1// SPDX-License-Identifier: GPL-2.0-only
2// Copyright (c) 2018-2021 Intel Corporation
3
4#include <linux/bitfield.h>
5#include <linux/peci.h>
6#include <linux/peci-cpu.h>
7#include <linux/slab.h>
8
9#include "internal.h"
10
11/*
12 * PECI device can be removed using sysfs, but the removal can also happen as
13 * a result of controller being removed.
14 * Mutex is used to protect PECI device from being double-deleted.
15 */
16static DEFINE_MUTEX(peci_device_del_lock);
17
18#define REVISION_NUM_MASK GENMASK(15, 8)
19static int peci_get_revision(struct peci_device *device, u8 *revision)
20{
21 struct peci_request *req;
22 u64 dib;
23
24 req = peci_xfer_get_dib(device);
25 if (IS_ERR(ptr: req))
26 return PTR_ERR(ptr: req);
27
28 /*
29 * PECI device may be in a state where it is unable to return a proper
30 * DIB, in which case it returns 0 as DIB value.
31 * Let's treat this as an error to avoid carrying on with the detection
32 * using invalid revision.
33 */
34 dib = peci_request_dib_read(req);
35 if (dib == 0) {
36 peci_request_free(req);
37 return -EIO;
38 }
39
40 *revision = FIELD_GET(REVISION_NUM_MASK, dib);
41
42 peci_request_free(req);
43
44 return 0;
45}
46
47static int peci_get_cpu_id(struct peci_device *device, u32 *cpu_id)
48{
49 struct peci_request *req;
50 int ret;
51
52 req = peci_xfer_pkg_cfg_readl(device, PECI_PCS_PKG_ID, PECI_PKG_ID_CPU_ID);
53 if (IS_ERR(ptr: req))
54 return PTR_ERR(ptr: req);
55
56 ret = peci_request_status(req);
57 if (ret)
58 goto out_req_free;
59
60 *cpu_id = peci_request_data_readl(req);
61out_req_free:
62 peci_request_free(req);
63
64 return ret;
65}
66
67static unsigned int peci_x86_cpu_family(unsigned int sig)
68{
69 unsigned int x86;
70
71 x86 = (sig >> 8) & 0xf;
72
73 if (x86 == 0xf)
74 x86 += (sig >> 20) & 0xff;
75
76 return x86;
77}
78
79static unsigned int peci_x86_cpu_model(unsigned int sig)
80{
81 unsigned int fam, model;
82
83 fam = peci_x86_cpu_family(sig);
84
85 model = (sig >> 4) & 0xf;
86
87 if (fam >= 0x6)
88 model += ((sig >> 16) & 0xf) << 4;
89
90 return model;
91}
92
93static int peci_device_info_init(struct peci_device *device)
94{
95 u8 revision;
96 u32 cpu_id;
97 int ret;
98
99 ret = peci_get_cpu_id(device, cpu_id: &cpu_id);
100 if (ret)
101 return ret;
102
103 device->info.family = peci_x86_cpu_family(sig: cpu_id);
104 device->info.model = peci_x86_cpu_model(sig: cpu_id);
105
106 ret = peci_get_revision(device, revision: &revision);
107 if (ret)
108 return ret;
109 device->info.peci_revision = revision;
110
111 device->info.socket_id = device->addr - PECI_BASE_ADDR;
112
113 return 0;
114}
115
116static int peci_detect(struct peci_controller *controller, u8 addr)
117{
118 /*
119 * PECI Ping is a command encoded by tx_len = 0, rx_len = 0.
120 * We expect correct Write FCS if the device at the target address
121 * is able to respond.
122 */
123 struct peci_request req = { 0 };
124 int ret;
125
126 mutex_lock(&controller->bus_lock);
127 ret = controller->ops->xfer(controller, addr, &req);
128 mutex_unlock(lock: &controller->bus_lock);
129
130 return ret;
131}
132
133static bool peci_addr_valid(u8 addr)
134{
135 return addr >= PECI_BASE_ADDR && addr < PECI_BASE_ADDR + PECI_DEVICE_NUM_MAX;
136}
137
138static int peci_dev_exists(struct device *dev, void *data)
139{
140 struct peci_device *device = to_peci_device(d: dev);
141 u8 *addr = data;
142
143 if (device->addr == *addr)
144 return -EBUSY;
145
146 return 0;
147}
148
149int peci_device_create(struct peci_controller *controller, u8 addr)
150{
151 struct peci_device *device;
152 int ret;
153
154 if (!peci_addr_valid(addr))
155 return -EINVAL;
156
157 /* Check if we have already detected this device before. */
158 ret = device_for_each_child(dev: &controller->dev, data: &addr, fn: peci_dev_exists);
159 if (ret)
160 return 0;
161
162 ret = peci_detect(controller, addr);
163 if (ret) {
164 /*
165 * Device not present or host state doesn't allow successful
166 * detection at this time.
167 */
168 if (ret == -EIO || ret == -ETIMEDOUT)
169 return 0;
170
171 return ret;
172 }
173
174 device = kzalloc(size: sizeof(*device), GFP_KERNEL);
175 if (!device)
176 return -ENOMEM;
177
178 device_initialize(dev: &device->dev);
179
180 device->addr = addr;
181 device->dev.parent = &controller->dev;
182 device->dev.bus = &peci_bus_type;
183 device->dev.type = &peci_device_type;
184
185 ret = peci_device_info_init(device);
186 if (ret)
187 goto err_put;
188
189 ret = dev_set_name(dev: &device->dev, name: "%d-%02x", controller->id, device->addr);
190 if (ret)
191 goto err_put;
192
193 ret = device_add(dev: &device->dev);
194 if (ret)
195 goto err_put;
196
197 return 0;
198
199err_put:
200 put_device(dev: &device->dev);
201
202 return ret;
203}
204
205void peci_device_destroy(struct peci_device *device)
206{
207 mutex_lock(&peci_device_del_lock);
208 if (!device->deleted) {
209 device_unregister(dev: &device->dev);
210 device->deleted = true;
211 }
212 mutex_unlock(lock: &peci_device_del_lock);
213}
214
215int __peci_driver_register(struct peci_driver *driver, struct module *owner,
216 const char *mod_name)
217{
218 driver->driver.bus = &peci_bus_type;
219 driver->driver.owner = owner;
220 driver->driver.mod_name = mod_name;
221
222 if (!driver->probe) {
223 pr_err("peci: trying to register driver without probe callback\n");
224 return -EINVAL;
225 }
226
227 if (!driver->id_table) {
228 pr_err("peci: trying to register driver without device id table\n");
229 return -EINVAL;
230 }
231
232 return driver_register(drv: &driver->driver);
233}
234EXPORT_SYMBOL_NS_GPL(__peci_driver_register, PECI);
235
236void peci_driver_unregister(struct peci_driver *driver)
237{
238 driver_unregister(drv: &driver->driver);
239}
240EXPORT_SYMBOL_NS_GPL(peci_driver_unregister, PECI);
241
242static void peci_device_release(struct device *dev)
243{
244 struct peci_device *device = to_peci_device(d: dev);
245
246 kfree(objp: device);
247}
248
249struct device_type peci_device_type = {
250 .groups = peci_device_groups,
251 .release = peci_device_release,
252};
253

source code of linux/drivers/peci/device.c