arch/sh/kernel/cpu/shmobile/pm_runtime.c

   1 /*
   2  * arch/sh/kernel/cpu/shmobile/pm_runtime.c
   3  *
   4  * Runtime PM support code for SuperH Mobile
   5  *
   6  *  Copyright (C) 2009 Magnus Damm
   7  *
   8  * This file is subject to the terms and conditions of the GNU General Public
   9  * License.  See the file "COPYING" in the main directory of this archive
  10  * for more details.
  11  */
  12 #include <linux/init.h>
  13 #include <linux/kernel.h>
  14 #include <linux/io.h>
  15 #include <linux/pm_runtime.h>
  16 #include <linux/platform_device.h>
  17 #include <linux/mutex.h>
  18 #include <asm/hwblk.h>
  19
  20 static DEFINE_SPINLOCK(hwblk_lock);
  21 static LIST_HEAD(hwblk_idle_list);
  22 static struct work_struct hwblk_work;
  23
  24 extern struct hwblk_info *hwblk_info;
  25
  26 static void platform_pm_runtime_not_idle(struct platform_device *pdev)
  27 {
  28         unsigned long flags;
  29
  30         /* remove device from idle list */
  31         spin_lock_irqsave(&hwblk_lock, flags);
  32         if (test_bit(PDEV_ARCHDATA_FLAG_IDLE, &pdev->archdata.flags)) {
  33                 list_del(&pdev->archdata.entry);
  34                 __clear_bit(PDEV_ARCHDATA_FLAG_IDLE, &pdev->archdata.flags);
  35         }
  36         spin_unlock_irqrestore(&hwblk_lock, flags);
  37 }
  38
  39 static int __platform_pm_runtime_resume(struct platform_device *pdev)
  40 {
  41         struct device *d = &pdev->dev;
  42         struct pdev_archdata *ad = &pdev->archdata;
  43         int hwblk = ad->hwblk_id;
  44         int ret = -ENOSYS;
  45
  46         dev_dbg(d, "__platform_pm_runtime_resume() [%d]\n", hwblk);
  47
  48         if (d->driver && d->driver->pm && d->driver->pm->runtime_resume) {
  49                 hwblk_enable(hwblk_info, hwblk);
  50                 ret = 0;
  51
  52                 if (test_bit(PDEV_ARCHDATA_FLAG_SUSP, &ad->flags)) {
  53                         ret = d->driver->pm->runtime_resume(d);
  54                         if (!ret)
  55                                 clear_bit(PDEV_ARCHDATA_FLAG_SUSP, &ad->flags);
  56                         else
  57                                 hwblk_disable(hwblk_info, hwblk);
  58                 }
  59         }
  60
  61         dev_dbg(d, "__platform_pm_runtime_resume() [%d] - returns %d\n",
  62                 hwblk, ret);
  63
  64         return ret;
  65 }
  66
  67 static int __platform_pm_runtime_suspend(struct platform_device *pdev)
  68 {
  69         struct device *d = &pdev->dev;
  70         struct pdev_archdata *ad = &pdev->archdata;
  71         int hwblk = ad->hwblk_id;
  72         int ret = -ENOSYS;
  73
  74         dev_dbg(d, "__platform_pm_runtime_suspend() [%d]\n", hwblk);
  75
  76         if (d->driver && d->driver->pm && d->driver->pm->runtime_suspend) {
  77                 BUG_ON(!test_bit(PDEV_ARCHDATA_FLAG_IDLE, &ad->flags));
  78
  79                 hwblk_enable(hwblk_info, hwblk);
  80                 ret = d->driver->pm->runtime_suspend(d);
  81                 hwblk_disable(hwblk_info, hwblk);
  82
  83                 if (!ret) {
  84                         set_bit(PDEV_ARCHDATA_FLAG_SUSP, &ad->flags);
  85                         platform_pm_runtime_not_idle(pdev);
  86                         hwblk_cnt_dec(hwblk_info, hwblk, HWBLK_CNT_IDLE);
  87                 }
  88         }
  89
  90         dev_dbg(d, "__platform_pm_runtime_suspend() [%d] - returns %d\n",
  91                 hwblk, ret);
  92
  93         return ret;
  94 }
  95
  96 static void platform_pm_runtime_work(struct work_struct *work)
  97 {
  98         struct platform_device *pdev;
  99         unsigned long flags;
 100         int ret;
 101
 102         /* go through the idle list and suspend one device at a time */
 103         do {
 104                 spin_lock_irqsave(&hwblk_lock, flags);
