[PATCH v2 10/15] peci: Add support for PECI device drivers
Dan Williams
dan.j.williams at intel.com
Sat Aug 28 07:19:59 AEST 2021
On Tue, Aug 3, 2021 at 4:36 AM Iwona Winiarska
<iwona.winiarska at intel.com> wrote:
>
> Here we're adding support for PECI device drivers, which unlike PECI
s/Here we're adding/Add/
> controller drivers are actually able to provide functionalities to
> userspace.
>
> We're also extending peci_request API to allow querying more details
s/We're also extending/Also, extend/
...for the most part imperative tense is the preferred tense, by
upstream maintainers, for changelogs.
> about PECI device (e.g. model/family), that's going to be used to find
> a compatible peci_driver.
>
> Signed-off-by: Iwona Winiarska <iwona.winiarska at intel.com>
> Reviewed-by: Pierre-Louis Bossart <pierre-louis.bossart at linux.intel.com>
> ---
> drivers/peci/Kconfig | 1 +
> drivers/peci/core.c | 49 +++++++++
> drivers/peci/device.c | 105 ++++++++++++++++++++
> drivers/peci/internal.h | 75 ++++++++++++++
> drivers/peci/request.c | 214 ++++++++++++++++++++++++++++++++++++++++
> include/linux/peci.h | 19 ++++
> lib/Kconfig | 2 +-
> 7 files changed, 464 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/peci/Kconfig b/drivers/peci/Kconfig
> index 99279df97a78..1d0532e3a801 100644
> --- a/drivers/peci/Kconfig
> +++ b/drivers/peci/Kconfig
> @@ -2,6 +2,7 @@
>
> menuconfig PECI
> tristate "PECI support"
> + select GENERIC_LIB_X86
GENERIC_LIB_X86 has dependencies, so this 'select' will make kbuild
unhappy when that dependency is not met. Given that this symbol
already selected by X86, it seems this just wants a "depends on
GENERIC_LIB_X86".
> help
> The Platform Environment Control Interface (PECI) is an interface
> that provides a communication channel to Intel processors and
> diff --git a/drivers/peci/core.c b/drivers/peci/core.c
> index c473acb3c2a0..33c07920493d 100644
> --- a/drivers/peci/core.c
> +++ b/drivers/peci/core.c
> @@ -157,8 +157,57 @@ struct peci_controller *devm_peci_controller_add(struct device *dev,
> }
> EXPORT_SYMBOL_NS_GPL(devm_peci_controller_add, PECI);
>
> +static const struct peci_device_id *
> +peci_bus_match_device_id(const struct peci_device_id *id, struct peci_device *device)
> +{
> + while (id->family != 0) {
> + if (id->family == device->info.family &&
> + id->model == device->info.model)
> + return id;
> + id++;
> + }
> +
> + return NULL;
> +}
> +
> +static int peci_bus_device_match(struct device *dev, struct device_driver *drv)
> +{
> + struct peci_device *device = to_peci_device(dev);
> + struct peci_driver *peci_drv = to_peci_driver(drv);
> +
> + if (dev->type != &peci_device_type)
> + return 0;
> +
> + if (peci_bus_match_device_id(peci_drv->id_table, device))
> + return 1;
Save a couple lines and do:
return peci_bus_match_device_id(...)
