1 /*
2 * IBM OPAL RTC driver
3 * Copyright (C) 2014 IBM
4 *
5 * This program is free software; you can redistribute it and/or modify
6 * it under the terms of the GNU General Public License as published by
7 * the Free Software Foundation; either version 2 of the License, or
8 * (at your option) any later version.
9 *
10 * This program is distributed in the hope that it will be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 * GNU General Public License for more details.
14 *
15 * You should have received a copy of the GNU General Public License
16 * along with this program.
17 */
18
19 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
20
21 #define DRVNAME "rtc-opal"
22
23 #include <linux/module.h>
24 #include <linux/err.h>
25 #include <linux/rtc.h>
26 #include <linux/delay.h>
27 #include <linux/bcd.h>
28 #include <linux/platform_device.h>
29 #include <linux/of.h>
30 #include <asm/opal.h>
31 #include <asm/firmware.h>
32
opal_to_tm(u32 y_m_d,u64 h_m_s_ms,struct rtc_time * tm)33 static void opal_to_tm(u32 y_m_d, u64 h_m_s_ms, struct rtc_time *tm)
34 {
35 tm->tm_year = ((bcd2bin(y_m_d >> 24) * 100) +
36 bcd2bin((y_m_d >> 16) & 0xff)) - 1900;
37 tm->tm_mon = bcd2bin((y_m_d >> 8) & 0xff) - 1;
38 tm->tm_mday = bcd2bin(y_m_d & 0xff);
39 tm->tm_hour = bcd2bin((h_m_s_ms >> 56) & 0xff);
40 tm->tm_min = bcd2bin((h_m_s_ms >> 48) & 0xff);
41 tm->tm_sec = bcd2bin((h_m_s_ms >> 40) & 0xff);
42
43 tm->tm_wday = -1;
44 }
45
tm_to_opal(struct rtc_time * tm,u32 * y_m_d,u64 * h_m_s_ms)46 static void tm_to_opal(struct rtc_time *tm, u32 *y_m_d, u64 *h_m_s_ms)
47 {
48 *y_m_d |= ((u32)bin2bcd((tm->tm_year + 1900) / 100)) << 24;
49 *y_m_d |= ((u32)bin2bcd((tm->tm_year + 1900) % 100)) << 16;
50 *y_m_d |= ((u32)bin2bcd((tm->tm_mon + 1))) << 8;
51 *y_m_d |= ((u32)bin2bcd(tm->tm_mday));
52
53 *h_m_s_ms |= ((u64)bin2bcd(tm->tm_hour)) << 56;
54 *h_m_s_ms |= ((u64)bin2bcd(tm->tm_min)) << 48;
55 *h_m_s_ms |= ((u64)bin2bcd(tm->tm_sec)) << 40;
56 }
57
opal_get_rtc_time(struct device * dev,struct rtc_time * tm)58 static int opal_get_rtc_time(struct device *dev, struct rtc_time *tm)
59 {
60 s64 rc = OPAL_BUSY;
61 int retries = 10;
62 u32 y_m_d;
63 u64 h_m_s_ms;
64 __be32 __y_m_d;
65 __be64 __h_m_s_ms;
66
67 while (rc == OPAL_BUSY || rc == OPAL_BUSY_EVENT) {
68 rc = opal_rtc_read(&__y_m_d, &__h_m_s_ms);
69 if (rc == OPAL_BUSY_EVENT) {
70 msleep(OPAL_BUSY_DELAY_MS);
71 opal_poll_events(NULL);
72 } else if (rc == OPAL_BUSY) {
73 msleep(OPAL_BUSY_DELAY_MS);
74 } else if (rc == OPAL_HARDWARE || rc == OPAL_INTERNAL_ERROR) {
75 if (retries--) {
76 msleep(10); /* Wait 10ms before retry */
77 rc = OPAL_BUSY; /* go around again */
78 }
79 }
80 }
81
82 if (rc != OPAL_SUCCESS)
83 return -EIO;
84
85 y_m_d = be32_to_cpu(__y_m_d);
86 h_m_s_ms = be64_to_cpu(__h_m_s_ms);
87 opal_to_tm(y_m_d, h_m_s_ms, tm);
88
89 return 0;
90 }
91
