Unverified Commit e6b9d8ed authored by Sunil V L's avatar Sunil V L Committed by Palmer Dabbelt
Browse files

drivers/acpi: RISC-V: Add RHCT related code 



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: default avatarSunil V L <sunilvl@ventanamicro.com>
Acked-by: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
Reviewed-by: default avatarAndrew Jones <ajones@ventanamicro.com>
Reviewed-by: default avatarPalmer Dabbelt <palmer@rivosinc.com>
Link: https://lore.kernel.org/r/20230515054928.2079268-11-sunilvl@ventanamicro.com


Signed-off-by: default avatarPalmer Dabbelt <palmer@rivosinc.com>
parent f9956119

arch/riscv/include/asm/acpi.h

+8 −0
Original line number Diff line number Diff line
@@ -62,6 +62,8 @@ static inline void arch_fix_phys_package_id(int num, u32 slot) { } 
void acpi_init_rintc_map(void);

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 void acpi_init_rintc_map(void) { }

static inline struct acpi_madt_rintc *acpi_cpu_get_madt_rintc(int cpu)
@@ -69,6 +71,12 @@ static inline struct acpi_madt_rintc *acpi_cpu_get_madt_rintc(int cpu) 
	return NULL;

}



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*/

drivers/acpi/Makefile

+2 −0
Original line number Diff line number Diff line
@@ -131,3 +131,5 @@ obj-y += dptf/ 
obj-$(CONFIG_ARM64)		+= arm64/



obj-$(CONFIG_ACPI_VIOT)		+= viot.o



obj-$(CONFIG_RISCV)		+= riscv/

drivers/acpi/riscv/Makefile

0 → 100644
+2 −0
Original line number Diff line number Diff line 
# SPDX-License-Identifier: GPL-2.0-only

obj-y 	+= rhct.o

drivers/acpi/riscv/rhct.c

0 → 100644
+83 −0
Original line number Diff line number Diff line 
// 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;

}