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

[Choong Yong Liang <yong.liang.choong@linux.intel.com>]

Hi Hans,

I will discuss it with David but currently he is on vacation. It might take 
some time to get the final output. Thank you.

On 22/6/2023 4:18 pm, Hans de Goede wrote:
> 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 */
>