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1da177e4 LT |
1 | /* |
2 | * MTD primitives for XIP support | |
3 | * | |
4 | * Author: Nicolas Pitre | |
5 | * Created: Nov 2, 2004 | |
6 | * Copyright: (C) 2004 MontaVista Software, Inc. | |
7 | * | |
8 | * This XIP support for MTD has been loosely inspired | |
9 | * by an earlier patch authored by David Woodhouse. | |
10 | * | |
11 | * This program is free software; you can redistribute it and/or modify | |
12 | * it under the terms of the GNU General Public License version 2 as | |
13 | * published by the Free Software Foundation. | |
14 | * | |
15 | * $Id: xip.h,v 1.2 2004/12/01 15:49:10 nico Exp $ | |
16 | */ | |
17 | ||
18 | #ifndef __LINUX_MTD_XIP_H__ | |
19 | #define __LINUX_MTD_XIP_H__ | |
20 | ||
21 | #include <linux/config.h> | |
22 | ||
23 | #ifdef CONFIG_MTD_XIP | |
24 | ||
25 | /* | |
26 | * Function that are modifying the flash state away from array mode must | |
27 | * obviously not be running from flash. The __xipram is therefore marking | |
28 | * those functions so they get relocated to ram. | |
29 | */ | |
30 | #define __xipram __attribute__ ((__section__ (".data"))) | |
31 | ||
32 | /* | |
33 | * We really don't want gcc to guess anything. | |
34 | * We absolutely _need_ proper inlining. | |
35 | */ | |
36 | #include <linux/compiler.h> | |
37 | ||
38 | /* | |
39 | * Each architecture has to provide the following macros. They must access | |
40 | * the hardware directly and not rely on any other (XIP) functions since they | |
41 | * won't be available when used (flash not in array mode). | |
42 | * | |
43 | * xip_irqpending() | |
44 | * | |
45 | * return non zero when any hardware interrupt is pending. | |
46 | * | |
47 | * xip_currtime() | |
48 | * | |
49 | * return a platform specific time reference to be used with | |
50 | * xip_elapsed_since(). | |
51 | * | |
52 | * xip_elapsed_since(x) | |
53 | * | |
54 | * return in usecs the elapsed timebetween now and the reference x as | |
55 | * returned by xip_currtime(). | |
56 | * | |
57 | * note 1: convertion to usec can be approximated, as long as the | |
58 | * returned value is <= the real elapsed time. | |
59 | * note 2: this should be able to cope with a few seconds without | |
60 | * overflowing. | |
97f927a4 TG |
61 | * |
62 | * xip_iprefetch() | |
63 | * | |
64 | * Macro to fill instruction prefetch | |
65 | * e.g. a series of nops: asm volatile (".rep 8; nop; .endr"); | |
1da177e4 LT |
66 | */ |
67 | ||
97f927a4 | 68 | #include <asm/mtd-xip.h> |
1da177e4 | 69 | |
97f927a4 | 70 | #ifndef xip_irqpending |
1da177e4 LT |
71 | |
72 | #warning "missing IRQ and timer primitives for XIP MTD support" | |
73 | #warning "some of the XIP MTD support code will be disabled" | |
74 | #warning "your system will therefore be unresponsive when writing or erasing flash" | |
75 | ||
76 | #define xip_irqpending() (0) | |
77 | #define xip_currtime() (0) | |
78 | #define xip_elapsed_since(x) (0) | |
79 | ||
80 | #endif | |
81 | ||
97f927a4 TG |
82 | #ifndef xip_iprefetch |
83 | #define xip_iprefetch() do { } while (0) | |
84 | #endif | |
85 | ||
1da177e4 LT |
86 | /* |
87 | * xip_cpu_idle() is used when waiting for a delay equal or larger than | |
88 | * the system timer tick period. This should put the CPU into idle mode | |
89 | * to save power and to be woken up only when some interrupts are pending. | |
97f927a4 | 90 | * This should not rely upon standard kernel code. |
1da177e4 | 91 | */ |
97f927a4 | 92 | #ifndef xip_cpu_idle |
1da177e4 LT |
93 | #define xip_cpu_idle() do { } while (0) |
94 | #endif | |
95 | ||
96 | #else | |
97 | ||
98 | #define __xipram | |
99 | ||
100 | #endif /* CONFIG_MTD_XIP */ | |
101 | ||
102 | #endif /* __LINUX_MTD_XIP_H__ */ |