Re: [PATCH v2 1/3] platform/x86/intel-uncore-freq: Uncore frequency control via TPMI

From: Ilpo Järvinen
Date: Thu Apr 20 2023 - 07:27:04 EST


On Tue, 18 Apr 2023, Srinivas Pandruvada wrote:

> Implement support of uncore frequency control via TPMI (Topology Aware
> Register and PM Capsule Interface). This driver provides the similar
> functionality as the current uncore frequency driver using MSRs.
>
> The hardware interface to read/write is basically substitution of MSR
> 0x620 and 0x621. There are specific MMIO offset and bits to get/set
> minimum and maximum uncore ratio, similar to MSRs.
>
> The scope of the uncore MSRs is package/die. But new generation of CPUs
> have more granular control at a cluster level. Each package/die can have
> multiple power domains, which further can have multiple clusters. The
> TPMI interface allows control at cluster level.
>
> The primary use case for uncore sysfs is to set maximum and minimum
> uncore frequency to reduce power consumption or latency. The current
> uncore sysfs control is per package/die. This is enough for the majority
> of users as workload will move to different power domains as it moves
> between different CPUs.
>
> The current uncore sysfs provides controls at package/die level. When
> user sets maximum/minimum limits, the driver sets the same limits to
> each cluster.
>
> Here number of power domains = number of resources in this aux device.
> There are offsets and bits to discover number of clusters and offset for
> each cluster level controls.
>
> The TPMI documentation can be downloaded from:
> https://github.com/intel/tpmi_power_management
>
> Signed-off-by: Srinivas Pandruvada <srinivas.pandruvada@xxxxxxxxxxxxxxx>
> Reviewed-by: Zhang Rui <rui.zhang@xxxxxxxxx>
> Tested-by: Wendy Wang <wendy.wang@xxxxxxxxx>
> ---
> v2
> - Changed mmio to u8* (Hans)
> - Not setting pd_info->uncore_base to NULL (Hans)
> - Handling failure of devm_kcalloc() (Hans)
> - Merged init/remove to probe/remove functions (Rui)
> - Log when platform is NULL (Rui)
>
> .../x86/intel/uncore-frequency/Kconfig | 4 +
> .../x86/intel/uncore-frequency/Makefile | 2 +
> .../uncore-frequency/uncore-frequency-tpmi.c | 338 ++++++++++++++++++
> 3 files changed, 344 insertions(+)
> create mode 100644 drivers/platform/x86/intel/uncore-frequency/uncore-frequency-tpmi.c
>
> diff --git a/drivers/platform/x86/intel/uncore-frequency/Kconfig b/drivers/platform/x86/intel/uncore-frequency/Kconfig
> index 21b209124916..a56d55056927 100644
> --- a/drivers/platform/x86/intel/uncore-frequency/Kconfig
> +++ b/drivers/platform/x86/intel/uncore-frequency/Kconfig
> @@ -6,9 +6,13 @@
> menu "Intel Uncore Frequency Control"
> depends on X86_64 || COMPILE_TEST
>
> +config INTEL_UNCORE_FREQ_CONTROL_TPMI
> + tristate
> +
> config INTEL_UNCORE_FREQ_CONTROL
> tristate "Intel Uncore frequency control driver"
> depends on X86_64
> + select INTEL_UNCORE_FREQ_CONTROL_TPMI if INTEL_TPMI
> help
> This driver allows control of Uncore frequency limits on
> supported server platforms.
> diff --git a/drivers/platform/x86/intel/uncore-frequency/Makefile b/drivers/platform/x86/intel/uncore-frequency/Makefile
> index e0f7968e8285..08ff57492b28 100644
> --- a/drivers/platform/x86/intel/uncore-frequency/Makefile
> +++ b/drivers/platform/x86/intel/uncore-frequency/Makefile
> @@ -7,3 +7,5 @@ obj-$(CONFIG_INTEL_UNCORE_FREQ_CONTROL) += intel-uncore-frequency.o