 105                 if (list_empty(&hwblk_idle_list))
 106                         pdev = NULL;
 107                 else
 108                         pdev = list_first_entry(&hwblk_idle_list,
 109                                                 struct platform_device,
 110                                                 archdata.entry);
 111                 spin_unlock_irqrestore(&hwblk_lock, flags);
 112
 113                 if (pdev) {
 114                         mutex_lock(&pdev->archdata.mutex);
 115                         ret = __platform_pm_runtime_suspend(pdev);
 116
 117                         /* at this point the platform device may be:
 118                          * suspended: ret = 0, FLAG_SUSP set, clock stopped
 119                          * failed: ret < 0, FLAG_IDLE set, clock stopped
 120                          */
 121                         mutex_unlock(&pdev->archdata.mutex);
 122                 } else {
 123                         ret = -ENODEV;
 124                 }
 125         } while (!ret);
 126 }
 127
 128 /* this function gets called from cpuidle context when all devices in the
 129  * main power domain are unused but some are counted as idle, ie the hwblk
 130  * counter values are (HWBLK_CNT_USAGE == 0) && (HWBLK_CNT_IDLE != 0)
 131  */
 132 void platform_pm_runtime_suspend_idle(void)
 133 {
 134         queue_work(pm_wq, &hwblk_work);
 135 }
 136
 137 int platform_pm_runtime_suspend(struct device *dev)
 138 {
 139         struct platform_device *pdev = to_platform_device(dev);
 140         struct pdev_archdata *ad = &pdev->archdata;
 141         unsigned long flags;
 142         int hwblk = ad->hwblk_id;
 143         int ret = 0;
 144
 145         dev_dbg(dev, "platform_pm_runtime_suspend() [%d]\n", hwblk);
 146
 147         /* ignore off-chip platform devices */
 148         if (!hwblk)
 149                 goto out;
 150
 151         /* interrupt context not allowed */
 152         might_sleep();
 153
 154         /* catch misconfigured drivers not starting with resume */
 155         if (test_bit(PDEV_ARCHDATA_FLAG_INIT, &pdev->archdata.flags)) {
 156                 ret = -EINVAL;
 157                 goto out;
 158         }
 159
 160         /* serialize */
 161         mutex_lock(&ad->mutex);
 162
 163         /* disable clock */
 164         hwblk_disable(hwblk_info, hwblk);
 165
 166         /* put device on idle list */
 167         spin_lock_irqsave(&hwblk_lock, flags);
 168         list_add_tail(&pdev->archdata.entry, &hwblk_idle_list);
 169         __set_bit(PDEV_ARCHDATA_FLAG_IDLE, &pdev->archdata.flags);
 170         spin_unlock_irqrestore(&hwblk_lock, flags);
 171
 172         /* increase idle count */
 173         hwblk_cnt_inc(hwblk_info, hwblk, HWBLK_CNT_IDLE);
 174
 175         /* at this point the platform device is:
 176          * idle: ret = 0, FLAG_IDLE set, clock stopped
 177          */
 178         mutex_unlock(&ad->mutex);
 179
 180 out:
 181         dev_dbg(dev, "platform_pm_runtime_suspend() [%d] returns %d\n",
 182                 hwblk, ret);
 183
 184         return ret;
 185 }
 186
 187 int platform_pm_runtime_resume(struct device *dev)
 188 {
 189         struct platform_device *pdev = to_platform_device(dev);
 190         struct pdev_archdata *ad = &pdev->archdata;
 191         int hwblk = ad->hwblk_id;
 192         int ret = 0;
 193
 194         dev_dbg(dev, "platform_pm_runtime_resume() [%d]\n", hwblk);
 195
 196         /* ignore off-chip platform devices */
 197         if (!hwblk)
 198                 goto out;
 199
 200         /* interrupt context not allowed */
 201         might_sleep();
 202
 203         /* serialize */
 204         mutex_lock(&ad->mutex);
 205
 206         /* make sure device is removed from idle list */
 207         platform_pm_runtime_not_idle(pdev);
