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