On Tue, 04 Apr 2023 11:20:23 PDT (-0700), [email protected] wrote:
> RHCT is a new table defined for RISC-V to communicate the
> features of the CPU to the OS. Create a new architecture folder
> in drivers/acpi and add RHCT parsing code.
>
> Signed-off-by: Sunil V L <[email protected]>
> Acked-by: Rafael J. Wysocki <[email protected]>
> Reviewed-by: Andrew Jones <[email protected]>
> ---
> arch/riscv/include/asm/acpi.h | 9 ++++
> drivers/acpi/Makefile | 2 +
> drivers/acpi/riscv/Makefile | 2 +
> drivers/acpi/riscv/rhct.c | 83 +++++++++++++++++++++++++++++++++++
> 4 files changed, 96 insertions(+)
> create mode 100644 drivers/acpi/riscv/Makefile
> create mode 100644 drivers/acpi/riscv/rhct.c
>
> diff --git a/arch/riscv/include/asm/acpi.h b/arch/riscv/include/asm/acpi.h
> index 1606dce8992e..2b3e78d5a13b 100644
> --- a/arch/riscv/include/asm/acpi.h
> +++ b/arch/riscv/include/asm/acpi.h
> @@ -61,6 +61,15 @@ static inline void arch_fix_phys_package_id(int num, u32 slot) { }
>
> struct acpi_madt_rintc *acpi_cpu_get_madt_rintc(int cpu);
> u32 get_acpi_id_for_cpu(int cpu);
> +int acpi_get_riscv_isa(struct acpi_table_header *table,
> + unsigned int cpu, const char **isa);
> +#else
> +static inline int acpi_get_riscv_isa(struct acpi_table_header *table,
> + unsigned int cpu, const char **isa)
> +{
> + return -EINVAL;
> +}
> +
> #endif /* CONFIG_ACPI */
>
> #endif /*_ASM_ACPI_H*/
> diff --git a/drivers/acpi/Makefile b/drivers/acpi/Makefile
> index feb36c0b9446..3fc5a0d54f6e 100644
> --- a/drivers/acpi/Makefile
> +++ b/drivers/acpi/Makefile
> @@ -131,3 +131,5 @@ obj-y += dptf/
> obj-$(CONFIG_ARM64) += arm64/
>
> obj-$(CONFIG_ACPI_VIOT) += viot.o
> +
> +obj-$(CONFIG_RISCV) += riscv/
> diff --git a/drivers/acpi/riscv/Makefile b/drivers/acpi/riscv/Makefile
> new file mode 100644
> index 000000000000..8b3b126e0b94
> --- /dev/null
> +++ b/drivers/acpi/riscv/Makefile
> @@ -0,0 +1,2 @@
> +# SPDX-License-Identifier: GPL-2.0-only
> +obj-y += rhct.o
> diff --git a/drivers/acpi/riscv/rhct.c b/drivers/acpi/riscv/rhct.c
> new file mode 100644
> index 000000000000..ea78d906a0fe
> --- /dev/null
> +++ b/drivers/acpi/riscv/rhct.c
> @@ -0,0 +1,83 @@
> +// SPDX-License-Identifier: GPL-2.0-only
> +/*
> + * Copyright (C) 2022-2023, Ventana Micro Systems Inc
> + * Author: Sunil V L <[email protected]>
> + *
> + */
> +
> +#define pr_fmt(fmt) "ACPI: RHCT: " fmt
> +
> +#include <linux/acpi.h>
> +
> +static struct acpi_table_header *acpi_get_rhct(void)
> +{
> + static struct acpi_table_header *rhct;
> + acpi_status status;
> +
> + /*
> + * RHCT will be used at runtime on every CPU, so we
> + * don't need to call acpi_put_table() to release the table mapping.
> + */
> + if (!rhct) {
> + status = acpi_get_table(ACPI_SIG_RHCT, 0, &rhct);
> + if (ACPI_FAILURE(status)) {
> + pr_warn_once("No RHCT table found\n");
> + return NULL;
> + }
> + }
> +
> + return rhct;
> +}
> +
> +/*
> + * During early boot, the caller should call acpi_get_table() and pass its pointer to
> + * these functions(and free up later). At run time, since this table can be used
> + * multiple times, NULL may be passed in order to use the cached table.
> + */
> +int acpi_get_riscv_isa(struct acpi_table_header *table, unsigned int cpu, const char **isa)
> +{
> + struct acpi_rhct_node_header *node, *ref_node, *end;
> + u32 size_hdr = sizeof(struct acpi_rhct_node_header);
> + u32 size_hartinfo = sizeof(struct acpi_rhct_hart_info);
> + struct acpi_rhct_hart_info *hart_info;
> + struct acpi_rhct_isa_string *isa_node;
> + struct acpi_table_rhct *rhct;
> + u32 *hart_info_node_offset;
> + u32 acpi_cpu_id = get_acpi_id_for_cpu(cpu);
> +
> + BUG_ON(acpi_disabled);
> +
> + if (!table) {
> + rhct = (struct acpi_table_rhct *)acpi_get_rhct();
> + if (!rhct)
> + return -ENOENT;
> + } else {
> + rhct = (struct acpi_table_rhct *)table;
> + }
> +
> + end = ACPI_ADD_PTR(struct acpi_rhct_node_header, rhct, rhct->header.length);
> +
> + for (node = ACPI_ADD_PTR(struct acpi_rhct_node_header, rhct, rhct->node_offset);
> + node < end;
> + node = ACPI_ADD_PTR(struct acpi_rhct_node_header, node, node->length)) {
> + if (node->type == ACPI_RHCT_NODE_TYPE_HART_INFO) {
> + hart_info = ACPI_ADD_PTR(struct acpi_rhct_hart_info, node, size_hdr);
> + hart_info_node_offset = ACPI_ADD_PTR(u32, hart_info, size_hartinfo);
> + if (acpi_cpu_id != hart_info->uid)
> + continue;
> +
> + for (int i = 0; i < hart_info->num_offsets; i++) {
> + ref_node = ACPI_ADD_PTR(struct acpi_rhct_node_header,
> + rhct, hart_info_node_offset[i]);
> + if (ref_node->type == ACPI_RHCT_NODE_TYPE_ISA_STRING) {
> + isa_node = ACPI_ADD_PTR(struct acpi_rhct_isa_string,
> + ref_node, size_hdr);
> + *isa = isa_node->isa;
> + return 0;
> + }
> + }
> + }
> + }
> +
> + return -1;
> +}
Reviewed-by: Palmer Dabbelt <[email protected]>