drivers/rtc/rtc-opal.c

   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
  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
  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
  58 static 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
  84 static 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  */
 109 static 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
 146         /* check if no alarm is set */
 147         if (y_m_d == 0 && h_m_s_ms == 0) {
 148                 pr_debug("No alarm is set\n");
 149                 rc = -ENOENT;
 150                 goto exit;
 151         } else {
 152                 pr_debug("Alarm set to %x %llx\n", y_m_d, h_m_s_ms);
 153         }
 154
 155         opal_to_tm(y_m_d, h_m_s_ms, &alarm->time);
 156
 157 exit:
 158         opal_async_release_token(token);
 159         return rc;
 160 }
 161
 162 /* Set Timed Power-On */
 163 static int opal_set_tpo_time(struct device *dev, struct rtc_wkalrm *alarm)
 164 {
 165         u64 h_m_s_ms = 0;
 166         struct opal_msg msg;
 167         u32 y_m_d = 0;
 168         int token, rc;
 169
 170         /* if alarm is enabled */
 171         if (alarm->enabled) {
 172                 tm_to_opal(&alarm->time, &y_m_d, &h_m_s_ms);
 173                 pr_debug("Alarm set to %x %llx\n", y_m_d, h_m_s_ms);
 174
 175         } else {
 176                 pr_debug("Alarm getting disabled\n");
 177         }
 178
 179         token = opal_async_get_token_interruptible();
 180         if (token < 0) {
 181                 if (token != -ERESTARTSYS)
 182                         pr_err("Failed to get the async token\n");
 183
 184                 return token;
 185         }
 186
 187         /* TPO, we care about hour and minute */
 188         rc = opal_tpo_write(token, y_m_d,
 189                             (u32)((h_m_s_ms >> 32) & 0xffff0000));
 190         if (rc != OPAL_ASYNC_COMPLETION) {
 191                 rc = -EIO;
 192                 goto exit;
 193         }
 194
 195         rc = opal_async_wait_response(token, &msg);
 196         if (rc) {
 197                 rc = -EIO;
 198                 goto exit;
 199         }
 200
 201         rc = opal_get_async_rc(msg);
 202         if (rc != OPAL_SUCCESS)
 203                 rc = -EIO;
 204
 205 exit:
 206         opal_async_release_token(token);
 207         return rc;
 208 }
 209
 210 int opal_tpo_alarm_irq_enable(struct device *dev, unsigned int enabled)
 211 {
 212         struct rtc_wkalrm alarm = { .enabled = 0 };
 213
 214         /*
 215          * TPO is automatically enabled when opal_set_tpo_time() is called with
 216          * non-zero rtc-time. We only handle disable case which needs to be
 217          * explicitly told to opal.
 218          */
 219         return enabled ? 0 : opal_set_tpo_time(dev, &alarm);
 220 }
 221
 222 static struct rtc_class_ops opal_rtc_ops = {
 223         .read_time      = opal_get_rtc_time,
 224         .set_time       = opal_set_rtc_time,
 225 };
 226
 227 static int opal_rtc_probe(struct platform_device *pdev)
 228 {
 229         struct rtc_device *rtc;
 230
 231         if (pdev->dev.of_node &&
 232             (of_property_read_bool(pdev->dev.of_node, "wakeup-source") ||
 233              of_property_read_bool(pdev->dev.of_node, "has-tpo")/* legacy */)) {
 234                 device_set_wakeup_capable(&pdev->dev, true);
 235                 opal_rtc_ops.read_alarm = opal_get_tpo_time;
 236                 opal_rtc_ops.set_alarm = opal_set_tpo_time;
 237                 opal_rtc_ops.alarm_irq_enable = opal_tpo_alarm_irq_enable;
 238         }
 239
 240         rtc = devm_rtc_device_register(&pdev->dev, DRVNAME, &opal_rtc_ops,
 241                                        THIS_MODULE);
 242         if (IS_ERR(rtc))
 243                 return PTR_ERR(rtc);
 244
 245         rtc->uie_unsupported = 1;
 246
 247         return 0;
 248 }
 249
 250 static const struct of_device_id opal_rtc_match[] = {
 251         {
 252                 .compatible     = "ibm,opal-rtc",
 253         },
 254         { }
 255 };
 256 MODULE_DEVICE_TABLE(of, opal_rtc_match);
 257
 258 static const struct platform_device_id opal_rtc_driver_ids[] = {
 259         {
 260                 .name           = "opal-rtc",
 261         },
 262         { }
 263 };
 264 MODULE_DEVICE_TABLE(platform, opal_rtc_driver_ids);
 265
 266 static struct platform_driver opal_rtc_driver = {
 267         .probe          = opal_rtc_probe,
 268         .id_table       = opal_rtc_driver_ids,
 269         .driver         = {
 270                 .name           = DRVNAME,
 271                 .of_match_table = opal_rtc_match,
 272         },
 273 };
 274
 275 static int __init opal_rtc_init(void)
 276 {
 277         if (!firmware_has_feature(FW_FEATURE_OPAL))
 278                 return -ENODEV;
 279
 280         return platform_driver_register(&opal_rtc_driver);
 281 }
 282
 283 static void __exit opal_rtc_exit(void)
 284 {
 285         platform_driver_unregister(&opal_rtc_driver);
 286 }
 287
 288 MODULE_AUTHOR("Neelesh Gupta <neelegup@linux.vnet.ibm.com>");
 289 MODULE_DESCRIPTION("IBM OPAL RTC driver");
 290 MODULE_LICENSE("GPL");
 291
 292 module_init(opal_rtc_init);
 293 module_exit(opal_rtc_exit);