Message-ID: <cd1b9ca5-27be-bcc1-6aa6-65d7196022e7@linux.intel.com>
Date: Thu, 28 Aug 2025 16:06:05 +0300 (EEST)
From: Ilpo Järvinen <ilpo.jarvinen@...ux.intel.com>
To: Xi Pardee <xi.pardee@...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

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.

> +				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.

> +				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.

> +	}
> +	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?

>  		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,
>  };
> 

-- 
 i.

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