1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 * IBM OPAL RTC driver
4 * Copyright (C) 2014 IBM
5 */
6
7 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
8
9 #define DRVNAME "rtc-opal"
10
11 #include <linux/module.h>
12 #include <linux/err.h>
13 #include <linux/rtc.h>
14 #include <linux/delay.h>
15 #include <linux/bcd.h>
16 #include <linux/platform_device.h>
17 #include <linux/of.h>
18 #include <asm/opal.h>
19 #include <asm/firmware.h>
20
opal_to_tm(u32 y_m_d,u64 h_m_s_ms,struct rtc_time * tm)21 static void opal_to_tm(u32 y_m_d, u64 h_m_s_ms, struct rtc_time *tm)
22 {
23 tm->tm_year = ((bcd2bin(y_m_d >> 24) * 100) +
24 bcd2bin((y_m_d >> 16) & 0xff)) - 1900;
25 tm->tm_mon = bcd2bin((y_m_d >> 8) & 0xff) - 1;
26 tm->tm_mday = bcd2bin(y_m_d & 0xff);
27 tm->tm_hour = bcd2bin((h_m_s_ms >> 56) & 0xff);
28 tm->tm_min = bcd2bin((h_m_s_ms >> 48) & 0xff);
29 tm->tm_sec = bcd2bin((h_m_s_ms >> 40) & 0xff);
30
31 tm->tm_wday = -1;
32 }
33
tm_to_opal(struct rtc_time * tm,u32 * y_m_d,u64 * h_m_s_ms)34 static void tm_to_opal(struct rtc_time *tm, u32 *y_m_d, u64 *h_m_s_ms)
35 {
36 *y_m_d |= ((u32)bin2bcd((tm->tm_year + 1900) / 100)) << 24;
37 *y_m_d |= ((u32)bin2bcd((tm->tm_year + 1900) % 100)) << 16;
38 *y_m_d |= ((u32)bin2bcd((tm->tm_mon + 1))) << 8;
39 *y_m_d |= ((u32)bin2bcd(tm->tm_mday));
40
41 *h_m_s_ms |= ((u64)bin2bcd(tm->tm_hour)) << 56;
42 *h_m_s_ms |= ((u64)bin2bcd(tm->tm_min)) << 48;
43 *h_m_s_ms |= ((u64)bin2bcd(tm->tm_sec)) << 40;
44 }
45
opal_get_rtc_time(struct device * dev,struct rtc_time * tm)46 static int opal_get_rtc_time(struct device *dev, struct rtc_time *tm)
47 {
48 s64 rc = OPAL_BUSY;
49 int retries = 10;
50 u32 y_m_d;
51 u64 h_m_s_ms;
52 __be32 __y_m_d;
53 __be64 __h_m_s_ms;
54
55 while (rc == OPAL_BUSY || rc == OPAL_BUSY_EVENT) {
56 rc = opal_rtc_read(&__y_m_d, &__h_m_s_ms);
57 if (rc == OPAL_BUSY_EVENT) {
58 msleep(OPAL_BUSY_DELAY_MS);
59 opal_poll_events(NULL);
60 } else if (rc == OPAL_BUSY) {
61 msleep(OPAL_BUSY_DELAY_MS);
62 } else if (rc == OPAL_HARDWARE || rc == OPAL_INTERNAL_ERROR) {
63 if (retries--) {
64 msleep(10); /* Wait 10ms before retry */
65 rc = OPAL_BUSY; /* go around again */
66 }
67 }
68 }
69
70 if (rc != OPAL_SUCCESS)
71 return -EIO;
72
73 y_m_d = be32_to_cpu(__y_m_d);
74 h_m_s_ms = be64_to_cpu(__h_m_s_ms);
75 opal_to_tm(y_m_d, h_m_s_ms, tm);
76
77 return 0;
78 }
79
opal_set_rtc_time(struct device * dev,struct rtc_time * tm)80 static int opal_set_rtc_time(struct device *dev, struct rtc_time *tm)
81 {
82 s64 rc = OPAL_BUSY;
83 int retries = 10;
84 u32 y_m_d = 0;
85 u64 h_m_s_ms = 0;
86
87 tm_to_opal(tm, &y_m_d, &h_m_s_ms);
88
89 while (rc == OPAL_BUSY || rc == OPAL_BUSY_EVENT) {
90 rc = opal_rtc_write(y_m_d, h_m_s_ms);
91 if (rc == OPAL_BUSY_EVENT) {
92 msleep(OPAL_BUSY_DELAY_MS);
93 opal_poll_events(NULL);
94 } else if (rc == OPAL_BUSY) {
95 msleep(OPAL_BUSY_DELAY_MS);
96 } else if (rc == OPAL_HARDWARE || rc == OPAL_INTERNAL_ERROR) {
97 if (retries--) {
98 msleep(10); /* Wait 10ms before retry */
99 rc = OPAL_BUSY; /* go around again */
100 }
101 }
102 }
