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// SPDX-License-Identifier: GPL-2.0-only
// Copyright (c) 2018-2021 Intel Corporation
#include <linux/peci.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);
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 = 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);
}
static void peci_device_release(struct device *dev)
{
struct peci_device *device = to_peci_device(dev);
kfree(device);
}
struct device_type peci_device_type = {
.groups = peci_device_groups,
.release = peci_device_release,
};
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