwu_alt_num_for_dfu_dev(dfu, dev_num, part, dfu_dev,
+					      alt_num);
+		if (!ret)
+			break;
+	}
+
+out:
+	dfu_free_entities();
+
+	return ret;
+}
+
+/**
+ * fwu_plat_get_alt_num() - Get the DFU alt number
+ * @dev: FWU metadata device
+ * @image_guid: GUID value of the image for which the alt num is to
+ *              be obtained
+ * @alt_num: The DFU alt number for the image that is to be updated
+ *
+ * Get the DFU alt number for the image that is to be updated. The
+ * image is identified with the image_guid parameter that is passed
+ * to the function.
+ *
+ * Note: This is a weak function and platforms can override this with
+ * their own implementation for obtaining the alt number value.
+ *
+ * Return: 0 if OK, -ve on error
+ *
+ */
+__weak int fwu_plat_get_alt_num(struct udevice *dev, efi_guid_t *image_guid,
+				u8 *alt_num)
+{
+	struct fwu_mdata_gpt_blk_priv *priv = dev_get_priv(dev);
+
+	return fwu_gpt_get_alt_num(dev_get_uclass_plat(priv->blk_dev),
+				   image_guid, alt_num, DFU_DEV_MMC);
+}