1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
|
/* -*- c -*- */
/*
* Copyright 2008-2011 Ettus Research LLC
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#include "sd.h"
#include "memory_map.h"
#include "stdint.h"
#include "stdio.h"
static inline void
sd_packarg(unsigned char *argument,unsigned int value)
{
argument[3] = (unsigned char)(value >> 24);
argument[2] = (unsigned char)(value >> 16);
argument[1] = (unsigned char)(value >> 8);
argument[0] = (unsigned char)(value);
}
int
sd_init(void)
{
unsigned char response[5];
unsigned char argument[4];
int i,j;
for(i=0;i<4;i++)
argument[i] = 0;
// Set clock to less than 400 kHz to start out
sdspi_regs->clkdiv = 128;
// Delay at least 74 cycles
sd_assert_cs();
for(i = 0; i < 100; i++)
sd_send_byte(SD_IDLE);
sd_deassert_cs();
// Initialization Sequence -- CMD0 CMD55 ACMD41 CMD58
// Put card in idle state
if(sd_send_command(SD_CMD0,SD_CMD0_R,response,argument)==0)
return 0; // Something went wrong in command
j = 0;
do {
j++;
if(sd_send_command(SD_CMD55,SD_CMD55_R,response,argument)==1)
sd_send_command(SD_ACMD41,SD_ACMD41_R,response,argument);
else
j = SD_IDLE_WAIT_MAX;
}
while(((response[0] & SD_MSK_IDLE) == SD_MSK_IDLE) && (j < SD_IDLE_WAIT_MAX));
if(j>= SD_IDLE_WAIT_MAX) // IDLE timeout exceeded, card asleep
return 0;
// CMD58 reads the SD card capabilities
if(sd_send_command(SD_CMD58,SD_CMD58_R,response,argument)==0)
return 0; // CMD58 FAIL
if((response[2] & SD_MSK_OCR_33) != SD_MSK_OCR_33)
return 0; // Card doesn't do 3.3V
//printf("OCR = %x %x %x %x\n",response[0],response[1],response[2],response[3]);
// Set blocklen here
sd_packarg(argument,SD_BLOCKLEN);
if(sd_send_command(SD_CMD16,SD_CMD16_R,response,argument)==0)
return 0; // Set Blocklen failed
// Reset back to high speed
sdspi_regs->clkdiv = 4;
//puts("finished init\n");
return 1;
}
int sd_send_command(unsigned char cmd,unsigned char response_type,
unsigned char *response,unsigned char *argument)
{
int i;
char response_length;
unsigned char tmp;
sd_assert_cs();
sd_send_byte((cmd & 0x3F) | 0x40);
for(i=3;i>=0;i--)
sd_send_byte(argument[i]);
sd_send_byte(SD_CRC); // Always the same
response_length = 0;
switch(response_type)
{
case SD_R1:
case SD_R1B:
response_length = 1;
break;
case SD_R2:
response_length = 2;
break;
case SD_R3:
response_length = 5;
break;
default:
break;
}
// Wait for a response, which will have a 0 start bit
i = 0;
do
{
tmp = sd_rcv_byte();
i++;
}
while(((tmp & 0x80) != 0) && i < SD_CMD_TIMEOUT);
if(i>= SD_CMD_TIMEOUT)
{
sd_deassert_cs();
//puts("cmd send timeout\n");
return 0;
}
for(i=response_length-1; i>=0; i--)
{
response[i] = tmp;
tmp = sd_rcv_byte();
}
i = 0;
if(response_type == SD_R1B)
{
do
{
i++;
tmp = sd_rcv_byte();
}
while(tmp != SD_IDLE);
sd_send_byte(SD_IDLE);
}
//puts("send cmd success\n");
sd_deassert_cs();
return 1;
}
int
sd_read_block (unsigned int blockaddr, unsigned char *buf)
{
unsigned char response[5];
unsigned char argument[4];
unsigned int i = 0;
unsigned char tmp;
blockaddr <<= SD_BLOCKLEN_NBITS;
sd_packarg(argument,blockaddr);
if(sd_send_command(SD_CMD17,SD_CMD17_R,response,argument)==0)
return 0; //Failed READ;
if(response[0] != 0)
return 0; //Misaligned READ
sd_assert_cs();
i = 0;
do
{
tmp = sd_rcv_byte();
i++;
}
while((tmp == 0xFF) && (i < SD_RD_TIMEOUT));
if((i>= SD_RD_TIMEOUT) ||((tmp & SD_MSK_TOK_DATAERROR) == 0))
{
sd_send_byte(SD_IDLE); // Send a dummy before quitting
return 0; // Data ERROR
}
for(i=0;i<SD_BLOCKLEN;i++)
buf[i] = sd_rcv_byte();
return 1;
}
int
sd_write_block(unsigned int blockaddr, const unsigned char *buf)
{
// FIXME not implemented yet
return 0;
}
|
