fs: add initial code to create the partition table

Makefile

@@ -24,6 +24,7 @@ obj-y += source/shell/flash.o
 obj-y += source/core/flash.o
 
 obj-y += source/fs/block.o
+obj-y += source/fs/part.o
 
 obj = $(addprefix $(BUILD)/, $(obj-y))
 

include/fs/part.h

@@ -0,0 +1,3 @@
+#pragma once
+
+int part_create(struct flash_dev *dev);

source/fs/part.c

@@ -0,0 +1,40 @@
+#include <stdint.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include <flash.h>
+#include <macros.h>
+
+#include <fs/block.h>
+#include <fs/part.h>
+
+struct part_hdr {
+	char magic[8];
+	char rsv[24];
+} __attribute__((packed));
+
+struct part_entry {
+	char label[16];
+	uint32_t start, end;
+	uint32_t flags;
+	uint32_t rsv;
+} __attribute__((packed));
+
+#define PART_MAGIC "FL-PART\x7f"
+
+int part_create(struct flash_dev *dev)
+{
+	struct part_hdr hdr;
+
+	if (block_is_erased(dev, 0, 4 * KIB) != 0 &&
+		flash_erase(dev, 0, 4 * KIB) != 0)
+		return -1;
+
+	memset(&hdr, 0, sizeof hdr);
+	memcpy(hdr.magic, PART_MAGIC, sizeof hdr.magic);
+
+	if (flash_write(dev, 0, &hdr, sizeof hdr) != 0)
+		return -1;
+
+	return 0;
+}