From c72dee7352106ae99223b72f54c53868e7e15216 Mon Sep 17 00:00:00 2001
From: koolkdev <koolkdev@gmail.com>
Date: Sun, 26 Mar 2017 00:05:10 +0300
Subject: [PATCH] Add sd_fat.c - access to the SD FAT32 in FS main thread

---
 ios_fs/source/sd_fat.c | 94 ++++++++++++++++++++++++++++++++++++++++++
 ios_fs/source/sd_fat.h |  8 ++++
 2 files changed, 102 insertions(+)
 create mode 100644 ios_fs/source/sd_fat.c
 create mode 100644 ios_fs/source/sd_fat.h

diff --git a/ios_fs/source/sd_fat.c b/ios_fs/source/sd_fat.c
new file mode 100644
index 0000000..76ae643
--- /dev/null
+++ b/ios_fs/source/sd_fat.c
@@ -0,0 +1,94 @@
+#include <stdio.h>
+#include "types.h"
+#include "imports.h"
+#include "devices.h"
+#include "sdio.h"
+#include "text.h"
+#include "sd_fat.h"
+
+unsigned char sd_io_buffer[0x40000]  __attribute__((aligned(0x40))) __attribute__((section(".io_buffer")));
+unsigned int fat_sector = 0;
+
+#define PARTITION_TYPE_FAT32		0x0c
+#define PARTITION_TYPE_FAT32_CHS	0x0b
+
+#define MBR_SIGNATURE				0x55AA
+#define EBR_SIGNATURE				MBR_SIGNATURE
+
+#define PARTITION_BOOTABLE			0x80 /* Bootable (active) */
+#define PARTITION_NONBOOTABLE		0x00 /* Non-bootable */
+#define PARTITION_TYPE_GPT			0xEE /* Indicates that a GPT header is available */
+
+typedef struct _PARTITION_RECORD {
+	u8 status;							  /* Partition status; see above */
+	u8 chs_start[3];						/* Cylinder-head-sector address to first block of partition */
+	u8 type;								/* Partition type; see above */
+	u8 chs_end[3];						  /* Cylinder-head-sector address to last block of partition */
+	u32 lba_start;						  /* Local block address to first sector of partition */
+	u32 block_count;						/* Number of blocks in partition */
+} __attribute__((__packed__)) PARTITION_RECORD;
+
+
+typedef struct _MASTER_BOOT_RECORD {
+	u8 code_area[446];					  /* Code area; normally empty */
+	PARTITION_RECORD partitions[4];		 /* 4 primary partitions */
+	u16 signature;						  /* MBR signature; 0xAA55 */
+} __attribute__((__packed__)) MASTER_BOOT_RECORD;
+
+int sd_fat_read(unsigned long sector, unsigned char *buffer, unsigned long sector_count)
+{
+	// It seems that sdcard_readwrite overwrite more bytes than requested with 0xff.... So I use io_buffer to read it.
+	if (sector_count * SDIO_BYTES_PER_SECTOR > sizeof(sd_io_buffer)) return 0;
+	int result = sdcard_readwrite(SDIO_READ, sd_io_buffer, sector_count, SDIO_BYTES_PER_SECTOR, fat_sector + sector, NULL, DEVICE_ID_SDCARD_PATCHED);
+	if (result) return 0;
+	memcpy(buffer, sd_io_buffer, sector_count * SDIO_BYTES_PER_SECTOR);
+	return 1;
+}
+
+int sd_fat_write(unsigned long sector, unsigned char *buffer, unsigned long sector_count)
+{
+	if (sector_count * SDIO_BYTES_PER_SECTOR > sizeof(sd_io_buffer)) return 0;
+	int result = sdcard_readwrite(SDIO_WRITE, buffer, sector_count, SDIO_BYTES_PER_SECTOR, fat_sector + sector, NULL, DEVICE_ID_SDCARD_PATCHED);
+	return result ? 0 : 1;
+}
+
+int InitSDCardFAT32()
+{
+	MASTER_BOOT_RECORD *mbr = (MASTER_BOOT_RECORD*)sd_io_buffer;
+	memset(mbr, 0, SDIO_BYTES_PER_SECTOR);
+
+	int result = sdcard_readwrite(SDIO_READ, mbr, 1, SDIO_BYTES_PER_SECTOR, 0, NULL, DEVICE_ID_SDCARD_PATCHED);
+	if(result != 0)
+	{
+		_printf(20, 40, "SD card read failed %i", result);
+		return result;
+	}
+
+	if (mbr->signature != MBR_SIGNATURE) {
+		_printf(20, 40, "SD not MBR");
+		return -1;
+	}
+
+	if (mbr->partitions[0].status != PARTITION_BOOTABLE && mbr->partitions[0].status != PARTITION_NONBOOTABLE) {
+		_printf(20, 40, "Invalid paritition status");
+		return -1;
+	}
+
+	if (mbr->partitions[0].type != PARTITION_TYPE_FAT32 && mbr->partitions[0].type != PARTITION_TYPE_FAT32_CHS) {
+		_printf(20, 40, "First paritition not FAT32");
+		return -1;
+	}
+
+	fat_sector = le32(mbr->partitions[0].lba_start);
+	
+	fl_init();
+
+	result = fl_attach_media(sd_fat_read, sd_fat_write);
+	if (result != FAT_INIT_OK)
+	{
+		_printf(20, 40, "FAT32 attach failed %i", result);
+		return result; 
+	}
+
+	return 0;
+}
diff --git a/ios_fs/source/sd_fat.h b/ios_fs/source/sd_fat.h
new file mode 100644
index 0000000..e9a3e07
--- /dev/null
+++ b/ios_fs/source/sd_fat.h
@@ -0,0 +1,8 @@
+#ifndef _DS_FAT_H_
+#define _DS_FAT_H_
+
+#include "fat/fat_filelib.h"
+
+int InitSDCardFAT32();
+
+#endif // _FAT32_FORMAT_H_