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arch: x86: add IPC mailbox accessor function and add SoC register access

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- Exports intel_pmc_ipc() for host access to the PMC IPC mailbox
- Enables the host to access specific SoC registers through the PMC
firmware using IPC commands. This access method is necessary for
registers that are not available through direct Memory-Mapped I/O (MMIO),
which is used for other accessible parts of the PMC.

Signed-off-by: David E. Box <david.e.box@linux.intel.com>
Signed-off-by: Chao Qin <chao.qin@intel.com>
Signed-off-by: Choong Yong Liang <yong.liang.choong@linux.intel.com>
Acked-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Link: https://patch.msgid.link/20250227121522.1802832-4-yong.liang.choong@linux.intel.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
This commit is contained in:
David E. Box 2025-02-27 20:15:19 +08:00 committed by Jakub Kicinski
parent 065d3cef99
commit 7e2f7e25f6
2 changed files with 95 additions and 0 deletions
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MAINTAINERS
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@ -11862,6 +11862,7 @@ L: platform-driver-x86@vger.kernel.org
S: Maintained
F: Documentation/ABI/testing/sysfs-platform-intel-pmc
F: drivers/platform/x86/intel/pmc/
F: linux/platform_data/x86/intel_pmc_ipc.h
INTEL PMIC GPIO DRIVERS
M: Andy Shevchenko <andy@kernel.org>

94
include/linux/platform_data/x86/intel_pmc_ipc.h Normal file
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@ -0,0 +1,94 @@
/* SPDX-License-Identifier: GPL-2.0 */
/*
* Intel Core SoC Power Management Controller Header File
*
* Copyright (c) 2025, Intel Corporation.
* All Rights Reserved.
*
*/
#ifndef INTEL_PMC_IPC_H
#define INTEL_PMC_IPC_H
#include <linux/acpi.h>
#define IPC_SOC_REGISTER_ACCESS 0xAA
#define IPC_SOC_SUB_CMD_READ 0x00
#define IPC_SOC_SUB_CMD_WRITE 0x01
#define PMC_IPCS_PARAM_COUNT 7
#define VALID_IPC_RESPONSE 5
struct pmc_ipc_cmd {
u32 cmd;
u32 sub_cmd;
u32 size;
u32 wbuf[4];
};
struct pmc_ipc_rbuf {
u32 buf[4];
};
/**
* intel_pmc_ipc() - PMC IPC Mailbox accessor
* @ipc_cmd: Prepared input command to send
* @rbuf: Allocated array for returned IPC data
*
* Return: 0 on success. Non-zero on mailbox error
*/
static inline int intel_pmc_ipc(struct pmc_ipc_cmd *ipc_cmd, struct pmc_ipc_rbuf *rbuf)
{
struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
union acpi_object params[PMC_IPCS_PARAM_COUNT] = {
{.type = ACPI_TYPE_INTEGER,},
{.type = ACPI_TYPE_INTEGER,},
{.type = ACPI_TYPE_INTEGER,},
{.type = ACPI_TYPE_INTEGER,},
{.type = ACPI_TYPE_INTEGER,},
{.type = ACPI_TYPE_INTEGER,},
{.type = ACPI_TYPE_INTEGER,},
};
struct acpi_object_list arg_list = { PMC_IPCS_PARAM_COUNT, params };
union acpi_object *obj;
int status;
if (!ipc_cmd || !rbuf)
return -EINVAL;
/*
* 0: IPC Command
* 1: IPC Sub Command
* 2: Size
* 3-6: Write Buffer for offset
*/
params[0].integer.value = ipc_cmd->cmd;
params[1].integer.value = ipc_cmd->sub_cmd;
params[2].integer.value = ipc_cmd->size;
params[3].integer.value = ipc_cmd->wbuf[0];
params[4].integer.value = ipc_cmd->wbuf[1];
params[5].integer.value = ipc_cmd->wbuf[2];
params[6].integer.value = ipc_cmd->wbuf[3];
status = acpi_evaluate_object(NULL, "\\IPCS", &arg_list, &buffer);
if (ACPI_FAILURE(status))
return -ENODEV;
obj = buffer.pointer;
if (obj && obj->type == ACPI_TYPE_PACKAGE &&
obj->package.count == VALID_IPC_RESPONSE) {
const union acpi_object *objs = obj->package.elements;
if ((u8)objs[0].integer.value != 0)
return -EINVAL;
rbuf->buf[0] = objs[1].integer.value;
rbuf->buf[1] = objs[2].integer.value;
rbuf->buf[2] = objs[3].integer.value;
rbuf->buf[3] = objs[4].integer.value;
} else {
return -EINVAL;
}
return 0;
}
#endif /* INTEL_PMC_IPC_H */