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 DRVNAME         "rtc-opal"
  20 #define pr_fmt(fmt)     DRVNAME ": " fmt
  21
  22 #include <linux/module.h>
  23 #include <linux/err.h>
  24 #include <linux/rtc.h>
  25 #include <linux/delay.h>
  26 #include <linux/bcd.h>
  27 #include <linux/platform_device.h>
  28 #include <linux/of.h>
  29 #include <asm/opal.h>
  30 #include <asm/firmware.h>
  31
  32 static void opal_to_tm(u32 y_m_d, u64 h_m_s_ms, struct rtc_time *tm)
  33 {
  34         tm->tm_year = ((bcd2bin(y_m_d >> 24) * 100) +
  35                        bcd2bin((y_m_d >> 16) & 0xff)) - 1900;
  36         tm->tm_mon  = bcd2bin((y_m_d >> 8) & 0xff) - 1;
  37         tm->tm_mday = bcd2bin(y_m_d & 0xff);
  38         tm->tm_hour = bcd2bin((h_m_s_ms >> 56) & 0xff);
  39         tm->tm_min  = bcd2bin((h_m_s_ms >> 48) & 0xff);
  40         tm->tm_sec  = bcd2bin((h_m_s_ms >> 40) & 0xff);
  41
  42         GregorianDay(tm);
  43 }
  44
  45 static void tm_to_opal(struct rtc_time *tm, u32 *y_m_d, u64 *h_m_s_ms)
  46 {
  47         *y_m_d |= ((u32)bin2bcd((tm->tm_year + 1900) / 100)) << 24;
  48         *y_m_d |= ((u32)bin2bcd((tm->tm_year + 1900) % 100)) << 16;
  49         *y_m_d |= ((u32)bin2bcd((tm->tm_mon + 1))) << 8;
  50         *y_m_d |= ((u32)bin2bcd(tm->tm_mday));
  51
  52         *h_m_s_ms |= ((u64)bin2bcd(tm->tm_hour)) << 56;
  53         *h_m_s_ms |= ((u64)bin2bcd(tm->tm_min)) << 48;
  54         *h_m_s_ms |= ((u64)bin2bcd(tm->tm_sec)) << 40;
  55 }
  56
  57 static int opal_get_rtc_time(struct device *dev, struct rtc_time *tm)
  58 {
  59         long rc = OPAL_BUSY;
  60         u32 y_m_d;
  61         u64 h_m_s_ms;
  62         __be32 __y_m_d;
  63         __be64 __h_m_s_ms;
  64
  65         while (rc == OPAL_BUSY || rc == OPAL_BUSY_EVENT) {
  66                 rc = opal_rtc_read(&__y_m_d, &__h_m_s_ms);
  67                 if (rc == OPAL_BUSY_EVENT)
  68                         opal_poll_events(NULL);
  69                 else
  70                         msleep(10);
  71         }
  72
  73         if (rc != OPAL_SUCCESS)
  74                 return -EIO;
  75
  76         y_m_d = be32_to_cpu(__y_m_d);
  77         h_m_s_ms = be64_to_cpu(__h_m_s_ms);
  78         opal_to_tm(y_m_d, h_m_s_ms, tm);
  79
  80         return 0;
  81 }
  82
  83 static int opal_set_rtc_time(struct device *dev, struct rtc_time *tm)
  84 {
  85         long rc = OPAL_BUSY;
  86         u32 y_m_d = 0;
  87         u64 h_m_s_ms = 0;
  88
  89         tm_to_opal(tm, &y_m_d, &h_m_s_ms);
  90         while (rc == OPAL_BUSY || rc == OPAL_BUSY_EVENT) {
  91                 rc = opal_rtc_write(y_m_d, h_m_s_ms);
  92                 if (rc == OPAL_BUSY_EVENT)
  93                         opal_poll_events(NULL);
  94                 else
  95                         msleep(10);
  96         }
  97
  98         return rc == OPAL_SUCCESS ? 0 : -EIO;
  99 }
 100
 101 /*
 102  * TPO  Timed Power-On
 103  *
 104  * TPO get/set OPAL calls care about the hour and min and to make it consistent
 105  * with the rtc utility time conversion functions, we use the 'u64' to store
 106  * its value and perform bit shift by 32 before use..
