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// SPDX-License-Identifier: GPL-2.0-only
// Copyright (c) 2018-2021 Intel Corporation
#include <linux/bitfield.h>
#include <linux/peci.h>
#include <linux/peci-cpu.h>
#include <linux/slab.h>
#include "internal.h"
/*
* PECI device can be removed using sysfs, but the removal can also happen as
* a result of controller being removed.
* Mutex is used to protect PECI device from being double-deleted.
*/
static DEFINE_MUTEX(peci_device_del_lock);
#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_xfer_get_dib(device);
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_dib_read(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_xfer_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 unsigned int peci_x86_cpu_family(unsigned int sig)
{
unsigned int x86;
x86 = (sig >> 8) & 0xf;
if (x86 == 0xf)
x86 += (sig >> 20) & 0xff;
return x86;
}
static unsigned int peci_x86_cpu_model(unsigned int sig)
{
unsigned int fam, model;
fam = peci_x86_cpu_family(sig);
model = (sig >> 4) & 0xf;
if (fam >= 0x6)
model += ((sig >> 16) & 0xf) << 4;
return model;
}
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.x86_vfm = IFM(peci_x86_cpu_family(cpu_id), peci_x86_cpu_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)
{
/*
* PECI Ping is a command encoded by tx_len = 0, rx_len = 0.
* We expect correct Write FCS if the device at the target address
* is able to respond.
*/
struct peci_request req = { 0 };
int ret;
mutex_lock(&controller->bus_lock);
ret = controller->ops->xfer(controller, addr, &req);
mutex_unlock(&controller->bus_lock);
return ret;
}
static bool peci_addr_valid(u8 addr)
{
return addr >= PECI_BASE_ADDR && addr < PECI_BASE_ADDR + PECI_DEVICE_NUM_MAX;
}
static int peci_dev_exists(struct device *dev, void *data)
{
struct peci_device *device = to_peci_device(dev);
u8 *addr = data;
if (device->addr == *addr)
return -EBUSY;
return 0;
}
int peci_device_create(struct peci_controller *controller, u8 addr)
{
struct peci_device *device;
int ret;
if (!peci_addr_valid(addr))
return -EINVAL;
/* Check if we have already detected this device before. */
ret = device_for_each_child(&controller->dev, &addr, peci_dev_exists);
if (ret)
return 0;
ret = peci_detect(controller, addr);
if (ret) {
/*
* Device not present or host state doesn't allow successful
* detection at this time.
*/
if (ret == -EIO || ret == -ETIMEDOUT)
return 0;
return ret;
}
device = kzalloc(sizeof(*device), GFP_KERNEL);
if (!device)
return -ENOMEM;
device_initialize(&device->dev);
device->addr = addr;
device->dev.parent = &controller->dev;
device->dev.bus = &peci_bus_type;
device->dev.type = &peci_device_type;
ret = peci_device_info_init(device);
if (ret)
goto err_put;
ret = dev_set_name(&device->dev, "%d-%02x", controller->id, device->addr);
if (ret)
goto err_put;
ret = device_add(&device->dev);
if (ret)
goto err_put;
return 0;
err_put:
put_device(&device->dev);
return ret;
}
void peci_device_destroy(struct peci_device *device)
{
mutex_lock(&peci_device_del_lock);
if (!device->deleted) {
device_unregister(&device->dev);
device->deleted = true;
}
mutex_unlock(&peci_device_del_lock);
}
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);
kfree(device);
}
const struct device_type peci_device_type = {
.groups = peci_device_groups,
.release = peci_device_release,
};
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