> intel-uncore-frequency-y := uncore-frequency.o
> obj-$(CONFIG_INTEL_UNCORE_FREQ_CONTROL) += intel-uncore-frequency-common.o
> intel-uncore-frequency-common-y := uncore-frequency-common.o
> +obj-$(CONFIG_INTEL_UNCORE_FREQ_CONTROL_TPMI) += intel-uncore-frequency-tpmi.o
> +intel-uncore-frequency-tpmi-y := uncore-frequency-tpmi.o
> diff --git a/drivers/platform/x86/intel/uncore-frequency/uncore-frequency-tpmi.c b/drivers/platform/x86/intel/uncore-frequency/uncore-frequency-tpmi.c
> new file mode 100644
> index 000000000000..5e454e9dd4a7
> --- /dev/null
> +++ b/drivers/platform/x86/intel/uncore-frequency/uncore-frequency-tpmi.c
> @@ -0,0 +1,338 @@
> +// SPDX-License-Identifier: GPL-2.0-only
> +/*
> + * uncore-frquency-tpmi: Uncore frequency scaling using TPMI
> + *
> + * Copyright (c) 2023, Intel Corporation.
> + * All Rights Reserved.
> + *
> + * The hardware interface to read/write is basically substitution of
> + * MSR 0x620 and 0x621.
> + * There are specific MMIO offset and bits to get/set minimum and
> + * maximum uncore ratio, similar to MSRs.
> + * The scope of the uncore MSRs was package scope. But TPMI allows
> + * new gen CPUs to have multiple uncore controls at uncore-cluster
> + * level. Each package can have multiple power domains which further
> + * can have multiple clusters.
> + * Here number of power domains = number of resources in this aux
> + * device. There are offsets and bits to discover number of clusters
> + * and offset for each cluster level controls.
> + *
> + */
> +
> +#include <linux/auxiliary_bus.h>
> +#include <linux/bitfield.h>
> +#include <linux/bits.h>
> +#include <linux/io.h>
> +#include <linux/module.h>
> +#include <linux/intel_tpmi.h>
> +
> +#include "uncore-frequency-common.h"
> +
> +#define UNCORE_HEADER_VERSION 1
> +#define UNCORE_HEADER_INDEX 0
> +#define UNCORE_FABRIC_CLUSTER_OFFSET 8
> +
> +/* status + control + adv_ctl1 + adv_ctl2 */
> +#define UNCORE_FABRIC_CLUSTER_SIZE (4 * 8)
> +
> +#define UNCORE_STATUS_INDEX 0
> +#define UNCORE_CONTROL_INDEX 8
> +
> +#define UNCORE_FREQ_KHZ_MULTIPLIER 100000
> +
> +struct tpmi_uncore_struct;
> +
> +/* Information for each cluster */
> +struct tpmi_uncore_cluster_info {
> + u8 __iomem *cluster_base;
> + struct uncore_data uncore_data;
> + struct tpmi_uncore_struct *uncore_root;
> +};
> +
> +/* Information for each power domain */
> +struct tpmi_uncore_power_domain_info {
> + u8 __iomem *uncore_base;
> + int ufs_header_ver;
> + int cluster_count;
> + struct tpmi_uncore_cluster_info *cluster_infos;
> +};
> +
> +/* Information for all power domains in a package */
> +struct tpmi_uncore_struct {
> + int power_domain_count;
> + struct tpmi_uncore_power_domain_info *pd_info;
> + struct tpmi_uncore_cluster_info root_cluster;
> +};
> +
> +#define UNCORE_GENMASK_MIN_RATIO GENMASK_ULL(21, 15)
> +#define UNCORE_GENMASK_MAX_RATIO GENMASK_ULL(14, 8)
> +
> +/* Helper function to read MMIO offset for max/min control frequency */
> +static void read_control_freq(struct tpmi_uncore_cluster_info *cluster_info,
> + unsigned int *min, unsigned int *max)
> +{
> + u64 control;
> +
> + control = readq(cluster_info->cluster_base + UNCORE_CONTROL_INDEX);
> + *max = FIELD_GET(UNCORE_GENMASK_MAX_RATIO, control) * UNCORE_FREQ_KHZ_MULTIPLIER;
> + *min = FIELD_GET(UNCORE_GENMASK_MIN_RATIO, control) * UNCORE_FREQ_KHZ_MULTIPLIER;
> +}
> +
> +#define UNCORE_MAX_RATIO 0x7F

