Re: [PATCH net-next 1/6] platform/x86: intel_pmc_core: Add IPC mailbox accessor function and add SoC register access

[Hans de Goede <hdegoede@redhat.com>]

Hi,

On 6/22/23 06:19, 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>

This seem to be 2 patches in 1:

1. Move core.h to include/linux/intel_pmc_core.h
2. The actual adding of IPC mailbox accessor function and add SoC register access

I wonder if you really need to move the entire core.h ?

IMHO it would be better to just add a new header with just the bits
which you actually need to export the desired functionality.

If you do believe that you really need to move core.h please split
this into 2 separate patches and please place the header in a x86
specific place, e.g. : include/linux/platform_data/x86/



Also note that a somewhat big refactor, to add support for
multiple PMCs for Meteor Lake is on its way to linux-next.

Currently this is available in my review-hans branch:

https://git.kernel.org/pub/scm/linux/kernel/git/pdx86/platform-drivers-x86.git/log/?h=review-hans

Please base a next version of this on this.

There also is the question of how to merge this. Assuming this is
ready for merging once 6.5-rc1 is out then I can merge this intel_pmc_core
change into an immutable branch and send a pull-req to the net folks
for this.

Regards,

Hans






> ---
>  MAINTAINERS                                   |  1 +
>  drivers/platform/x86/intel/pmc/adl.c          |  2 +-
>  drivers/platform/x86/intel/pmc/cnp.c          |  2 +-
>  drivers/platform/x86/intel/pmc/core.c         | 63 ++++++++++++++++++-
>  drivers/platform/x86/intel/pmc/icl.c          |  2 +-
>  drivers/platform/x86/intel/pmc/mtl.c          |  2 +-
>  drivers/platform/x86/intel/pmc/spt.c          |  2 +-
>  drivers/platform/x86/intel/pmc/tgl.c          |  2 +-
>  .../core.h => include/linux/intel_pmc_core.h  | 27 +++++++-
>  9 files changed, 95 insertions(+), 8 deletions(-)
>  rename drivers/platform/x86/intel/pmc/core.h => include/linux/intel_pmc_core.h (95%)
> 
> diff --git a/MAINTAINERS b/MAINTAINERS
> index cb14589d14ab..bdb08a79a5f8 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -10581,6 +10581,7 @@ L:	platform-driver-x86@vger.kernel.org
>  S:	Maintained
>  F:	Documentation/ABI/testing/sysfs-platform-intel-pmc
>  F:	drivers/platform/x86/intel/pmc/
> +F:	include/linux/intel_pmc_core*
>  
>  INTEL PMIC GPIO DRIVERS
>  M:	Andy Shevchenko <andy@kernel.org>
> diff --git a/drivers/platform/x86/intel/pmc/adl.c b/drivers/platform/x86/intel/pmc/adl.c
> index 5cbd40979f2a..b6a376c536c0 100644
> --- a/drivers/platform/x86/intel/pmc/adl.c
> +++ b/drivers/platform/x86/intel/pmc/adl.c
> @@ -8,7 +8,7 @@
>   *
>   */
>  
> -#include "core.h"
> +#include <linux/intel_pmc_core.h>
>  
>  /* Alder Lake: PGD PFET Enable Ack Status Register(s) bitmap */
>  const struct pmc_bit_map adl_pfear_map[] = {
> diff --git a/drivers/platform/x86/intel/pmc/cnp.c b/drivers/platform/x86/intel/pmc/cnp.c
> index 7fb38815c4eb..504034cc5ec3 100644
> --- a/drivers/platform/x86/intel/pmc/cnp.c
> +++ b/drivers/platform/x86/intel/pmc/cnp.c
> @@ -8,7 +8,7 @@
>   *
>   */
>  
> -#include "core.h"
> +#include <linux/intel_pmc_core.h>
>  
>  /* Cannon Lake: PGD PFET Enable Ack Status Register(s) bitmap */
>  const struct pmc_bit_map cnp_pfear_map[] = {
> diff --git a/drivers/platform/x86/intel/pmc/core.c b/drivers/platform/x86/intel/pmc/core.c
> index da6e7206d38b..0d60763c5144 100644
> --- a/drivers/platform/x86/intel/pmc/core.c
> +++ b/drivers/platform/x86/intel/pmc/core.c
