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	long rc = OPAL_BUSY;
 61	u32 y_m_d;
 62	u64 h_m_s_ms;
 63	__be32 __y_m_d;
 64	__be64 __h_m_s_ms;
 65
 66	while (rc == OPAL_BUSY || rc == OPAL_BUSY_EVENT) {
 67		rc = opal_rtc_read(&__y_m_d, &__h_m_s_ms);
 68		if (rc == OPAL_BUSY_EVENT)
 69			opal_poll_events(NULL);
 70		else
 71			msleep(10);
 72	}
 73
 74	if (rc != OPAL_SUCCESS)
 75		return -EIO;
 76
 77	y_m_d = be32_to_cpu(__y_m_d);
 78	h_m_s_ms = be64_to_cpu(__h_m_s_ms);
 79	opal_to_tm(y_m_d, h_m_s_ms, tm);
 80
 81	return 0;
 82}
 83
 84static int opal_set_rtc_time(struct device *dev, struct rtc_time *tm)
 85{
 86	long rc = OPAL_BUSY;
 87	u32 y_m_d = 0;
 88	u64 h_m_s_ms = 0;
 89
 90	tm_to_opal(tm, &y_m_d, &h_m_s_ms);
 91	while (rc == OPAL_BUSY || rc == OPAL_BUSY_EVENT) {
 92		rc = opal_rtc_write(y_m_d, h_m_s_ms);
 93		if (rc == OPAL_BUSY_EVENT)
 94			opal_poll_events(NULL);
 95		else
 96			msleep(10);
 97	}
 98
 99	return rc == OPAL_SUCCESS ? 0 : -EIO;
100}
101
102/*
103 * TPO	Timed Power-On
104 *
105 * TPO get/set OPAL calls care about the hour and min and to make it consistent
106 * with the rtc utility time conversion functions, we use the 'u64' to store
107 * its value and perform bit shift by 32 before use..
108 */
109static int opal_get_tpo_time(struct device *dev, struct rtc_wkalrm *alarm)
110{
111	__be32 __y_m_d, __h_m;
112	struct opal_msg msg;
113	int rc, token;
114	u64 h_m_s_ms;
115	u32 y_m_d;
116
117	token = opal_async_get_token_interruptible();
118	if (token < 0) {
119		if (token != -ERESTARTSYS)
120			pr_err("Failed to get the async token\n");
121
122		return token;
123	}
124
125	rc = opal_tpo_read(token, &__y_m_d, &__h_m);
126	if (rc != OPAL_ASYNC_COMPLETION) {
127		rc = -EIO;
128		goto exit;
129	}
130
131	rc = opal_async_wait_response(token, &msg);
132	if (rc) {
133		rc = -EIO;
134		goto exit;
135	}
136
137	rc = opal_get_async_rc(msg);
138	if (rc != OPAL_SUCCESS) {
139		rc = -EIO;
140		goto exit;
141	}
142
143	y_m_d = be32_to_cpu(__y_m_d);
144	h_m_s_ms = ((u64)be32_to_cpu(__h_m) << 32);
145	opal_to_tm(y_m_d, h_m_s_ms, &alarm->time);
146
147exit:
148	opal_async_release_token(token);
149	return rc;
150}
151
152/* Set Timed Power-On */
153static int opal_set_tpo_time(struct device *dev, struct rtc_wkalrm *alarm)
154{
155	u64 h_m_s_ms = 0;
156	struct opal_msg msg;
157	u32 y_m_d = 0;
158	int token, rc;
159
160	tm_to_opal(&alarm->time, &y_m_d, &h_m_s_ms);
161
162	token = opal_async_get_token_interruptible();
163	if (token < 0) {
164		if (token != -ERESTARTSYS)
165			pr_err("Failed to get the async token\n");
166
167		return token;
168	}
169
170	/* TPO, we care about hour and minute */
171	rc = opal_tpo_write(token, y_m_d,
172			    (u32)((h_m_s_ms >> 32) & 0xffff0000));
173	if (rc != OPAL_ASYNC_COMPLETION) {
174		rc = -EIO;
175		goto exit;
176	}
177
178	rc = opal_async_wait_response(token, &msg);
179	if (rc) {
180		rc = -EIO;
181		goto exit;
182	}
183
184	rc = opal_get_async_rc(msg);
185	if (rc != OPAL_SUCCESS)
186		rc = -EIO;
187
188exit:
189	opal_async_release_token(token);
190	return rc;
191}
192
193static struct rtc_class_ops opal_rtc_ops = {
194	.read_time	= opal_get_rtc_time,
195	.set_time	= opal_set_rtc_time,
196};
197
198static int opal_rtc_probe(struct platform_device *pdev)
199{
200	struct rtc_device *rtc;
201
202	if (pdev->dev.of_node &&
203	    (of_property_read_bool(pdev->dev.of_node, "wakeup-source") ||
204	     of_property_read_bool(pdev->dev.of_node, "has-tpo")/* legacy */)) {
205		device_set_wakeup_capable(&pdev->dev, true);
206		opal_rtc_ops.read_alarm	= opal_get_tpo_time;
207		opal_rtc_ops.set_alarm = opal_set_tpo_time;
208	}
209
210	rtc = devm_rtc_device_register(&pdev->dev, DRVNAME, &opal_rtc_ops,
211				       THIS_MODULE);
212	if (IS_ERR(rtc))
213		return PTR_ERR(rtc);
214
215	rtc->uie_unsupported = 1;
216
217	return 0;
218}
219
220static const struct of_device_id opal_rtc_match[] = {
221	{
222		.compatible	= "ibm,opal-rtc",
223	},
224	{ }
225};
226MODULE_DEVICE_TABLE(of, opal_rtc_match);
227
228static const struct platform_device_id opal_rtc_driver_ids[] = {
229	{
230		.name		= "opal-rtc",
231	},
232	{ }
233};
234MODULE_DEVICE_TABLE(platform, opal_rtc_driver_ids);
235
236static struct platform_driver opal_rtc_driver = {
237	.probe		= opal_rtc_probe,
238	.id_table	= opal_rtc_driver_ids,
239	.driver		= {
240		.name		= DRVNAME,
241		.of_match_table	= opal_rtc_match,
242	},
243};
244
245static int __init opal_rtc_init(void)
246{
247	if (!firmware_has_feature(FW_FEATURE_OPAL))
248		return -ENODEV;
249
250	return platform_driver_register(&opal_rtc_driver);
251}
252
253static void __exit opal_rtc_exit(void)
254{
255	platform_driver_unregister(&opal_rtc_driver);
256}
257
258MODULE_AUTHOR("Neelesh Gupta <neelegup@linux.vnet.ibm.com>");
259MODULE_DESCRIPTION("IBM OPAL RTC driver");
260MODULE_LICENSE("GPL");
261
262module_init(opal_rtc_init);
263module_exit(opal_rtc_exit);