tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
1// SPDX-License-Identifier: GPL-2.0
2//
3// Copyright 2018 Google LLC.
4
5#include <linux/completion.h>
6#include <linux/delay.h>
7#include <linux/kernel.h>
8#include <linux/module.h>
9#include <linux/mfd/cros_ec.h>
10#include <linux/mfd/cros_ec_commands.h>
11#include <linux/of.h>
12#include <linux/platform_device.h>
13#include <linux/rpmsg.h>
14#include <linux/slab.h>
15
16#define EC_MSG_TIMEOUT_MS 200
17#define HOST_COMMAND_MARK 1
18#define HOST_EVENT_MARK 2
19
20/**
21 * struct cros_ec_rpmsg_response - rpmsg message format from from EC.
22 *
23 * @type: The type of message, should be either HOST_COMMAND_MARK or
24 * HOST_EVENT_MARK, representing that the message is a response to
25 * host command, or a host event.
26 * @data: ec_host_response for host command.
27 */
28struct cros_ec_rpmsg_response {
29 u8 type;
30 u8 data[] __aligned(4);
31};
32
33/**
34 * struct cros_ec_rpmsg - information about a EC over rpmsg.
35 *
36 * @rpdev: rpmsg device we are connected to
37 * @xfer_ack: completion for host command transfer.
38 * @host_event_work: Work struct for pending host event.
39 */
40struct cros_ec_rpmsg {
41 struct rpmsg_device *rpdev;
42 struct completion xfer_ack;
43 struct work_struct host_event_work;
44};
45
46/**
47 * cros_ec_cmd_xfer_rpmsg - Transfer a message over rpmsg and receive the reply
48 *
49 * @ec_dev: ChromeOS EC device
50 * @ec_msg: Message to transfer
51 *
52 * This is only used for old EC proto version, and is not supported for this
53 * driver.
54 *
55 * Return: -EINVAL
56 */
57static int cros_ec_cmd_xfer_rpmsg(struct cros_ec_device *ec_dev,
58 struct cros_ec_command *ec_msg)
59{
60 return -EINVAL;
61}
62
63/**
64 * cros_ec_pkt_xfer_rpmsg - Transfer a packet over rpmsg and receive the reply
65 *
66 * @ec_dev: ChromeOS EC device
67 * @ec_msg: Message to transfer
68 *
69 * Return: number of bytes of the reply on success or negative error code.
70 */
71static int cros_ec_pkt_xfer_rpmsg(struct cros_ec_device *ec_dev,
72 struct cros_ec_command *ec_msg)
73{
74 struct cros_ec_rpmsg *ec_rpmsg = ec_dev->priv;
75 struct rpmsg_device *rpdev = ec_rpmsg->rpdev;
76 struct ec_host_response *response;
77 unsigned long timeout;
78 int len;
79 int ret;
80 u8 sum;
81 int i;
82
83 ec_msg->result = 0;
84 len = cros_ec_prepare_tx(ec_dev, ec_msg);
85 dev_dbg(ec_dev->dev, "prepared, len=%d\n", len);
86
87 reinit_completion(&ec_rpmsg->xfer_ack);
88 ret = rpmsg_send(rpdev->ept, ec_dev->dout, len);
89 if (ret) {
90 dev_err(ec_dev->dev, "rpmsg send failed\n");
91 return ret;
92 }
93
94 timeout = msecs_to_jiffies(EC_MSG_TIMEOUT_MS);
95 ret = wait_for_completion_timeout(&ec_rpmsg->xfer_ack, timeout);
96 if (!ret) {
97 dev_err(ec_dev->dev, "rpmsg send timeout\n");
98 return -EIO;
99 }
100
101 /* check response error code */
102 response = (struct ec_host_response *)ec_dev->din;
103 ec_msg->result = response->result;
104
105 ret = cros_ec_check_result(ec_dev, ec_msg);
106 if (ret)
107 goto exit;
108
109 if (response->data_len > ec_msg->insize) {
110 dev_err(ec_dev->dev, "packet too long (%d bytes, expected %d)",
111 response->data_len, ec_msg->insize);
112 ret = -EMSGSIZE;
113 goto exit;
114 }
115
116 /* copy response packet payload and compute checksum */
117 memcpy(ec_msg->data, ec_dev->din + sizeof(*response),
118 response->data_len);
119
120 sum = 0;
121 for (i = 0; i < sizeof(*response) + response->data_len; i++)
122 sum += ec_dev->din[i];
123
124 if (sum) {
125 dev_err(ec_dev->dev, "bad packet checksum, calculated %x\n",
126 sum);
127 ret = -EBADMSG;
128 goto exit;
129 }
130
131 ret = response->data_len;
132exit:
133 if (ec_msg->command == EC_CMD_REBOOT_EC)
