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/*
* Copyright (c) 2016-2023, Arm Limited and Contributors. All rights reserved.
*
* SPDX-License-Identifier: BSD-3-Clause
*/
#include <asm_macros.S>
#include <lib/psci/psci.h>
#include <platform_def.h>
.globl psci_do_pwrdown_cache_maintenance
.globl psci_do_pwrup_cache_maintenance
.globl psci_power_down_wfi
/* -----------------------------------------------------------------------
* void psci_do_pwrdown_cache_maintenance(unsigned int power level);
*
* This function performs cache maintenance for the specified power
* level. The levels of cache affected are determined by the power
* level which is passed as the argument i.e. level 0 results
* in a flush of the L1 cache. Both the L1 and L2 caches are flushed
* for a higher power level.
*
* Additionally, this function also ensures that stack memory is correctly
* flushed out to avoid coherency issues due to a change in its memory
* attributes after the data cache is disabled.
* -----------------------------------------------------------------------
*/
func psci_do_pwrdown_cache_maintenance
push {r4, lr}
/* ----------------------------------------------
* Turn OFF cache and do stack maintenance
* prior to cpu operations . This sequence is
* different from AArch64 because in AArch32 the
* assembler routines for cpu operations utilize
* the stack whereas in AArch64 it doesn't.
* ----------------------------------------------
*/
mov r4, r0
bl do_stack_maintenance
/* ---------------------------------------------
* Invoke CPU-specifc power down operations for
* the appropriate level
* ---------------------------------------------
*/
mov r0, r4
pop {r4, lr}
b prepare_cpu_pwr_dwn
endfunc psci_do_pwrdown_cache_maintenance
/* -----------------------------------------------------------------------
* void psci_do_pwrup_cache_maintenance(void);
*
* This function performs cache maintenance after this cpu is powered up.
* Currently, this involves managing the used stack memory before turning
* on the data cache.
* -----------------------------------------------------------------------
*/
func psci_do_pwrup_cache_maintenance
/* r12 is pushed to meet the 8 byte stack alignment requirement */
push {r12, lr}
/* ---------------------------------------------
* Ensure any inflight stack writes have made it
* to main memory.
* ---------------------------------------------
*/
dmb st
/* ---------------------------------------------
* Calculate and store the size of the used
* stack memory in r1. Calculate and store the
* stack base address in r0.
* ---------------------------------------------
*/
bl plat_get_my_stack
mov r1, sp
sub r1, r0, r1
mov r0, sp
bl inv_dcache_range
/* ---------------------------------------------
* Enable the data cache.
* ---------------------------------------------
*/
ldcopr r0, SCTLR
orr r0, r0, #SCTLR_C_BIT
stcopr r0, SCTLR
isb
pop {r12, pc}
endfunc psci_do_pwrup_cache_maintenance
/* ---------------------------------------------
* void do_stack_maintenance(void)
* Do stack maintenance by flushing the used
* stack to the main memory and invalidating the
* remainder.
* ---------------------------------------------
*/
func do_stack_maintenance
push {r4, lr}
bl plat_get_my_stack
/* Turn off the D-cache */
ldcopr r1, SCTLR
bic r1, #SCTLR_C_BIT
stcopr r1, SCTLR
isb
/* ---------------------------------------------
* Calculate and store the size of the used
* stack memory in r1.
* ---------------------------------------------
*/
mov r4, r0
mov r1, sp
sub r1, r0, r1
mov r0, sp
bl flush_dcache_range
/* ---------------------------------------------
* Calculate and store the size of the unused
* stack memory in r1. Calculate and store the
* stack base address in r0.
* ---------------------------------------------
*/
sub r0, r4, #PLATFORM_STACK_SIZE
sub r1, sp, r0
bl inv_dcache_range
pop {r4, pc}
endfunc do_stack_maintenance
/* -----------------------------------------------------------------------
* This function is called to indicate to the power controller that it
* is safe to power down this cpu. It should not exit the wfi and will
* be released from reset upon power up.
* -----------------------------------------------------------------------
*/
func psci_power_down_wfi
dsb sy // ensure write buffer empty
1:
wfi
b 1b
endfunc psci_power_down_wfi
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