opal_set_rtc_time(struct device * dev,struct rtc_time * tm)92 static int opal_set_rtc_time(struct device *dev, struct rtc_time *tm)
93 {
94 s64 rc = OPAL_BUSY;
95 int retries = 10;
96 u32 y_m_d = 0;
97 u64 h_m_s_ms = 0;
98
99 tm_to_opal(tm, &y_m_d, &h_m_s_ms);
100
101 while (rc == OPAL_BUSY || rc == OPAL_BUSY_EVENT) {
102 rc = opal_rtc_write(y_m_d, h_m_s_ms);
103 if (rc == OPAL_BUSY_EVENT) {
104 msleep(OPAL_BUSY_DELAY_MS);
105 opal_poll_events(NULL);
106 } else if (rc == OPAL_BUSY) {
107 msleep(OPAL_BUSY_DELAY_MS);
108 } else if (rc == OPAL_HARDWARE || rc == OPAL_INTERNAL_ERROR) {
109 if (retries--) {
110 msleep(10); /* Wait 10ms before retry */
111 rc = OPAL_BUSY; /* go around again */
112 }
113 }
114 }
115
116 return rc == OPAL_SUCCESS ? 0 : -EIO;
117 }
118
119 /*
120 * TPO Timed Power-On
121 *
122 * TPO get/set OPAL calls care about the hour and min and to make it consistent
123 * with the rtc utility time conversion functions, we use the 'u64' to store
124 * its value and perform bit shift by 32 before use..
125 */
opal_get_tpo_time(struct device * dev,struct rtc_wkalrm * alarm)126 static int opal_get_tpo_time(struct device *dev, struct rtc_wkalrm *alarm)
127 {
128 __be32 __y_m_d, __h_m;
129 struct opal_msg msg;
130 int rc, token;
131 u64 h_m_s_ms;
132 u32 y_m_d;
133
134 token = opal_async_get_token_interruptible();
135 if (token < 0) {
136 if (token != -ERESTARTSYS)
137 pr_err("Failed to get the async token\n");
138
139 return token;
140 }
141
142 rc = opal_tpo_read(token, &__y_m_d, &__h_m);
143 if (rc != OPAL_ASYNC_COMPLETION) {
144 rc = -EIO;
145 goto exit;
146 }
147
148 rc = opal_async_wait_response(token, &msg);
149 if (rc) {
150 rc = -EIO;
151 goto exit;
152 }
153
154 rc = opal_get_async_rc(msg);
155 if (rc != OPAL_SUCCESS) {
156 rc = -EIO;
157 goto exit;
158 }
159
160 y_m_d = be32_to_cpu(__y_m_d);
161 h_m_s_ms = ((u64)be32_to_cpu(__h_m) << 32);
162
163 /* check if no alarm is set */
164 if (y_m_d == 0 && h_m_s_ms == 0) {
165 pr_debug("No alarm is set\n");
166 rc = -ENOENT;
167 goto exit;
168 } else {
169 pr_debug("Alarm set to %x %llx\n", y_m_d, h_m_s_ms);
170 }
171
172 opal_to_tm(y_m_d, h_m_s_ms, &alarm->time);
173
174 exit:
175 opal_async_release_token(token);
176 return rc;
177 }
178
179 /* Set Timed Power-On */
opal_set_tpo_time(struct device * dev,struct rtc_wkalrm * alarm)180 static int opal_set_tpo_time(struct device *dev, struct rtc_wkalrm *alarm)
181 {
182 u64 h_m_s_ms = 0;
183 struct opal_msg msg;
184 u32 y_m_d = 0;
185 int token, rc;
186
187 /* if alarm is enabled */
188 if (alarm->enabled) {
189 tm_to_opal(&alarm->time, &y_m_d, &h_m_s_ms);
190 pr_debug("Alarm set to %x %llx\n", y_m_d, h_m_s_ms);
191
192 } else {
193 pr_debug("Alarm getting disabled\n");
194 }
195
196 token = opal_async_get_token_interruptible();
197 if (token < 0) {
198 if (token != -ERESTARTSYS)
199 pr_err("Failed to get the async token\n");
200
201 return token;
202 }
203
