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17#include <linux/mfd/cros_ec.h>
18#include <linux/delay.h>
19#include <linux/device.h>
20#include <linux/module.h>
21#include <linux/slab.h>
22
23#define EC_COMMAND_RETRIES 50
24
25static int prepare_packet(struct cros_ec_device *ec_dev,
26 struct cros_ec_command *msg)
27{
28 struct ec_host_request *request;
29 u8 *out;
30 int i;
31 u8 csum = 0;
32
33 BUG_ON(ec_dev->proto_version != EC_HOST_REQUEST_VERSION);
34 BUG_ON(msg->outsize + sizeof(*request) > ec_dev->dout_size);
35
36 out = ec_dev->dout;
37 request = (struct ec_host_request *)out;
38 request->struct_version = EC_HOST_REQUEST_VERSION;
39 request->checksum = 0;
40 request->command = msg->command;
41 request->command_version = msg->version;
42 request->reserved = 0;
43 request->data_len = msg->outsize;
44
45 for (i = 0; i < sizeof(*request); i++)
46 csum += out[i];
47
48
49 memcpy(out + sizeof(*request), msg->data, msg->outsize);
50 for (i = 0; i < msg->outsize; i++)
51 csum += msg->data[i];
52
53 request->checksum = -csum;
54
55 return sizeof(*request) + msg->outsize;
56}
57
58static int send_command(struct cros_ec_device *ec_dev,
59 struct cros_ec_command *msg)
60{
61 int ret;
62
63 if (ec_dev->proto_version > 2)
64 ret = ec_dev->pkt_xfer(ec_dev, msg);
65 else
66 ret = ec_dev->cmd_xfer(ec_dev, msg);
67
68 if (msg->result == EC_RES_IN_PROGRESS) {
69 int i;
70 struct cros_ec_command *status_msg;
71 struct ec_response_get_comms_status *status;
72
73 status_msg = kmalloc(sizeof(*status_msg) + sizeof(*status),
74 GFP_KERNEL);
75 if (!status_msg)
76 return -ENOMEM;
77
78 status_msg->version = 0;
79 status_msg->command = EC_CMD_GET_COMMS_STATUS;
80 status_msg->insize = sizeof(*status);
81 status_msg->outsize = 0;
82
83
84
85
86
87 for (i = 0; i < EC_COMMAND_RETRIES; i++) {
88 usleep_range(10000, 11000);
89
90 ret = ec_dev->cmd_xfer(ec_dev, status_msg);
91 if (ret < 0)
92 break;
93
94 msg->result = status_msg->result;
95 if (status_msg->result != EC_RES_SUCCESS)
96 break;
97
98 status = (struct ec_response_get_comms_status *)
99 status_msg->data;
100 if (!(status->flags & EC_COMMS_STATUS_PROCESSING))
101 break;
102 }
103
104 kfree(status_msg);
105 }
106
107 return ret;
108}
109
110int cros_ec_prepare_tx(struct cros_ec_device *ec_dev,
111 struct cros_ec_command *msg)
112{
113 u8 *out;
114 u8 csum;
115 int i;
116
117 if (ec_dev->proto_version > 2)
118 return prepare_packet(ec_dev, msg);
119
120 BUG_ON(msg->outsize > EC_PROTO2_MAX_PARAM_SIZE);
121 out = ec_dev->dout;
122 out[0] = EC_CMD_VERSION0 + msg->version;
123 out[1] = msg->command;
124 out[2] = msg->outsize;
125 csum = out[0] + out[1] + out[2];
126 for (i = 0; i < msg->outsize; i++)
127 csum += out[EC_MSG_TX_HEADER_BYTES + i] = msg->data[i];
128 out[EC_MSG_TX_HEADER_BYTES + msg->outsize] = csum;
129
130 return EC_MSG_TX_PROTO_BYTES + msg->outsize;
131}
132EXPORT_SYMBOL(cros_ec_prepare_tx);
133
134int cros_ec_check_result(struct cros_ec_device *ec_dev,
135 struct cros_ec_command *msg)
136{
137 switch (msg->result) {
138 case EC_RES_SUCCESS:
139 return 0;
140 case EC_RES_IN_PROGRESS:
