Thomas Gleixner | d2912cb | 2019-06-04 10:11:33 +0200 | [diff] [blame^] | 1 | /* SPDX-License-Identifier: GPL-2.0-only */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2 | /* |
| 3 | * MTD primitives for XIP support |
| 4 | * |
| 5 | * Author: Nicolas Pitre |
| 6 | * Created: Nov 2, 2004 |
| 7 | * Copyright: (C) 2004 MontaVista Software, Inc. |
| 8 | * |
| 9 | * This XIP support for MTD has been loosely inspired |
| 10 | * by an earlier patch authored by David Woodhouse. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 11 | */ |
| 12 | |
| 13 | #ifndef __LINUX_MTD_XIP_H__ |
| 14 | #define __LINUX_MTD_XIP_H__ |
| 15 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 16 | |
| 17 | #ifdef CONFIG_MTD_XIP |
| 18 | |
| 19 | /* |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 20 | * We really don't want gcc to guess anything. |
| 21 | * We absolutely _need_ proper inlining. |
| 22 | */ |
| 23 | #include <linux/compiler.h> |
| 24 | |
| 25 | /* |
Nicolas Pitre | fb02587 | 2005-10-17 22:03:19 +0100 | [diff] [blame] | 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 | */ |
Arnd Bergmann | 129f6c4 | 2017-07-21 22:26:25 +0200 | [diff] [blame] | 30 | #ifdef CONFIG_XIP_KERNEL |
| 31 | #define __xipram noinline __attribute__ ((__section__ (".xiptext"))) |
| 32 | #endif |
Nicolas Pitre | fb02587 | 2005-10-17 22:03:19 +0100 | [diff] [blame] | 33 | |
| 34 | /* |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 35 | * Each architecture has to provide the following macros. They must access |
| 36 | * the hardware directly and not rely on any other (XIP) functions since they |
| 37 | * won't be available when used (flash not in array mode). |
| 38 | * |
| 39 | * xip_irqpending() |
| 40 | * |
| 41 | * return non zero when any hardware interrupt is pending. |
| 42 | * |
| 43 | * xip_currtime() |
| 44 | * |
| 45 | * return a platform specific time reference to be used with |
| 46 | * xip_elapsed_since(). |
| 47 | * |
| 48 | * xip_elapsed_since(x) |
| 49 | * |
| 50 | * return in usecs the elapsed timebetween now and the reference x as |
| 51 | * returned by xip_currtime(). |
| 52 | * |
Lucas De Marchi | 25985ed | 2011-03-30 22:57:33 -0300 | [diff] [blame] | 53 | * note 1: conversion to usec can be approximated, as long as the |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 54 | * returned value is <= the real elapsed time. |
| 55 | * note 2: this should be able to cope with a few seconds without |
| 56 | * overflowing. |
Thomas Gleixner | 97f927a | 2005-07-07 16:50:16 +0200 | [diff] [blame] | 57 | * |
| 58 | * xip_iprefetch() |
Thomas Gleixner | 61ecfa8 | 2005-11-07 11:15:31 +0000 | [diff] [blame] | 59 | * |
Thomas Gleixner | 97f927a | 2005-07-07 16:50:16 +0200 | [diff] [blame] | 60 | * Macro to fill instruction prefetch |
Thomas Gleixner | 61ecfa8 | 2005-11-07 11:15:31 +0000 | [diff] [blame] | 61 | * e.g. a series of nops: asm volatile (".rep 8; nop; .endr"); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 62 | */ |
| 63 | |
Thomas Gleixner | 97f927a | 2005-07-07 16:50:16 +0200 | [diff] [blame] | 64 | #include <asm/mtd-xip.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 65 | |
Thomas Gleixner | 97f927a | 2005-07-07 16:50:16 +0200 | [diff] [blame] | 66 | #ifndef xip_irqpending |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 67 | |
| 68 | #warning "missing IRQ and timer primitives for XIP MTD support" |
| 69 | #warning "some of the XIP MTD support code will be disabled" |
| 70 | #warning "your system will therefore be unresponsive when writing or erasing flash" |
| 71 | |
| 72 | #define xip_irqpending() (0) |
| 73 | #define xip_currtime() (0) |
| 74 | #define xip_elapsed_since(x) (0) |
| 75 | |
| 76 | #endif |
| 77 | |
Thomas Gleixner | 97f927a | 2005-07-07 16:50:16 +0200 | [diff] [blame] | 78 | #ifndef xip_iprefetch |
| 79 | #define xip_iprefetch() do { } while (0) |
| 80 | #endif |
| 81 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 82 | /* |
| 83 | * xip_cpu_idle() is used when waiting for a delay equal or larger than |
| 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 some interrupts are pending. |
Thomas Gleixner | 97f927a | 2005-07-07 16:50:16 +0200 | [diff] [blame] | 86 | * This should not rely upon standard kernel code. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 87 | */ |
Thomas Gleixner | 97f927a | 2005-07-07 16:50:16 +0200 | [diff] [blame] | 88 | #ifndef xip_cpu_idle |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 89 | #define xip_cpu_idle() do { } while (0) |
| 90 | #endif |
| 91 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 92 | #endif /* CONFIG_MTD_XIP */ |
| 93 | |
Arnd Bergmann | 129f6c4 | 2017-07-21 22:26:25 +0200 | [diff] [blame] | 94 | #ifndef __xipram |
| 95 | #define __xipram |
| 96 | #endif |
| 97 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 98 | #endif /* __LINUX_MTD_XIP_H__ */ |