On Fri, 22 Sep 2023, David E. Box wrote:
> Export symbols to allow access to Intel PMT Telemetry data on available
> devices. Provides APIs to search, register, and read telemetry using a
> kref managed pointer that serves as a handle to a telemetry endpoint.
>
> Signed-off-by: David E. Box <david.e.box@xxxxxxxxxxxxxxx>
> ---
> drivers/platform/x86/intel/pmt/class.c | 21 ++-
> drivers/platform/x86/intel/pmt/class.h | 14 ++
> drivers/platform/x86/intel/pmt/telemetry.c | 198 ++++++++++++++++++++-
> drivers/platform/x86/intel/pmt/telemetry.h | 129 ++++++++++++++
> 4 files changed, 354 insertions(+), 8 deletions(-)
> create mode 100644 drivers/platform/x86/intel/pmt/telemetry.h
>
> diff --git a/drivers/platform/x86/intel/pmt/class.c b/drivers/platform/x86/intel/pmt/class.c
> index 142a24e3727d..4b53940a64e2 100644
> --- a/drivers/platform/x86/intel/pmt/class.c
> +++ b/drivers/platform/x86/intel/pmt/class.c
> @@ -17,7 +17,7 @@
> #include "../vsec.h"
> #include "class.h"
>
> -#define PMT_XA_START 0
> +#define PMT_XA_START 1
How is that related to what the changelog states, that is, exporting some
API???
> #define PMT_XA_MAX INT_MAX
> #define PMT_XA_LIMIT XA_LIMIT(PMT_XA_START, PMT_XA_MAX)
> #define GUID_SPR_PUNIT 0x9956f43f
> @@ -247,6 +247,7 @@ static int intel_pmt_dev_register(struct intel_pmt_entry *entry,
> struct intel_pmt_namespace *ns,
> struct device *parent)
> {
> + struct intel_vsec_device *ivdev = dev_to_ivdev(parent);
> struct resource res = {0};
> struct device *dev;
> int ret;
> @@ -270,7 +271,7 @@ static int intel_pmt_dev_register(struct intel_pmt_entry *entry,
> if (ns->attr_grp) {
> ret = sysfs_create_group(entry->kobj, ns->attr_grp);
> if (ret)
> - goto fail_sysfs;
> + goto fail_sysfs_create_group;
> }
>
> /* if size is 0 assume no data buffer, so no file needed */
> @@ -295,13 +296,23 @@ static int intel_pmt_dev_register(struct intel_pmt_entry *entry,
> entry->pmt_bin_attr.size = entry->size;
>
> ret = sysfs_create_bin_file(&dev->kobj, &entry->pmt_bin_attr);
> - if (!ret)
> - return 0;
> + if (ret)
> + goto fail_ioremap;
>
> + if (ns->pmt_add_endpoint) {
> + ret = ns->pmt_add_endpoint(entry, ivdev->pcidev);
> + if (ret)
> + goto fail_add_endpoint;
> + }
> +
> + return 0;
> +
> +fail_add_endpoint:
> + sysfs_remove_bin_file(entry->kobj, &entry->pmt_bin_attr);
> fail_ioremap:
> if (ns->attr_grp)
> sysfs_remove_group(entry->kobj, ns->attr_grp);
> -fail_sysfs:
> +fail_sysfs_create_group:
> device_unregister(dev);
> fail_dev_create:
> xa_erase(ns->xa, entry->devid);
> diff --git a/drivers/platform/x86/intel/pmt/class.h b/drivers/platform/x86/intel/pmt/class.h
> index e477a19f6700..d23c63b73ab7 100644
> --- a/drivers/platform/x86/intel/pmt/class.h
> +++ b/drivers/platform/x86/intel/pmt/class.h
> @@ -9,6 +9,7 @@
> #include <linux/io.h>
>
> #include "../vsec.h"
> +#include "telemetry.h"
>
> /* PMT access types */
> #define ACCESS_BARID 2
> @@ -18,6 +19,16 @@
> #define GET_BIR(v) ((v) & GENMASK(2, 0))
> #define GET_ADDRESS(v) ((v) & GENMASK(31, 3))
