kernel/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         GregorianDay(tm);
  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 = be64_to_cpu(msg.params[1]);
 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
 147 exit:
 148         opal_async_release_token(token);
 149         return rc;
 150 }
 151
 152 /* Set Timed Power-On */
 153 static int opal_set_tpo_time(struct device *dev, struct rtc_wkalrm *alarm)
 154 {
 155         u64 h_m_s_ms = 0, token;
 156         struct opal_msg msg;
 157         u32 y_m_d = 0;
 158         int 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 = be64_to_cpu(msg.params[1]);
 185         if (rc != OPAL_SUCCESS)
 186                 rc = -EIO;
 187
 188 exit:
 189         opal_async_release_token(token);
 190         return rc;
 191 }
 192
 193 static const struct rtc_class_ops opal_rtc_ops = {
 194         .read_time      = opal_get_rtc_time,
 195         .set_time       = opal_set_rtc_time,
 196         .read_alarm     = opal_get_tpo_time,
 197         .set_alarm      = opal_set_tpo_time,
 198 };
 199
 200 static int opal_rtc_probe(struct platform_device *pdev)
 201 {
 202         struct rtc_device *rtc;
 203
 204         if (pdev->dev.of_node && of_get_property(pdev->dev.of_node, "has-tpo",
 205                                                  NULL))
 206                 device_set_wakeup_capable(&pdev->dev, true);
 207
 208         rtc = devm_rtc_device_register(&pdev->dev, DRVNAME, &opal_rtc_ops,
 209                                        THIS_MODULE);
 210         if (IS_ERR(rtc))
 211                 return PTR_ERR(rtc);
 212
 213         rtc->uie_unsupported = 1;
 214
 215         return 0;
 216 }
 217
 218 static const struct of_device_id opal_rtc_match[] = {
 219         {
 220                 .compatible     = "ibm,opal-rtc",
 221         },
 222         { }
 223 };
 224 MODULE_DEVICE_TABLE(of, opal_rtc_match);
 225
 226 static const struct platform_device_id opal_rtc_driver_ids[] = {
 227         {
 228                 .name           = "opal-rtc",
 229         },
 230         { }
 231 };
 232 MODULE_DEVICE_TABLE(platform, opal_rtc_driver_ids);
 233
 234 static struct platform_driver opal_rtc_driver = {
 235         .probe          = opal_rtc_probe,
 236         .id_table       = opal_rtc_driver_ids,
 237         .driver         = {
 238                 .name           = DRVNAME,
 239                 .owner          = THIS_MODULE,
 240                 .of_match_table = opal_rtc_match,
 241         },
 242 };
 243
 244 static int __init opal_rtc_init(void)
 245 {
 246         if (!firmware_has_feature(FW_FEATURE_OPAL))
 247                 return -ENODEV;
 248
 249         return platform_driver_register(&opal_rtc_driver);
 250 }
 251
 252 static void __exit opal_rtc_exit(void)
 253 {
 254         platform_driver_unregister(&opal_rtc_driver);
 255 }
 256
 257 MODULE_AUTHOR("Neelesh Gupta <neelegup@linux.vnet.ibm.com>");
 258 MODULE_DESCRIPTION("IBM OPAL RTC driver");
 259 MODULE_LICENSE("GPL");
 260
 261 module_init(opal_rtc_init);
 262 module_exit(opal_rtc_exit);