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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.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,
- };
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