> +
> + return 0;
> +}
> +
> +static int peci_bus_device_probe(struct device *dev)
> +{
> + struct peci_device *device = to_peci_device(dev);
> + struct peci_driver *driver = to_peci_driver(dev->driver);
> +
> + return driver->probe(device, peci_bus_match_device_id(driver->id_table, device));
> +}
> +
> +static int peci_bus_device_remove(struct device *dev)
Note, in linux-next this prototype has changed to:
void (*remove)(struct device *dev);
https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git/tree/include/linux/device/bus.h
> +{
> + struct peci_device *device = to_peci_device(dev);
> + struct peci_driver *driver = to_peci_driver(dev->driver);
> +
> + if (driver->remove)
> + driver->remove(device);
> +
> + return 0;
> +}
> +
> struct bus_type peci_bus_type = {
> .name = "peci",
> + .match = peci_bus_device_match,
> + .probe = peci_bus_device_probe,
> + .remove = peci_bus_device_remove,
> .bus_groups = peci_bus_groups,
> };
>
> diff --git a/drivers/peci/device.c b/drivers/peci/device.c
> index d77d9dabd51e..a78c02399574 100644
> --- a/drivers/peci/device.c
> +++ b/drivers/peci/device.c
> @@ -1,11 +1,85 @@
> // SPDX-License-Identifier: GPL-2.0-only
> // Copyright (c) 2018-2021 Intel Corporation
>
> +#include <linux/bitfield.h>
> #include <linux/peci.h>
> #include <linux/slab.h>
> +#include <linux/x86/cpu.h>
>
> #include "internal.h"
>
> +#define REVISION_NUM_MASK GENMASK(15, 8)
> +static int peci_get_revision(struct peci_device *device, u8 *revision)
> +{
> + struct peci_request *req;
> + u64 dib;
> +
> + req = peci_get_dib(device);
I would expect peci_get_dib() to return @dib.
> + if (IS_ERR(req))
> + return PTR_ERR(req);
> +
> + /*
> + * PECI device may be in a state where it is unable to return a proper
> + * DIB, in which case it returns 0 as DIB value.
> + * Let's treat this as an error to avoid carrying on with the detection
> + * using invalid revision.
> + */
> + dib = peci_request_data_dib(req);
I would expect peci_request_data_dib() to make a request.
A stack allocated peci_request passed to peci_get_dib() that returns
an error code would seem to be cleaner than this current organization.
> + if (dib == 0) {
> + peci_request_free(req);
> + return -EIO;
> + }
> +
> + *revision = FIELD_GET(REVISION_NUM_MASK, dib);
> +
> + peci_request_free(req);
> +
> + return 0;
> +}
> +
> +static int peci_get_cpu_id(struct peci_device *device, u32 *cpu_id)
> +{
> + struct peci_request *req;
> + int ret;
> +
> + req = peci_pkg_cfg_readl(device, PECI_PCS_PKG_ID, PECI_PKG_ID_CPU_ID);
> + if (IS_ERR(req))
> + return PTR_ERR(req);
> +
> + ret = peci_request_status(req);
> + if (ret)
> + goto out_req_free;
> +
> + *cpu_id = peci_request_data_readl(req);
> +out_req_free:
> + peci_request_free(req);
> +
> + return ret;
> +}
> +
> +static int peci_device_info_init(struct peci_device *device)
> +{
> + u8 revision;
> + u32 cpu_id;
> + int ret;
> +
> + ret = peci_get_cpu_id(device, &cpu_id);
> + if (ret)
> + return ret;
> +
> + device->info.family = x86_family(cpu_id);
> + device->info.model = x86_model(cpu_id);
> +
> + ret = peci_get_revision(device, &revision);
> + if (ret)
> + return ret;
> + device->info.peci_revision = revision;
> +
> + device->info.socket_id = device->addr - PECI_BASE_ADDR;
> +
> + return 0;
> +}
> +
> static int peci_detect(struct peci_controller *controller, u8 addr)
> {
> struct peci_request *req;
> @@ -79,6 +153,10 @@ int peci_device_create(struct peci_controller *controller, u8 addr)
> device->dev.bus = &peci_bus_type;
> device->dev.type = &peci_device_type;
>
> + ret = peci_device_info_init(device);
> + if (ret)
> + goto err_free;
> +
> ret = dev_set_name(&device->dev, "%d-%02x", controller->id, device->addr);
> if (ret)
> goto err_free;
> @@ -102,6 +180,33 @@ void peci_device_destroy(struct peci_device *device)