FIELD_MAX(UNCORE_GENMASK_MAX_RATIO) ?

> +
> +/* Callback for sysfs read for max/min frequencies. Called under mutex locks */
> +static int uncore_read_control_freq(struct uncore_data *data, unsigned int *min,
> + unsigned int *max)
> +{
> + struct tpmi_uncore_cluster_info *cluster_info;
> + struct tpmi_uncore_struct *uncore_root;
> + int i, _min = 0, _max = 0;
> +
> + cluster_info = container_of(data, struct tpmi_uncore_cluster_info, uncore_data);
> + uncore_root = cluster_info->uncore_root;
> +
> + *min = UNCORE_MAX_RATIO * UNCORE_FREQ_KHZ_MULTIPLIER;
> + *max = 0;
> +
> + /*
> + * Get the max/min by looking at each cluster. Get the lowest
> + * min and highest max.
> + */
> + for (i = 0; i < uncore_root->power_domain_count; ++i) {
> + int j;
> +
> + for (j = 0; j < uncore_root->pd_info[i].cluster_count; ++j) {
> + read_control_freq(&uncore_root->pd_info[i].cluster_infos[j],
> + &_min, &_max);
> + if (*min > _min)
> + *min = _min;
> + if (*max < _max)
> + *max = _max;
> + }
> + }
> +
> + return 0;
> +}
> +
> +/* Helper function to write MMIO offset for max/min control frequency */
> +static void write_control_freq(struct tpmi_uncore_cluster_info *cluster_info, unsigned int input,
> + unsigned int min_max)
> +{
> + u64 control;
> +
> + control = readq(cluster_info->cluster_base + UNCORE_CONTROL_INDEX);
> +
> + if (min_max) {
> + control &= ~UNCORE_GENMASK_MAX_RATIO;
> + control |= FIELD_PREP(UNCORE_GENMASK_MAX_RATIO, input);
> + } else {
> + control &= ~UNCORE_GENMASK_MIN_RATIO;
> + control |= FIELD_PREP(UNCORE_GENMASK_MIN_RATIO, input);
> + }
> +
> + writeq(control, (cluster_info->cluster_base + UNCORE_CONTROL_INDEX));
> +}
> +
> +/* Callback for sysfs write for max/min frequencies. Called under mutex locks */
> +static int uncore_write_control_freq(struct uncore_data *data, unsigned int input,
> + unsigned int min_max)
> +{
> + struct tpmi_uncore_cluster_info *cluster_info;
> + struct tpmi_uncore_struct *uncore_root;
> + int i;
> +
> + input /= UNCORE_FREQ_KHZ_MULTIPLIER;
> + if (!input || input > UNCORE_MAX_RATIO)
> + return -EINVAL;
> +
> + cluster_info = container_of(data, struct tpmi_uncore_cluster_info, uncore_data);
> + uncore_root = cluster_info->uncore_root;
> +
> + /* Update each cluster in a package */
> + for (i = 0; i < uncore_root->power_domain_count; ++i) {
> + int j;
> +
> + for (j = 0; j < uncore_root->pd_info[i].cluster_count; ++j)
> + write_control_freq(&uncore_root->pd_info[i].cluster_infos[j],
> + input, min_max);
> + }
> +
> + return 0;
> +}
> +
> +/* Callback for sysfs read for the current uncore frequency. Called under mutex locks */
> +static int uncore_read_freq(struct uncore_data *data, unsigned int *freq)
> +{
> + return -ENODATA;
> +}
> +
> +#define UNCORE_GENMASK_VERSION GENMASK_ULL(7, 0)

GENMASK makes the name little bit confusing (what is "uncore genmask" ??).
Either drop it entirely (my preference) or add _MASK to the end instead.

> +#define UNCORE_LOCAL_FABRIC_CLUSTER_ID_MASK GENMASK_ULL(15, 8)
> +#define UNCORE_CLUSTER_OFF_MASK GENMASK_ULL(7, 0)
> +#define UNCORE_MAX_CLUSTER_PER_DOMAIN 8
> +
> +static int uncore_probe(struct auxiliary_device *auxdev, const struct auxiliary_device_id *id)
> +{
> + struct intel_tpmi_plat_info *plat_info;
> + struct tpmi_uncore_struct *tpmi_uncore;
> + int ret, i, pkg = 0;
> + int num_resources;
> +
> + /* Get number of power domains, which is equal to number of resources */
> + num_resources = tpmi_get_resource_count(auxdev);
> + if (!num_resources)
> + return -EINVAL;
> +
> + /* Register callbacks to uncore core */
> + ret = uncore_freq_common_init(uncore_read_control_freq, uncore_write_control_freq,
> + uncore_read_freq);
> + if (ret)
> + return ret;
> +
> + /* Allocate uncore instance per package */
> + tpmi_uncore = devm_kzalloc(&auxdev->dev, sizeof(*tpmi_uncore), GFP_KERNEL);
> + if (!tpmi_uncore) {
> + ret = -ENOMEM;
> + goto err_rem_common;
> + }
> +
> + /* Allocate memory for all power domains in a package */
> + tpmi_uncore->pd_info = devm_kcalloc(&auxdev->dev, num_resources,
> + sizeof(*tpmi_uncore->pd_info),
> + GFP_KERNEL);
> + if (!tpmi_uncore->pd_info) {
> + ret = -ENOMEM;
> + goto err_rem_common;
> + }
> +
> + tpmi_uncore->power_domain_count = num_resources;
> +
> + /* Get the package ID from the TPMI core */
> + plat_info = tpmi_get_platform_data(auxdev);
> + if (plat_info)
> + pkg = plat_info->package_id;
> + else
> + dev_info(&auxdev->dev, "Platform information is NULL\n");
> +
> + for (i = 0; i < num_resources; ++i) {
> + struct tpmi_uncore_power_domain_info *pd_info;
> + struct resource *res;
> + u64 cluster_offset;
> + u8 cluster_mask;
> + int mask, j;
> + u64 header;
> +
> + res = tpmi_get_resource_at_index(auxdev, i);
> + if (!res)
> + continue;
> +
> + pd_info = &tpmi_uncore->pd_info[i];
> +
> + pd_info->uncore_base = devm_ioremap_resource(&auxdev->dev, res);
> + if (IS_ERR(pd_info->uncore_base)) {
> + ret = PTR_ERR(pd_info->uncore_base);
> + goto err_rem_common;
> + }
> +
> + /* Check for version and skip this resource if there is mismatch */
> + header = readq(pd_info->uncore_base);
> + pd_info->ufs_header_ver = header & UNCORE_GENMASK_VERSION;
> + if (pd_info->ufs_header_ver != UNCORE_HEADER_VERSION) {
> + dev_info(&auxdev->dev, "Uncore: Unsupported version:%d\n",
> + pd_info->ufs_header_ver);
> + continue;
> + }
> +
> + /* Get Cluster ID Mask */
> + cluster_mask = FIELD_GET(UNCORE_LOCAL_FABRIC_CLUSTER_ID_MASK, header);
> + if (!cluster_mask) {
> + dev_info(&auxdev->dev, "Uncore: Invalid cluster mask:%x\n", cluster_mask);
> + continue;
> + }
> +
> + /* Find out number of clusters in this resource */
> + mask = 0x01;
> + for (j = 0; j < UNCORE_MAX_CLUSTER_PER_DOMAIN; ++j) {
> + if (cluster_mask & mask)
> + pd_info->cluster_count++;
> + mask <<= 1;
> + }

