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// SPDX-License-Identifier: GPL-2.0-only
/*
* Copyright (C) 2022-2023, Ventana Micro Systems Inc
* Author: Sunil V L <sunilvl@ventanamicro.com>
*
*/
#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;
}
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