103
104 return rc == OPAL_SUCCESS ? 0 : -EIO;
105 }
106
107 /*
108 * TPO Timed Power-On
109 *
110 * TPO get/set OPAL calls care about the hour and min and to make it consistent
111 * with the rtc utility time conversion functions, we use the 'u64' to store
112 * its value and perform bit shift by 32 before use..
113 */
opal_get_tpo_time(struct device * dev,struct rtc_wkalrm * alarm)114 static int opal_get_tpo_time(struct device *dev, struct rtc_wkalrm *alarm)
115 {
116 __be32 __y_m_d, __h_m;
117 struct opal_msg msg;
118 int rc, token;
119 u64 h_m_s_ms;
120 u32 y_m_d;
121
122 token = opal_async_get_token_interruptible();
123 if (token < 0) {
124 if (token != -ERESTARTSYS)
125 pr_err("Failed to get the async token\n");
126
127 return token;
128 }
129
130 rc = opal_tpo_read(token, &__y_m_d, &__h_m);
131 if (rc != OPAL_ASYNC_COMPLETION) {
132 rc = -EIO;
133 goto exit;
134 }
135
136 rc = opal_async_wait_response(token, &msg);
137 if (rc) {
138 rc = -EIO;
139 goto exit;
140 }
141
142 rc = opal_get_async_rc(msg);
143 if (rc != OPAL_SUCCESS) {
144 rc = -EIO;
145 goto exit;
146 }
147
148 y_m_d = be32_to_cpu(__y_m_d);
149 h_m_s_ms = ((u64)be32_to_cpu(__h_m) << 32);
150
151 /* check if no alarm is set */
152 if (y_m_d == 0 && h_m_s_ms == 0) {
153 pr_debug("No alarm is set\n");
154 rc = -ENOENT;
155 goto exit;
156 } else {
157 pr_debug("Alarm set to %x %llx\n", y_m_d, h_m_s_ms);
158 }
159
160 opal_to_tm(y_m_d, h_m_s_ms, &alarm->time);
161
162 exit:
163 opal_async_release_token(token);
164 return rc;
165 }
166
167 /* Set Timed Power-On */
opal_set_tpo_time(struct device * dev,struct rtc_wkalrm * alarm)168 static int opal_set_tpo_time(struct device *dev, struct rtc_wkalrm *alarm)
169 {
170 u64 h_m_s_ms = 0;
171 struct opal_msg msg;
172 u32 y_m_d = 0;
173 int token, rc;
174
175 /* if alarm is enabled */
176 if (alarm->enabled) {
177 tm_to_opal(&alarm->time, &y_m_d, &h_m_s_ms);
178 pr_debug("Alarm set to %x %llx\n", y_m_d, h_m_s_ms);
179
180 } else {
181 pr_debug("Alarm getting disabled\n");
182 }
183
184 token = opal_async_get_token_interruptible();
185 if (token < 0) {
186 if (token != -ERESTARTSYS)
187 pr_err("Failed to get the async token\n");
188
189 return token;
190 }
191
192 /* TPO, we care about hour and minute */
193 rc = opal_tpo_write(token, y_m_d,
194 (u32)((h_m_s_ms >> 32) & 0xffff0000));
195 if (rc != OPAL_ASYNC_COMPLETION) {
196 rc = -EIO;
197 goto exit;
198 }
199
200 rc = opal_async_wait_response(token, &msg);
201 if (rc) {
202 rc = -EIO;
203 goto exit;
204 }
205
206 rc = opal_get_async_rc(msg);
207 if (rc != OPAL_SUCCESS)
208 rc = -EIO;
209
210 exit:
211 opal_async_release_token(token);
212 return rc;
213 }
214
opal_tpo_alarm_irq_enable(struct device * dev,unsigned int enabled)215 static int opal_tpo_alarm_irq_enable(struct device *dev, unsigned int enabled)
216 {
217 struct rtc_wkalrm alarm = { .enabled = 0 };
218
219 /*
220 * TPO is automatically enabled when opal_set_tpo_time() is called with
221 * non-zero rtc-time. We only handle disable case which needs to be
222 * explicitly told to opal.