134 msleep(EC_REBOOT_DELAY_MS);
135
136 return ret;
137}
138
139static void
140cros_ec_rpmsg_host_event_function(struct work_struct *host_event_work)
141{
142 struct cros_ec_rpmsg *ec_rpmsg = container_of(host_event_work,
143 struct cros_ec_rpmsg,
144 host_event_work);
145 struct cros_ec_device *ec_dev = dev_get_drvdata(&ec_rpmsg->rpdev->dev);
146 bool wake_event = true;
147 int ret;
148
149 ret = cros_ec_get_next_event(ec_dev, &wake_event);
150
151 /*
152 * Signal only if wake host events or any interrupt if
153 * cros_ec_get_next_event() returned an error (default value for
154 * wake_event is true)
155 */
156 if (wake_event && device_may_wakeup(ec_dev->dev))
157 pm_wakeup_event(ec_dev->dev, 0);
158
159 if (ret > 0)
160 blocking_notifier_call_chain(&ec_dev->event_notifier,
161 0, ec_dev);
162}
163
164static int cros_ec_rpmsg_callback(struct rpmsg_device *rpdev, void *data,
165 int len, void *priv, u32 src)
166{
167 struct cros_ec_device *ec_dev = dev_get_drvdata(&rpdev->dev);
168 struct cros_ec_rpmsg *ec_rpmsg = ec_dev->priv;
169 struct cros_ec_rpmsg_response *resp;
170
171 if (!len) {
172 dev_warn(ec_dev->dev, "rpmsg received empty response");
173 return -EINVAL;
174 }
175
176 resp = data;
177 len -= offsetof(struct cros_ec_rpmsg_response, data);
178 if (resp->type == HOST_COMMAND_MARK) {
179 if (len > ec_dev->din_size) {
180 dev_warn(ec_dev->dev,
181 "received length %d > din_size %d, truncating",
182 len, ec_dev->din_size);
183 len = ec_dev->din_size;
184 }
185
186 memcpy(ec_dev->din, resp->data, len);
187 complete(&ec_rpmsg->xfer_ack);
188 } else if (resp->type == HOST_EVENT_MARK) {
189 schedule_work(&ec_rpmsg->host_event_work);
190 } else {
191 dev_warn(ec_dev->dev, "rpmsg received invalid type = %d",
192 resp->type);
193 return -EINVAL;
194 }
195
196 return 0;
197}
198
199static int cros_ec_rpmsg_probe(struct rpmsg_device *rpdev)
200{
201 struct device *dev = &rpdev->dev;
202 struct cros_ec_rpmsg *ec_rpmsg;
203 struct cros_ec_device *ec_dev;
204
205 ec_dev = devm_kzalloc(dev, sizeof(*ec_dev), GFP_KERNEL);
206 if (!ec_dev)
207 return -ENOMEM;
208
209 ec_rpmsg = devm_kzalloc(dev, sizeof(*ec_rpmsg), GFP_KERNEL);
210 if (!ec_rpmsg)
211 return -ENOMEM;
212
213 ec_dev->dev = dev;
214 ec_dev->priv = ec_rpmsg;
215 ec_dev->cmd_xfer = cros_ec_cmd_xfer_rpmsg;
216 ec_dev->pkt_xfer = cros_ec_pkt_xfer_rpmsg;
217 ec_dev->phys_name = dev_name(&rpdev->dev);
218 ec_dev->din_size = sizeof(struct ec_host_response) +
219 sizeof(struct ec_response_get_protocol_info);
220 ec_dev->dout_size = sizeof(struct ec_host_request);
221 dev_set_drvdata(dev, ec_dev);
222
223 ec_rpmsg->rpdev = rpdev;
224 init_completion(&ec_rpmsg->xfer_ack);
225 INIT_WORK(&ec_rpmsg->host_event_work,
226 cros_ec_rpmsg_host_event_function);
227
228 return cros_ec_register(ec_dev);
229}
230
231static void cros_ec_rpmsg_remove(struct rpmsg_device *rpdev)
232{
233 struct cros_ec_device *ec_dev = dev_get_drvdata(&rpdev->dev);
234 struct cros_ec_rpmsg *ec_rpmsg = ec_dev->priv;
235
236 cancel_work_sync(&ec_rpmsg->host_event_work);
237}
238
239static const struct of_device_id cros_ec_rpmsg_of_match[] = {
240 { .compatible = "google,cros-ec-rpmsg", },
241 { }
242};
243MODULE_DEVICE_TABLE(of, cros_ec_rpmsg_of_match);
244
245static struct rpmsg_driver cros_ec_driver_rpmsg = {
246 .drv = {
247 .name = "cros-ec-rpmsg",
248 .of_match_table = cros_ec_rpmsg_of_match,
249 },
250 .probe = cros_ec_rpmsg_probe,
251 .remove = cros_ec_rpmsg_remove,
252 .callback = cros_ec_rpmsg_callback,
253};
254
255module_rpmsg_driver(cros_ec_driver_rpmsg);
256
257MODULE_LICENSE("GPL v2");
258MODULE_DESCRIPTION("ChromeOS EC multi function device (rpmsg)");