xref: /openbmc/linux/drivers/peci/device.c (revision 93e1821c)
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)
peci_get_revision(struct peci_device * device,u8 * revision)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(req))
26 		return PTR_ERR(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 
peci_get_cpu_id(struct peci_device * device,u32 * cpu_id)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(req))
54 		return PTR_ERR(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 
peci_x86_cpu_family(unsigned int sig)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 
peci_x86_cpu_model(unsigned int sig)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 
peci_device_info_init(struct peci_device * device)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);
100 	if (ret)
101 		return ret;
102 
103 	device->info.family = peci_x86_cpu_family(cpu_id);
104 	device->info.model = peci_x86_cpu_model(cpu_id);
105 
106 	ret = peci_get_revision(device, &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 
peci_detect(struct peci_controller * controller,u8 addr)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(&controller->bus_lock);
129 
130 	return ret;
131 }
132 
peci_addr_valid(u8 addr)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 
peci_dev_exists(struct device * dev,void * data)138 static int peci_dev_exists(struct device *dev, void *data)
139 {
140 	struct peci_device *device = to_peci_device(dev);
141 	u8 *addr = data;
142 
143 	if (device->addr == *addr)
144 		return -EBUSY;
145 
146 	return 0;
147 }
148 
peci_device_create(struct peci_controller * controller,u8 addr)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(&controller->dev, &addr, 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(sizeof(*device), GFP_KERNEL);
175 	if (!device)
176 		return -ENOMEM;
177 
178 	device_initialize(&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(&device->dev, "%d-%02x", controller->id, device->addr);
190 	if (ret)
191 		goto err_put;
192 
193 	ret = device_add(&device->dev);
194 	if (ret)
195 		goto err_put;
196 
197 	return 0;
198 
199 err_put:
200 	put_device(&device->dev);
201 
202 	return ret;
203 }
204 
peci_device_destroy(struct peci_device * device)205 void peci_device_destroy(struct peci_device *device)
206 {
207 	mutex_lock(&peci_device_del_lock);
208 	if (!device->deleted) {
209 		device_unregister(&device->dev);
210 		device->deleted = true;
211 	}
212 	mutex_unlock(&peci_device_del_lock);
213 }
214 
__peci_driver_register(struct peci_driver * driver,struct module * owner,const char * mod_name)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(&driver->driver);
233 }
234 EXPORT_SYMBOL_NS_GPL(__peci_driver_register, PECI);
235 
peci_driver_unregister(struct peci_driver * driver)236 void peci_driver_unregister(struct peci_driver *driver)
237 {
238 	driver_unregister(&driver->driver);
239 }
240 EXPORT_SYMBOL_NS_GPL(peci_driver_unregister, PECI);
241 
peci_device_release(struct device * dev)242 static void peci_device_release(struct device *dev)
243 {
244 	struct peci_device *device = to_peci_device(dev);
245 
246 	kfree(device);
247 }
248 
249 struct device_type peci_device_type = {
250 	.groups		= peci_device_groups,
251 	.release	= peci_device_release,
252 };
253