> @@ -16,6 +16,7 @@
>  #include <linux/delay.h>
>  #include <linux/dmi.h>
>  #include <linux/io.h>
> +#include <linux/intel_pmc_core.h>
>  #include <linux/module.h>
>  #include <linux/pci.h>
>  #include <linux/slab.h>
> @@ -26,7 +27,9 @@
>  #include <asm/msr.h>
>  #include <asm/tsc.h>
>  
> -#include "core.h"
> +#define PMC_IPCS_PARAM_COUNT           7
> +
> +static const struct x86_cpu_id *pmc_cpu_id;
>  
>  /* Maximum number of modes supported by platfoms that has low power mode capability */
>  const char *pmc_lpm_modes[] = {
> @@ -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 (!pmc_cpu_id || !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_dev *pmcdev, int reg_offset)
>  {
>  	return readl(pmcdev->regbase + reg_offset);
> @@ -1130,6 +1190,7 @@ static int pmc_core_probe(struct platform_device *pdev)
>  	mutex_init(&pmcdev->lock);
>  	core_init(pmcdev);
>  
> +	pmc_cpu_id = cpu_id;
>  
>  	if (lpit_read_residency_count_address(&slp_s0_addr)) {
>  		pmcdev->base_addr = PMC_BASE_ADDR_DEFAULT;
> diff --git a/drivers/platform/x86/intel/pmc/icl.c b/drivers/platform/x86/intel/pmc/icl.c
> index 2f11b1a6daeb..f18048ff9382 100644
> --- a/drivers/platform/x86/intel/pmc/icl.c
> +++ b/drivers/platform/x86/intel/pmc/icl.c
> @@ -8,7 +8,7 @@
>   *
>   */
>  
> -#include "core.h"
> +#include <linux/intel_pmc_core.h>
>  
>  const struct pmc_bit_map icl_pfear_map[] = {
>  	{"RES_65",		BIT(0)},
> diff --git a/drivers/platform/x86/intel/pmc/mtl.c b/drivers/platform/x86/intel/pmc/mtl.c
> index e8cc156412ce..7897f5fe9881 100644
> --- a/drivers/platform/x86/intel/pmc/mtl.c
> +++ b/drivers/platform/x86/intel/pmc/mtl.c
> @@ -9,7 +9,7 @@
>   */
>  
>  #include <linux/pci.h>
> -#include "core.h"
> +#include <linux/intel_pmc_core.h>
>  
>  const struct pmc_reg_map mtl_reg_map = {
>  	.pfear_sts = ext_tgl_pfear_map,
> diff --git a/drivers/platform/x86/intel/pmc/spt.c b/drivers/platform/x86/intel/pmc/spt.c
> index e16982236778..95ce490cf5d6 100644
> --- a/drivers/platform/x86/intel/pmc/spt.c
> +++ b/drivers/platform/x86/intel/pmc/spt.c
> @@ -8,7 +8,7 @@
>   *
>   */
>  
> -#include "core.h"
> +#include <linux/intel_pmc_core.h>
>  
>  const struct pmc_bit_map spt_pll_map[] = {
>  	{"MIPI PLL",			SPT_PMC_BIT_MPHY_CMN_LANE0},
> diff --git a/drivers/platform/x86/intel/pmc/tgl.c b/drivers/platform/x86/intel/pmc/tgl.c
> index c245ada849d0..a1719d809497 100644
> --- a/drivers/platform/x86/intel/pmc/tgl.c
> +++ b/drivers/platform/x86/intel/pmc/tgl.c
> @@ -8,7 +8,7 @@
>   *
>   */
>  
> -#include "core.h"
> +#include <linux/intel_pmc_core.h>
>  
>  #define ACPI_S0IX_DSM_UUID		"57a6512e-3979-4e9d-9708-ff13b2508972"
>  #define ACPI_GET_LOW_MODE_REGISTERS	1
> diff --git a/drivers/platform/x86/intel/pmc/core.h b/include/linux/intel_pmc_core.h
> similarity index 95%
> rename from drivers/platform/x86/intel/pmc/core.h
> rename to include/linux/intel_pmc_core.h
> index 9ca9b9746719..82810e8b92a2 100644
> --- a/drivers/platform/x86/intel/pmc/core.h
> +++ b/include/linux/intel_pmc_core.h
> @@ -250,7 +250,16 @@ enum ppfear_regs {
>  #define MTL_LPM_STATUS_OFFSET			0x1700
>  #define MTL_LPM_LIVE_STATUS_OFFSET		0x175C
>  
> -extern const char *pmc_lpm_modes[];
> +#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];
> +};
>  
>  struct pmc_bit_map {
>  	const char *name;
> @@ -427,4 +436,20 @@ static const struct file_operations __name ## _fops = {			\
>  	.release	= single_release,				\
>  }
>  
> +#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 /* PMC_CORE_H */