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 | */ |
16 | static DEFINE_MUTEX(peci_device_del_lock); |
17 | |
18 | #define REVISION_NUM_MASK GENMASK(15, 8) |
19 | static 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 | |
47 | static 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); |
61 | out_req_free: |
62 | peci_request_free(req); |
63 | |
64 | return ret; |
65 | } |
66 | |
67 | static 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 | |
79 | static 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 | |
93 | static 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 | |
116 | static 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 | |
133 | static bool peci_addr_valid(u8 addr) |
134 | { |
135 | return addr >= PECI_BASE_ADDR && addr < PECI_BASE_ADDR + PECI_DEVICE_NUM_MAX; |
136 | } |
137 | |
138 | static 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 | |
149 | int 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 | |
199 | err_put: |
200 | put_device(dev: &device->dev); |
201 | |
202 | return ret; |
203 | } |
204 | |
205 | void 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 | |
215 | int __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 | } |
234 | EXPORT_SYMBOL_NS_GPL(__peci_driver_register, PECI); |
235 | |
236 | void peci_driver_unregister(struct peci_driver *driver) |
237 | { |
238 | driver_unregister(drv: &driver->driver); |
239 | } |
240 | EXPORT_SYMBOL_NS_GPL(peci_driver_unregister, PECI); |
241 | |
242 | static 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 | |
249 | struct device_type peci_device_type = { |
250 | .groups = peci_device_groups, |
251 | .release = peci_device_release, |
252 | }; |
253 | |