Message-ID: <f920bd2e-9020-4b1c-85bb-63b8d61cfde8@linux.intel.com>
Date: Fri, 5 Sep 2025 10:31:15 -0700
From: Xi Pardee <xi.pardee@...ux.intel.com>
To: Ilpo Järvinen <ilpo.jarvinen@...ux.intel.com>
Cc: irenic.rajneesh@...il.com, david.e.box@...ux.intel.com,
 Hans de Goede <hdegoede@...hat.com>, platform-driver-x86@...r.kernel.org,
 LKML <linux-kernel@...r.kernel.org>, linux-pm@...r.kernel.org
Subject: Re: [PATCH v3 4/6] platform/x86:intel/pmc: Show substate requirement
 for S0ix blockers

Hi Ilpo,

Thanks for the review.

On 8/28/2025 6:06 AM, Ilpo Järvinen wrote:
> On Fri, 15 Aug 2025, Xi Pardee wrote:
>
>> Add support to read and show S0ix blocker substate requirements.
>> Starting from Panther Lake, substate requirement data is provided
>> based on S0ix blockers instead of all low power mode requirements.
>> For platforms that support this new feature, add support to display
>> substate requirements based on S0ix blockers.
>>
>> Change the "substate_requirements" attribute of Intel PMC Core
>> driver to show the substate requirements for each S0ix blocker
>> and the corresponding S0ix blocker value.
>>
>> Signed-off-by: Xi Pardee <xi.pardee@...ux.intel.com>
>> ---
>>   drivers/platform/x86/intel/pmc/arl.c  |   4 +
>>   drivers/platform/x86/intel/pmc/core.c | 126 ++++++++++++++++++++++++--
>>   drivers/platform/x86/intel/pmc/core.h |  14 +++
>>   drivers/platform/x86/intel/pmc/lnl.c  |   2 +
>>   drivers/platform/x86/intel/pmc/mtl.c  |   2 +
>>   5 files changed, 138 insertions(+), 10 deletions(-)
>>
>> diff --git a/drivers/platform/x86/intel/pmc/arl.c b/drivers/platform/x86/intel/pmc/arl.c
>> index 9d66d65e75779..17ad87b392abe 100644
>> --- a/drivers/platform/x86/intel/pmc/arl.c
>> +++ b/drivers/platform/x86/intel/pmc/arl.c
>> @@ -725,9 +725,11 @@ struct pmc_dev_info arl_pmc_dev = {
>>   	.dmu_guid = ARL_PMT_DMU_GUID,
>>   	.regmap_list = arl_pmc_info_list,
>>   	.map = &arl_socs_reg_map,
>> +	.sub_req_show = &pmc_core_substate_req_regs_fops,
>>   	.suspend = cnl_suspend,
>>   	.resume = arl_resume,
>>   	.init = arl_core_init,
>> +	.sub_req = pmc_core_pmt_get_lpm_req,
>>   };
>>   
>>   struct pmc_dev_info arl_h_pmc_dev = {
>> @@ -735,7 +737,9 @@ struct pmc_dev_info arl_h_pmc_dev = {
>>   	.dmu_guid = ARL_PMT_DMU_GUID,
>>   	.regmap_list = arl_pmc_info_list,
>>   	.map = &mtl_socm_reg_map,
>> +	.sub_req_show = &pmc_core_substate_req_regs_fops,
>>   	.suspend = cnl_suspend,
>>   	.resume = arl_h_resume,
>>   	.init = arl_h_core_init,
>> +	.sub_req = pmc_core_pmt_get_lpm_req,
>>   };
>> diff --git a/drivers/platform/x86/intel/pmc/core.c b/drivers/platform/x86/intel/pmc/core.c
>> index cbfdcdc50ad21..a0b948a875a5a 100644
>> --- a/drivers/platform/x86/intel/pmc/core.c
>> +++ b/drivers/platform/x86/intel/pmc/core.c