>
> +struct pci_dev;
> +
> +struct telem_endpoint {
> + struct pci_dev *pcidev;
> + struct telem_header header;
> + void __iomem *base;
> + bool present;
> + struct kref kref;
> +};
> +
> struct intel_pmt_header {
> u32 base_offset;
> u32 size;
> @@ -26,6 +37,7 @@ struct intel_pmt_header {
> };
>
> struct intel_pmt_entry {
> + struct telem_endpoint *ep;
> struct intel_pmt_header header;
> struct bin_attribute pmt_bin_attr;
> struct kobject *kobj;
> @@ -43,6 +55,8 @@ struct intel_pmt_namespace {
> const struct attribute_group *attr_grp;
> int (*pmt_header_decode)(struct intel_pmt_entry *entry,
> struct device *dev);
> + int (*pmt_add_endpoint)(struct intel_pmt_entry *entry,
> + struct pci_dev *pdev);
> };
>
> bool intel_pmt_is_early_client_hw(struct device *dev);
> diff --git a/drivers/platform/x86/intel/pmt/telemetry.c b/drivers/platform/x86/intel/pmt/telemetry.c
> index f86080e8bebd..8b099580cc2c 100644
> --- a/drivers/platform/x86/intel/pmt/telemetry.c
> +++ b/drivers/platform/x86/intel/pmt/telemetry.c
> @@ -30,6 +30,14 @@
> /* Used by client hardware to identify a fixed telemetry entry*/
> #define TELEM_CLIENT_FIXED_BLOCK_GUID 0x10000000
>
> +#define NUM_BYTES_QWORD(v) ((v) << 3)
> +#define SAMPLE_ID_OFFSET(v) ((v) << 3)
> +
> +#define NUM_BYTES_DWORD(v) ((v) << 2)
> +#define SAMPLE_ID_OFFSET32(v) ((v) << 2)
> +
> +static DEFINE_MUTEX(ep_lock);
> +
> enum telem_type {
> TELEM_TYPE_PUNIT = 0,
> TELEM_TYPE_CRASHLOG,
> @@ -84,21 +92,203 @@ static int pmt_telem_header_decode(struct intel_pmt_entry *entry,
> return 0;
> }
>
> +static int pmt_telem_add_endpoint(struct intel_pmt_entry *entry,
> + struct pci_dev *pdev)
> +{
> + struct telem_endpoint *ep;
> +
> + /*
> + * Endpoint lifetimes are managed by kref, not devres.
> + */
> + entry->ep = kzalloc(sizeof(*(entry->ep)), GFP_KERNEL);
> + if (!entry->ep)
> + return -ENOMEM;
> +
> + ep = entry->ep;
> + ep->pcidev = pdev;
> + ep->header.access_type = entry->header.access_type;
> + ep->header.guid = entry->header.guid;
> + ep->header.base_offset = entry->header.base_offset;
> + ep->header.size = entry->header.size;
> + ep->base = entry->base;
> + ep->present = true;
> +
> + kref_init(&ep->kref);
> +
> + return 0;
> +}
> +
> static DEFINE_XARRAY_ALLOC(telem_array);
> static struct intel_pmt_namespace pmt_telem_ns = {
> .name = "telem",
> .xa = &telem_array,
> .pmt_header_decode = pmt_telem_header_decode,
> + .pmt_add_endpoint = pmt_telem_add_endpoint,
> };
>
> +/* Called when all users unregister and the device is removed */
> +static void pmt_telem_ep_release(struct kref *kref)
> +{
> + struct telem_endpoint *ep;
> +
> + ep = container_of(kref, struct telem_endpoint, kref);
> + kfree(ep);
> +}
> +
> +/*
> + * driver api
> + */
> +int pmt_telem_get_next_endpoint(int start)
> +{
> + struct intel_pmt_entry *entry;
> + unsigned long found_idx;
> +
> + mutex_lock(&ep_lock);
> + xa_for_each_start(&telem_array, found_idx, entry, start) {
> + /*
> + * Return first found index after start.
