1/*
2 * YAFFS: Yet another FFS. A NAND-flash specific file system.
3 * yaffs_ramdisk.c: yaffs ram disk component
4 *
5 * Copyright (C) 2002 Aleph One Ltd.
6 *
7 * Created by Charles Manning <charles@aleph1.co.uk>
8 *
9 * This program is free software; you can redistribute it and/or modify
10 * it under the terms of the GNU General Public License version 2 as
11 * published by the Free Software Foundation.
12 *
13 */
14
15// This provides a rma disk under yaffs.
16// NB this is not intended for NAND emulation.
17// Use this with dev->useNANDECC enabled, then ECC overheads are not required.
18
19const char *yaffs_ramdisk_c_version = "$Id: yaffs_ramdisk.c,v 1.2 2004/11/22 03:22:25 charles Exp $";
20
21
22#include "yportenv.h"
23
24#include "yaffs_ramdisk.h"
25#include "yaffs_guts.h"
26#include "devextras.h"
27#include "yaffs_packedtags1.h"
28
29
30
31#define SIZE_IN_MB 2
32
33#define BLOCK_SIZE (32 * 528)
34#define BLOCKS_PER_MEG ((1024*1024)/(32 * 512))
35
36
37
38
39
40typedef struct
41{
42	__u8 data[528]; // Data + spare
43} yramdisk_Page;
44
45typedef struct
46{
47	yramdisk_Page page[32]; // The pages in the block
48
49} yramdisk_Block;
50
51
52
53typedef struct
54{
55	yramdisk_Block **block;
56	int nBlocks;
57} yramdisk_Device;
58
59static yramdisk_Device ramdisk;
60
61static int  CheckInit(yaffs_Device *dev)
62{
63	static int initialised = 0;
64
65	int i;
66	int fail = 0;
67	//int nBlocks;
68	int nAllocated = 0;
69
70	if(initialised)
71	{
72		return YAFFS_OK;
73	}
74
75	initialised = 1;
76
77
78	ramdisk.nBlocks = (SIZE_IN_MB * 1024 * 1024)/(16 * 1024);
79
80	ramdisk.block = YMALLOC(sizeof(yramdisk_Block *) * ramdisk.nBlocks);
81
82	if(!ramdisk.block) return 0;
83
84	for(i=0; i <ramdisk.nBlocks; i++)
85	{
86		ramdisk.block[i] = NULL;
87	}
88
89	for(i=0; i <ramdisk.nBlocks && !fail; i++)
90	{
91		if((ramdisk.block[i] = YMALLOC(sizeof(yramdisk_Block))) == 0)
92		{
93			fail = 1;
94		}
95		else
96		{
97			yramdisk_EraseBlockInNAND(dev,i);
98			nAllocated++;
99		}
100	}
101
102	if(fail)
103	{
104		for(i = 0; i < nAllocated; i++)
105		{
106			YFREE(ramdisk.block[i]);
107		}
108		YFREE(ramdisk.block);
109
110		T(YAFFS_TRACE_ALWAYS,("Allocation failed, could only allocate %dMB of %dMB requested.\n",
111		   nAllocated/64,ramdisk.nBlocks * 528));
112		return 0;
113	}
114
115
116	return 1;
117}
118
119int yramdisk_WriteChunkWithTagsToNAND(yaffs_Device *dev,int chunkInNAND,const __u8 *data, yaffs_ExtendedTags *tags)
120{
121	int blk;
122	int pg;
123
124
125	CheckInit(dev);
126
127	blk = chunkInNAND/32;
128	pg = chunkInNAND%32;
129
130
131	if(data)
132	{
133		memcpy(ramdisk.block[blk]->page[pg].data,data,512);
134	}
135
136
137	if(tags)
138	{
139		yaffs_PackedTags1 pt;
140
141		yaffs_PackTags1(&pt,tags);
142		memcpy(&ramdisk.block[blk]->page[pg].data[512],&pt,sizeof(pt));
143	}
144
145	return YAFFS_OK;
146
147}
148
149
150int yramdisk_ReadChunkWithTagsFromNAND(yaffs_Device *dev,int chunkInNAND, __u8 *data, yaffs_ExtendedTags *tags)
151{
152	int blk;
153	int pg;
154
155
156	CheckInit(dev);
157
158	blk = chunkInNAND/32;
159	pg = chunkInNAND%32;
160
161
162	if(data)
163	{
164		memcpy(data,ramdisk.block[blk]->page[pg].data,512);
165	}
166
167
168	if(tags)
169	{
170		yaffs_PackedTags1 pt;
171
172		memcpy(&pt,&ramdisk.block[blk]->page[pg].data[512],sizeof(pt));
173		yaffs_UnpackTags1(tags,&pt);
174
175	}
176
177	return YAFFS_OK;
178}
179
180
181int yramdisk_CheckChunkErased(yaffs_Device *dev,int chunkInNAND)
182{
183	int blk;
184	int pg;
185	int i;
186
187
188	CheckInit(dev);
189
190	blk = chunkInNAND/32;
191	pg = chunkInNAND%32;
192
193
194	for(i = 0; i < 528; i++)
195	{
196		if(ramdisk.block[blk]->page[pg].data[i] != 0xFF)
197		{
198			return YAFFS_FAIL;
199		}
200	}
201
202	return YAFFS_OK;
203
204}
205
206int yramdisk_EraseBlockInNAND(yaffs_Device *dev, int blockNumber)
207{
208
209	CheckInit(dev);
210
211	if(blockNumber < 0 || blockNumber >= ramdisk.nBlocks)
212	{
213		T(YAFFS_TRACE_ALWAYS,("Attempt to erase non-existant block %d\n",blockNumber));
214		return YAFFS_FAIL;
215	}
216	else
217	{
218		memset(ramdisk.block[blockNumber],0xFF,sizeof(yramdisk_Block));
219		return YAFFS_OK;
220	}
221
222}
223
224int yramdisk_InitialiseNAND(yaffs_Device *dev)
225{
226	//dev->useNANDECC = 1; // force on useNANDECC which gets faked.
227						 // This saves us doing ECC checks.
228
229	return YAFFS_OK;
230}
231
232
233