> device_unregister(&device->dev);
> }
>
> +int __peci_driver_register(struct peci_driver *driver, struct module *owner,
> + const char *mod_name)
> +{
> + driver->driver.bus = &peci_bus_type;
> + driver->driver.owner = owner;
> + driver->driver.mod_name = mod_name;
> +
> + if (!driver->probe) {
> + pr_err("peci: trying to register driver without probe callback\n");
> + return -EINVAL;
> + }
> +
> + if (!driver->id_table) {
> + pr_err("peci: trying to register driver without device id table\n");
> + return -EINVAL;
> + }
> +
> + return driver_register(&driver->driver);
> +}
> +EXPORT_SYMBOL_NS_GPL(__peci_driver_register, PECI);
> +
> +void peci_driver_unregister(struct peci_driver *driver)
> +{
> + driver_unregister(&driver->driver);
> +}
> +EXPORT_SYMBOL_NS_GPL(peci_driver_unregister, PECI);
> +
> static void peci_device_release(struct device *dev)
> {
> struct peci_device *device = to_peci_device(dev);
> diff --git a/drivers/peci/internal.h b/drivers/peci/internal.h
> index 978e12c8e1d3..d661e1b65694 100644
> --- a/drivers/peci/internal.h
> +++ b/drivers/peci/internal.h
> @@ -19,6 +19,34 @@ struct peci_request;
> struct peci_request *peci_request_alloc(struct peci_device *device, u8 tx_len, u8 rx_len);
> void peci_request_free(struct peci_request *req);
>
> +int peci_request_status(struct peci_request *req);
> +u64 peci_request_data_dib(struct peci_request *req);
> +
> +u8 peci_request_data_readb(struct peci_request *req);
> +u16 peci_request_data_readw(struct peci_request *req);
> +u32 peci_request_data_readl(struct peci_request *req);
> +u64 peci_request_data_readq(struct peci_request *req);
> +
> +struct peci_request *peci_get_dib(struct peci_device *device);
> +struct peci_request *peci_get_temp(struct peci_device *device);
> +
> +struct peci_request *peci_pkg_cfg_readb(struct peci_device *device, u8 index, u16 param);
> +struct peci_request *peci_pkg_cfg_readw(struct peci_device *device, u8 index, u16 param);
> +struct peci_request *peci_pkg_cfg_readl(struct peci_device *device, u8 index, u16 param);
> +struct peci_request *peci_pkg_cfg_readq(struct peci_device *device, u8 index, u16 param);
> +
> +/**
> + * struct peci_device_id - PECI device data to match
> + * @data: pointer to driver private data specific to device
> + * @family: device family
> + * @model: device model
> + */
> +struct peci_device_id {
> + const void *data;
> + u16 family;
> + u8 model;
> +};
> +
> extern struct device_type peci_device_type;
> extern const struct attribute_group *peci_device_groups[];
>
> @@ -28,6 +56,53 @@ void peci_device_destroy(struct peci_device *device);
> extern struct bus_type peci_bus_type;
> extern const struct attribute_group *peci_bus_groups[];
>
> +/**
> + * struct peci_driver - PECI driver
> + * @driver: inherit device driver
> + * @probe: probe callback
> + * @remove: remove callback
> + * @id_table: PECI device match table to decide which device to bind
> + */
> +struct peci_driver {
> + struct device_driver driver;
> + int (*probe)(struct peci_device *device, const struct peci_device_id *id);
> + void (*remove)(struct peci_device *device);
> + const struct peci_device_id *id_table;
> +};
> +
> +static inline struct peci_driver *to_peci_driver(struct device_driver *d)
> +{
> + return container_of(d, struct peci_driver, driver);
> +}
> +
> +int __peci_driver_register(struct peci_driver *driver, struct module *owner,
> + const char *mod_name);
> +/**
> + * peci_driver_register() - register PECI driver
> + * @driver: the driver to be registered
> + * @owner: owner module of the driver being registered
> + * @mod_name: module name string
> + *
> + * PECI drivers that don't need to do anything special in module init should
> + * use the convenience "module_peci_driver" macro instead
> + *
> + * Return: zero on success, else a negative error code.