>> @@ -851,6 +851,68 @@ static void pmc_core_substate_req_header_show(struct seq_file *s, int pmc_index,
>>   	}
>>   }
>>   
>> +static int pmc_core_substate_blk_req_show(struct seq_file *s, void *unused)
>> +{
>> +	struct pmc_dev *pmcdev = s->private;
>> +	unsigned int pmc_index;
>> +
>> +	for (pmc_index = 0; pmc_index < ARRAY_SIZE(pmcdev->pmcs); pmc_index++) {
>> +		const struct pmc_bit_map **maps;
>> +		unsigned int arr_size, r_idx;
>> +		u32 offset, counter;
>> +		u32 *lpm_req_regs;
>> +		struct pmc *pmc;
>> +
>> +		pmc = pmcdev->pmcs[pmc_index];
>> +		if (!pmc || !pmc->lpm_req_regs)
>> +			continue;
>> +
>> +		lpm_req_regs = pmc->lpm_req_regs;
>> +		maps = pmc->map->s0ix_blocker_maps;
>> +		offset = pmc->map->s0ix_blocker_offset;
>> +		arr_size = pmc_core_lpm_get_arr_size(maps);
>> +
>> +		/* Display the header */
>> +		pmc_core_substate_req_header_show(s, pmc_index, HEADER_VALUE);
>> +
>> +		for (r_idx = 0; r_idx < arr_size; r_idx++) {
>> +			const struct pmc_bit_map *map;
>> +
>> +			for (map = maps[r_idx]; map->name; map++) {
>> +				int mode;
>> +
>> +				if (!map->blk)
>> +					continue;
>> +
>> +				counter = pmc_core_reg_read(pmc, offset);
>> +				seq_printf(s, "pmc%d: %34s |", pmc_index, map->name);
> For printing unsigned int, use %u.
Will change to %u in next version.
>
>> +				pmc_for_each_mode(mode, pmcdev) {
>> +					bool required = *lpm_req_regs & BIT(mode);
>> +
>> +					seq_printf(s, " %9s |", required ? "Required" : " ");
>> +				}
>> +				seq_printf(s, " %9d |\n", counter);
> Use %u for u32.
Will change to %u in next version.
>
>> +				offset += map->blk * S0IX_BLK_SIZE;
>> +				lpm_req_regs++;
>> +			}
>> +		}
>> +	}
>> +	return 0;
>> +}
>> +
>> +static int pmc_core_substate_blk_req_open(struct inode *inode, struct file *file)
>> +{
>> +	return single_open(file, pmc_core_substate_blk_req_show, inode->i_private);
>> +}
>> +
>> +const struct file_operations pmc_core_substate_blk_req_fops = {
>> +	.owner		= THIS_MODULE,
>> +	.open		= pmc_core_substate_blk_req_open,
>> +	.read		= seq_read,
>> +	.llseek		= seq_lseek,
>> +	.release	= single_release,
>> +};
>> +
>>   static int pmc_core_substate_req_regs_show(struct seq_file *s, void *unused)
>>   {
>>   	struct pmc_dev *pmcdev = s->private;
>> @@ -941,7 +1003,19 @@ static int pmc_core_substate_req_regs_show(struct seq_file *s, void *unused)
>>   	}
>>   	return 0;
>>   }
>> -DEFINE_SHOW_ATTRIBUTE(pmc_core_substate_req_regs);
>> +
>> +static int pmc_core_substate_req_regs_open(struct inode *inode, struct file *file)
>> +{
>> +	return single_open(file, pmc_core_substate_req_regs_show, inode->i_private);
>> +}
>> +
>> +const struct file_operations pmc_core_substate_req_regs_fops = {
>> +	.owner		= THIS_MODULE,
>> +	.open		= pmc_core_substate_req_regs_open,
>> +	.read		= seq_read,
