linux-kernel - Re: [PATCH v2 4/5] platform/x86: ISST: Process read/write blocked feature status

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Message-ID: <d3b0dd08-4eca-4268-8b13-e60bd3d85524@redhat.com>
Date:   Mon, 4 Dec 2023 15:06:14 +0100
From:   Hans de Goede <hdegoede@...hat.com>
To:     Srinivas Pandruvada <srinivas.pandruvada@...ux.intel.com>,
        markgross@...nel.org, ilpo.jarvinen@...ux.intel.com,
        andriy.shevchenko@...ux.intel.com
Cc:     platform-driver-x86@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2 4/5] platform/x86: ISST: Process read/write blocked
 feature status

Hi,

On 11/30/23 22:47, Srinivas Pandruvada wrote:
> When a feature is read blocked, don't continue to read SST information
> and register with SST core.
> 
> When the feature is write blocked, continue to offer read interface for
> SST parameters, but don't allow any operation to change state. A state
> change results from SST level change, feature change or class of service
> change.
> 
> Signed-off-by: Srinivas Pandruvada <srinivas.pandruvada@...ux.intel.com>
> ---
> v2
> - Change read_blocked, write_blocked to bool
> - Move the check for power_domain_info->write_blocked for SST-CP
> to only write operations

Thanks, patch looks good to me:

Reviewed-by: Hans de Goede <hdegoede@...hat.com>

Did you drop Ilpo's Reviewed-by from v1 on purpose
because of the changes ? Or did you forget to add it ?

Regards,

Hans


> 
>  .../intel/speed_select_if/isst_tpmi_core.c    | 25 +++++++++++++++++++
>  1 file changed, 25 insertions(+)
> 
> diff --git a/drivers/platform/x86/intel/speed_select_if/isst_tpmi_core.c b/drivers/platform/x86/intel/speed_select_if/isst_tpmi_core.c
> index 0b6d2c864437..2662fbbddf0c 100644
> --- a/drivers/platform/x86/intel/speed_select_if/isst_tpmi_core.c
> +++ b/drivers/platform/x86/intel/speed_select_if/isst_tpmi_core.c
> @@ -234,6 +234,7 @@ struct perf_level {
>   * @saved_clos_configs:	Save SST-CP CLOS configuration to store restore for suspend/resume
>   * @saved_clos_assocs:	Save SST-CP CLOS association to store restore for suspend/resume
>   * @saved_pp_control:	Save SST-PP control information to store restore for suspend/resume
> + * @write_blocked:	Write operation is blocked, so can't change SST state
>   *
>   * This structure is used store complete SST information for a power_domain. This information
>   * is used to read/write request for any SST IOCTL. Each physical CPU package can have multiple
> @@ -259,6 +260,7 @@ struct tpmi_per_power_domain_info {
>  	u64 saved_clos_configs[4];
>  	u64 saved_clos_assocs[4];
>  	u64 saved_pp_control;
> +	bool write_blocked;
>  };
>  
>  /**
> @@ -515,6 +517,9 @@ static long isst_if_clos_param(void __user *argp)
>  		return -EINVAL;
>  
>  	if (clos_param.get_set) {
> +		if (power_domain_info->write_blocked)
> +			return -EPERM;
> +
>  		_write_cp_info("clos.min_freq", clos_param.min_freq_mhz,
>  			       (SST_CLOS_CONFIG_0_OFFSET + clos_param.clos * SST_REG_SIZE),
>  			       SST_CLOS_CONFIG_MIN_START, SST_CLOS_CONFIG_MIN_WIDTH,
> @@ -602,6 +607,9 @@ static long isst_if_clos_assoc(void __user *argp)
>  
>  		power_domain_info = &sst_inst->power_domain_info[punit_id];
>  
> +		if (assoc_cmds.get_set && power_domain_info->write_blocked)
> +			return -EPERM;
> +
>  		offset = SST_CLOS_ASSOC_0_OFFSET +
>  				(punit_cpu_no / SST_CLOS_ASSOC_CPUS_PER_REG) * SST_REG_SIZE;
>  		shift = punit_cpu_no % SST_CLOS_ASSOC_CPUS_PER_REG;
> @@ -752,6 +760,9 @@ static int isst_if_set_perf_level(void __user *argp)
>  	if (!power_domain_info)
>  		return -EINVAL;
>  
> +	if (power_domain_info->write_blocked)
> +		return -EPERM;
> +
>  	if (!(power_domain_info->pp_header.allowed_level_mask & BIT(perf_level.level)))
>  		return -EINVAL;
>  
> @@ -809,6 +820,9 @@ static int isst_if_set_perf_feature(void __user *argp)
>  	if (!power_domain_info)
>  		return -EINVAL;
>  
> +	if (power_domain_info->write_blocked)
> +		return -EPERM;
> +
>  	_write_pp_info("perf_feature", perf_feature.feature, SST_PP_CONTROL_OFFSET,
>  		       SST_PP_FEATURE_STATE_START, SST_PP_FEATURE_STATE_WIDTH,
>  		       SST_MUL_FACTOR_NONE)
> @@ -1257,11 +1271,21 @@ static long isst_if_def_ioctl(struct file *file, unsigned int cmd,
>  
>  int tpmi_sst_dev_add(struct auxiliary_device *auxdev)
>  {
> +	bool read_blocked = 0, write_blocked = 0;
>  	struct intel_tpmi_plat_info *plat_info;
>  	struct tpmi_sst_struct *tpmi_sst;
>  	int i, ret, pkg = 0, inst = 0;
>  	int num_resources;
>  
> +	ret = tpmi_get_feature_status(auxdev, TPMI_ID_SST, &read_blocked, &write_blocked);
> +	if (ret)
> +		dev_info(&auxdev->dev, "Can't read feature status: ignoring read/write blocked status\n");
> +
> +	if (read_blocked) {
> +		dev_info(&auxdev->dev, "Firmware has blocked reads, exiting\n");
> +		return -ENODEV;
> +	}
> +
>  	plat_info = tpmi_get_platform_data(auxdev);
>  	if (!plat_info) {
>  		dev_err(&auxdev->dev, "No platform info\n");
> @@ -1306,6 +1330,7 @@ int tpmi_sst_dev_add(struct auxiliary_device *auxdev)
>  		tpmi_sst->power_domain_info[i].package_id = pkg;
>  		tpmi_sst->power_domain_info[i].power_domain_id = i;
>  		tpmi_sst->power_domain_info[i].auxdev = auxdev;
> +		tpmi_sst->power_domain_info[i].write_blocked = write_blocked;
>  		tpmi_sst->power_domain_info[i].sst_base = devm_ioremap_resource(&auxdev->dev, res);
>  		if (IS_ERR(tpmi_sst->power_domain_info[i].sst_base))
>  			return PTR_ERR(tpmi_sst->power_domain_info[i].sst_base);