fw: Add pre loaded flash app and flash data storage

- Add per app flash storage
  - Adds four data areas. An app can allocate an area. Once allocated
    the area is tied to the CDI of the app and can only be
    read/written/deallocated by the same app.
- Add two pre loaded app slots to flash
  - Load an app from the first slot at boot. The app digest must match a
    specific digest specified in firmware.
  - Optionally load an app from the second slot
- Add a resetinfo area in FW_RAM which is used to signal an app's intent
  of resetting the system and, optionally, pass data to firmware or the
  next app in a bootchain.

Co-authored-by: Jonas Thörnblad <jonas@tillitis.se>
Co-authored-by: Mikael Ågren <mikael@tillitis.se>
Co-authored-by: Daniel Jobson <jobson@tillitis.se>

hw/application_fpga/fw/tk1/partition_table.c

@@ -0,0 +1,106 @@
+// Copyright (C) 2024 - Tillitis AB
+// SPDX-License-Identifier: GPL-2.0-only
+
+#include <stdint.h>
+#include <tkey/assert.h>
+#include <tkey/lib.h>
+
+#include "blake2s/blake2s.h"
+#include "flash.h"
+#include "partition_table.h"
+#include "proto.h"
+
+static enum part_status part_status;
+
+enum part_status part_get_status(void)
+{
+	return part_status;
+}
+
+static void part_digest(struct partition_table *part_table, uint8_t *out_digest,
+			size_t out_len);
+
+static void part_digest(struct partition_table *part_table, uint8_t *out_digest,
+			size_t out_len)
+{
+	int blake2err = 0;
+
+	uint8_t key[16] = {
+	    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+	};
+
+	assert(part_table != NULL);
+	assert(out_digest != NULL);
+
+	blake2err = blake2s(out_digest, out_len, key, sizeof(key), part_table,
+			    sizeof(struct partition_table));
+
+	assert(blake2err == 0);
+}
+
+// part_table_read reads and verifies the partition table storage,
+// first trying slot 0, then slot 1 if slot 0 does not verify.
+//
+// It stores the partition table in storage.
+//
+// Returns negative values on errors.
+int part_table_read(struct partition_table_storage *storage)
+{
+	uint32_t offset[2] = {
+	    ADDR_PARTITION_TABLE_0,
+	    ADDR_PARTITION_TABLE_1,
+	};
+	uint8_t check_digest[PART_DIGEST_SIZE] = {0};
+
+	if (storage == NULL) {
+		return -1;
+	}
+
+	flash_release_powerdown();
+	(void)memset(storage, 0x00, sizeof(*storage));
+
+	for (int i = 0; i < 2; i++) {
+		if (flash_read_data(offset[i], (uint8_t *)storage,
+				    sizeof(*storage)) != 0) {
+			return -1;
+		}
+		part_digest(&storage->table, check_digest,
+			    sizeof(check_digest));
+
+		if (memeq(check_digest, storage->check_digest,
+			  sizeof(check_digest))) {
+			if (i == 1) {
+				part_status = PART_SLOT0_INVALID;
+			}
+
+			return 0;
+		}
+	}
+
+	return -1;
+}
+
+int part_table_write(struct partition_table_storage *storage)
+{
+	uint32_t offset[2] = {
+	    ADDR_PARTITION_TABLE_0,
+	    ADDR_PARTITION_TABLE_1,
+	};
+
+	if (storage == NULL) {
+		return -1;
+	}
+
+	part_digest(&storage->table, storage->check_digest,
+		    sizeof(storage->check_digest));
+
+	for (int i = 0; i < 2; i++) {
+		flash_sector_erase(offset[i]);
+		if (flash_write_data(offset[i], (uint8_t *)storage,
+				     sizeof(*storage)) != 0) {
+			return -1;
+		}
+	}
+
+	return 0;
+}