o add snes fatfs dummy

o add fatfs custom chip to bsnes
o finishes fatfs linux backend smaple

tools/bsnes/chip/fatfs/diskio.cpp

@@ -0,0 +1,168 @@
+
+#include "integer.h"
+#include "diskio.h"
+
+static volatile
+DSTATUS Stat = STA_NOINIT;  /* Disk status */
+
+
+/* Interface
+** Scratch Buffer
+addr        3 byte            
+size        1 byte
+
+** Call Interface
+cmd         1 byte
+sector      4 bytes
+count       1 byte
+return      1 byte
+
+** Commands
+    * disk_init
+    * disk_read
+    * disk_write
+*/ 
+
+/*-----------------------------------------------------------------------*/
+/* Initialize Disk Drive                                                 */
+/*-----------------------------------------------------------------------*/
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <unistd.h>
+#include <fcntl.h>
+#include <sys/mman.h>
+#include <string.h>
+
+#define IMAGE_NAME "disk00.vfat"
+
+BYTE  *image_addr;
+
+DSTATUS disk_initialize (BYTE drv) {
+    if (drv) return STA_NOINIT;             /* Supports only single drive */
+
+    Stat |= STA_NOINIT;
+
+    int fd = open(IMAGE_NAME, O_RDWR);
+    if (fd == -1) {
+   	    perror("Error opening file for writing");
+   	    exit(EXIT_FAILURE);
+      }
+
+    int size = lseek(fd,0,SEEK_END);
+    lseek(fd,0,SEEK_SET);
+    printf("Open Image (size %i)\n",size);
+    
+    image_addr = (BYTE*)mmap(0, size, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0);
+    if (image_addr == MAP_FAILED) {
+	    close(fd);
+	    perror("Error mmapping the file");
+	    exit(EXIT_FAILURE);
+    }
+    
+    Stat &= ~STA_NOINIT;                    /* When device goes ready, clear STA_NOINIT */
+    return Stat;
+}
+
+
+/*-----------------------------------------------------------------------*/
+/* Return Disk Status                                                    */
+/*-----------------------------------------------------------------------*/
+
+DSTATUS disk_status (BYTE drv){
+    if (drv) return STA_NOINIT;     /* Supports only single drive */
+    return Stat;
+}
+
+
+/*-----------------------------------------------------------------------*/
+/* Read Sector(s)                                                        */
+/*-----------------------------------------------------------------------*/
+
+DRESULT disk_read (
+    BYTE drv,       /* Physical drive nmuber (0) */
+    BYTE *buff,     /* Data buffer to store read data */
+    DWORD sector,   /* Sector number (LBA) */
+    BYTE count      /* Sector count (1..255) */
+)
+{
+    BYTE c, iord_l, iord_h;
+    if (drv || !count) return RES_PARERR;
+    if (Stat & STA_NOINIT) return RES_NOTRDY;
+
+    DWORD offset = sector  * 512;
+    int size = count * 512;
+    printf("disk_read: sector=%li count=%i addr=%p off=%li size=%i\n",sector,count,image_addr + offset,offset,size);
+    memcpy(buff,image_addr + offset,size);
+    return RES_OK;
+}
+
+/*-----------------------------------------------------------------------*/
+/* Write Sector(s)                                                       */
+/*-----------------------------------------------------------------------*/
+
+#if _READONLY == 0
+DRESULT disk_write (
+    BYTE drv,           /* Physical drive nmuber (0) */
+    const BYTE *buff,   /* Data to be written */
+    DWORD sector,       /* Sector number (LBA) */
+    BYTE count          /* Sector count (1..255) */
+)
+{
+
+    if (drv || !count) return RES_PARERR;
+    if (Stat & STA_NOINIT) return RES_NOTRDY;
+
+    DWORD offset = sector  * 512;
+    int size = count * 512;
+    printf("disk_write: sector=%li count=%i addr=%p off=%li size=%i\n",sector,count,image_addr + offset,offset,size);
+    memcpy(image_addr + offset,buff,size);
+    return RES_OK;
+}
+#endif /* _READONLY */
+
+/*-----------------------------------------------------------------------*/
+/* Miscellaneous Functions                                               */
+/*-----------------------------------------------------------------------*/
+
+#if _USE_IOCTL != 0
+DRESULT disk_ioctl (
+    BYTE drv,       /* Physical drive nmuber (0) */
+    BYTE ctrl,      /* Control code */
+    void *buff      /* Buffer to send/receive data block */
+)
+{
+    BYTE n, w, ofs, dl, dh, *ptr = (BYTE*)buff;
+
+
+    if (drv) return RES_PARERR;
+    if (Stat & STA_NOINIT) return RES_NOTRDY;
+
+    switch (ctrl) {
+        case GET_SECTOR_COUNT : /* Get number of sectors on the disk (DWORD) */
+            printf("disk_ioctl: GET_SECTOR_COUNT\n");
+            ofs = 60; w = 2; n = 0;
+            break;
+
+        case GET_SECTOR_SIZE :  /* Get sectors on the disk (WORD) */
+            printf("disk_ioctl: GET_SECTOR_SIZE\n");
+            *(WORD*)buff = 512;
+            return RES_OK;
+
+        case GET_BLOCK_SIZE :   /* Get erase block size in sectors (DWORD) */
+            printf("disk_ioctl: GET_BLOCK_SIZE\n");
+            *(DWORD*)buff = 32;
+            return RES_OK;
+
+        default:
+            return RES_PARERR;
+    }
+    return RES_OK;
+}
+#endif /* _USE_IOCTL != 0 */
+
+
+
+