pd_info->cluster_count = hweight8(cluster_mask);

?


--
i.

> +
> + pd_info->cluster_infos = devm_kcalloc(&auxdev->dev, pd_info->cluster_count,
> + sizeof(struct tpmi_uncore_cluster_info),
> + GFP_KERNEL);
> + if (!pd_info->cluster_infos) {
> + ret = -ENOMEM;
> + goto err_rem_common;
> + }
> + /*
> + * Each byte in the register point to status and control
> + * registers belonging to cluster id 0-8.
> + */
> + cluster_offset = readq(pd_info->uncore_base +
> + UNCORE_FABRIC_CLUSTER_OFFSET);
> +
> + for (j = 0; j < pd_info->cluster_count; ++j) {
> + struct tpmi_uncore_cluster_info *cluster_info;
> +
> + /* Get the offset for this cluster */
> + mask = (cluster_offset & UNCORE_CLUSTER_OFF_MASK);
> + /* Offset in QWORD, so change to bytes */
> + mask <<= 3;
> +
> + cluster_info = &pd_info->cluster_infos[j];
> +
> + cluster_info->cluster_base = pd_info->uncore_base + mask;
> +
> + cluster_info->uncore_data.package_id = pkg;
> + /* There are no dies like Cascade Lake */
> + cluster_info->uncore_data.die_id = 0;
> +
> + /* Point to next cluster offset */
> + cluster_offset >>= UNCORE_MAX_CLUSTER_PER_DOMAIN;
> + }
> + }
> +
> + auxiliary_set_drvdata(auxdev, tpmi_uncore);
> +
> + tpmi_uncore->root_cluster.uncore_root = tpmi_uncore;
> + tpmi_uncore->root_cluster.uncore_data.package_id = pkg;
> + ret = uncore_freq_add_entry(&tpmi_uncore->root_cluster.uncore_data, 0);
> + if (ret)
> + goto err_rem_common;
> +
> + return 0;
> +
> +err_rem_common:
> + uncore_freq_common_exit();
> +
> + return ret;
> +}
> +
> +static void uncore_remove(struct auxiliary_device *auxdev)
> +{
> + struct tpmi_uncore_struct *tpmi_uncore = auxiliary_get_drvdata(auxdev);
> +
> + uncore_freq_remove_die_entry(&tpmi_uncore->root_cluster.uncore_data);
> +
> + uncore_freq_common_exit();
> +}
> +
> +static const struct auxiliary_device_id intel_uncore_id_table[] = {
> + { .name = "intel_vsec.tpmi-uncore" },
> + {}
> +};
> +MODULE_DEVICE_TABLE(auxiliary, intel_uncore_id_table);
> +
> +static struct auxiliary_driver intel_uncore_aux_driver = {
> + .id_table = intel_uncore_id_table,
> + .remove = uncore_remove,
> + .probe = uncore_probe,
> +};
> +
> +module_auxiliary_driver(intel_uncore_aux_driver);
> +
> +MODULE_IMPORT_NS(INTEL_TPMI);
> +MODULE_IMPORT_NS(INTEL_UNCORE_FREQUENCY);
> +MODULE_DESCRIPTION("Intel TPMI UFS Driver");
> +MODULE_LICENSE("GPL");
>