| Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 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__ */ |