>> +	.llseek		= seq_lseek,
>> +	.release	= single_release,
>> +};
>>   
>>   static unsigned int pmc_core_get_crystal_freq(void)
>>   {
>> @@ -1274,7 +1348,7 @@ static void pmc_core_dbgfs_unregister(struct pmc_dev *pmcdev)
>>   	debugfs_remove_recursive(pmcdev->dbgfs_dir);
>>   }
>>   
>> -static void pmc_core_dbgfs_register(struct pmc_dev *pmcdev)
>> +static void pmc_core_dbgfs_register(struct pmc_dev *pmcdev, struct pmc_dev_info *pmc_dev_info)
>>   {
>>   	struct pmc *primary_pmc = pmcdev->pmcs[PMC_IDX_MAIN];
>>   	struct dentry *dir;
>> @@ -1341,7 +1415,7 @@ static void pmc_core_dbgfs_register(struct pmc_dev *pmcdev)
>>   	if (primary_pmc->lpm_req_regs) {
>>   		debugfs_create_file("substate_requirements", 0444,
>>   				    pmcdev->dbgfs_dir, pmcdev,
>> -				    &pmc_core_substate_req_regs_fops);
>> +				    pmc_dev_info->sub_req_show);
>>   	}
>>   
>>   	if (primary_pmc->map->pson_residency_offset && pmc_core_is_pson_residency_enabled(pmcdev)) {
>> @@ -1409,8 +1483,7 @@ static u32 pmc_core_find_guid(struct pmc_info *list, const struct pmc_reg_map *m
>>    * +----+---------------------------------------------------------+
>>    *
>>    */
>> -static int pmc_core_pmt_get_lpm_req(struct pmc_dev *pmcdev, struct pmc *pmc,
>> -				    struct telem_endpoint *ep)
>> +int pmc_core_pmt_get_lpm_req(struct pmc_dev *pmcdev, struct pmc *pmc, struct telem_endpoint *ep)
>>   {
>>   	const u8 *lpm_indices;
>>   	int num_maps, mode_offset = 0;
>> @@ -1448,7 +1521,37 @@ static int pmc_core_pmt_get_lpm_req(struct pmc_dev *pmcdev, struct pmc *pmc,
>>   	return ret;
>>   }
>>   
>> -static int pmc_core_get_telem_info(struct pmc_dev *pmcdev, int func)
>> +int pmc_core_pmt_get_blk_sub_req(struct pmc_dev *pmcdev, struct pmc *pmc,
>> +				 struct telem_endpoint *ep)
>> +{
>> +	u32 num_blocker, sample_id;
>> +	unsigned int index;
>> +	u32 *req_offset;
>> +	int ret;
>> +
>> +	num_blocker = pmc->map->num_s0ix_blocker;
>> +	sample_id = pmc->map->blocker_req_offset;
>> +
>> +	pmc->lpm_req_regs = devm_kcalloc(&pmcdev->pdev->dev, num_blocker,
>> +					 sizeof(u32), GFP_KERNEL);
>> +	if (!pmc->lpm_req_regs)
>> +		return -ENOMEM;
>> +
>> +	req_offset = pmc->lpm_req_regs;
>> +	for (index = 0; index < num_blocker; index++) {
>> +		ret = pmt_telem_read32(ep, sample_id, req_offset, 1);
>> +		if (ret) {
>> +			dev_err(&pmcdev->pdev->dev,
>> +				"couldn't read Low Power Mode requirements: %d\n", ret);
>> +			return ret;
>> +		}
>> +		sample_id++;
>> +		req_offset++;
> These two look superfluous variables as they move in-sync with index and
> xx + index or xx[index] could be used instead? I can see the pointer one
> might make things a bit nicer looking, but if you preserve it, it should
> be incremented inside the for loop's increment, not here.

