diff options
Diffstat (limited to 'drivers/peci/device.c')
-rw-r--r-- | drivers/peci/device.c | 120 |
1 files changed, 120 insertions, 0 deletions
diff --git a/drivers/peci/device.c b/drivers/peci/device.c new file mode 100644 index 000000000000..2b3a2d893aaf --- /dev/null +++ b/drivers/peci/device.c @@ -0,0 +1,120 @@ +// 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 = { + .release = peci_device_release, +}; |