fuzev2: prevent button light flickering when accessing µSD
[kugel-rb.git] / firmware / hotswap.c
blob79595e45914d554f9c1fc8ad42a629a2dba2636f
1 /***************************************************************************
2 * __________ __ ___.
3 * Open \______ \ ____ ____ | | _\_ |__ _______ ___
4 * Source | _// _ \_/ ___\| |/ /| __ \ / _ \ \/ /
5 * Jukebox | | ( <_> ) \___| < | \_\ ( <_> > < <
6 * Firmware |____|_ /\____/ \___ >__|_ \|___ /\____/__/\_ \
7 * \/ \/ \/ \/ \/
8 * $Id$
10 * Copyright (C) 2004 by Jens Arnold
12 * This program is free software; you can redistribute it and/or
13 * modify it under the terms of the GNU General Public License
14 * as published by the Free Software Foundation; either version 2
15 * of the License, or (at your option) any later version.
17 * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
18 * KIND, either express or implied.
20 ****************************************************************************/
21 #include <stdbool.h>
22 #include "config.h"
23 #if (CONFIG_STORAGE & STORAGE_MMC)
24 #include "ata_mmc.h"
25 #else
26 #include "hotswap.h"
27 #endif
29 /* helper function to extract n (<=32) bits from an arbitrary position.
30 counting from MSB to LSB */
31 unsigned long card_extract_bits(
32 const unsigned long *p, /* the start of the bitfield array */
33 unsigned int start, /* bit no. to start reading */
34 unsigned int size) /* how many bits to read */
36 unsigned int long_index, bit_index;
37 unsigned long result;
39 /* we assume words of CSD/CID are stored most significant word first */
40 start = 127 - start;
42 long_index = start / 32;
43 bit_index = start % 32;
45 result = p[long_index] << bit_index;
47 if (bit_index + size > 32) /* crossing longword boundary */
48 result |= p[long_index+1] >> (32 - bit_index);
50 result >>= 32 - size;
52 return result;