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Import SD handling from http://www.roland-riegel.de/sd-reader/index.html Use smaller build options
author Matt Johnston <matt@ucc.asn.au>
date Tue, 25 Jun 2013 13:55:11 +0800
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18:021e6e0006f4 19:5f9a40d6991b
1
2 /*
3 * Copyright (c) 2006-2012 by Roland Riegel <[email protected]>
4 *
5 * This file is free software; you can redistribute it and/or modify
6 * it under the terms of either the GNU General Public License version 2
7 * or the GNU Lesser General Public License version 2.1, both as
8 * published by the Free Software Foundation.
9 */
10
11 #include "byteordering.h"
12 #include "partition.h"
13 #include "partition_config.h"
14 #include "sd-reader_config.h"
15
16 #include <string.h>
17
18 #if USE_DYNAMIC_MEMORY
19 #include <stdlib.h>
20 #endif
21
22 /**
23 * \addtogroup partition Partition table support
24 *
25 * Support for reading partition tables and access to partitions.
26 *
27 * @{
28 */
29 /**
30 * \file
31 * Partition table implementation (license: GPLv2 or LGPLv2.1)
32 *
33 * \author Roland Riegel
34 */
35
36 /**
37 * \addtogroup partition_config Configuration of partition table support
38 * Preprocessor defines to configure the partition support.
39 */
40
41 #if !USE_DYNAMIC_MEMORY
42 static struct partition_struct partition_handles[PARTITION_COUNT];
43 #endif
44
45 /**
46 * Opens a partition.
47 *
48 * Opens a partition by its index number and returns a partition
49 * handle which describes the opened partition.
50 *
51 * \note This function does not support extended partitions.
52 *
53 * \param[in] device_read A function pointer which is used to read from the disk.
54 * \param[in] device_read_interval A function pointer which is used to read in constant intervals from the disk.
55 * \param[in] device_write A function pointer which is used to write to the disk.
56 * \param[in] device_write_interval A function pointer which is used to write a data stream to disk.
57 * \param[in] index The index of the partition which should be opened, range 0 to 3.
58 * A negative value is allowed as well. In this case, the partition opened is
59 * not checked for existance, begins at offset zero, has a length of zero
60 * and is of an unknown type. Use this in case you want to open the whole device
61 * as a single partition (e.g. for "super floppy" use).
62 * \returns 0 on failure, a partition descriptor on success.
63 * \see partition_close
64 */
65 struct partition_struct* partition_open(device_read_t device_read, device_read_interval_t device_read_interval, device_write_t device_write, device_write_interval_t device_write_interval, int8_t index)
66 {
67 struct partition_struct* new_partition = 0;
68 uint8_t buffer[0x10];
69
70 if(!device_read || !device_read_interval || index >= 4)
71 return 0;
72
73 if(index >= 0)
74 {
75 /* read specified partition table index */
76 if(!device_read(0x01be + index * 0x10, buffer, sizeof(buffer)))
77 return 0;
78
79 /* abort on empty partition entry */
80 if(buffer[4] == 0x00)
81 return 0;
82 }
83
84 /* allocate partition descriptor */
85 #if USE_DYNAMIC_MEMORY
86 new_partition = malloc(sizeof(*new_partition));
87 if(!new_partition)
88 return 0;
89 #else
90 new_partition = partition_handles;
91 uint8_t i;
92 for(i = 0; i < PARTITION_COUNT; ++i)
93 {
94 if(new_partition->type == PARTITION_TYPE_FREE)
95 break;
96
97 ++new_partition;
98 }
99 if(i >= PARTITION_COUNT)
100 return 0;
101 #endif
102
103 memset(new_partition, 0, sizeof(*new_partition));
104
105 /* fill partition descriptor */
106 new_partition->device_read = device_read;
107 new_partition->device_read_interval = device_read_interval;
108 new_partition->device_write = device_write;
109 new_partition->device_write_interval = device_write_interval;
110
111 if(index >= 0)
112 {
113 new_partition->type = buffer[4];
114 new_partition->offset = read32(&buffer[8]);
115 new_partition->length = read32(&buffer[12]);
116 }
117 else
118 {
119 new_partition->type = 0xff;
120 }
121
122 return new_partition;
123 }
124
125 /**
126 * Closes a partition.
127 *
128 * This function destroys a partition descriptor which was
129 * previously obtained from a call to partition_open().
130 * When this function returns, the given descriptor will be
131 * invalid.
132 *
133 * \param[in] partition The partition descriptor to destroy.
134 * \returns 0 on failure, 1 on success.
135 * \see partition_open
136 */
137 uint8_t partition_close(struct partition_struct* partition)
138 {
139 if(!partition)
140 return 0;
141
142 /* destroy partition descriptor */
143 #if USE_DYNAMIC_MEMORY
144 free(partition);
145 #else
146 partition->type = PARTITION_TYPE_FREE;
147 #endif
148
149 return 1;
150 }
151
152 /**
153 * @}
154 */
155