diff mbox series

[net-next,v2,1/5] platform/x86: intel_pmc_core: Add IPC mailbox accessor function and add SoC register access

Message ID 20230804084527.2082302-2-yong.liang.choong@linux.intel.com (mailing list archive)
State Changes Requested
Delegated to: Netdev Maintainers
Headers show
Series TSN auto negotiation between 1G and 2.5G | expand

Checks

Context Check Description
netdev/series_format success Posting correctly formatted
netdev/tree_selection success Clearly marked for net-next, async
netdev/fixes_present success Fixes tag not required for -next series
netdev/header_inline success No static functions without inline keyword in header files
netdev/build_32bit success Errors and warnings before: 1328 this patch: 1328
netdev/cc_maintainers warning 1 maintainers not CCed: david.e.box@intel.com
netdev/build_clang success Errors and warnings before: 1351 this patch: 1351
netdev/verify_signedoff success Signed-off-by tag matches author and committer
netdev/deprecated_api success None detected
netdev/check_selftest success No net selftest shell script
netdev/verify_fixes success No Fixes tag
netdev/build_allmodconfig_warn success Errors and warnings before: 1351 this patch: 1351
netdev/checkpatch success total: 0 errors, 0 warnings, 0 checks, 126 lines checked
netdev/kdoc success Errors and warnings before: 0 this patch: 0
netdev/source_inline success Was 0 now: 0

Commit Message

Choong Yong Liang Aug. 4, 2023, 8:45 a.m. UTC 
From: "David E. Box" <david.e.box@linux.intel.com>

- Exports intel_pmc_core_ipc() for host access to the PMC IPC mailbox
- Add support to use IPC command allows host to access SoC registers
through PMC firmware that are otherwise inaccessible to the host due to
security policies.

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>
---
 MAINTAINERS                                   |  1 +
 drivers/platform/x86/intel/pmc/core.c         | 60 +++++++++++++++++++
 .../linux/platform_data/x86/intel_pmc_core.h  | 41 +++++++++++++
 3 files changed, 102 insertions(+)
 create mode 100644 include/linux/platform_data/x86/intel_pmc_core.h

Comments

Hans de Goede Aug. 7, 2023, 11:02 a.m. UTC | #1 
Hi David,

On 8/4/23 10:45, Choong Yong Liang wrote:
> From: "David E. Box" <david.e.box@linux.intel.com>
> 
> - Exports intel_pmc_core_ipc() for host access to the PMC IPC mailbox
> - Add support to use IPC command allows host to access SoC registers
> through PMC firmware that are otherwise inaccessible to the host due to
> security policies.
> 
> 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>

The new exported intel_pmc_core_ipc() function does not seem to
depend on any existing PMC code.

IMHO it would be better to put this in a new .c file under
arch/x86/platform/intel/ this is where similar helpers like
the iosf_mbi functions also live.

This also avoids Kconfig complications. Currently the
drivers/platform/x86/intel/pmc/core.c code is only
build if CONFIG_X86_PLATFORM_DEVICES and
CONFIG_INTEL_PMC_CORE are both set. So if a driver
wants to make sure this is enabled by selecting them
then it needs to select both.

Talking about Kconfig:

#if IS_ENABLED(CONFIG_INTEL_PMC_CORE)
int intel_pmc_core_ipc(struct pmc_ipc_cmd *ipc_cmd, u32 *rbuf);
#else
static inline int intel_pmc_core_ipc(struct pmc_ipc_cmd *ipc_cmd, u32 *rbuf)
{
	return -ENODEV;
}
#endif /* CONFIG_INTEL_PMC_CORE */

Notice that CONFIG_INTEL_PMC_CORE is a tristate, so pmc might be build as a module where as a consumer of intel_pmc_core_ipc() might end up builtin in which case this will not work without extra Kconfig protection. And if you are going to add extra Kconfig you might just as well select or depend on INTEL_PMC_CORE and drop the #if .

