diff options
Diffstat (limited to 'lib/psci/aarch32/psci_helpers.S')
| -rw-r--r-- | lib/psci/aarch32/psci_helpers.S | 149 |
1 files changed, 149 insertions, 0 deletions
diff --git a/lib/psci/aarch32/psci_helpers.S b/lib/psci/aarch32/psci_helpers.S new file mode 100644 index 0000000..4e1013c --- /dev/null +++ b/lib/psci/aarch32/psci_helpers.S @@ -0,0 +1,149 @@ +/* + * 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 |