141 dev_dbg(ec_dev->dev, "command 0x%02x in progress\n",
142 msg->command);
143 return -EAGAIN;
144 default:
145 dev_dbg(ec_dev->dev, "command 0x%02x returned %d\n",
146 msg->command, msg->result);
147 return 0;
148 }
149}
150EXPORT_SYMBOL(cros_ec_check_result);
151
152static int cros_ec_host_command_proto_query(struct cros_ec_device *ec_dev,
153 int devidx,
154 struct cros_ec_command *msg)
155{
156
157
158
159
160
161
162 int ret;
163
164 if (!ec_dev->pkt_xfer)
165 return -EPROTONOSUPPORT;
166
167 memset(msg, 0, sizeof(*msg));
168 msg->command = EC_CMD_PASSTHRU_OFFSET(devidx) | EC_CMD_GET_PROTOCOL_INFO;
169 msg->insize = sizeof(struct ec_response_get_protocol_info);
170
171 ret = send_command(ec_dev, msg);
172
173 if (ret < 0) {
174 dev_dbg(ec_dev->dev,
175 "failed to check for EC[%d] protocol version: %d\n",
176 devidx, ret);
177 return ret;
178 }
179
180 if (devidx > 0 && msg->result == EC_RES_INVALID_COMMAND)
181 return -ENODEV;
182 else if (msg->result != EC_RES_SUCCESS)
183 return msg->result;
184
185 return 0;
186}
187
188static int cros_ec_host_command_proto_query_v2(struct cros_ec_device *ec_dev)
189{
190 struct cros_ec_command *msg;
191 struct ec_params_hello *hello_params;
192 struct ec_response_hello *hello_response;
193 int ret;
194 int len = max(sizeof(*hello_params), sizeof(*hello_response));
195
196 msg = kmalloc(sizeof(*msg) + len, GFP_KERNEL);
197 if (!msg)
198 return -ENOMEM;
199
200 msg->version = 0;
201 msg->command = EC_CMD_HELLO;
202 hello_params = (struct ec_params_hello *)msg->data;
203 msg->outsize = sizeof(*hello_params);
204 hello_response = (struct ec_response_hello *)msg->data;
205 msg->insize = sizeof(*hello_response);
206
207 hello_params->in_data = 0xa0b0c0d0;
208
209 ret = send_command(ec_dev, msg);
210
211 if (ret < 0) {
212 dev_dbg(ec_dev->dev,
213 "EC failed to respond to v2 hello: %d\n",
214 ret);
215 goto exit;
216 } else if (msg->result != EC_RES_SUCCESS) {
217 dev_err(ec_dev->dev,
218 "EC responded to v2 hello with error: %d\n",
219 msg->result);
220 ret = msg->result;
221 goto exit;
222 } else if (hello_response->out_data != 0xa1b2c3d4) {
223 dev_err(ec_dev->dev,
224 "EC responded to v2 hello with bad result: %u\n",
225 hello_response->out_data);
226 ret = -EBADMSG;
227 goto exit;
228 }
229
230 ret = 0;
231
232 exit:
233 kfree(msg);
234 return ret;
235}
236
237int cros_ec_query_all(struct cros_ec_device *ec_dev)
238{
239 struct device *dev = ec_dev->dev;
240 struct cros_ec_command *proto_msg;
241 struct ec_response_get_protocol_info *proto_info;
242 int ret;
243
244 proto_msg = kzalloc(sizeof(*proto_msg) + sizeof(*proto_info),
245 GFP_KERNEL);
246 if (!proto_msg)
247 return -ENOMEM;
248
249
250 ec_dev->proto_version = 3;
251 ret = cros_ec_host_command_proto_query(ec_dev, 0, proto_msg);
252
253 if (ret == 0) {
254 proto_info = (struct ec_response_get_protocol_info *)
255 proto_msg->data;
256 ec_dev->max_request = proto_info->max_request_packet_size -
257 sizeof(struct ec_host_request);
258 ec_dev->max_response = proto_info->max_response_packet_size -
259 sizeof(struct ec_host_response);
