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
 33static 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
 46static 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
 58static 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
 92static 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 */
126static 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
174exit:
175	opal_async_release_token(token);
176	return rc;
177}
178
179/* Set Timed Power-On */
180static 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
222exit:
223	opal_async_release_token(token);
224	return rc;
225}
226
227int 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
239static struct rtc_class_ops opal_rtc_ops = {
240	.read_time	= opal_get_rtc_time,
241	.set_time	= opal_set_rtc_time,
242};
243
244static 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
267static const struct of_device_id opal_rtc_match[] = {
268	{
269		.compatible	= "ibm,opal-rtc",
270	},
271	{ }
272};
273MODULE_DEVICE_TABLE(of, opal_rtc_match);
274
275static const struct platform_device_id opal_rtc_driver_ids[] = {
276	{
277		.name		= "opal-rtc",
278	},
279	{ }
280};
281MODULE_DEVICE_TABLE(platform, opal_rtc_driver_ids);
282
283static 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
292static 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
300static void __exit opal_rtc_exit(void)
301{
302	platform_driver_unregister(&opal_rtc_driver);
303}
304
305MODULE_AUTHOR("Neelesh Gupta <neelegup@linux.vnet.ibm.com>");
306MODULE_DESCRIPTION("IBM OPAL RTC driver");
307MODULE_LICENSE("GPL");
308
309module_init(opal_rtc_init);
310module_exit(opal_rtc_exit);