diff options
Diffstat (limited to 'drivers/peci/device.c')
| -rw-r--r-- | drivers/peci/device.c | 252 |
1 files changed, 252 insertions, 0 deletions
diff --git a/drivers/peci/device.c b/drivers/peci/device.c new file mode 100644 index 000000000..e6b0bffb1 --- /dev/null +++ b/drivers/peci/device.c @@ -0,0 +1,252 @@ +// 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.family = peci_x86_cpu_family(cpu_id); + device->info.model = 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); +} + +struct device_type peci_device_type = { + .groups = peci_device_groups, + .release = peci_device_release, +}; |