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         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                         opal_poll_events(NULL);
  71                 else if (retries-- && (rc == OPAL_HARDWARE
  72                                        || rc == OPAL_INTERNAL_ERROR))
  73                         msleep(10);
  74                 else if (rc != OPAL_BUSY && rc != OPAL_BUSY_EVENT)
  75                         break;
  76         }
  77
  78         if (rc != OPAL_SUCCESS)
  79                 return -EIO;
  80
  81         y_m_d = be32_to_cpu(__y_m_d);
  82         h_m_s_ms = be64_to_cpu(__h_m_s_ms);
  83         opal_to_tm(y_m_d, h_m_s_ms, tm);
  84
  85         return 0;
  86 }
  87
  88 static int opal_set_rtc_time(struct device *dev, struct rtc_time *tm)
  89 {
  90         long rc = OPAL_BUSY;
  91         int retries = 10;
  92         u32 y_m_d = 0;
  93         u64 h_m_s_ms = 0;
  94
  95         tm_to_opal(tm, &y_m_d, &h_m_s_ms);
  96         while (rc == OPAL_BUSY || rc == OPAL_BUSY_EVENT) {
  97                 rc = opal_rtc_write(y_m_d, h_m_s_ms);
  98                 if (rc == OPAL_BUSY_EVENT)
  99                         opal_poll_events(NULL);
 100                 else if (retries-- && (rc == OPAL_HARDWARE
 101                                        || rc == OPAL_INTERNAL_ERROR))
 102                         msleep(10);
 103                 else if (rc != OPAL_BUSY && rc != OPAL_BUSY_EVENT)
 104                         break;
 105         }
 106
 107         return rc == OPAL_SUCCESS ? 0 : -EIO;
 108 }
 109
 110 /*
 111  * TPO  Timed Power-On
 112  *
 113  * TPO get/set OPAL calls care about the hour and min and to make it consistent
 114  * with the rtc utility time conversion functions, we use the 'u64' to store
 115  * its value and perform bit shift by 32 before use..
 116  */
 117 static int opal_get_tpo_time(struct device *dev, struct rtc_wkalrm *alarm)
 118 {
 119         __be32 __y_m_d, __h_m;
 120         struct opal_msg msg;
 121         int rc, token;
 122         u64 h_m_s_ms;
 123         u32 y_m_d;
 124
 125         token = opal_async_get_token_interruptible();
 126         if (token < 0) {
 127                 if (token != -ERESTARTSYS)
 128                         pr_err("Failed to get the async token\n");
 129
 130                 return token;
 131         }
 132
 133         rc = opal_tpo_read(token, &__y_m_d, &__h_m);
 134         if (rc != OPAL_ASYNC_COMPLETION) {
 135                 rc = -EIO;
 136                 goto exit;
 137         }
 138
 139         rc = opal_async_wait_response(token, &msg);
 140         if (rc) {
 141                 rc = -EIO;
 142                 goto exit;
 143         }
 144
 145         rc = opal_get_async_rc(msg);
 146         if (rc != OPAL_SUCCESS) {
 147                 rc = -EIO;
 148                 goto exit;
 149         }
 150
 151         y_m_d = be32_to_cpu(__y_m_d);
 152         h_m_s_ms = ((u64)be32_to_cpu(__h_m) << 32);
 153
 154         /* check if no alarm is set */
 155         if (y_m_d == 0 && h_m_s_ms == 0) {
 156                 pr_debug("No alarm is set\n");
 157                 rc = -ENOENT;
 158                 goto exit;
 159         } else {
 160                 pr_debug("Alarm set to %x %llx\n", y_m_d, h_m_s_ms);
 161         }
 162
 163         opal_to_tm(y_m_d, h_m_s_ms, &alarm->time);
 164
 165 exit:
 166         opal_async_release_token(token);
 167         return rc;
 168 }
 169
 170 /* Set Timed Power-On */
 171 static int opal_set_tpo_time(struct device *dev, struct rtc_wkalrm *alarm)
 172 {
 173         u64 h_m_s_ms = 0;
 174         struct opal_msg msg;
 175         u32 y_m_d = 0;
 176         int token, rc;
 177
 178         /* if alarm is enabled */
 179         if (alarm->enabled) {
 180                 tm_to_opal(&alarm->time, &y_m_d, &h_m_s_ms);
 181                 pr_debug("Alarm set to %x %llx\n", y_m_d, h_m_s_ms);
