From: "David E. Box" <david.e.box@xxxxxxxxxxxxxxx>
- 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@xxxxxxxxxxxxxxx>
Signed-off-by: Chao Qin <chao.qin@xxxxxxxxx>
Signed-off-by: Choong Yong Liang <yong.liang.choong@xxxxxxxxxxxxxxx>
---
MAINTAINERS | 1 +
.../linux/platform_data/x86/intel_pmc_ipc.h | 94 +++++++++++++++++++
2 files changed, 95 insertions(+)
create mode 100644 include/linux/platform_data/x86/intel_pmc_ipc.h
diff --git a/MAINTAINERS b/MAINTAINERS
index 8019d5a97546..aff084824b89 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -11864,6 +11864,7 @@ L: platform-driver-x86@xxxxxxxxxxxxxxx
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@xxxxxxxxxx>
diff --git a/include/linux/platform_data/x86/intel_pmc_ipc.h b/include/linux/platform_data/x86/intel_pmc_ipc.h
new file mode 100644
index 000000000000..6e603a8c075f
--- /dev/null
+++ b/include/linux/platform_data/x86/intel_pmc_ipc.h
@@ -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 */
--
2.34.1
