1 /* SPDX-License-Identifier: GPL-2.0-only */ <<
2 /* 1 /*
3 * MTD primitives for XIP support 2 * MTD primitives for XIP support
4 * 3 *
5 * Author: Nicolas Pitre 4 * Author: Nicolas Pitre
6 * Created: Nov 2, 2004 5 * Created: Nov 2, 2004
7 * Copyright: (C) 2004 MontaVista Software, 6 * Copyright: (C) 2004 MontaVista Software, Inc.
8 * 7 *
9 * This XIP support for MTD has been loosely i 8 * This XIP support for MTD has been loosely inspired
10 * by an earlier patch authored by David Woodh 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.
11 */ 14 */
12 15
13 #ifndef __LINUX_MTD_XIP_H__ 16 #ifndef __LINUX_MTD_XIP_H__
14 #define __LINUX_MTD_XIP_H__ 17 #define __LINUX_MTD_XIP_H__
15 18
16 19
17 #ifdef CONFIG_MTD_XIP 20 #ifdef CONFIG_MTD_XIP
18 21
19 /* 22 /*
20 * We really don't want gcc to guess anything. 23 * We really don't want gcc to guess anything.
21 * We absolutely _need_ proper inlining. 24 * We absolutely _need_ proper inlining.
22 */ 25 */
23 #include <linux/compiler.h> 26 #include <linux/compiler.h>
24 27
25 /* 28 /*
26 * Function that are modifying the flash state 29 * Function that are modifying the flash state away from array mode must
27 * obviously not be running from flash. The _ 30 * obviously not be running from flash. The __xipram is therefore marking
28 * those functions so they get relocated to ra 31 * those functions so they get relocated to ram.
29 */ 32 */
30 #ifdef CONFIG_XIP_KERNEL 33 #ifdef CONFIG_XIP_KERNEL
31 #define __xipram noinline __section(".xiptext" !! 34 #define __xipram noinline __attribute__ ((__section__ (".xiptext")))
32 #endif 35 #endif
33 36
34 /* 37 /*
35 * Each architecture has to provide the follow 38 * Each architecture has to provide the following macros. They must access
36 * the hardware directly and not rely on any o 39 * the hardware directly and not rely on any other (XIP) functions since they
37 * won't be available when used (flash not in 40 * won't be available when used (flash not in array mode).
38 * 41 *
39 * xip_irqpending() 42 * xip_irqpending()
40 * 43 *
41 * return non zero when any hardware inte 44 * return non zero when any hardware interrupt is pending.
42 * 45 *
43 * xip_currtime() 46 * xip_currtime()
44 * 47 *
45 * return a platform specific time refere 48 * return a platform specific time reference to be used with
46 * xip_elapsed_since(). 49 * xip_elapsed_since().
47 * 50 *
48 * xip_elapsed_since(x) 51 * xip_elapsed_since(x)
49 * 52 *
50 * return in usecs the elapsed timebetwee 53 * return in usecs the elapsed timebetween now and the reference x as
51 * returned by xip_currtime(). 54 * returned by xip_currtime().
52 * 55 *
53 * note 1: conversion to usec can be appr 56 * note 1: conversion to usec can be approximated, as long as the
54 * returned value is <= the real 57 * returned value is <= the real elapsed time.
55 * note 2: this should be able to cope wi 58 * note 2: this should be able to cope with a few seconds without
56 * overflowing. 59 * overflowing.
57 * 60 *
58 * xip_iprefetch() 61 * xip_iprefetch()
59 * 62 *
60 * Macro to fill instruction prefetch 63 * Macro to fill instruction prefetch
61 * e.g. a series of nops: asm volatile ( 64 * e.g. a series of nops: asm volatile (".rep 8; nop; .endr");
62 */ 65 */
63 66
64 #include <asm/mtd-xip.h> 67 #include <asm/mtd-xip.h>
65 68
66 #ifndef xip_irqpending 69 #ifndef xip_irqpending
67 70
68 #warning "missing IRQ and timer primitives for 71 #warning "missing IRQ and timer primitives for XIP MTD support"
69 #warning "some of the XIP MTD support code wil 72 #warning "some of the XIP MTD support code will be disabled"
70 #warning "your system will therefore be unresp 73 #warning "your system will therefore be unresponsive when writing or erasing flash"
71 74
72 #define xip_irqpending() (0) 75 #define xip_irqpending() (0)
73 #define xip_currtime() (0) 76 #define xip_currtime() (0)
74 #define xip_elapsed_since(x) (0) 77 #define xip_elapsed_since(x) (0)
75 78
76 #endif 79 #endif
77 80
78 #ifndef xip_iprefetch 81 #ifndef xip_iprefetch
79 #define xip_iprefetch() do { } while ( 82 #define xip_iprefetch() do { } while (0)
80 #endif 83 #endif
81 84
82 /* 85 /*
83 * xip_cpu_idle() is used when waiting for a d 86 * xip_cpu_idle() is used when waiting for a delay equal or larger than
84 * the system timer tick period. This should 87 * the system timer tick period. This should put the CPU into idle mode
85 * to save power and to be woken up only when 88 * to save power and to be woken up only when some interrupts are pending.
86 * This should not rely upon standard kernel c 89 * This should not rely upon standard kernel code.
87 */ 90 */
88 #ifndef xip_cpu_idle 91 #ifndef xip_cpu_idle
89 #define xip_cpu_idle() do { } while (0) 92 #define xip_cpu_idle() do { } while (0)
90 #endif 93 #endif
91 94
92 #endif /* CONFIG_MTD_XIP */ 95 #endif /* CONFIG_MTD_XIP */
93 96
94 #ifndef __xipram 97 #ifndef __xipram
95 #define __xipram 98 #define __xipram
96 #endif 99 #endif
97 100
98 #endif /* __LINUX_MTD_XIP_H__ */ 101 #endif /* __LINUX_MTD_XIP_H__ */
99 102
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