> + */
> +#define peci_driver_register(driver) \
> + __peci_driver_register(driver, THIS_MODULE, KBUILD_MODNAME)
> +void peci_driver_unregister(struct peci_driver *driver);
> +
> +/**
> + * module_peci_driver() - helper macro for registering a modular PECI driver
> + * @__peci_driver: peci_driver struct
> + *
> + * Helper macro for PECI drivers which do not do anything special in module
> + * init/exit. This eliminates a lot of boilerplate. Each module may only
> + * use this macro once, and calling it replaces module_init() and module_exit()
> + */
> +#define module_peci_driver(__peci_driver) \
> + module_driver(__peci_driver, peci_driver_register, peci_driver_unregister)
> +
> extern struct device_type peci_controller_type;
>
> int peci_controller_scan_devices(struct peci_controller *controller);
> diff --git a/drivers/peci/request.c b/drivers/peci/request.c
> index 81b567bc7b87..fe032d5a5e1b 100644
> --- a/drivers/peci/request.c
> +++ b/drivers/peci/request.c
> @@ -1,13 +1,140 @@
> // SPDX-License-Identifier: GPL-2.0-only
> // Copyright (c) 2021 Intel Corporation
>
> +#include <linux/bug.h>
> #include <linux/export.h>
> #include <linux/peci.h>
> #include <linux/slab.h>
> #include <linux/types.h>
>
> +#include <asm/unaligned.h>
> +
> #include "internal.h"
>
> +#define PECI_GET_DIB_CMD 0xf7
> +#define PECI_GET_DIB_WR_LEN 1
> +#define PECI_GET_DIB_RD_LEN 8
> +
> +#define PECI_RDPKGCFG_CMD 0xa1
> +#define PECI_RDPKGCFG_WR_LEN 5
> +#define PECI_RDPKGCFG_RD_LEN_BASE 1
> +#define PECI_WRPKGCFG_CMD 0xa5
> +#define PECI_WRPKGCFG_WR_LEN_BASE 6
> +#define PECI_WRPKGCFG_RD_LEN 1
> +
> +/* Device Specific Completion Code (CC) Definition */
> +#define PECI_CC_SUCCESS 0x40
> +#define PECI_CC_NEED_RETRY 0x80
> +#define PECI_CC_OUT_OF_RESOURCE 0x81
> +#define PECI_CC_UNAVAIL_RESOURCE 0x82
> +#define PECI_CC_INVALID_REQ 0x90
> +#define PECI_CC_MCA_ERROR 0x91
> +#define PECI_CC_CATASTROPHIC_MCA_ERROR 0x93
> +#define PECI_CC_FATAL_MCA_ERROR 0x94
> +#define PECI_CC_PARITY_ERR_GPSB_OR_PMSB 0x98
> +#define PECI_CC_PARITY_ERR_GPSB_OR_PMSB_IERR 0x9B
> +#define PECI_CC_PARITY_ERR_GPSB_OR_PMSB_MCA 0x9C
> +
> +#define PECI_RETRY_BIT BIT(0)
> +
> +#define PECI_RETRY_TIMEOUT msecs_to_jiffies(700)
> +#define PECI_RETRY_INTERVAL_MIN msecs_to_jiffies(1)
> +#define PECI_RETRY_INTERVAL_MAX msecs_to_jiffies(128)
> +
> +static u8 peci_request_data_cc(struct peci_request *req)
> +{
> + return req->rx.buf[0];
> +}
> +
> +/**
> + * peci_request_status() - return -errno based on PECI completion code
> + * @req: the PECI request that contains response data with completion code
> + *
> + * It can't be used for Ping(), GetDIB() and GetTemp() - for those commands we
> + * don't expect completion code in the response.