 107  */
 108 static int opal_get_tpo_time(struct device *dev, struct rtc_wkalrm *alarm)
 109 {
 110         __be32 __y_m_d, __h_m;
 111         struct opal_msg msg;
 112         int rc, token;
 113         u64 h_m_s_ms;
 114         u32 y_m_d;
 115
 116         token = opal_async_get_token_interruptible();
 117         if (token < 0) {
 118                 if (token != -ERESTARTSYS)
 119                         pr_err("Failed to get the async token\n");
 120
 121                 return token;
 122         }
 123
 124         rc = opal_tpo_read(token, &__y_m_d, &__h_m);
 125         if (rc != OPAL_ASYNC_COMPLETION) {
 126                 rc = -EIO;
 127                 goto exit;
 128         }
 129
 130         rc = opal_async_wait_response(token, &msg);
 131         if (rc) {
 132                 rc = -EIO;
 133                 goto exit;
 134         }
 135
 136         rc = be64_to_cpu(msg.params[1]);
 137         if (rc != OPAL_SUCCESS) {
 138                 rc = -EIO;
 139                 goto exit;
 140         }
 141
 142         y_m_d = be32_to_cpu(__y_m_d);
 143         h_m_s_ms = ((u64)be32_to_cpu(__h_m) << 32);
 144         opal_to_tm(y_m_d, h_m_s_ms, &alarm->time);
 145
 146 exit:
 147         opal_async_release_token(token);
 148         return rc;
 149 }
 150
 151 /* Set Timed Power-On */
 152 static int opal_set_tpo_time(struct device *dev, struct rtc_wkalrm *alarm)
 153 {
 154         u64 h_m_s_ms = 0, token;
 155         struct opal_msg msg;
 156         u32 y_m_d = 0;
 157         int rc;
 158
 159         tm_to_opal(&alarm->time, &y_m_d, &h_m_s_ms);
 160
 161         token = opal_async_get_token_interruptible();
 162         if (token < 0) {
 163                 if (token != -ERESTARTSYS)
 164                         pr_err("Failed to get the async token\n");
 165
 166                 return token;
 167         }
 168
 169         /* TPO, we care about hour and minute */
 170         rc = opal_tpo_write(token, y_m_d,
 171                             (u32)((h_m_s_ms >> 32) & 0xffff0000));
 172         if (rc != OPAL_ASYNC_COMPLETION) {
 173                 rc = -EIO;
 174                 goto exit;
 175         }
 176
 177         rc = opal_async_wait_response(token, &msg);
 178         if (rc) {
 179                 rc = -EIO;
 180                 goto exit;
 181         }
 182
 183         rc = be64_to_cpu(msg.params[1]);
 184         if (rc != OPAL_SUCCESS)
 185                 rc = -EIO;
 186
 187 exit:
 188         opal_async_release_token(token);
 189         return rc;
 190 }
 191
 192 static const struct rtc_class_ops opal_rtc_ops = {
 193         .read_time      = opal_get_rtc_time,
 194         .set_time       = opal_set_rtc_time,
 195         .read_alarm     = opal_get_tpo_time,
 196         .set_alarm      = opal_set_tpo_time,
 197 };
 198
 199 static int opal_rtc_probe(struct platform_device *pdev)
 200 {
 201         struct rtc_device *rtc;
 202
 203         if (pdev->dev.of_node && of_get_property(pdev->dev.of_node, "has-tpo",
 204                                                  NULL))
 205                 device_set_wakeup_capable(&pdev->dev, true);
 206
 207         rtc = devm_rtc_device_register(&pdev->dev, DRVNAME, &opal_rtc_ops,
 208                                        THIS_MODULE);
 209         if (IS_ERR(rtc))
 210                 return PTR_ERR(rtc);
 211
 212         rtc->uie_unsupported = 1;
 213
 214         return 0;
 215 }
 216
 217 static const struct of_device_id opal_rtc_match[] = {
 218         {
 219                 .compatible     = "ibm,opal-rtc",
 220         },
 221         { }
 222 };
 223 MODULE_DEVICE_TABLE(of, opal_rtc_match);
 224
 225 static const struct platform_device_id opal_rtc_driver_ids[] = {
 226         {
 227                 .name           = "opal-rtc",
 228         },
 229         { }
 230 };
 231 MODULE_DEVICE_TABLE(platform, opal_rtc_driver_ids);
 232
 233 static struct platform_driver opal_rtc_driver = {
 234         .probe          = opal_rtc_probe,
 235         .id_table       = opal_rtc_driver_ids,
 236         .driver         = {
 237                 .name           = DRVNAME,
 238                 .owner          = THIS_MODULE,
 239                 .of_match_table = opal_rtc_match,
 240         },
 241 };
 242
 243 static int __init opal_rtc_init(void)
 244 {
 245         if (!firmware_has_feature(FW_FEATURE_OPAL))
 246                 return -ENODEV;
 247
 248         return platform_driver_register(&opal_rtc_driver);
 249 }
 250
 251 static void __exit opal_rtc_exit(void)
 252 {
 253         platform_driver_unregister(&opal_rtc_driver);
 254 }
 255
 256 MODULE_AUTHOR("Neelesh Gupta <neelegup@linux.vnet.ibm.com>");
 257 MODULE_DESCRIPTION("IBM OPAL RTC driver");
 258 MODULE_LICENSE("GPL");
 259
 260 module_init(opal_rtc_init);
 261 module_exit(opal_rtc_exit);