arm-trusted-firmware/services/std_svc/psci/psci_entry.S
Sandrine Bailleux 52010cc779 Rationalize reset handling code
The attempt to run the CPU reset code as soon as possible after reset
results in highly complex conditional code relating to the
RESET_TO_BL31 option.

This patch relaxes this requirement a little. In the BL1, BL3-1 and
PSCI entrypoints code, the sequence of operations is now as follows:
 1) Detect whether it is a cold or warm boot;
 2) For cold boot, detect whether it is the primary or a secondary
    CPU. This is needed to handle multiple CPUs entering cold reset
    simultaneously;
 3) Run the CPU init code.

This patch also abstracts the EL3 registers initialisation done by
the BL1, BL3-1 and PSCI entrypoints into common code.

This improves code re-use and consolidates the code flows for
different types of systems.

NOTE: THE FUNCTION plat_secondary_cold_boot() IS NOW EXPECTED TO
NEVER RETURN. THIS PATCH FORCES PLATFORM PORTS THAT RELIED ON THE
FORMER RETRY LOOP AT THE CALL SITE TO MODIFY THEIR IMPLEMENTATION.
OTHERWISE, SECONDARY CPUS WILL PANIC.

Change-Id: If5ecd74d75bee700b1bd718d23d7556b8f863546
2015-06-04 11:38:54 +01:00

125 lines
4.5 KiB
ArmAsm

/*
* Copyright (c) 2013-2015, ARM Limited and Contributors. All rights reserved.
*
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*
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*/
#include <arch.h>
#include <asm_macros.S>
#include <el3_common_macros.S>
#include <psci.h>
#include <xlat_tables.h>
.globl psci_aff_on_finish_entry
.globl psci_aff_suspend_finish_entry
.globl psci_power_down_wfi
/* -----------------------------------------------------
* This cpu has been physically powered up. Depending
* upon whether it was resumed from suspend or simply
* turned on, call the common power on finisher with
* the handlers (chosen depending upon original state).
* -----------------------------------------------------
*/
func psci_aff_on_finish_entry
adr x23, psci_afflvl_on_finishers
b psci_aff_common_finish_entry
psci_aff_suspend_finish_entry:
adr x23, psci_afflvl_suspend_finishers
psci_aff_common_finish_entry:
/*
* On the warm boot path, most of the EL3 initialisations performed by
* 'el3_entrypoint_common' must be skipped:
*
* - No need to determine the type of boot, we know it is a warm boot.
*
* - Do not try to distinguish between primary and secondary CPUs, this
* notion only exists for a cold boot.
*
* - No need to initialise the memory or the C runtime environment,
* it has been done once and for all on the cold boot path.
*/
el3_entrypoint_common \
_set_endian=0 \
_warm_boot_mailbox=0 \
_secondary_cold_boot=0 \
_init_memory=0 \
_init_c_runtime=0 \
_exception_vectors=runtime_exceptions
/* --------------------------------------------
* Enable the MMU with the DCache disabled. It
* is safe to use stacks allocated in normal
* memory as a result. All memory accesses are
* marked nGnRnE when the MMU is disabled. So
* all the stack writes will make it to memory.
* All memory accesses are marked Non-cacheable
* when the MMU is enabled but D$ is disabled.
* So used stack memory is guaranteed to be
* visible immediately after the MMU is enabled
* Enabling the DCache at the same time as the
* MMU can lead to speculatively fetched and
* possibly stale stack memory being read from
* other caches. This can lead to coherency
* issues.
* --------------------------------------------
*/
mov x0, #DISABLE_DCACHE
bl bl31_plat_enable_mmu
/* ---------------------------------------------
* Call the finishers starting from affinity
* level 0.
* ---------------------------------------------
*/
bl get_power_on_target_afflvl
mov x2, x23
mov x1, x0
mov x0, #MPIDR_AFFLVL0
bl psci_afflvl_power_on_finish
b el3_exit
endfunc psci_aff_on_finish_entry
/* --------------------------------------------
* 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. 'wfi_spill' is used to catch erroneous
* exits from wfi.
* --------------------------------------------
*/
func psci_power_down_wfi
dsb sy // ensure write buffer empty
wfi
wfi_spill:
b wfi_spill
endfunc psci_power_down_wfi