223 */
224 return enabled ? 0 : opal_set_tpo_time(dev, &alarm);
225 }
226
227 static const struct rtc_class_ops opal_rtc_ops = {
228 .read_time = opal_get_rtc_time,
229 .set_time = opal_set_rtc_time,
230 .read_alarm = opal_get_tpo_time,
231 .set_alarm = opal_set_tpo_time,
232 .alarm_irq_enable = opal_tpo_alarm_irq_enable,
233 };
234
opal_rtc_probe(struct platform_device * pdev)235 static int opal_rtc_probe(struct platform_device *pdev)
236 {
237 struct rtc_device *rtc;
238
239 rtc = devm_rtc_allocate_device(&pdev->dev);
240 if (IS_ERR(rtc))
241 return PTR_ERR(rtc);
242
243 if (pdev->dev.of_node &&
244 (of_property_read_bool(pdev->dev.of_node, "wakeup-source") ||
245 of_property_read_bool(pdev->dev.of_node, "has-tpo")/* legacy */))
246 device_set_wakeup_capable(&pdev->dev, true);
247 else
248 clear_bit(RTC_FEATURE_ALARM, rtc->features);
249
250 rtc->ops = &opal_rtc_ops;
251 rtc->range_min = RTC_TIMESTAMP_BEGIN_0000;
252 rtc->range_max = RTC_TIMESTAMP_END_9999;
253 rtc->uie_unsupported = 1;
254
255 return devm_rtc_register_device(rtc);
256 }
257
258 static const struct of_device_id opal_rtc_match[] = {
259 {
260 .compatible = "ibm,opal-rtc",
261 },
262 { }
263 };
264 MODULE_DEVICE_TABLE(of, opal_rtc_match);
265
266 static const struct platform_device_id opal_rtc_driver_ids[] = {
267 {
268 .name = "opal-rtc",
269 },
270 { }
271 };
272 MODULE_DEVICE_TABLE(platform, opal_rtc_driver_ids);
273
274 static struct platform_driver opal_rtc_driver = {
275 .probe = opal_rtc_probe,
276 .id_table = opal_rtc_driver_ids,
277 .driver = {
278 .name = DRVNAME,
279 .of_match_table = opal_rtc_match,
280 },
281 };
282
opal_rtc_init(void)283 static int __init opal_rtc_init(void)
284 {
285 if (!firmware_has_feature(FW_FEATURE_OPAL))
286 return -ENODEV;
287
288 return platform_driver_register(&opal_rtc_driver);
289 }
290
opal_rtc_exit(void)291 static void __exit opal_rtc_exit(void)
292 {
293 platform_driver_unregister(&opal_rtc_driver);
294 }
295
296 MODULE_AUTHOR("Neelesh Gupta <neelegup@linux.vnet.ibm.com>");
297 MODULE_DESCRIPTION("IBM OPAL RTC driver");
298 MODULE_LICENSE("GPL");
299
300 module_init(opal_rtc_init);
301 module_exit(opal_rtc_exit);
302