Will rename sample_id to sample_offset and use sample_offset + index as 
argument in pmt_telem_read32() call instead.

Will move req_offset++ inside the for loop's increment in next version.

>> +	}
>> +	return 0;
>> +}
>> +
>> +static int pmc_core_get_telem_info(struct pmc_dev *pmcdev, struct pmc_dev_info *pmc_dev_info)
>>   {
>>   	struct pci_dev *pcidev __free(pci_dev_put) = NULL;
>>   	struct telem_endpoint *ep;
>> @@ -1456,11 +1559,12 @@ static int pmc_core_get_telem_info(struct pmc_dev *pmcdev, int func)
>>   	u32 guid;
>>   	int ret;
>>   
>> -	pcidev = pci_get_domain_bus_and_slot(0, 0, PCI_DEVFN(20, func));
>> +	pcidev = pci_get_domain_bus_and_slot(0, 0, PCI_DEVFN(20, pmc_dev_info->pci_func));
>>   	if (!pcidev)
>>   		return -ENODEV;
>>   
>>   	for (i = 0; i < ARRAY_SIZE(pmcdev->pmcs); ++i) {
>> +		int (*sub_req)(struct pmc_dev *pmcdev, struct pmc *pmc, struct telem_endpoint *ep);
>>   		struct pmc *pmc;
>>   
>>   		pmc = pmcdev->pmcs[i];
>> @@ -1477,7 +1581,9 @@ static int pmc_core_get_telem_info(struct pmc_dev *pmcdev, int func)
>>   			return -EPROBE_DEFER;
>>   		}
>>   
>> -		ret = pmc_core_pmt_get_lpm_req(pmcdev, pmc, ep);
>> +		sub_req = pmc_dev_info->sub_req;
>> +		ret = sub_req(pmcdev, pmc, ep);
>> +
> Please don't separate a call and its error handling with empty lines.
>
> Why is the sub_req variable necessary?

The sub_req is not necessary. Will remove it in next version.

Thanks!