> + *
> + * Return: -errno
> + */
> +int peci_request_status(struct peci_request *req)
> +{
> + u8 cc = peci_request_data_cc(req);
> +
> + if (cc != PECI_CC_SUCCESS)
> + dev_dbg(&req->device->dev, "ret: %#02x\n", cc);
> +
> + switch (cc) {
> + case PECI_CC_SUCCESS:
> + return 0;
> + case PECI_CC_NEED_RETRY:
> + case PECI_CC_OUT_OF_RESOURCE:
> + case PECI_CC_UNAVAIL_RESOURCE:
> + return -EAGAIN;
> + case PECI_CC_INVALID_REQ:
> + return -EINVAL;
> + case PECI_CC_MCA_ERROR:
> + case PECI_CC_CATASTROPHIC_MCA_ERROR:
> + case PECI_CC_FATAL_MCA_ERROR:
> + case PECI_CC_PARITY_ERR_GPSB_OR_PMSB:
> + case PECI_CC_PARITY_ERR_GPSB_OR_PMSB_IERR:
> + case PECI_CC_PARITY_ERR_GPSB_OR_PMSB_MCA:
> + return -EIO;
> + }
> +
> + WARN_ONCE(1, "Unknown PECI completion code: %#02x\n", cc);
> +
> + return -EIO;
> +}
> +EXPORT_SYMBOL_NS_GPL(peci_request_status, PECI);
> +
> +static int peci_request_xfer(struct peci_request *req)
> +{
> + struct peci_device *device = req->device;
> + struct peci_controller *controller = to_peci_controller(device->dev.parent);
> + int ret;
> +
> + mutex_lock(&controller->bus_lock);
> + ret = controller->ops->xfer(controller, device->addr, req);
> + mutex_unlock(&controller->bus_lock);
> +
> + return ret;
> +}
> +
> +static int peci_request_xfer_retry(struct peci_request *req)
> +{
> + long wait_interval = PECI_RETRY_INTERVAL_MIN;
> + struct peci_device *device = req->device;
> + struct peci_controller *controller = to_peci_controller(device->dev.parent);
> + unsigned long start = jiffies;
> + int ret;
> +
> + /* Don't try to use it for ping */
> + if (WARN_ON(!req->rx.buf))
> + return 0;
> +
> + do {
> + ret = peci_request_xfer(req);
> + if (ret) {
> + dev_dbg(&controller->dev, "xfer error: %d\n", ret);
> + return ret;
> + }
> +
> + if (peci_request_status(req) != -EAGAIN)
> + return 0;
> +
> + /* Set the retry bit to indicate a retry attempt */
> + req->tx.buf[1] |= PECI_RETRY_BIT;
> +
> + if (schedule_timeout_interruptible(wait_interval))
> + return -ERESTARTSYS;
> +
> + wait_interval = min_t(long, wait_interval * 2, PECI_RETRY_INTERVAL_MAX);
> + } while (time_before(jiffies, start + PECI_RETRY_TIMEOUT));
> +
> + dev_dbg(&controller->dev, "request timed out\n");
> +
> + return -ETIMEDOUT;
> +}
> +
> /**
> * peci_request_alloc() - allocate &struct peci_requests
> * @device: PECI device to which request is going to be sent
> @@ -48,3 +175,90 @@ void peci_request_free(struct peci_request *req)
> kfree(req);
> }
> EXPORT_SYMBOL_NS_GPL(peci_request_free, PECI);
> +
> +struct peci_request *peci_get_dib(struct peci_device *device)
> +{
> + struct peci_request *req;
> + int ret;
> +
> + req = peci_request_alloc(device, PECI_GET_DIB_WR_LEN, PECI_GET_DIB_RD_LEN);
> + if (!req)
> + return ERR_PTR(-ENOMEM);
> +
> + req->tx.buf[0] = PECI_GET_DIB_CMD;
> +
> + ret = peci_request_xfer(req);
> + if (ret) {
> + peci_request_free(req);
> + return ERR_PTR(ret);
> + }
> +
> + return req;
> +}
> +EXPORT_SYMBOL_NS_GPL(peci_get_dib, PECI);
> +
> +static struct peci_request *
> +__pkg_cfg_read(struct peci_device *device, u8 index, u16 param, u8 len)
> +{
> + struct peci_request *req;
> + int ret;
> +
> + req = peci_request_alloc(device, PECI_RDPKGCFG_WR_LEN, PECI_RDPKGCFG_RD_LEN_BASE + len);
> + if (!req)
> + return ERR_PTR(-ENOMEM);
> +
> + req->tx.buf[0] = PECI_RDPKGCFG_CMD;
> + req->tx.buf[1] = 0;
> + req->tx.buf[2] = index;
> + put_unaligned_le16(param, &req->tx.buf[3]);