> + * 0 is not valid id.
> + */
I guess this has to do with the 0->1 change I flagged above. But if that's
the case, it absolutely must be mentioned in the changelog with
explanation!
> + if (found_idx > start)
> + break;
> + }
> + mutex_unlock(&ep_lock);
> +
> + return found_idx == start ? 0 : found_idx;
Why you need signed values in/out? Should this function just be using
unsigned int (or long) for start and return value?
> +}
> +EXPORT_SYMBOL_NS_GPL(pmt_telem_get_next_endpoint, INTEL_PMT_TELEMETRY);
> +
> +struct telem_endpoint *pmt_telem_register_endpoint(int devid)
> +{
> + struct intel_pmt_entry *entry;
> + unsigned long index = devid;
> +
> + mutex_lock(&ep_lock);
> + entry = xa_find(&telem_array, &index, index, XA_PRESENT);
> + if (!entry) {
> + mutex_unlock(&ep_lock);
> + return ERR_PTR(-ENXIO);
> + }
> +
> + kref_get(&entry->ep->kref);
> + mutex_unlock(&ep_lock);
> +
> + return entry->ep;
> +}
> +EXPORT_SYMBOL_NS_GPL(pmt_telem_register_endpoint, INTEL_PMT_TELEMETRY);
> +
> +void pmt_telem_unregister_endpoint(struct telem_endpoint *ep)
> +{
> + kref_put(&ep->kref, pmt_telem_ep_release);
> +}
> +EXPORT_SYMBOL_NS_GPL(pmt_telem_unregister_endpoint, INTEL_PMT_TELEMETRY);
> +
> +int pmt_telem_get_endpoint_info(int devid,
> + struct telem_endpoint_info *info)
> +{
> + struct intel_pmt_entry *entry;
> + unsigned long index = devid;
> + int err = 0;
> +
> + if (!info)
> + return -EINVAL;
> +
> + mutex_lock(&ep_lock);
> + entry = xa_find(&telem_array, &index, index, XA_PRESENT);
> + if (!entry) {
> + err = -ENXIO;
> + goto unlock;
> + }
> +
> + info->pdev = entry->ep->pcidev;
> + info->header = entry->ep->header;
> +
> +unlock:
> + mutex_unlock(&ep_lock);
> + return err;
> +
> +}
> +EXPORT_SYMBOL_NS_GPL(pmt_telem_get_endpoint_info, INTEL_PMT_TELEMETRY);
> +
> +int
> +pmt_telem_read(struct telem_endpoint *ep, u32 id, u64 *data, u32 count)
> +{
> + u32 offset, size;
> +
> + if (!ep->present)
> + return -ENODEV;
> +
> + offset = SAMPLE_ID_OFFSET(id);
> + size = ep->header.size;
> +
> + if ((offset + NUM_BYTES_QWORD(count)) > size)
Extra parenthesis.
--
i.
