1 /*
2 * Copyright (C) 2007 Michael Brown <mbrown@fensystems.co.uk>.
3 *
4 * This program is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU General Public License as
6 * published by the Free Software Foundation; either version 2 of the
7 * License, or any later version.
8 *
9 * This program is distributed in the hope that it will be useful, but
10 * WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
12 * General Public License for more details.
13 *
14 * You should have received a copy of the GNU General Public License
15 * along with this program; if not, write to the Free Software
16 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
17 */
18
19 FILE_LICENCE ( GPL2_OR_LATER );
20
21 #include <gpxe/blockdev.h>
22 #include <gpxe/ramdisk.h>
23
24 /**
25 * @file
26 *
27 * RAM disks
28 *
29 */
30
31 static inline __attribute__ (( always_inline )) struct ramdisk *
block_to_ramdisk(struct block_device * blockdev)32 block_to_ramdisk ( struct block_device *blockdev ) {
33 return container_of ( blockdev, struct ramdisk, blockdev );
34 }
35
36 /**
37 * Read block
38 *
39 * @v blockdev Block device
40 * @v block Block number
41 * @v count Block count
42 * @v buffer Data buffer
43 * @ret rc Return status code
44 */
ramdisk_read(struct block_device * blockdev,uint64_t block,unsigned long count,userptr_t buffer)45 static int ramdisk_read ( struct block_device *blockdev, uint64_t block,
46 unsigned long count, userptr_t buffer ) {
47 struct ramdisk *ramdisk = block_to_ramdisk ( blockdev );
48 unsigned long offset = ( block * blockdev->blksize );
49 unsigned long length = ( count * blockdev->blksize );
50
51 DBGC ( ramdisk, "RAMDISK %p reading [%lx,%lx)\n",
52 ramdisk, offset, length );
53
54 memcpy_user ( buffer, 0, ramdisk->data, offset, length );
55 return 0;
56 }
57
58 /**
59 * Write block
60 *
61 * @v blockdev Block device
62 * @v block Block number
63 * @v count Block count
64 * @v buffer Data buffer
65 * @ret rc Return status code
66 */
ramdisk_write(struct block_device * blockdev,uint64_t block,unsigned long count,userptr_t buffer)67 static int ramdisk_write ( struct block_device *blockdev, uint64_t block,
68 unsigned long count, userptr_t buffer ) {
69 struct ramdisk *ramdisk = block_to_ramdisk ( blockdev );
70 unsigned long offset = ( block * blockdev->blksize );
71 unsigned long length = ( count * blockdev->blksize );
72
73 DBGC ( ramdisk, "RAMDISK %p writing [%lx,%lx)\n",
74 ramdisk, offset, length );
75
76 memcpy_user ( ramdisk->data, offset, buffer, 0, length );
77 return 0;
78 }
79
80 static struct block_device_operations ramdisk_operations = {
81 .read = ramdisk_read,
82 .write = ramdisk_write
83 };
84
init_ramdisk(struct ramdisk * ramdisk,userptr_t data,size_t len,unsigned int blksize)85 int init_ramdisk ( struct ramdisk *ramdisk, userptr_t data, size_t len,
86 unsigned int blksize ) {
87
88 if ( ! blksize )
89 blksize = 512;
90
91 ramdisk->data = data;
92 ramdisk->blockdev.op = &ramdisk_operations;
93 ramdisk->blockdev.blksize = blksize;
94 ramdisk->blockdev.blocks = ( len / blksize );
95
96 return 0;
97 }
98