/*
* sh7372 lowlevel sleep code for "Core Standby Mode"
*
* Copyright (C) 2011 Magnus Damm
*
* In "Core Standby Mode" the ARM core is off, but L2 cache is still on
*
* Based on mach-omap2/sleep34xx.S
*
* (C) Copyright 2007 Texas Instruments
* Karthik Dasu <karthik-dp@ti.com>
*
* (C) Copyright 2004 Texas Instruments, <www.ti.com>
* Richard Woodruff <r-woodruff2@ti.com>
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License as
* published by the Free Software Foundation; either version 2 of
* the License, or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR /PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston,
* MA 02111-1307 USA
*/
#include <linux/linkage.h>
#include <asm/assembler.h>
#define SMFRAM 0xe6a70000
.align
kernel_flush:
.word v7_flush_dcache_all
.align 3
ENTRY(sh7372_cpu_suspend)
stmfd sp!, {r0-r12, lr} @ save registers on stack
ldr r8, =SMFRAM
mov r4, sp @ Store sp
mrs r5, spsr @ Store spsr
mov r6, lr @ Store lr
stmia r8!, {r4-r6}
mrc p15, 0, r4, c1, c0, 2 @ Coprocessor access control register
mrc p15, 0, r5, c2, c0, 0 @ TTBR0
mrc p15, 0, r6, c2, c0, 1 @ TTBR1
mrc p15, 0, r7, c2, c0, 2 @ TTBCR
stmia r8!, {r4-r7}
mrc p15, 0, r4, c3, c0, 0 @ Domain access Control Register
mrc p15, 0, r5, c10, c2, 0 @ PRRR
mrc p15, 0, r6, c10, c2, 1 @ NMRR
stmia r8!,{r4-r6}
mrc p15, 0, r4, c13, c0, 1 @ Context ID
mrc p15, 0, r5, c13, c0, 2 @ User r/w thread and process ID
mrc p15, 0, r6, c12, c0, 0 @ Secure or NS vector base address
mrs r7, cpsr @ Store current cpsr
stmia r8!, {r4-r7}
mrc p15, 0, r4, c1, c0, 0 @ save control register
stmia r8!, {r4}
/*
* jump out to kernel flush routine
* - reuse that code is better
* - it executes in a cached space so is faster than refetch per-block
* - should be faster and will change with kernel
* - 'might' have to copy address, load and jump to it
* Flush all data from the L1 data cache before disabling
* SCTLR.C bit.
*/
ldr r1, kernel_flush
mov lr, pc
bx r1
/*
* Clear the SCTLR.C bit to prevent further data cache
* allocation. Clearing SCTLR.C would make all the data accesses
* strongly ordered and would not hit the cache.
*/
mrc p15, 0, r0, c1, c0, 0
bic r0, r0, #(1 << 2) @ Disable the C bit
mcr p15, 0, r0, c1, c0, 0
isb
/*
* Invalidate L1 data cache. Even though only invalidate is
* necessary exported flush API is used here. Doing clean
* on already clean cache would be almost NOP.
*/
ldr r1, kernel_flush
blx r1
/*
* The kernel doesn't interwork: v7_flush_dcache_all in particluar will
* always return in Thumb state when CONFIG_THUMB2_KERNEL is enabled.
* This sequence switches back to ARM. Note that .align may insert a
* nop: bx pc needs to be word-aligned in order to work.
*/
THUMB( .thumb )
THUMB( .align )
THUMB( bx pc )
THUMB( nop )
.arm
/* Data memory barrier and Data sync barrier */
dsb
dmb
/*
* ===================================
* == WFI instruction => Enter idle ==
* ===================================
*/
wfi @ wait for interrupt
/*
* ===================================
* == Resume path for non-OFF modes ==
* ===================================
*/
mrc p15, 0, r0, c1, c0, 0
tst r0, #(1 << 2) @ Check C bit enabled?