Regards,

Hans






> ---
>  MAINTAINERS                                   |  1 +
>  drivers/platform/x86/intel/pmc/core.c         | 60 +++++++++++++++++++
>  .../linux/platform_data/x86/intel_pmc_core.h  | 41 +++++++++++++
>  3 files changed, 102 insertions(+)
>  create mode 100644 include/linux/platform_data/x86/intel_pmc_core.h
> 
> diff --git a/MAINTAINERS b/MAINTAINERS
> index 069e176d607a..8a034dee9da9 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -10648,6 +10648,7 @@ 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_core.h
>  
>  INTEL PMIC GPIO DRIVERS
>  M:	Andy Shevchenko <andy@kernel.org>
> diff --git a/drivers/platform/x86/intel/pmc/core.c b/drivers/platform/x86/intel/pmc/core.c
> index 5a36b3f77bc5..6fb1b0f453d8 100644
> --- a/drivers/platform/x86/intel/pmc/core.c
> +++ b/drivers/platform/x86/intel/pmc/core.c
> @@ -20,6 +20,7 @@
>  #include <linux/pci.h>
>  #include <linux/slab.h>
>  #include <linux/suspend.h>
> +#include <linux/platform_data/x86/intel_pmc_core.h>
>  
>  #include <asm/cpu_device_id.h>
>  #include <asm/intel-family.h>
> @@ -28,6 +29,8 @@
>  
>  #include "core.h"
>  
> +#define PMC_IPCS_PARAM_COUNT           7
> +
>  /* Maximum number of modes supported by platfoms that has low power mode capability */
>  const char *pmc_lpm_modes[] = {
>  	"S0i2.0",
> @@ -53,6 +56,63 @@ const struct pmc_bit_map msr_map[] = {
>  	{}
>  };
>  
> +int intel_pmc_core_ipc(struct pmc_ipc_cmd *ipc_cmd, u32 *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;
> +	/* Check if the number of elements in package is 5 */
> +	if (obj && obj->type == ACPI_TYPE_PACKAGE && obj->package.count == 5) {
> +		const union acpi_object *objs = obj->package.elements;
> +
> +		if ((u8)objs[0].integer.value != 0)
> +			return -EINVAL;
> +
> +		rbuf[0] = objs[1].integer.value;
> +		rbuf[1] = objs[2].integer.value;
> +		rbuf[2] = objs[3].integer.value;
> +		rbuf[3] = objs[4].integer.value;
> +	} else {
> +		return -EINVAL;
> +	}
> +
> +	return 0;
> +}
> +EXPORT_SYMBOL(intel_pmc_core_ipc);
> +
>  static inline u32 pmc_core_reg_read(struct pmc *pmc, int reg_offset)
>  {
>  	return readl(pmc->regbase + reg_offset);
> diff --git a/include/linux/platform_data/x86/intel_pmc_core.h b/include/linux/platform_data/x86/intel_pmc_core.h
> new file mode 100644
> index 000000000000..9bb3394fedcf
> --- /dev/null
> +++ b/include/linux/platform_data/x86/intel_pmc_core.h
> @@ -0,0 +1,41 @@
> +/* SPDX-License-Identifier: GPL-2.0 */
> +/*
> + * Intel Core SoC Power Management Controller Header File
> + *
> + * Copyright (c) 2023, Intel Corporation.
> + * All Rights Reserved.
> + *
> + * Authors: Choong Yong Liang <yong.liang.choong@linux.intel.com>
> + *          David E. Box <david.e.box@linux.intel.com>
> + */
> +#ifndef INTEL_PMC_CORE_H
> +#define INTEL_PMC_CORE_H
> +
> +#define IPC_SOC_REGISTER_ACCESS			0xAA
> +#define IPC_SOC_SUB_CMD_READ			0x00
> +#define IPC_SOC_SUB_CMD_WRITE			0x01
> +
> +struct pmc_ipc_cmd {
> +	u32 cmd;
> +	u32 sub_cmd;
> +	u32 size;
> +	u32 wbuf[4];
> +};
> +
> +#if IS_ENABLED(CONFIG_INTEL_PMC_CORE)
> +/**
> + * intel_pmc_core_ipc() - PMC IPC Mailbox accessor
> + * @ipc_cmd:  struct pmc_ipc_cmd prepared with input to send
> + * @rbuf:     Allocated u32[4] array for returned IPC data
> + *
> + * Return: 0 on success. Non-zero on mailbox error
> + */
> +int intel_pmc_core_ipc(struct pmc_ipc_cmd *ipc_cmd, u32 *rbuf);
> +#else
> +static inline int intel_pmc_core_ipc(struct pmc_ipc_cmd *ipc_cmd, u32 *rbuf)
> +{
> +	return -ENODEV;
> +}
> +#endif /* CONFIG_INTEL_PMC_CORE */
> +
> +#endif /* INTEL_PMC_CORE_H */
David E. Box Aug. 10, 2023, 4:36 p.m. UTC | #2 
Hi Hans,