> +
> + ret = peci_request_xfer_retry(req);
> + if (ret) {
> + peci_request_free(req);
> + return ERR_PTR(ret);
> + }
> +
> + return req;
> +}
> +
> +u8 peci_request_data_readb(struct peci_request *req)
> +{
> + return req->rx.buf[1];
> +}
> +EXPORT_SYMBOL_NS_GPL(peci_request_data_readb, PECI);
> +
> +u16 peci_request_data_readw(struct peci_request *req)
> +{
> + return get_unaligned_le16(&req->rx.buf[1]);
> +}
> +EXPORT_SYMBOL_NS_GPL(peci_request_data_readw, PECI);
> +
> +u32 peci_request_data_readl(struct peci_request *req)
> +{
> + return get_unaligned_le32(&req->rx.buf[1]);
> +}
> +EXPORT_SYMBOL_NS_GPL(peci_request_data_readl, PECI);
> +
> +u64 peci_request_data_readq(struct peci_request *req)
> +{
> + return get_unaligned_le64(&req->rx.buf[1]);
> +}
> +EXPORT_SYMBOL_NS_GPL(peci_request_data_readq, PECI);
> +
> +u64 peci_request_data_dib(struct peci_request *req)
> +{
> + return get_unaligned_le64(&req->rx.buf[0]);
> +}
> +EXPORT_SYMBOL_NS_GPL(peci_request_data_dib, PECI);
> +
> +#define __read_pkg_config(x, type) \
> +struct peci_request *peci_pkg_cfg_##x(struct peci_device *device, u8 index, u16 param) \
> +{ \
> + return __pkg_cfg_read(device, index, param, sizeof(type)); \
> +} \
> +EXPORT_SYMBOL_NS_GPL(peci_pkg_cfg_##x, PECI)
> +
> +__read_pkg_config(readb, u8);
> +__read_pkg_config(readw, u16);
> +__read_pkg_config(readl, u32);
> +__read_pkg_config(readq, u64);
> diff --git a/include/linux/peci.h b/include/linux/peci.h
> index 26e0a4e73b50..dcf1c53f4e40 100644
> --- a/include/linux/peci.h
> +++ b/include/linux/peci.h
> @@ -14,6 +14,14 @@
> */
> #define PECI_REQUEST_MAX_BUF_SIZE 32
>
> +#define PECI_PCS_PKG_ID 0 /* Package Identifier Read */
> +#define PECI_PKG_ID_CPU_ID 0x0000 /* CPUID Info */
> +#define PECI_PKG_ID_PLATFORM_ID 0x0001 /* Platform ID */
> +#define PECI_PKG_ID_DEVICE_ID 0x0002 /* Uncore Device ID */
> +#define PECI_PKG_ID_MAX_THREAD_ID 0x0003 /* Max Thread ID */
> +#define PECI_PKG_ID_MICROCODE_REV 0x0004 /* CPU Microcode Update Revision */
> +#define PECI_PKG_ID_MCA_ERROR_LOG 0x0005 /* Machine Check Status */
> +
> struct peci_controller;
> struct peci_request;
>
> @@ -59,6 +67,11 @@ static inline struct peci_controller *to_peci_controller(void *d)
> * struct peci_device - PECI device
> * @dev: device object to register PECI device to the device model
> * @controller: manages the bus segment hosting this PECI device
> + * @info: PECI device characteristics
> + * @info.family: device family
> + * @info.model: device model
> + * @info.peci_revision: PECI revision supported by the PECI device
> + * @info.socket_id: the socket ID represented by the PECI device
> * @addr: address used on the PECI bus connected to the parent controller
> *
> * A peci_device identifies a single device (i.e. CPU) connected to a PECI bus.
> @@ -67,6 +80,12 @@ static inline struct peci_controller *to_peci_controller(void *d)
> */
> struct peci_device {
> struct device dev;
> + struct {
> + u16 family;
> + u8 model;
> + u8 peci_revision;
> + u8 socket_id;
> + } info;
> u8 addr;
> };
>
> diff --git a/lib/Kconfig b/lib/Kconfig
> index e538d4d773bd..7f7972d357c2 100644
> --- a/lib/Kconfig
> +++ b/lib/Kconfig
> @@ -718,4 +718,4 @@ config ASN1_ENCODER
>
> config GENERIC_LIB_X86
> bool
> - depends on X86
> + depends on X86 || PECI
This looks broken, what in the GENERIC_LIB_X86 implementation depends on peci?
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