/*
* linux/arch/arm/kernel/iwmmxt.S
*
* XScale iWMMXt (Concan) context switching and handling
*
* Initial code:
* Copyright (c) 2003, Intel Corporation
*
* Full lazy switching support, optimizations and more, by Nicolas Pitre
* Copyright (c) 2003-2004, 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.
*/
#include <linux/linkage.h>
#include <asm/ptrace.h>
#include <asm/thread_info.h>
#include <asm/asm-offsets.h>
#define MMX_WR0 (0x00)
#define MMX_WR1 (0x08)
#define MMX_WR2 (0x10)
#define MMX_WR3 (0x18)
#define MMX_WR4 (0x20)
#define MMX_WR5 (0x28)
#define MMX_WR6 (0x30)
#define MMX_WR7 (0x38)
#define MMX_WR8 (0x40)
#define MMX_WR9 (0x48)
#define MMX_WR10 (0x50)
#define MMX_WR11 (0x58)
#define MMX_WR12 (0x60)
#define MMX_WR13 (0x68)
#define MMX_WR14 (0x70)
#define MMX_WR15 (0x78)
#define MMX_WCSSF (0x80)
#define MMX_WCASF (0x84)
#define MMX_WCGR0 (0x88)
#define MMX_WCGR1 (0x8C)
#define MMX_WCGR2 (0x90)
#define MMX_WCGR3 (0x94)
#define MMX_SIZE (0x98)
.text
/*
* Lazy switching of Concan coprocessor context
*
* r10 = struct thread_info pointer
* r9 = ret_from_exception
* lr = undefined instr exit
*
* called from prefetch exception handler with interrupts disabled
*/
ENTRY(iwmmxt_task_enable)
mrc p15, 0, r2, c15, c1, 0
tst r2, #0x3 @ CP0 and CP1 accessible?
movne pc, lr @ if so no business here
orr r2, r2, #0x3 @ enable access to CP0 and CP1
mcr p15, 0, r2, c15, c1, 0
ldr r3, =concan_owner
add r0, r10, #TI_IWMMXT_STATE @ get task Concan save area
ldr r2, [sp, #60] @ current task pc value
ldr r1, [r3] @ get current Concan owner
str r0, [r3] @ this task now owns Concan regs
sub r2, r2, #4 @ adjust pc back
str r2, [sp, #60]
mrc p15, 0, r2, c2, c0, 0
mov r2, r2 @ cpwait
teq r1, #0 @ test for last ownership
mov lr, r9 @ normal exit from exception
beq concan_load @ no owner, skip save
concan_save:
tmrc r2, wCon
@ CUP? wCx
tst r2, #0x1
beq 1f
concan_dump:
wstrw wCSSF, [r1, #MMX_WCSSF]
wstrw wCASF, [r1, #MMX_WCASF]
wstrw wCGR0, [r1, #MMX_WCGR0]
wstrw wCGR1, [r1, #MMX_WCGR1]
wstrw wCGR2, [r1, #MMX_WCGR2]
wstrw wCGR3, [r1, #MMX_WCGR3]
1: @ MUP? wRn
tst r2, #0x2
beq 2f
wstrd wR0, [r1, #MMX_WR0]
wstrd wR1, [r1, #MMX_WR1]
wstrd wR2, [r1, #MMX_WR2]
wstrd wR3, [r1, #MMX_WR3]
wstrd wR4, [r1, #MMX_WR4]
wstrd wR5, [r1, #MMX_WR5]
wstrd wR6, [r1, #MMX_WR6]
wstrd wR7, [r1, #MMX_WR7]
wstrd wR8, [r1, #MMX_WR8]
wstrd wR9, [r1, #MMX_WR9]
wstrd wR10, [r1, #MMX_WR10]
wstrd wR11, [r1, #MMX_WR11]
wstrd wR12, [r1, #MMX_WR12]
wstrd wR13, [r1, #MMX_WR13]
wstrd wR14, [r1, #MMX_WR14]
wstrd wR15, [r1, #MMX_WR15]
2: teq r0, #0 @ anything to load?
moveq pc, lr
concan_load:
@ Load wRn
wldrd wR0, [r0, #MMX_WR0]
wldrd wR1, [r0, #MMX_WR1]
wldrd wR2, [r0, #MMX_WR2]
wldrd wR3, [r0, #MMX_WR3]
wldrd wR4, [r0, #MMX_WR4]
wldrd wR5, [r0, #MMX_WR5]
wldrd wR6, [r0, #MMX_WR6]
wldrd wR7, [r0, #MMX_WR7]
wldrd wR8, [r0, #MMX_WR8]
wldrd wR9, [r0, #MMX_WR9]
wldrd wR10, [r0, #MMX_WR10]
wldrd wR11, [r0, #MMX_WR11]
wldrd wR12, [r0, #MMX_WR12]
wldrd wR13, [r0, #MMX_WR13]
wldrd wR14, [r0, #MMX_WR14]
wldrd wR15, [r0, #MMX_WR15]
@ Load wCx
wldrw wCSSF, [r0, #MMX_WCSSF]
wldrw wCASF, [r0, #MMX_WCASF]
wldrw wCGR0, [r0, #MMX_WCGR0]
wldrw wCGR1, [r0, #MMX_WCGR1]
wldrw wCGR2, [r0, #MMX_WCGR2]
wldrw wCGR3, [r0, #MMX_WCGR3]
@ clear CUP/MUP (only if r1 != 0)
teq r1, #0
mov r2, #0
moveq pc, lr
tmcr wCon, r2
mov pc, lr
/*
* Back up Concan regs to save area and disable access to them
* (mainly for gdb or sleep mode usage)
*
* r0 = struct thread_info pointer of target task or NULL for any
*/
ENTRY(iwmmxt_task_disable)
stmfd sp!, {r4, lr}
mrs ip, cpsr
orr r2, ip, #PSR_I_BIT @ disable interrupts
msr cpsr_c, r2
ldr r3, =concan_owner
add r2, r0, #TI_IWMMXT_STATE @ get task Concan save area
ldr r1, [r3] @ get current Concan owner
teq r1, #0 @ any current owner?