260 ec_dev->proto_version =
261 min(EC_HOST_REQUEST_VERSION,
262 fls(proto_info->protocol_versions) - 1);
263 dev_dbg(ec_dev->dev,
264 "using proto v%u\n",
265 ec_dev->proto_version);
266
267 ec_dev->din_size = ec_dev->max_response +
268 sizeof(struct ec_host_response) +
269 EC_MAX_RESPONSE_OVERHEAD;
270 ec_dev->dout_size = ec_dev->max_request +
271 sizeof(struct ec_host_request) +
272 EC_MAX_REQUEST_OVERHEAD;
273
274
275
276
277 ret = cros_ec_host_command_proto_query(ec_dev, 1, proto_msg);
278
279 if (ret) {
280 dev_dbg(ec_dev->dev, "no PD chip found: %d\n", ret);
281 ec_dev->max_passthru = 0;
282 } else {
283 dev_dbg(ec_dev->dev, "found PD chip\n");
284 ec_dev->max_passthru =
285 proto_info->max_request_packet_size -
286 sizeof(struct ec_host_request);
287 }
288 } else {
289
290 ec_dev->proto_version = 2;
291 ret = cros_ec_host_command_proto_query_v2(ec_dev);
292
293 if (ret == 0) {
294
295 dev_dbg(ec_dev->dev, "falling back to proto v2\n");
296
297 ec_dev->max_request = EC_PROTO2_MAX_PARAM_SIZE;
298 ec_dev->max_response = EC_PROTO2_MAX_PARAM_SIZE;
299 ec_dev->max_passthru = 0;
300 ec_dev->pkt_xfer = NULL;
301 ec_dev->din_size = EC_MSG_BYTES;
302 ec_dev->dout_size = EC_MSG_BYTES;
303 } else {
304
305
306
307
308
309 ec_dev->proto_version = EC_PROTO_VERSION_UNKNOWN;
310 dev_dbg(ec_dev->dev, "EC query failed: %d\n", ret);
311 goto exit;
312 }
313 }
314
315 devm_kfree(dev, ec_dev->din);
316 devm_kfree(dev, ec_dev->dout);
317
318 ec_dev->din = devm_kzalloc(dev, ec_dev->din_size, GFP_KERNEL);
319 if (!ec_dev->din) {
320 ret = -ENOMEM;
321 goto exit;
322 }
323
324 ec_dev->dout = devm_kzalloc(dev, ec_dev->dout_size, GFP_KERNEL);
325 if (!ec_dev->dout) {
326 devm_kfree(dev, ec_dev->din);
327 ret = -ENOMEM;
328 goto exit;
329 }
330
331exit:
332 kfree(proto_msg);
333 return ret;
334}
335EXPORT_SYMBOL(cros_ec_query_all);
336
337int cros_ec_cmd_xfer(struct cros_ec_device *ec_dev,
338 struct cros_ec_command *msg)
339{
340 int ret;
341
342 mutex_lock(&ec_dev->lock);
343 if (ec_dev->proto_version == EC_PROTO_VERSION_UNKNOWN) {
344 ret = cros_ec_query_all(ec_dev);
345 if (ret) {
346 dev_err(ec_dev->dev,
347 "EC version unknown and query failed; aborting command\n");
348 mutex_unlock(&ec_dev->lock);
349 return ret;
350 }
351 }
352
353 if (msg->insize > ec_dev->max_response) {
354 dev_dbg(ec_dev->dev, "clamping message receive buffer\n");
355 msg->insize = ec_dev->max_response;
356 }
357
358 if (msg->command < EC_CMD_PASSTHRU_OFFSET(1)) {
359 if (msg->outsize > ec_dev->max_request) {
360 dev_err(ec_dev->dev,
361 "request of size %u is too big (max: %u)\n",
362 msg->outsize,
363 ec_dev->max_request);
364 mutex_unlock(&ec_dev->lock);
365 return -EMSGSIZE;
366 }
367 } else {
368 if (msg->outsize > ec_dev->max_passthru) {
369 dev_err(ec_dev->dev,
370 "passthru rq of size %u is too big (max: %u)\n",
371 msg->outsize,
372 ec_dev->max_passthru);
373 mutex_unlock(&ec_dev->lock);
374 return -EMSGSIZE;
375 }
376 }
377 ret = send_command(ec_dev, msg);
378 mutex_unlock(&ec_dev->lock);
379
380 return ret;
381}
382EXPORT_SYMBOL(cros_ec_cmd_xfer);
383