> + return -EINVAL;
> +
> + memcpy_fromio(data, ep->base + offset, NUM_BYTES_QWORD(count));
> +
> + return ep->present ? 0 : -EPIPE;
> +}
> +EXPORT_SYMBOL_NS_GPL(pmt_telem_read, INTEL_PMT_TELEMETRY);
> +
> +int
> +pmt_telem_read32(struct telem_endpoint *ep, u32 id, u32 *data, u32 count)
> +{
> + u32 offset, size;
> +
> + if (!ep->present)
> + return -ENODEV;
> +
> + offset = SAMPLE_ID_OFFSET32(id);
> + size = ep->header.size;
> +
> + if ((offset + NUM_BYTES_DWORD(count)) > size)
> + return -EINVAL;
> +
> + memcpy_fromio(data, ep->base + offset, NUM_BYTES_DWORD(count));
> +
> + return ep->present ? 0 : -EPIPE;
> +}
> +EXPORT_SYMBOL_NS_GPL(pmt_telem_read32, INTEL_PMT_TELEMETRY);
> +
> +struct telem_endpoint *
> +pmt_telem_find_and_register_endpoint(struct pci_dev *pcidev, u32 guid, u16 pos)
> +{
> + int devid = 0;
> + int inst = 0;
> + int err = 0;
> +
> + while ((devid = pmt_telem_get_next_endpoint(devid))) {
> + struct telem_endpoint_info ep_info;
> +
> + err = pmt_telem_get_endpoint_info(devid, &ep_info);
> + if (err)
> + return ERR_PTR(err);
> +
> + if (ep_info.header.guid == guid && ep_info.pdev == pcidev) {
> + if (inst == pos)
> + return pmt_telem_register_endpoint(devid);
> + ++inst;
> + }
> + }
> +
> + return ERR_PTR(-ENXIO);
> +}
> +EXPORT_SYMBOL_NS_GPL(pmt_telem_find_and_register_endpoint, INTEL_PMT_TELEMETRY);
> +
> static void pmt_telem_remove(struct auxiliary_device *auxdev)
> {
> struct pmt_telem_priv *priv = auxiliary_get_drvdata(auxdev);
> int i;
>
> - for (i = 0; i < priv->num_entries; i++)
> - intel_pmt_dev_destroy(&priv->entry[i], &pmt_telem_ns);
> -}
> + mutex_lock(&ep_lock);
> + for (i = 0; i < priv->num_entries; i++) {
> + struct intel_pmt_entry *entry = &priv->entry[i];
> +
> + kref_put(&entry->ep->kref, pmt_telem_ep_release);
> + intel_pmt_dev_destroy(entry, &pmt_telem_ns);
> + }
> + mutex_unlock(&ep_lock);
> +};
>
> static int pmt_telem_probe(struct auxiliary_device *auxdev, const struct auxiliary_device_id *id)
> {
> @@ -117,7 +307,9 @@ static int pmt_telem_probe(struct auxiliary_device *auxdev, const struct auxilia
> for (i = 0; i < intel_vsec_dev->num_resources; i++) {
> struct intel_pmt_entry *entry = &priv->entry[priv->num_entries];
>
> + mutex_lock(&ep_lock);
> ret = intel_pmt_dev_create(entry, &pmt_telem_ns, intel_vsec_dev, i);
> + mutex_unlock(&ep_lock);
> if (ret < 0)
> goto abort_probe;
> if (ret)
> diff --git a/drivers/platform/x86/intel/pmt/telemetry.h b/drivers/platform/x86/intel/pmt/telemetry.h
> new file mode 100644
> index 000000000000..a8cd64330438
> --- /dev/null
> +++ b/drivers/platform/x86/intel/pmt/telemetry.h
> @@ -0,0 +1,129 @@
> +/* SPDX-License-Identifier: GPL-2.0 */
> +#ifndef _TELEMETRY_H
> +#define _TELEMETRY_H
> +
> +/* Telemetry types */
> +#define PMT_TELEM_TELEMETRY 0
> +#define PMT_TELEM_CRASHLOG 1
> +
> +struct telem_endpoint;
> +struct pci_dev;
> +
> +struct telem_header {
> + u8 access_type;
> + u16 size;
> + u32 guid;
> + u32 base_offset;
> +};
> +
> +struct telem_endpoint_info {
> + struct pci_dev *pdev;
> + struct telem_header header;
> +};
> +
> +/**
> + * pmt_telem_get_next_endpoint() - Get next device id for a telemetry endpoint
> + * @start: starting devid to look from
> + *
> + * This functions can be used in a while loop predicate to retrieve the devid
> + * of all available telemetry endpoints. Functions pmt_telem_get_next_endpoint()
> + * and pmt_telem_register_endpoint() can be used inside of the loop to examine
> + * endpoint info and register to receive a pointer to the endpoint. The pointer
> + * is then usable in the telemetry read calls to access the telemetry data.