204 /* TPO, we care about hour and minute */
205 rc = opal_tpo_write(token, y_m_d,
206 (u32)((h_m_s_ms >> 32) & 0xffff0000));
207 if (rc != OPAL_ASYNC_COMPLETION) {
208 rc = -EIO;
209 goto exit;
210 }
211
212 rc = opal_async_wait_response(token, &msg);
213 if (rc) {
214 rc = -EIO;
215 goto exit;
216 }
217
218 rc = opal_get_async_rc(msg);
219 if (rc != OPAL_SUCCESS)
220 rc = -EIO;
221
222 exit:
223 opal_async_release_token(token);
224 return rc;
225 }
226
opal_tpo_alarm_irq_enable(struct device * dev,unsigned int enabled)227 int opal_tpo_alarm_irq_enable(struct device *dev, unsigned int enabled)
228 {
229 struct rtc_wkalrm alarm = { .enabled = 0 };
230
231 /*
232 * TPO is automatically enabled when opal_set_tpo_time() is called with
233 * non-zero rtc-time. We only handle disable case which needs to be
234 * explicitly told to opal.
235 */
236 return enabled ? 0 : opal_set_tpo_time(dev, &alarm);
237 }
238
239 static struct rtc_class_ops opal_rtc_ops = {
240 .read_time = opal_get_rtc_time,
241 .set_time = opal_set_rtc_time,
242 };
243
opal_rtc_probe(struct platform_device * pdev)244 static int opal_rtc_probe(struct platform_device *pdev)
245 {
246 struct rtc_device *rtc;
247
248 if (pdev->dev.of_node &&
249 (of_property_read_bool(pdev->dev.of_node, "wakeup-source") ||
250 of_property_read_bool(pdev->dev.of_node, "has-tpo")/* legacy */)) {
251 device_set_wakeup_capable(&pdev->dev, true);
252 opal_rtc_ops.read_alarm = opal_get_tpo_time;
253 opal_rtc_ops.set_alarm = opal_set_tpo_time;
254 opal_rtc_ops.alarm_irq_enable = opal_tpo_alarm_irq_enable;
255 }
256
257 rtc = devm_rtc_device_register(&pdev->dev, DRVNAME, &opal_rtc_ops,
258 THIS_MODULE);
259 if (IS_ERR(rtc))
260 return PTR_ERR(rtc);
261
262 rtc->uie_unsupported = 1;
263
264 return 0;
265 }
266
267 static const struct of_device_id opal_rtc_match[] = {
268 {
269 .compatible = "ibm,opal-rtc",
270 },
271 { }
272 };
273 MODULE_DEVICE_TABLE(of, opal_rtc_match);
274
275 static const struct platform_device_id opal_rtc_driver_ids[] = {
276 {
277 .name = "opal-rtc",
278 },
279 { }
280 };
281 MODULE_DEVICE_TABLE(platform, opal_rtc_driver_ids);
282
283 static struct platform_driver opal_rtc_driver = {
284 .probe = opal_rtc_probe,
285 .id_table = opal_rtc_driver_ids,
286 .driver = {
287 .name = DRVNAME,
288 .of_match_table = opal_rtc_match,
289 },
290 };
291
opal_rtc_init(void)292 static int __init opal_rtc_init(void)
293 {
294 if (!firmware_has_feature(FW_FEATURE_OPAL))
295 return -ENODEV;
296
297 return platform_driver_register(&opal_rtc_driver);
298 }
299
opal_rtc_exit(void)300 static void __exit opal_rtc_exit(void)
301 {
302 platform_driver_unregister(&opal_rtc_driver);
303 }
304
305 MODULE_AUTHOR("Neelesh Gupta <neelegup@linux.vnet.ibm.com>");
306 MODULE_DESCRIPTION("IBM OPAL RTC driver");
307 MODULE_LICENSE("GPL");
308
309 module_init(opal_rtc_init);
310 module_exit(opal_rtc_exit);
311