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/*
* linux/arch/arm/mm/proc-xscale.S
*
* Author: Nicolas Pitre
* Created: November 2000
* Copyright: (C) 2000, 2001 MontaVista Software Inc.
*
* 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.
*
* MMU functions for the Intel XScale CPUs
*
* 2001 Aug 21:
* some contributions by Brett Gaines <brett.w.gaines@intel.com>
* Copyright 2001 by Intel Corp.
*
* 2001 Sep 08:
* Completely revisited, many important fixes
* Nicolas Pitre <nico@fluxnic.net>
*/
#include <linux/linkage.h>
#include <linux/init.h>
#include <asm/assembler.h>
#include <asm/hwcap.h>
#include <asm/pgtable.h>
#include <asm/pgtable-hwdef.h>
#include <asm/page.h>
#include <asm/ptrace.h>
#include "proc-macros.S"
/*
* This is the maximum size of an area which will be flushed. If the area
* is larger than this, then we flush the whole cache
*/
#define MAX_AREA_SIZE 32768
/*
* the cache line size of the I and D cache
*/
#define CACHELINESIZE 32
/*
* the size of the data cache
*/
#define CACHESIZE 32768
/*
* Virtual address used to allocate the cache when flushed
*
* This must be an address range which is _never_ used. It should
* apparently have a mapping in the corresponding page table for
* compatibility with future CPUs that _could_ require it. For instance we
* don't care.
*
* This must be aligned on a 2*CACHESIZE boundary. The code selects one of
* the 2 areas in alternance each time the clean_d_cache macro is used.
* Without this the XScale core exhibits cache eviction problems and no one
* knows why.
*
* Reminder: the vector table is located at 0xffff0000-0xffff0fff.
*/
#define CLEAN_ADDR 0xfffe0000
/*
* This macro is used to wait for a CP15 write and is needed
* when we have to ensure that the last operation to the co-pro
* was completed before continuing with operation.
*/
.macro cpwait, rd
mrc p15, 0, \rd, c2, c0, 0 @ arbitrary read of cp15
mov \rd, \rd @ wait for completion
sub pc, pc, #4 @ flush instruction pipeline
.endm
.macro cpwait_ret, lr, rd
mrc p15, 0, \rd, c2, c0, 0 @ arbitrary read of cp15
sub pc, \lr, \rd, LSR #32 @ wait for completion and
@ flush instruction pipeline
.endm
/*
* This macro cleans the entire dcache using line allocate.
* The main loop has been unrolled to reduce loop overhead.
* rd and rs are two scratch registers.
*/
.macro clean_d_cache, rd, rs
ldr \rs, =clean_addr
ldr \rd, [\rs]
eor \rd, \rd, #CACHESIZE
str \rd, [\rs]
add \rs, \rd, #CACHESIZE
1: mcr p15, 0, \rd, c7, c2, 5 @ allocate D cache line
add \rd, \rd, #CACHELINESIZE
mcr p15, 0, \rd, c7, c2, 5 @ allocate D cache line
add \rd, \rd, #CACHELINESIZE
mcr p15, 0, \rd, c7, c2, 5 @ allocate D cache line
add \rd, \rd, #CACHELINESIZE
mcr p15, 0, \rd, c7, c2, 5 @ allocate D cache line
add \rd, \rd, #CACHELINESIZE
teq \rd, \rs
bne 1b
.endm
.data
.align 2
clean_addr: .word CLEAN_ADDR
.text
/*
* cpu_xscale_proc_init()
*
* Nothing too exciting at the moment
*/
ENTRY(cpu_xscale_proc_init)
@ enable write buffer coalescing. Some bootloader disable it
mrc p15, 0, r1, c1, c0, 1
bic r1, r1, #1
mcr p15, 0, r1, c1, c0, 1
ret lr
/*
* cpu_xscale_proc_fin()
*/
ENTRY(cpu_xscale_proc_fin)
mrc p15, 0, r0, c1, c0, 0 @ ctrl register
bic r0, r0, #0x1800 @ ...IZ...........
bic r0, r0, #0x0006 @ .............CA.
mcr p15, 0, r0, c1, c0, 0 @ disable caches
ret lr
/*
* cpu_xscale_reset(loc)
*
* Perform a soft reset of the system. Put the CPU into the
* same state as it would be if it had been reset, and branch
* to what would be the reset vector.
*
* loc: location to jump to for soft reset
*
* Beware PXA270 erratum E7.
*/
.align 5
.pushsection .idmap.text, "ax"
ENTRY(cpu_xscale_reset)
mov r1, #PSR_F_BIT|PSR_I_BIT|SVC_MODE
msr cpsr_c, r1 @ reset CPSR
mcr p15, 0, r1, c10, c4, 1 @ unlock I-TLB
mcr p15, 0, r1, c8, c5, 0 @ invalidate I-TLB
mrc p15, 0, r1, c1, c0, 0 @ ctrl register
bic r1, r1, #0x0086 @ ........B....CA.
bic r1, r1, #0x3900 @ ..VIZ..S........
sub pc, pc, #4 @ flush pipeline
@ *** cache line aligned ***
mcr p15, 0, r1, c1, c0, 0 @ ctrl register
bic r1, r1, #0x0001 @ ...............M
mcr p15, 0, ip, c7, c7, 0 @ invalidate I,D caches & BTB
mcr p15, 0, r1, c1, c0, 0 @ ctrl register
@ CAUTION: MMU turned off from this point. We count on the pipeline
@ already containing those two last instructions to survive.
mcr p15, 0, ip, c8, c7, 0 @ invalidate I & D TLBs
ret r0
ENDPROC(cpu_xscale_reset)
.popsection
/*
* cpu_xscale_do_idle()
*
* Cause the processor to idle
*
* For now we do nothing but go to idle mode for every case
*
* XScale supports clock switching, but using idle mode support
* allows external hardware to react to system state changes.
*/
.align 5
ENTRY(cpu_xscale_do_idle)
mov r0, #1
mcr p14, 0, r0, c7, c0, 0 @ Go to IDLE
ret lr
/* ================================= CACHE ================================ */
/*
* flush_icache_all()
*
* Unconditionally clean and invalidate the entire icache.
*/
ENTRY(xscale_flush_icache_all)
mov r0, #0
mcr p15, 0, r0, c7, c5, 0 @ invalidate I cache
ret lr
ENDPROC(xscale_flush_icache_all)
/*
* flush_user_cache_all()
*
* Invalidate all cache entries in a particular address
* space.
*/
ENTRY(xscale_flush_user_cache_all)
/* FALLTHROUGH */
/*
* flush_kern_cache_all()
*
* Clean and invalidate the entire cache.
*/
ENTRY(xscale_flush_kern_cache_all)
mov r2, #VM_EXEC
mov ip, #0
__flush_whole_cache:
clean_d_cache r0, r1
tst r2, #VM_EXEC
mcrne p15, 0, ip, c7, c5, 0 @ Invalidate I cache & BTB
mcrne p15, 0, ip, c7
|