diff options
Diffstat (limited to 'arch/arm/cpu')
| -rw-r--r-- | arch/arm/cpu/armv8/Makefile | 1 | ||||
| -rw-r--r-- | arch/arm/cpu/armv8/acpi_park_v8.S | 113 | ||||
| -rw-r--r-- | arch/arm/cpu/armv8/start.S | 12 |
3 files changed, 126 insertions, 0 deletions
diff --git a/arch/arm/cpu/armv8/Makefile b/arch/arm/cpu/armv8/Makefile index 8747d2eb186..2e71ff2dc97 100644 --- a/arch/arm/cpu/armv8/Makefile +++ b/arch/arm/cpu/armv8/Makefile @@ -29,6 +29,7 @@ obj-$(CONFIG_ARM_SMCCC) += smccc-call.o ifndef CONFIG_XPL_BUILD obj-$(CONFIG_ARMV8_SPIN_TABLE) += spin_table.o spin_table_v8.o +obj-$(CONFIG_ACPI_PARKING_PROTOCOL) += acpi_park_v8.o else obj-$(CONFIG_ARCH_SUNXI) += fel_utils.o endif diff --git a/arch/arm/cpu/armv8/acpi_park_v8.S b/arch/arm/cpu/armv8/acpi_park_v8.S new file mode 100644 index 00000000000..0bc605d28df --- /dev/null +++ b/arch/arm/cpu/armv8/acpi_park_v8.S @@ -0,0 +1,113 @@ +/* SPDX-License-Identifier: GPL-2.0+ */ +/* + * Copyright (C) 2024 9elements GmbH + * Author: Patrick Rudolph <patrick.rudolph@9elements.com> + * + * This file provides ARMv8 specific code for the generic part of the + * ACPI parking protocol implementation. It contains the spinning code + * that will be installed into the parking protocol and it points the + * secondary CPUs to their own parking protocol page once it has been + * set up by the generic part. + */ + +#include <asm/acpi_table.h> +#include <linux/linkage.h> + +/* Filled by C code */ +.global acpi_pp_tables +acpi_pp_tables: + .quad 0 + +.global acpi_pp_etables +acpi_pp_etables: + .quad 0 + +/* Read by C code */ +.global acpi_pp_code_size +acpi_pp_code_size: + .word __secondary_pp_code_end - __secondary_pp_code_start + +.global acpi_pp_secondary_jump +ENTRY(acpi_pp_secondary_jump) +0: + /* + * Cannot use atomic operations since the MMU and D-cache + * might be off. Use the MPIDR instead to find the spintable. + */ + + /* Check if parking protocol table is ready */ + ldr x1, =acpi_pp_tables + ldr x0, [x1] + cbnz x0, 0f + wfe + b 0b + +0: /* Get end of page tables in x3 */ + ldr x1, =acpi_pp_etables + ldr x3, [x1] + + /* Get own CPU ID in w2 */ + mrs x2, mpidr_el1 + lsr x9, x2, #32 + bfi x2, x9, #24, #8 /* w2 is aff3:aff2:aff1:aff0 */ + +0: /* Loop over all parking protocol pages */ + cmp x0, x3 + b.ge hlt + + /* Fetch CPU_ID from current page */ + ldr x1, [x0, #ACPI_PP_CPU_ID_OFFSET] + lsr x9, x1, #32 + bfi x1, x9, #24, #8 /* w1 is aff3:aff2:aff1:aff0 */ + + /* Compare CPU_IDs */ + cmp w1, w2 + b.eq 0f + + add x0, x0, #ACPI_PP_PAGE_SIZE + b 0b + +hlt: wfi + b hlt /* Should never happen. */ + +0: /* x0 points to the 4K-aligned, parking protocol page */ + add x2, x0, #ACPI_PP_CPU_CODE_OFFSET + + /* Jump to spin code in own parking protocol page */ + br x2 +ENDPROC(acpi_pp_secondary_jump) + +.align 8 +__secondary_pp_code_start: +.global acpi_pp_code_start +ENTRY(acpi_pp_code_start) + /* x0 points to the 4K-aligned, parking protocol page */ + + /* Prepare defines for spinning code */ + mov w3, #ACPI_PP_CPU_ID_INVALID + mov x2, #ACPI_PP_JMP_ADR_INVALID + + /* Mark parking protocol page as ready */ + str w3, [x0, #ACPI_PP_CPU_ID_OFFSET] + dsb sy + +0: wfe + ldr w1, [x0, #ACPI_PP_CPU_ID_OFFSET] + + /* Check CPU ID is valid */ + cmp w1, w3 + b.eq 0b + + /* Check jump address valid */ + ldr x1, [x0, #ACPI_PP_CPU_JMP_OFFSET] + cmp x1, x2 + b.eq 0b + + /* Clear jump address before jump */ + str x2, [x0, #ACPI_PP_CPU_JMP_OFFSET] + dsb sy + + br x1 +ENDPROC(acpi_pp_code_start) + /* Secondary Boot Code ends here */ +__secondary_pp_code_end: diff --git a/arch/arm/cpu/armv8/start.S b/arch/arm/cpu/armv8/start.S index 4a3b9f60e46..d3a8a7c4787 100644 --- a/arch/arm/cpu/armv8/start.S +++ b/arch/arm/cpu/armv8/start.S @@ -178,6 +178,18 @@ pie_fixup_done: branch_if_master x0, master_cpu b spin_table_secondary_jump /* never return */ +#elif defined(CONFIG_ACPI_PARKING_PROTOCOL) && !defined(CONFIG_SPL_BUILD) + branch_if_master x0, master_cpu + /* + * Waits for ACPI parking protocol memory to be allocated and the spin-table + * code to be written. Once ready the secondary CPUs will jump and spin in + * their own 4KiB memory region, which is also used as mailbox, until released + * by the OS. + * The mechanism is similar to the DT enable-method = "spin-table", but works + * with ACPI enabled platforms. + */ + b acpi_pp_secondary_jump + /* never return */ #elif defined(CONFIG_ARMV8_MULTIENTRY) branch_if_master x0, master_cpu |