 182
 183         } else {
 184                 pr_debug("Alarm getting disabled\n");
 185         }
 186
 187         token = opal_async_get_token_interruptible();
 188         if (token < 0) {
 189                 if (token != -ERESTARTSYS)
 190                         pr_err("Failed to get the async token\n");
 191
 192                 return token;
 193         }
 194
 195         /* TPO, we care about hour and minute */
 196         rc = opal_tpo_write(token, y_m_d,
 197                             (u32)((h_m_s_ms >> 32) & 0xffff0000));
 198         if (rc != OPAL_ASYNC_COMPLETION) {
 199                 rc = -EIO;
 200                 goto exit;
 201         }
 202
 203         rc = opal_async_wait_response(token, &msg);
 204         if (rc) {
 205                 rc = -EIO;
 206                 goto exit;
 207         }
 208
 209         rc = opal_get_async_rc(msg);
 210         if (rc != OPAL_SUCCESS)
 211                 rc = -EIO;
 212
 213 exit:
 214         opal_async_release_token(token);
 215         return rc;
 216 }
 217
 218 int opal_tpo_alarm_irq_enable(struct device *dev, unsigned int enabled)
 219 {
 220         struct rtc_wkalrm alarm = { .enabled = 0 };
 221
 222         /*
 223          * TPO is automatically enabled when opal_set_tpo_time() is called with
 224          * non-zero rtc-time. We only handle disable case which needs to be
 225          * explicitly told to opal.
 226          */
 227         return enabled ? 0 : opal_set_tpo_time(dev, &alarm);
 228 }
 229
 230 static struct rtc_class_ops opal_rtc_ops = {
 231         .read_time      = opal_get_rtc_time,
 232         .set_time       = opal_set_rtc_time,
 233 };
 234
 235 static int opal_rtc_probe(struct platform_device *pdev)
 236 {
 237         struct rtc_device *rtc;
 238
 239         if (pdev->dev.of_node &&
 240             (of_property_read_bool(pdev->dev.of_node, "wakeup-source") ||
 241              of_property_read_bool(pdev->dev.of_node, "has-tpo")/* legacy */)) {
 242                 device_set_wakeup_capable(&pdev->dev, true);
 243                 opal_rtc_ops.read_alarm = opal_get_tpo_time;
 244                 opal_rtc_ops.set_alarm = opal_set_tpo_time;
 245                 opal_rtc_ops.alarm_irq_enable = opal_tpo_alarm_irq_enable;
 246         }
 247
 248         rtc = devm_rtc_device_register(&pdev->dev, DRVNAME, &opal_rtc_ops,
 249                                        THIS_MODULE);
 250         if (IS_ERR(rtc))
 251                 return PTR_ERR(rtc);
 252
 253         rtc->uie_unsupported = 1;
 254
 255         return 0;
 256 }
 257
 258 static const struct of_device_id opal_rtc_match[] = {
 259         {
 260                 .compatible     = "ibm,opal-rtc",
 261         },
 262         { }
 263 };
 264 MODULE_DEVICE_TABLE(of, opal_rtc_match);
 265
 266 static const struct platform_device_id opal_rtc_driver_ids[] = {
 267         {
 268                 .name           = "opal-rtc",
 269         },
 270         { }
 271 };
 272 MODULE_DEVICE_TABLE(platform, opal_rtc_driver_ids);
 273
 274 static struct platform_driver opal_rtc_driver = {
 275         .probe          = opal_rtc_probe,
 276         .id_table       = opal_rtc_driver_ids,
 277         .driver         = {
 278                 .name           = DRVNAME,
 279                 .of_match_table = opal_rtc_match,
 280         },
 281 };
 282
 283 static int __init opal_rtc_init(void)
 284 {
 285         if (!firmware_has_feature(FW_FEATURE_OPAL))
 286                 return -ENODEV;
 287
 288         return platform_driver_register(&opal_rtc_driver);
 289 }
 290
 291 static void __exit opal_rtc_exit(void)
 292 {
 293         platform_driver_unregister(&opal_rtc_driver);
 294 }
 295
 296 MODULE_AUTHOR("Neelesh Gupta <neelegup@linux.vnet.ibm.com>");
 297 MODULE_DESCRIPTION("IBM OPAL RTC driver");
 298 MODULE_LICENSE("GPL");
 299
 300 module_init(opal_rtc_init);
 301 module_exit(opal_rtc_exit);