source: uKadecot/trunk/pfatfs/diskio.c@ 154

Last change on this file since 154 was 154, checked in by coas-nagasima, 8 years ago

SDカードの中身を/~/でアクセスできるよう変更
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File size: 3.7 KB
Line 
1/*-----------------------------------------------------------------------*/
2/* PFF - Low level disk control module for Win32 (C)ChaN, 2014 */
3/*-----------------------------------------------------------------------*/
4
5#include <string.h>
6#include "pffconf.h"
7#include "diskio.h"
8
9/*--------------------------------------------------------------------------
10
11 Module Private Functions
12
13---------------------------------------------------------------------------*/
14
15#define MAX_DRIVES 1 /* Max number of physical drives to be used */
16
17#define SZ_RAMDISK 768 /* Size of RAM disk [kB] */
18#define SS_RAMDISK 512 /* Sector size of RAM disk [byte] */
19
20#ifndef _MSC_VER
21#define RamDisk ((unsigned char *)0xfff00000)
22#else
23unsigned char RamDisk[SZ_RAMDISK * 1024];
24extern void win_disk_initialize(void *ramDisk, int size);
25#endif
26
27typedef struct {
28 DSTATUS status;
29 WORD sz_sector;
30 DWORD wofs;
31 DWORD wip;
32 DWORD n_sectors;
33} RD_STAT;
34
35static volatile
36RD_STAT Stat[MAX_DRIVES];
37
38static
39BYTE Buffer[SS_RAMDISK];
40
41static
42int get_status(volatile RD_STAT *stat) {
43 stat->sz_sector = SS_RAMDISK;
44 if(stat->sz_sector < _MIN_SS || stat->sz_sector > _MAX_SS) return 0;
45 stat->n_sectors = SZ_RAMDISK * 1024 / SS_RAMDISK;
46 stat->status = 0;
47 return 1;
48}
49
50/*-----------------------------------------------------------------------*/
51/* Initialize Disk Drive */
52/*-----------------------------------------------------------------------*/
53DSTATUS ramdisk_initialize (void)
54{
55 DSTATUS sta;
56#ifdef _MSC_VER
57 win_disk_initialize(RamDisk, sizeof(RamDisk));
58#endif
59 get_status(&Stat[0]);
60 sta = Stat[0].status;
61 Stat[0].wip = 0;
62
63 return sta;
64}
65
66/*-----------------------------------------------------------------------*/
67/* Get Disk Status */
68/*-----------------------------------------------------------------------*/
69DSTATUS ramdisk_get_status (void)
70{
71 return Stat[0].status;
72}
73
74/*-----------------------------------------------------------------------*/
75/* Read Partial Sector */
76/*-----------------------------------------------------------------------*/
77DRESULT ramdisk_readp (
78 BYTE* buff, /* Data read buffer */
79 DWORD sector, /* Sector number (LBA) */
80 UINT offset, /* Offset in the sector */
81 UINT count /* Byte count */
82)
83{
84 DRESULT res;
85 int dofs;
86
87
88 if(Stat[0].status & STA_NOINIT) return RES_NOTRDY;
89
90 if(sector >= Stat[0].n_sectors || !count || offset + count > Stat[0].sz_sector/* || Stat[0].wip*/) {
91 res = RES_PARERR;
92 }
93 else {
94 if(buff) {
95 dofs = sector * Stat[0].sz_sector;
96 memcpy(buff, &RamDisk[dofs + offset], count);
97 res = RES_OK;
98 }
99 else {
100 res = RES_OK;
101 }
102 }
103
104 return res;
105}
106
107/*-----------------------------------------------------------------------*/
108/* Write Partial Sector */
109/*-----------------------------------------------------------------------*/
110DRESULT ramdisk_writep (
111 const BYTE* buff, /* Pointer to the write data */
112 DWORD sc /* Sector number (LBA), Number of bytes to send */
113)
114{
115 DRESULT res;
116 int dofs;
117
118 if(Stat[0].status & STA_NOINIT) return RES_NOTRDY;
119
120 if(!buff) {
121 if(sc) {
122 Stat[0].wip = sc;
123 Stat[0].wofs = 0;
124 memset(Buffer, 0, sizeof Buffer);
125 res = RES_OK;
126 }
127 else {
128 if(Stat[0].wip) {
129 dofs = Stat[0].wip * Stat[0].sz_sector;
130 memcpy(RamDisk + dofs, Buffer, Stat[0].sz_sector);
131 Stat[0].wip = 0;
132 res = RES_OK;
133 }
134 else {
135 res = RES_OK;
136 }
137 }
138 }
139 else {
140 if(Stat[0].wofs + sc > Stat[0].sz_sector) sc = Stat[0].sz_sector - Stat[0].wofs;
141 memcpy(&Buffer[Stat[0].wofs], buff, sc);
142 Stat[0].wofs += sc;
143 res = RES_OK;
144 }
145
146 return res;
147}
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