On Mon, 2023-08-07 at 13:02 +0200, Hans de Goede wrote:
> > Hi David,
> > 
> > On 8/4/23 10:45, Choong Yong Liang wrote:
> > > > From: "David E. Box" <david.e.box@linux.intel.com>
> > > > 
> > > > - Exports intel_pmc_core_ipc() for host access to the PMC IPC mailbox
> > > > - Add support to use IPC command allows host to access SoC registers
> > > > through PMC firmware that are otherwise inaccessible to the host due to
> > > > security policies.
> > > > 
> > > > 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>
> > 
> > The new exported intel_pmc_core_ipc() function does not seem to
> > depend on any existing PMC code.
> > 
> > IMHO it would be better to put this in a new .c file under
> > arch/x86/platform/intel/ this is where similar helpers like
> > the iosf_mbi functions also live.
> > 
> > This also avoids Kconfig complications. Currently the
> > drivers/platform/x86/intel/pmc/core.c code is only
> > build if CONFIG_X86_PLATFORM_DEVICES and
> > CONFIG_INTEL_PMC_CORE are both set. So if a driver
> > wants to make sure this is enabled by selecting them
> > then it needs to select both.

Yeah, makes sense. This is an old patch. Once upon a time the PMC driver was
going to use the IPC to access some registers but we were able to get them from
elsewhere. The patch was brought back for the TSN use case. But you're correct
that arch/x86/platform/intel makes more sense if the function is to be exported
now and doesn't require to PMC driver to discover the interface. We'll do that.

> > 
> > Talking about Kconfig:
> > 
> > #if IS_ENABLED(CONFIG_INTEL_PMC_CORE)
> > int intel_pmc_core_ipc(struct pmc_ipc_cmd *ipc_cmd, u32 *rbuf);
> > #else
> > static inline int intel_pmc_core_ipc(struct pmc_ipc_cmd *ipc_cmd, u32 *rbuf)
> > {
> >         return -ENODEV;
> > }
> > #endif /* CONFIG_INTEL_PMC_CORE */
> > 
> > Notice that CONFIG_INTEL_PMC_CORE is a tristate, so pmc might be build as a
> > > module where as a consumer of intel_pmc_core_ipc() might end up builtin in
> > > which case this will not work without extra Kconfig protection. And if you
> > are > going to add extra Kconfig you might just as well select or depend on
> > > INTEL_PMC_CORE and drop the #if .

Sure. Thanks.