orreq r0, r0, #(1 << 2) @ Enable the C bit if cleared
mcreq p15, 0, r0, c1, c0, 0
isb
/*
* ===================================
* == Exit point from non-OFF modes ==
* ===================================
*/
ldmfd sp!, {r0-r12, pc} @ restore regs and return
.pool
.align 12
.text
.global sh7372_cpu_resume
sh7372_cpu_resume:
mov r1, #0
/*
* Invalidate all instruction caches to PoU
* and flush branch target cache
*/
mcr p15, 0, r1, c7, c5, 0
ldr r3, =SMFRAM
ldmia r3!, {r4-r6}
mov sp, r4 @ Restore sp
msr spsr_cxsf, r5 @ Restore spsr
mov lr, r6 @ Restore lr
ldmia r3!, {r4-r7}
mcr p15, 0, r4, c1, c0, 2 @ Coprocessor access Control Register
mcr p15, 0, r5, c2, c0, 0 @ TTBR0
mcr p15, 0, r6, c2, c0, 1 @ TTBR1
mcr p15, 0, r7, c2, c0, 2 @ TTBCR
ldmia r3!,{r4-r6}
mcr p15, 0, r4, c3, c0, 0 @ Domain access Control Register
mcr p15, 0, r5, c10, c2, 0 @ PRRR
mcr p15, 0, r6, c10, c2, 1 @ NMRR
ldmia r3!,{r4-r7}
mcr p15, 0, r4, c13, c0, 1 @ Context ID
mcr p15, 0, r5, c13, c0, 2 @ User r/w thread and process ID
mrc p15, 0, r6, c12, c0, 0 @ Secure or NS vector base address
msr cpsr, r7 @ store cpsr
/* Starting to enable MMU here */
mrc p15, 0, r7, c2, c0, 2 @ Read TTBRControl
/* Extract N (0:2) bits and decide whether to use TTBR0 or TTBR1 */
and r7, #0x7
cmp r7, #0x0
beq usettbr0
ttbr_error:
/*
* More work needs to be done to support N[0:2] value other than 0
* So looping here so that the error can be detected
*/
b ttbr_error
.align
cache_pred_disable_mask:
.word 0xFFFFE7FB
ttbrbit_mask:
.word 0xFFFFC000
table_index_mask:
.word 0xFFF00000
table_entry:
.word 0x00000C02
usettbr0:
mrc p15, 0, r2, c2, c0, 0
ldr r5, ttbrbit_mask
and r2, r5
mov r4, pc
ldr r5, table_index_mask
and r4, r5 @ r4 = 31 to 20 bits of pc
/* Extract the value to be written to table entry */
ldr r6, table_entry
/* r6 has the value to be written to table entry */
add r6, r6, r4
/* Getting the address of table entry to modify */
lsr r4, #18
/* r2 has the location which needs to be modified */
add r2, r4
ldr r4, [r2]
str r6, [r2] /* modify the table entry */
mov r7, r6
mov r5, r2
mov r6, r4
/* r5 = original page table address */
/* r6 = original page table data */
mov r0, #0
mcr p15, 0, r0, c7, c5, 4 @ Flush prefetch buffer
mcr p15, 0, r0, c7, c5, 6 @ Invalidate branch predictor array
mcr p15, 0, r0, c8, c5, 0 @ Invalidate instruction TLB
mcr p15, 0, r0, c8, c6, 0 @ Invalidate data TLB
/*
* Restore control register. This enables the MMU.
* The caches and prediction are not enabled here, they
* will be enabled after restoring the MMU table entry.
*/
ldmia r3!, {r4}
stmia r3!, {r5} /* save original page table address */
stmia r3!, {r6} /* save original page table data */
stmia r3!, {r7} /* save modified page table data */
ldr r2, cache_pred_disable_mask
and r4, r2
mcr p15, 0, r4, c1, c0, 0
dsb
isb
ldr r0, =restoremmu_on
bx r0
/*
* ==============================
* == Exit point from OFF mode ==
* ==============================
*/
restoremmu_on:
ldmfd sp!, {r0-r12, pc} @ restore regs and return