 208
 209         /* decrease idle count */
 210         if (!test_bit(PDEV_ARCHDATA_FLAG_INIT, &pdev->archdata.flags) &&
 211             !test_bit(PDEV_ARCHDATA_FLAG_SUSP, &pdev->archdata.flags))
 212                 hwblk_cnt_dec(hwblk_info, hwblk, HWBLK_CNT_IDLE);
 213
 214         /* resume the device if needed */
 215         ret = __platform_pm_runtime_resume(pdev);
 216
 217         /* the driver has been initialized now, so clear the init flag */
 218         clear_bit(PDEV_ARCHDATA_FLAG_INIT, &pdev->archdata.flags);
 219
 220         /* at this point the platform device may be:
 221          * resumed: ret = 0, flags = 0, clock started
 222          * failed: ret < 0, FLAG_SUSP set, clock stopped
 223          */
 224         mutex_unlock(&ad->mutex);
 225 out:
 226         dev_dbg(dev, "platform_pm_runtime_resume() [%d] returns %d\n",
 227                 hwblk, ret);
 228
 229         return ret;
 230 }
 231
 232 int platform_pm_runtime_idle(struct device *dev)
 233 {
 234         struct platform_device *pdev = to_platform_device(dev);
 235         int hwblk = pdev->archdata.hwblk_id;
 236         int ret = 0;
 237
 238         dev_dbg(dev, "platform_pm_runtime_idle() [%d]\n", hwblk);
 239
 240         /* ignore off-chip platform devices */
 241         if (!hwblk)
 242                 goto out;
 243
 244         /* interrupt context not allowed, use pm_runtime_put()! */
 245         might_sleep();
 246
 247         /* suspend synchronously to disable clocks immediately */
 248         ret = pm_runtime_suspend(dev);
 249 out:
 250         dev_dbg(dev, "platform_pm_runtime_idle() [%d] done!\n", hwblk);
 251         return ret;
 252 }
 253
 254 static int platform_bus_notify(struct notifier_block *nb,
 255                                unsigned long action, void *data)
 256 {
 257         struct device *dev = data;
 258         struct platform_device *pdev = to_platform_device(dev);
 259         int hwblk = pdev->archdata.hwblk_id;
 260
 261         /* ignore off-chip platform devices */
 262         if (!hwblk)
 263                 return 0;
 264
 265         switch (action) {
 266         case BUS_NOTIFY_ADD_DEVICE:
 267                 INIT_LIST_HEAD(&pdev->archdata.entry);
 268                 mutex_init(&pdev->archdata.mutex);
 269                 /* platform devices without drivers should be disabled */
 270                 hwblk_enable(hwblk_info, hwblk);
 271                 hwblk_disable(hwblk_info, hwblk);
 272                 /* make sure driver re-inits itself once */
 273                 __set_bit(PDEV_ARCHDATA_FLAG_INIT, &pdev->archdata.flags);
 274                 break;
 275         /* TODO: add BUS_NOTIFY_BIND_DRIVER and increase idle count */
 276         case BUS_NOTIFY_BOUND_DRIVER:
 277                 /* keep track of number of devices in use per hwblk */
 278                 hwblk_cnt_inc(hwblk_info, hwblk, HWBLK_CNT_DEVICES);
 279                 break;
 280         case BUS_NOTIFY_UNBOUND_DRIVER:
 281                 /* keep track of number of devices in use per hwblk */
 282                 hwblk_cnt_dec(hwblk_info, hwblk, HWBLK_CNT_DEVICES);
 283                 /* make sure driver re-inits itself once */
 284                 __set_bit(PDEV_ARCHDATA_FLAG_INIT, &pdev->archdata.flags);
 285                 break;
 286         case BUS_NOTIFY_DEL_DEVICE:
 287                 break;
 288         }
 289         return 0;
 290 }
 291
 292 static struct notifier_block platform_bus_notifier = {
 293         .notifier_call = platform_bus_notify
 294 };
 295
 296 static int __init sh_pm_runtime_init(void)
 297 {
 298         INIT_WORK(&hwblk_work, platform_pm_runtime_work);
 299
 300         bus_register_notifier(&platform_bus_type, &platform_bus_notifier);
 301         return 0;
 302 }
 303 core_initcall(sh_pm_runtime_init);