/* * MTD primitives for XIP support * * Author: Nicolas Pitre * Created: Nov 2, 2004 * Copyright: (C) 2004 MontaVista Software, Inc. * * This XIP support for MTD has been loosely inspired * by an earlier patch authored by David Woodhouse. * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License version 2 as * published by the Free Software Foundation. * * $Id: xip.h,v 1.2 2004/12/01 15:49:10 nico Exp $ */ #ifndef __LINUX_MTD_XIP_H__ #define __LINUX_MTD_XIP_H__ #include <linux/config.h> #ifdef CONFIG_MTD_XIP /* * Function that are modifying the flash state away from array mode must * obviously not be running from flash. The __xipram is therefore marking * those functions so they get relocated to ram. */ #define __xipram __attribute__ ((__section__ (".data"))) /* * We really don't want gcc to guess anything. * We absolutely _need_ proper inlining. */ #include <linux/compiler.h> /* * Each architecture has to provide the following macros. They must access * the hardware directly and not rely on any other (XIP) functions since they * won't be available when used (flash not in array mode). * * xip_irqpending() * * return non zero when any hardware interrupt is pending. * * xip_currtime() * * return a platform specific time reference to be used with * xip_elapsed_since(). * * xip_elapsed_since(x) * * return in usecs the elapsed timebetween now and the reference x as * returned by xip_currtime(). * * note 1: convertion to usec can be approximated, as long as the * returned value is <= the real elapsed time. * note 2: this should be able to cope with a few seconds without * overflowing. */ #if defined(CONFIG_ARCH_SA1100) || defined(CONFIG_ARCH_PXA) #include <asm/hardware.h> #ifdef CONFIG_ARCH_PXA #include <asm/arch/pxa-regs.h> #endif #define xip_irqpending() (ICIP & ICMR) /* we sample OSCR and convert desired delta to usec (1/4 ~= 1000000/3686400) */ #define xip_currtime() (OSCR) #define xip_elapsed_since(x) (signed)((OSCR - (x)) / 4) #else #warning "missing IRQ and timer primitives for XIP MTD support" #warning "some of the XIP MTD support code will be disabled" #warning "your system will therefore be unresponsive when writing or erasing flash" #define xip_irqpending() (0) #define xip_currtime() (0) #define xip_elapsed_since(x) (0) #endif /* * xip_cpu_idle() is used when waiting for a delay equal or larger than * the system timer tick period. This should put the CPU into idle mode * to save power and to be woken up only when some interrupts are pending. * As above, this should not rely upon standard kernel code. */ #if defined(CONFIG_CPU_XSCALE) #define xip_cpu_idle() asm volatile ("mcr p14, 0, %0, c7, c0, 0" :: "r" (1)) #else #define xip_cpu_idle() do { } while (0) #endif #else #define __xipram #endif /* CONFIG_MTD_XIP */ #endif /* __LINUX_MTD_XIP_H__ */