beq 1f @ no: quit
teq r0, #0 @ any owner?
teqne r1, r2 @ or specified one?
bne 1f @ no: quit
mrc p15, 0, r4, c15, c1, 0
orr r4, r4, #0x3 @ enable access to CP0 and CP1
mcr p15, 0, r4, c15, c1, 0
mov r0, #0 @ nothing to load
str r0, [r3] @ no more current owner
mrc p15, 0, r2, c2, c0, 0
mov r2, r2 @ cpwait
bl concan_save
bic r4, r4, #0x3 @ disable access to CP0 and CP1
mcr p15, 0, r4, c15, c1, 0
mrc p15, 0, r2, c2, c0, 0
mov r2, r2 @ cpwait
1: msr cpsr_c, ip @ restore interrupt mode
ldmfd sp!, {r4, pc}
/*
* Copy Concan state to given memory address
*
* r0 = struct thread_info pointer of target task
* r1 = memory address where to store Concan state
*
* this is called mainly in the creation of signal stack frames
*/
ENTRY(iwmmxt_task_copy)
mrs ip, cpsr
orr r2, ip, #PSR_I_BIT @ disable interrupts
msr cpsr_c, r2
ldr r3, =concan_owner
add r2, r0, #TI_IWMMXT_STATE @ get task Concan save area
ldr r3, [r3] @ get current Concan owner
teq r2, r3 @ does this task own it...
beq 1f
@ current Concan values are in the task save area
msr cpsr_c, ip @ restore interrupt mode
mov r0, r1
mov r1, r2
mov r2, #MMX_SIZE
b memcpy
1: @ this task owns Concan regs -- grab a copy from there
mov r0, #0 @ nothing to load
mov r2, #3 @ save all regs
mov r3, lr @ preserve return address
bl concan_dump
msr cpsr_c, ip @ restore interrupt mode
mov pc, r3
/*
* Restore Concan state from given memory address
*
* r0 = struct thread_info pointer of target task
* r1 = memory address where to get Concan state from
*
* this is used to restore Concan state when unwinding a signal stack frame
*/
ENTRY(iwmmxt_task_restore)
mrs ip, cpsr
orr r2, ip, #PSR_I_BIT @ disable interrupts
msr cpsr_c, r2
ldr r3, =concan_owner
add r2, r0, #TI_IWMMXT_STATE @ get task Concan save area
ldr r3, [r3] @ get current Concan owner
bic r2, r2, #0x7 @ 64-bit alignment
teq r2, r3 @ does this task own it...
beq 1f
@ this task doesn't own Concan regs -- use its save area
msr cpsr_c, ip @ restore interrupt mode
mov r0, r2
mov r2, #MMX_SIZE
b memcpy
1: @ this task owns Concan regs -- load them directly
mov r0, r1
mov r1, #0 @ don't clear CUP/MUP
mov r3, lr @ preserve return address
bl concan_load
msr cpsr_c, ip @ restore interrupt mode
mov pc, r3
/*
* Concan handling on task switch
*
* r0 = previous task_struct pointer (must be preserved)
* r1 = previous thread_info pointer
* r2 = next thread_info.cpu_domain pointer (must be preserved)
*
* Called only from __switch_to with task preemption disabled.
* No need to care about preserving r4 and above.
*/
ENTRY(iwmmxt_task_switch)
mrc p15, 0, r4, c15, c1, 0
tst r4, #0x3 @ CP0 and CP1 accessible?
bne 1f @ yes: block them for next task
ldr r5, =concan_owner
add r6, r2, #(TI_IWMMXT_STATE - TI_CPU_DOMAIN) @ get next task Concan save area
ldr r5, [r5] @ get current Concan owner
teq r5, r6 @ next task owns it?
movne pc, lr @ no: leave Concan disabled
1: eor r4, r4, #3 @ flip Concan access
mcr p15, 0, r4, c15, c1, 0
mrc p15, 0, r4, c2, c0, 0
sub pc, lr, r4, lsr #32 @ cpwait and return
/*
* Remove Concan ownership of given task
*
* r0 = struct thread_info pointer
*/
ENTRY(iwmmxt_task_release)
mrs r2, cpsr
orr ip, r2, #PSR_I_BIT @ disable interrupts
msr cpsr_c, ip
ldr r3, =concan_owner
add r0, r0, #TI_IWMMXT_STATE @ get task Concan save area
ldr r1, [r3] @ get current Concan owner
eors r0, r0, r1 @ if equal...
streq r0, [r3] @ then clear ownership
msr cpsr_c, r2 @ restore interrupts
mov pc, lr
.data
concan_owner:
.word 0
