[PATCH 09/14] peci: Add support for PECI device drivers

Iwona Winiarska
2021-07-12T22:10:12Z

Here we're adding support for PECI device drivers, which unlike PECI
controller drivers are actually able to provide functionalities to
userspace.

We're also extending peci_request API to allow querying more details
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@intel.com>
Reviewed-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
---
drivers/peci/Kconfig | 1 +
drivers/peci/core.c | 49 +++++++++
drivers/peci/device.c | 99 ++++++++++++++++++
drivers/peci/internal.h | 75 ++++++++++++++
drivers/peci/request.c | 217 ++++++++++++++++++++++++++++++++++++++++
include/linux/peci.h | 19 ++++
lib/Kconfig | 2 +-
7 files changed, 461 insertions(+), 1 deletion(-)

diff --git a/drivers/peci/Kconfig b/drivers/peci/Kconfig
index 0d0ee8009713..27c31535843c 100644
--- a/drivers/peci/Kconfig
+++ b/drivers/peci/Kconfig
@@ -2,6 +2,7 @@

menuconfig PECI
tristate "PECI support"
+ select 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 ae7a9572cdf3..94426b7f2618 100644
--- a/drivers/peci/core.c
+++ b/drivers/peci/core.c
@@ -143,8 +143,57 @@ void peci_controller_remove(struct peci_controller *controller)
}
EXPORT_SYMBOL_NS_GPL(peci_controller_remove, 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;
+
+ 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)
+{
+ 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 1124862211e2..8c4bd1ebbc29 100644
--- a/drivers/peci/device.c
+++ b/drivers/peci/device.c
@@ -1,11 +1,79 @@
// 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);
+ if (IS_ERR(req))
+ return PTR_ERR(req);
+
+ dib = peci_request_data_dib(req);
+ 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;
@@ -75,6 +143,10 @@ 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;
@@ -98,6 +170,33 @@ 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 6b139adaf6b8..c891c93e077a 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 78cee51dfae1..48354455b554 100644
--- a/drivers/peci/request.c
+++ b/drivers/peci/request.c
@@ -1,13 +1,142 @@
// 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_WRITE_LEN 5
+#define PECI_RDPKGCFG_READ_LEN_BASE 1
+#define PECI_WRPKGCFG_CMD 0xa5
+#define PECI_WRPKGCFG_WRITE_LEN_BASE 6
+#define PECI_WRPKGCFG_READ_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 = device->controller;
+ int ret;
+
+ mutex_lock(&controller->bus_lock);
+ ret = controller->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 = device->controller;
+ 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 *= 2;
+ if (wait_interval > PECI_RETRY_INTERVAL_MAX)
+ wait_interval = 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_request with buffers with given lengths
* @device: PECI device to which request is going to be sent
@@ -72,3 +201,91 @@ 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_WRITE_LEN,
+ PECI_RDPKGCFG_READ_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 cdf3008321fd..f9f37b874011 100644
--- a/include/linux/peci.h
+++ b/include/linux/peci.h
@@ -9,6 +9,14 @@
#include <linux/mutex.h>
#include <linux/types.h>

+#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_request;

/**
@@ -41,6 +49,11 @@ 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.
@@ -50,6 +63,12 @@ static inline struct peci_controller *to_peci_controller(void *d)
struct peci_device {
struct device dev;
struct peci_controller *controller;
+ struct {
+ u16 family;
+ u8 model;
+ u8 peci_revision;
+ u8 socket_id;
+ } info;
u8 addr;
};

diff --git a/lib/Kconfig b/lib/Kconfig
index cc28bc1f2d84..a74e6c0fa75c 100644
--- a/lib/Kconfig
+++ b/lib/Kconfig
@@ -721,5 +721,5 @@ config ASN1_ENCODER

config GENERIC_LIB_X86
bool
- depends on X86
+ depends on X86 || PECI
default n
--
2.31.1