David

> > 
> > Regards,
> > 
> > Hans
> > 
> > 
> > 
> > 
> > 
> > 
> > > > ---
> > > >  MAINTAINERS                                   |  1 +
> > > >  drivers/platform/x86/intel/pmc/core.c         | 60 +++++++++++++++++++
> > > >  .../linux/platform_data/x86/intel_pmc_core.h  | 41 +++++++++++++
> > > >  3 files changed, 102 insertions(+)
> > > >  create mode 100644 include/linux/platform_data/x86/intel_pmc_core.h
> > > > 
> > > > diff --git a/MAINTAINERS b/MAINTAINERS
> > > > index 069e176d607a..8a034dee9da9 100644
> > > > --- a/MAINTAINERS
> > > > +++ b/MAINTAINERS
> > > > @@ -10648,6 +10648,7 @@ 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_core.h
> > > >  
> > > >  INTEL PMIC GPIO DRIVERS
> > > >  M:     Andy Shevchenko <andy@kernel.org>
> > > > diff --git a/drivers/platform/x86/intel/pmc/core.c > >
> > > > b/drivers/platform/x86/intel/pmc/core.c
> > > > index 5a36b3f77bc5..6fb1b0f453d8 100644
> > > > --- a/drivers/platform/x86/intel/pmc/core.c
> > > > +++ b/drivers/platform/x86/intel/pmc/core.c
> > > > @@ -20,6 +20,7 @@
> > > >  #include <linux/pci.h>
> > > >  #include <linux/slab.h>
> > > >  #include <linux/suspend.h>
> > > > +#include <linux/platform_data/x86/intel_pmc_core.h>
> > > >  
> > > >  #include <asm/cpu_device_id.h>
> > > >  #include <asm/intel-family.h>
> > > > @@ -28,6 +29,8 @@
> > > >  
> > > >  #include "core.h"
> > > >  
> > > > +#define PMC_IPCS_PARAM_COUNT           7
> > > > +
> > > >  /* Maximum number of modes supported by platfoms that has low power
> > > > mode > > capability */
> > > >  const char *pmc_lpm_modes[] = {
> > > >         "S0i2.0",
> > > > @@ -53,6 +56,63 @@ const struct pmc_bit_map msr_map[] = {
> > > >         {}
> > > >  };
> > > >  
> > > > +int intel_pmc_core_ipc(struct pmc_ipc_cmd *ipc_cmd, u32 *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;
> > > > +       /* Check if the number of elements in package is 5 */
> > > > +       if (obj && obj->type == ACPI_TYPE_PACKAGE && obj->package.count
> > > > == > > 5) {
> > > > +               const union acpi_object *objs = obj->package.elements;
> > > > +
> > > > +               if ((u8)objs[0].integer.value != 0)
> > > > +                       return -EINVAL;
> > > > +
> > > > +               rbuf[0] = objs[1].integer.value;
> > > > +               rbuf[1] = objs[2].integer.value;
> > > > +               rbuf[2] = objs[3].integer.value;
> > > > +               rbuf[3] = objs[4].integer.value;
> > > > +       } else {
> > > > +               return -EINVAL;
> > > > +       }
> > > > +
> > > > +       return 0;
> > > > +}
> > > > +EXPORT_SYMBOL(intel_pmc_core_ipc);
> > > > +
> > > >  static inline u32 pmc_core_reg_read(struct pmc *pmc, int reg_offset)
> > > >  {
> > > >         return readl(pmc->regbase + reg_offset);
> > > > diff --git a/include/linux/platform_data/x86/intel_pmc_core.h > >
> > > > b/include/linux/platform_data/x86/intel_pmc_core.h
> > > > new file mode 100644
> > > > index 000000000000..9bb3394fedcf
> > > > --- /dev/null
> > > > +++ b/include/linux/platform_data/x86/intel_pmc_core.h
> > > > @@ -0,0 +1,41 @@
> > > > +/* SPDX-License-Identifier: GPL-2.0 */
> > > > +/*
> > > > + * Intel Core SoC Power Management Controller Header File
> > > > + *
> > > > + * Copyright (c) 2023, Intel Corporation.
> > > > + * All Rights Reserved.
> > > > + *
> > > > + * Authors: Choong Yong Liang <yong.liang.choong@linux.intel.com>
> > > > + *          David E. Box <david.e.box@linux.intel.com>
> > > > + */
> > > > +#ifndef INTEL_PMC_CORE_H
> > > > +#define INTEL_PMC_CORE_H
> > > > +
> > > > +#define IPC_SOC_REGISTER_ACCESS                        0xAA
> > > > +#define IPC_SOC_SUB_CMD_READ                   0x00
> > > > +#define IPC_SOC_SUB_CMD_WRITE                  0x01
> > > > +
> > > > +struct pmc_ipc_cmd {
> > > > +       u32 cmd;
> > > > +       u32 sub_cmd;
> > > > +       u32 size;
> > > > +       u32 wbuf[4];
> > > > +};
> > > > +
> > > > +#if IS_ENABLED(CONFIG_INTEL_PMC_CORE)
> > > > +/**
> > > > + * intel_pmc_core_ipc() - PMC IPC Mailbox accessor
> > > > + * @ipc_cmd:  struct pmc_ipc_cmd prepared with input to send
> > > > + * @rbuf:     Allocated u32[4] array for returned IPC data
> > > > + *
> > > > + * Return: 0 on success. Non-zero on mailbox error
> > > > + */
> > > > +int intel_pmc_core_ipc(struct pmc_ipc_cmd *ipc_cmd, u32 *rbuf);
> > > > +#else
> > > > +static inline int intel_pmc_core_ipc(struct pmc_ipc_cmd *ipc_cmd, u32 >
> > > > > *rbuf)
> > > > +{
> > > > +       return -ENODEV;
> > > > +}
> > > > +#endif /* CONFIG_INTEL_PMC_CORE */
> > > > +
> > > > +#endif /* INTEL_PMC_CORE_H */
> >
diff mbox series