Xi

>
>>   		pmt_telem_unregister_endpoint(ep);
>>   		if (ret)
>>   			return ret;
>> @@ -1592,7 +1698,7 @@ int generic_core_init(struct pmc_dev *pmcdev, struct pmc_dev_info *pmc_dev_info)
>>   		pmc_core_punit_pmt_init(pmcdev, pmc_dev_info->dmu_guid);
>>   
>>   	if (ssram) {
>> -		ret = pmc_core_get_telem_info(pmcdev, pmc_dev_info->pci_func);
>> +		ret = pmc_core_get_telem_info(pmcdev, pmc_dev_info);
>>   		if (ret)
>>   			goto unmap_regbase;
>>   	}
>> @@ -1766,7 +1872,7 @@ static int pmc_core_probe(struct platform_device *pdev)
>>   	pmcdev->pmc_xram_read_bit = pmc_core_check_read_lock_bit(primary_pmc);
>>   	pmc_core_do_dmi_quirks(primary_pmc);
>>   
>> -	pmc_core_dbgfs_register(pmcdev);
>> +	pmc_core_dbgfs_register(pmcdev, pmc_dev_info);
>>   	pm_report_max_hw_sleep(FIELD_MAX(SLP_S0_RES_COUNTER_MASK) *
>>   			       pmc_core_adjust_slp_s0_step(primary_pmc, 1));
>>   
>> diff --git a/drivers/platform/x86/intel/pmc/core.h b/drivers/platform/x86/intel/pmc/core.h
>> index 4a94a4ee031e6..bfe8fba808063 100644
>> --- a/drivers/platform/x86/intel/pmc/core.h
>> +++ b/drivers/platform/x86/intel/pmc/core.h
>> @@ -344,6 +344,8 @@ struct pmc_bit_map {
>>    * @pm_read_disable_bit: Bit index to read PMC_READ_DISABLE
>>    * @slps0_dbg_offset:	PWRMBASE offset to SLP_S0_DEBUG_REG*
>>    * @s0ix_blocker_offset PWRMBASE offset to S0ix blocker counter
>> + * @num_s0ix_blocker:	Number of S0ix blockers
>> + * @blocker_req_offset:	Telemetry offset to S0ix blocker low power mode substate requirement table
>>    *
>>    * Each PCH has unique set of register offsets and bit indexes. This structure
>>    * captures them to have a common implementation.
>> @@ -369,6 +371,8 @@ struct pmc_reg_map {
>>   	const u32 ltr_ignore_max;
>>   	const u32 pm_vric1_offset;
>>   	const u32 s0ix_blocker_offset;
>> +	const u32 num_s0ix_blocker;
>> +	const u32 blocker_req_offset;
>>   	/* Low Power Mode registers */
>>   	const int lpm_num_maps;
>>   	const int lpm_num_modes;
>> @@ -474,18 +478,22 @@ enum pmc_index {
>>    *			SSRAM support.
>>    * @map:		Pointer to a pmc_reg_map struct that contains platform
>>    *			specific attributes of the primary PMC
>> + * @sub_req_show:	File operations to show substate requirements
>>    * @suspend:		Function to perform platform specific suspend
>>    * @resume:		Function to perform platform specific resume
>>    * @init:		Function to perform platform specific init action
>> + * @sub_req:		Function to achieve low power mode substate requirements
>>    */
>>   struct pmc_dev_info {
>>   	u8 pci_func;
>>   	u32 dmu_guid;
>>   	struct pmc_info *regmap_list;
>>   	const struct pmc_reg_map *map;
>> +	const struct file_operations *sub_req_show;
>>   	void (*suspend)(struct pmc_dev *pmcdev);
>>   	int (*resume)(struct pmc_dev *pmcdev);
>>   	int (*init)(struct pmc_dev *pmcdev, struct pmc_dev_info *pmc_dev_info);
>> +	int (*sub_req)(struct pmc_dev *pmcdev, struct pmc *pmc, struct telem_endpoint *ep);
>>   };
>>   
>>   extern const struct pmc_bit_map msr_map[];
>> @@ -531,6 +539,12 @@ extern struct pmc_dev_info ptl_pmc_dev;
>>   
>>   void cnl_suspend(struct pmc_dev *pmcdev);
>>   int cnl_resume(struct pmc_dev *pmcdev);
>> +int pmc_core_pmt_get_lpm_req(struct pmc_dev *pmcdev, struct pmc *pmc, struct telem_endpoint *ep);
>> +int pmc_core_pmt_get_blk_sub_req(struct pmc_dev *pmcdev, struct pmc *pmc,
>> +				 struct telem_endpoint *ep);
>> +
>> +extern const struct file_operations pmc_core_substate_req_regs_fops;
>> +extern const struct file_operations pmc_core_substate_blk_req_fops;
>>   
>>   #define pmc_for_each_mode(mode, pmcdev)						\
>>   	for (unsigned int __i = 0, __cond;					\
>> diff --git a/drivers/platform/x86/intel/pmc/lnl.c b/drivers/platform/x86/intel/pmc/lnl.c
>> index e08a77c778c2c..6fa027e7071f4 100644
>> --- a/drivers/platform/x86/intel/pmc/lnl.c
>> +++ b/drivers/platform/x86/intel/pmc/lnl.c
>> @@ -574,7 +574,9 @@ struct pmc_dev_info lnl_pmc_dev = {
>>   	.pci_func = 2,
>>   	.regmap_list = lnl_pmc_info_list,
>>   	.map = &lnl_socm_reg_map,
>> +	.sub_req_show = &pmc_core_substate_req_regs_fops,
>>   	.suspend = cnl_suspend,
>>   	.resume = lnl_resume,
>>   	.init = lnl_core_init,
>> +	.sub_req = pmc_core_pmt_get_lpm_req,
>>   };
>> diff --git a/drivers/platform/x86/intel/pmc/mtl.c b/drivers/platform/x86/intel/pmc/mtl.c
>> index faa13a7ee688f..0b87e10f864e6 100644
>> --- a/drivers/platform/x86/intel/pmc/mtl.c
>> +++ b/drivers/platform/x86/intel/pmc/mtl.c
>> @@ -997,7 +997,9 @@ struct pmc_dev_info mtl_pmc_dev = {
>>   	.dmu_guid = MTL_PMT_DMU_GUID,
>>   	.regmap_list = mtl_pmc_info_list,
>>   	.map = &mtl_socm_reg_map,
>> +	.sub_req_show = &pmc_core_substate_req_regs_fops,
>>   	.suspend = cnl_suspend,
>>   	.resume = mtl_resume,
>>   	.init = mtl_core_init,
>> +	.sub_req = pmc_core_pmt_get_lpm_req,
>>   };
>>

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