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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 <sunilvl@ventanamicro.com> Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Reviewed-by: Andrew Jones <ajones@ventanamicro.com> Reviewed-by: Palmer Dabbelt <palmer@rivosinc.com> Link: https://lore.kernel.org/r/20230515054928.2079268-11-sunilvl@ventanamicro.com Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
83 lines
2.3 KiB
C
83 lines
2.3 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
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/*
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* Copyright (C) 2022-2023, Ventana Micro Systems Inc
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* Author: Sunil V L <sunilvl@ventanamicro.com>
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*
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*/
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#define pr_fmt(fmt) "ACPI: RHCT: " fmt
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#include <linux/acpi.h>
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static struct acpi_table_header *acpi_get_rhct(void)
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{
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static struct acpi_table_header *rhct;
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acpi_status status;
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/*
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* RHCT will be used at runtime on every CPU, so we
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* don't need to call acpi_put_table() to release the table mapping.
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*/
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if (!rhct) {
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status = acpi_get_table(ACPI_SIG_RHCT, 0, &rhct);
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if (ACPI_FAILURE(status)) {
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pr_warn_once("No RHCT table found\n");
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return NULL;
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}
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}
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return rhct;
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}
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/*
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* During early boot, the caller should call acpi_get_table() and pass its pointer to
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* these functions(and free up later). At run time, since this table can be used
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* multiple times, NULL may be passed in order to use the cached table.
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*/
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int acpi_get_riscv_isa(struct acpi_table_header *table, unsigned int cpu, const char **isa)
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{
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struct acpi_rhct_node_header *node, *ref_node, *end;
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u32 size_hdr = sizeof(struct acpi_rhct_node_header);
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u32 size_hartinfo = sizeof(struct acpi_rhct_hart_info);
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struct acpi_rhct_hart_info *hart_info;
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struct acpi_rhct_isa_string *isa_node;
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struct acpi_table_rhct *rhct;
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u32 *hart_info_node_offset;
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u32 acpi_cpu_id = get_acpi_id_for_cpu(cpu);
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BUG_ON(acpi_disabled);
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if (!table) {
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rhct = (struct acpi_table_rhct *)acpi_get_rhct();
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if (!rhct)
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return -ENOENT;
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} else {
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rhct = (struct acpi_table_rhct *)table;
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}
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end = ACPI_ADD_PTR(struct acpi_rhct_node_header, rhct, rhct->header.length);
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for (node = ACPI_ADD_PTR(struct acpi_rhct_node_header, rhct, rhct->node_offset);
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node < end;
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node = ACPI_ADD_PTR(struct acpi_rhct_node_header, node, node->length)) {
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if (node->type == ACPI_RHCT_NODE_TYPE_HART_INFO) {
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hart_info = ACPI_ADD_PTR(struct acpi_rhct_hart_info, node, size_hdr);
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hart_info_node_offset = ACPI_ADD_PTR(u32, hart_info, size_hartinfo);
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if (acpi_cpu_id != hart_info->uid)
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continue;
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for (int i = 0; i < hart_info->num_offsets; i++) {
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ref_node = ACPI_ADD_PTR(struct acpi_rhct_node_header,
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rhct, hart_info_node_offset[i]);
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if (ref_node->type == ACPI_RHCT_NODE_TYPE_ISA_STRING) {
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isa_node = ACPI_ADD_PTR(struct acpi_rhct_isa_string,
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ref_node, size_hdr);
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*isa = isa_node->isa;
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return 0;
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}
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}
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}
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}
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return -1;
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}
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