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