> + *
> + * Return:
> + * * devid - devid of the next present endpoint from start
> + * * 0 - when no more endpoints are present after start
> + */
> +int pmt_telem_get_next_endpoint(int start);
> +
> +/**
> + * pmt_telem_register_endpoint() - Register a telemetry endpoint
> + * @devid: device id/handle of the telemetry endpoint
> + *
> + * Increments the kref usage counter for the endpoint.
> + *
> + * Return:
> + * * endpoint - On success returns pointer to the telemetry endpoint
> + * * -ENXIO - telemetry endpoint not found
> + */
> +struct telem_endpoint *pmt_telem_register_endpoint(int devid);
> +
> +/**
> + * pmt_telem_unregister_endpoint() - Unregister a telemetry endpoint
> + * @ep: ep structure to populate.
> + *
> + * Decrements the kref usage counter for the endpoint.
> + */
> +void pmt_telem_unregister_endpoint(struct telem_endpoint *ep);
> +
> +/**
> + * pmt_telem_get_endpoint_info() - Get info for an endpoint from its devid
> + * @devid: device id/handle of the telemetry endpoint
> + * @info: Endpoint info structure to be populated
> + *
> + * Return:
> + * * 0 - Success
> + * * -ENXIO - telemetry endpoint not found for the devid
> + * * -EINVAL - @info is NULL
> + */
> +int pmt_telem_get_endpoint_info(int devid,
> + struct telem_endpoint_info *info);
> +
> +/**
> + * pmt_telem_find_and_register_endpoint() - Get a telemetry endpoint from
> + * pci_dev device, guid and pos
> + * @pdev: PCI device inside the Intel vsec
> + * @guid: GUID of the telemetry space
> + * @pos: Instance of the guid
> + *
> + * Return:
> + * * endpoint - On success returns pointer to the telemetry endpoint
> + * * -ENXIO - telemetry endpoint not found
> + */
> +struct telem_endpoint *pmt_telem_find_and_register_endpoint(struct pci_dev *pcidev,
> + u32 guid, u16 pos);
> +
> +/**
> + * pmt_telem_read() - Read qwords from counter sram using sample id
> + * @ep: Telemetry endpoint to be read
> + * @id: The beginning sample id of the metric(s) to be read
> + * @data: Allocated qword buffer
> + * @count: Number of qwords requested
> + *
> + * Callers must ensure reads are aligned. When the call returns -ENODEV,
> + * the device has been removed and callers should unregister the telemetry
> + * endpoint.
> + *
> + * Return:
> + * * 0 - Success
> + * * -ENODEV - The device is not present.
> + * * -EINVAL - The offset is out bounds
> + * * -EPIPE - The device was removed during the read. Data written
> + * but should be considered invalid.
> + */
> +int pmt_telem_read(struct telem_endpoint *ep, u32 id, u64 *data,
> + u32 count);
> +
> +/**
> + * pmt_telem_read32() - Read qwords from counter sram using sample id
> + * @ep: Telemetry endpoint to be read
> + * @id: The beginning sample id of the metric(s) to be read
> + * @data: Allocated dword buffer
> + * @count: Number of dwords requested
> + *
> + * Callers must ensure reads are aligned. When the call returns -ENODEV,
> + * the device has been removed and callers should unregister the telemetry
> + * endpoint.
> + *
> + * Return:
> + * * 0 - Success
> + * * -ENODEV - The device is not present.
> + * * -EINVAL - The offset is out bounds
> + * * -EPIPE - The device was removed during the read. Data written
> + * but should be considered invalid.
> + */
> +int pmt_telem_read32(struct telem_endpoint *ep, u32 id, u32 *data,
> + u32 count);
> +
> +#endif
>