Patch

diff --git a/MAINTAINERS b/MAINTAINERS
index 069e176d607a..8a034dee9da9 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -10648,6 +10648,7 @@  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_core.h
 
 INTEL PMIC GPIO DRIVERS
 M:	Andy Shevchenko <andy@kernel.org>
diff --git a/drivers/platform/x86/intel/pmc/core.c b/drivers/platform/x86/intel/pmc/core.c
index 5a36b3f77bc5..6fb1b0f453d8 100644
--- a/drivers/platform/x86/intel/pmc/core.c
+++ b/drivers/platform/x86/intel/pmc/core.c
@@ -20,6 +20,7 @@ 
 #include <linux/pci.h>
 #include <linux/slab.h>
 #include <linux/suspend.h>
+#include <linux/platform_data/x86/intel_pmc_core.h>
 
 #include <asm/cpu_device_id.h>
 #include <asm/intel-family.h>
@@ -28,6 +29,8 @@ 
 
 #include "core.h"
 
+#define PMC_IPCS_PARAM_COUNT           7
+
 /* Maximum number of modes supported by platfoms that has low power mode capability */
 const char *pmc_lpm_modes[] = {
 	"S0i2.0",
@@ -53,6 +56,63 @@  const struct pmc_bit_map msr_map[] = {
 	{}
 };
 
+int intel_pmc_core_ipc(struct pmc_ipc_cmd *ipc_cmd, u32 *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;
+	/* Check if the number of elements in package is 5 */
+	if (obj && obj->type == ACPI_TYPE_PACKAGE && obj->package.count == 5) {
+		const union acpi_object *objs = obj->package.elements;
+
+		if ((u8)objs[0].integer.value != 0)
+			return -EINVAL;
+
+		rbuf[0] = objs[1].integer.value;
+		rbuf[1] = objs[2].integer.value;
+		rbuf[2] = objs[3].integer.value;
+		rbuf[3] = objs[4].integer.value;
+	} else {
+		return -EINVAL;
+	}
+
+	return 0;
+}
+EXPORT_SYMBOL(intel_pmc_core_ipc);
+
 static inline u32 pmc_core_reg_read(struct pmc *pmc, int reg_offset)
 {
 	return readl(pmc->regbase + reg_offset);
diff --git a/include/linux/platform_data/x86/intel_pmc_core.h b/include/linux/platform_data/x86/intel_pmc_core.h
new file mode 100644
index 000000000000..9bb3394fedcf
--- /dev/null
+++ b/include/linux/platform_data/x86/intel_pmc_core.h
@@ -0,0 +1,41 @@ 
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Intel Core SoC Power Management Controller Header File
+ *
+ * Copyright (c) 2023, Intel Corporation.
+ * All Rights Reserved.
+ *
+ * Authors: Choong Yong Liang <yong.liang.choong@linux.intel.com>
+ *          David E. Box <david.e.box@linux.intel.com>
+ */
+#ifndef INTEL_PMC_CORE_H
+#define INTEL_PMC_CORE_H
+
+#define IPC_SOC_REGISTER_ACCESS			0xAA
+#define IPC_SOC_SUB_CMD_READ			0x00
+#define IPC_SOC_SUB_CMD_WRITE			0x01
+
+struct pmc_ipc_cmd {
+	u32 cmd;
+	u32 sub_cmd;
+	u32 size;
+	u32 wbuf[4];
+};
+
+#if IS_ENABLED(CONFIG_INTEL_PMC_CORE)
+/**
+ * intel_pmc_core_ipc() - PMC IPC Mailbox accessor
+ * @ipc_cmd:  struct pmc_ipc_cmd prepared with input to send
+ * @rbuf:     Allocated u32[4] array for returned IPC data
+ *
+ * Return: 0 on success. Non-zero on mailbox error
+ */
+int intel_pmc_core_ipc(struct pmc_ipc_cmd *ipc_cmd, u32 *rbuf);
+#else
+static inline int intel_pmc_core_ipc(struct pmc_ipc_cmd *ipc_cmd, u32 *rbuf)
+{
+	return -ENODEV;
+}
+#endif /* CONFIG_INTEL_PMC_CORE */
+
+#endif /* INTEL_PMC_CORE_H */