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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. | |
61 | */ | |
62 | ||
63 | #if defined(CONFIG_ARCH_SA1100) || defined(CONFIG_ARCH_PXA) | |
64 | ||
65 | #include <asm/hardware.h> | |
66 | #ifdef CONFIG_ARCH_PXA | |
67 | #include <asm/arch/pxa-regs.h> | |
68 | #endif | |
69 | ||
70 | #define xip_irqpending() (ICIP & ICMR) | |
71 | ||
72 | /* we sample OSCR and convert desired delta to usec (1/4 ~= 1000000/3686400) */ | |
73 | #define xip_currtime() (OSCR) | |
74 | #define xip_elapsed_since(x) (signed)((OSCR - (x)) / 4) | |
75 | ||
76 | #else | |
77 | ||
78 | #warning "missing IRQ and timer primitives for XIP MTD support" | |
79 | #warning "some of the XIP MTD support code will be disabled" | |
80 | #warning "your system will therefore be unresponsive when writing or erasing flash" | |
81 | ||
82 | #define xip_irqpending() (0) | |
83 | #define xip_currtime() (0) | |
84 | #define xip_elapsed_since(x) (0) | |
85 | ||
86 | #endif | |
87 | ||
88 | /* | |
89 | * xip_cpu_idle() is used when waiting for a delay equal or larger than | |
90 | * the system timer tick period. This should put the CPU into idle mode | |
91 | * to save power and to be woken up only when some interrupts are pending. | |
92 | * As above, this should not rely upon standard kernel code. | |
93 | */ | |
94 | ||
95 | #if defined(CONFIG_CPU_XSCALE) | |
96 | #define xip_cpu_idle() asm volatile ("mcr p14, 0, %0, c7, c0, 0" :: "r" (1)) | |
97 | #else | |
98 | #define xip_cpu_idle() do { } while (0) | |
99 | #endif | |
100 | ||
101 | #else | |
102 | ||
103 | #define __xipram | |
104 | ||
105 | #endif /* CONFIG_MTD_XIP */ | |
106 | ||
107 | #endif /* __LINUX_MTD_XIP_H__ */ |