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

Hans de Goede
2023-12-04T14:06:35Z

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@linux.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@redhat.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);