projects / linux.git / blame
| Commit | Line | Data |
|---|---|---|
| 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. | |
| 1da177e4 LT |
14 | */ |
| 15 | ||
| 16 | #ifndef __LINUX_MTD_XIP_H__ | |
| 17 | #define __LINUX_MTD_XIP_H__ | |
| 18 | ||
| 1da177e4 LT |
19 | |
| 20 | #ifdef CONFIG_MTD_XIP | |
| 21 | ||
| 1da177e4 LT |
22 | /* |
| 23 | * We really don't want gcc to guess anything. | |
| 24 | * We absolutely _need_ proper inlining. | |
| 25 | */ | |
| 26 | #include <linux/compiler.h> | |
| 27 | ||
| fb025873 NP |
28 | /* |
| 29 | * Function that are modifying the flash state away from array mode must | |
| 30 | * obviously not be running from flash. The __xipram is therefore marking | |
| 31 | * those functions so they get relocated to ram. | |
| 32 | */ | |
| 33 | #define __xipram noinline __attribute__ ((__section__ (".data"))) | |
| 34 | ||
| 1da177e4 LT |
35 | /* |
| 36 | * Each architecture has to provide the following macros. They must access | |
| 37 | * the hardware directly and not rely on any other (XIP) functions since they | |
| 38 | * won't be available when used (flash not in array mode). | |
| 39 | * | |
| 40 | * xip_irqpending() | |
| 41 | * | |
| 42 | * return non zero when any hardware interrupt is pending. | |
| 43 | * | |
| 44 | * xip_currtime() | |
| 45 | * | |
| 46 | * return a platform specific time reference to be used with | |
| 47 | * xip_elapsed_since(). | |
| 48 | * | |
| 49 | * xip_elapsed_since(x) | |
| 50 | * | |
| 51 | * return in usecs the elapsed timebetween now and the reference x as | |
| 52 | * returned by xip_currtime(). | |
| 53 | * | |
| 54 | * note 1: convertion to usec can be approximated, as long as the | |
| 55 | * returned value is <= the real elapsed time. | |
| 56 | * note 2: this should be able to cope with a few seconds without | |
| 57 | * overflowing. | |
| 97f927a4 TG |
58 | * |
| 59 | * xip_iprefetch() | |
| 61ecfa87 | 60 | * |
| 97f927a4 | 61 | * Macro to fill instruction prefetch |
| 61ecfa87 | 62 | * e.g. a series of nops: asm volatile (".rep 8; nop; .endr"); |
| 1da177e4 LT |
63 | */ |
| 64 | ||
| 97f927a4 | 65 | #include <asm/mtd-xip.h> |
| 1da177e4 | 66 | |
| 97f927a4 | 67 | #ifndef xip_irqpending |
| 1da177e4 LT |
68 | |
| 69 | #warning "missing IRQ and timer primitives for XIP MTD support" | |
| 70 | #warning "some of the XIP MTD support code will be disabled" | |
| 71 | #warning "your system will therefore be unresponsive when writing or erasing flash" | |
| 72 | ||
| 73 | #define xip_irqpending() (0) | |
| 74 | #define xip_currtime() (0) | |
| 75 | #define xip_elapsed_since(x) (0) | |
| 76 | ||
| 77 | #endif | |
| 78 | ||
| 97f927a4 TG |
79 | #ifndef xip_iprefetch |
| 80 | #define xip_iprefetch() do { } while (0) | |
| 81 | #endif | |
| 82 | ||
| 1da177e4 LT |
83 | /* |
| 84 | * xip_cpu_idle() is used when waiting for a delay equal or larger than | |
| 85 | * the system timer tick period. This should put the CPU into idle mode | |
| 86 | * to save power and to be woken up only when some interrupts are pending. | |
| 97f927a4 | 87 | * This should not rely upon standard kernel code. |
| 1da177e4 | 88 | */ |
| 97f927a4 | 89 | #ifndef xip_cpu_idle |
| 1da177e4 LT |
90 | #define xip_cpu_idle() do { } while (0) |
| 91 | #endif | |
| 92 | ||
| 93 | #else | |
| 94 | ||
| 95 | #define __xipram | |
| 96 | ||
| 97 | #endif /* CONFIG_MTD_XIP */ | |
| 98 | ||
| 99 | #endif /* __LINUX_MTD_XIP_H__ */ |