drivers/mmc/core/host.c

   1 /*
   2  *  linux/drivers/mmc/core/host.c
   3  *
   4  *  Copyright (C) 2003 Russell King, All Rights Reserved.
   5  *  Copyright (C) 2007 Pierre Ossman
   6  *
   7  * This program is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License version 2 as
   9  * published by the Free Software Foundation.
  10  *
  11  *  MMC host class device management
  12  */
  13
  14 #include <linux/device.h>
  15 #include <linux/err.h>
  16 #include <linux/idr.h>
  17 #include <linux/pagemap.h>
  18
  19 #include <linux/mmc/host.h>
  20
  21 #include "core.h"
  22 #include "host.h"
  23
  24 #define cls_dev_to_mmc_host(d)  container_of(d, struct mmc_host, class_dev)
  25
  26 static void mmc_host_classdev_release(struct device *dev)
  27 {
  28         struct mmc_host *host = cls_dev_to_mmc_host(dev);
  29         kfree(host);
  30 }
  31
  32 static struct class mmc_host_class = {
  33         .name           = "mmc_host",
  34         .dev_release    = mmc_host_classdev_release,
  35 };
  36
  37 int mmc_register_host_class(void)
  38 {
  39         return class_register(&mmc_host_class);
  40 }
  41
  42 void mmc_unregister_host_class(void)
  43 {
  44         class_unregister(&mmc_host_class);
  45 }
  46
  47 static DEFINE_IDR(mmc_host_idr);
  48 static DEFINE_SPINLOCK(mmc_host_lock);
  49
  50 /**
  51  *      mmc_alloc_host - initialise the per-host structure.
  52  *      @extra: sizeof private data structure
  53  *      @dev: pointer to host device model structure
  54  *
  55  *      Initialise the per-host structure.
  56  */
  57 struct mmc_host *mmc_alloc_host(int extra, struct device *dev)
  58 {
  59         struct mmc_host *host;
  60
  61         host = kzalloc(sizeof(struct mmc_host) + extra, GFP_KERNEL);
  62         if (!host)
  63                 return NULL;
  64
  65         host->parent = dev;
  66         host->class_dev.parent = dev;
  67         host->class_dev.class = &mmc_host_class;
  68         device_initialize(&host->class_dev);
  69
  70         spin_lock_init(&host->lock);
  71         init_waitqueue_head(&host->wq);
  72         INIT_DELAYED_WORK(&host->detect, mmc_rescan);
  73
  74         /*
  75          * By default, hosts do not support SGIO or large requests.
  76          * They have to set these according to their abilities.
  77          */
  78         host->max_hw_segs = 1;
  79         host->max_phys_segs = 1;
  80         host->max_seg_size = PAGE_CACHE_SIZE;
  81
  82         host->max_req_size = PAGE_CACHE_SIZE;
  83         host->max_blk_size = 512;
  84         host->max_blk_count = PAGE_CACHE_SIZE / 512;
  85
  86         return host;
  87 }
  88
  89 EXPORT_SYMBOL(mmc_alloc_host);
  90
  91 /**
  92  *      mmc_add_host - initialise host hardware
  93  *      @host: mmc host
  94  *
  95  *      Register the host with the driver model. The host must be
  96  *      prepared to start servicing requests before this function
  97  *      completes.
  98  */
  99 int mmc_add_host(struct mmc_host *host)
 100 {
 101         int err;
 102
 103         if (!idr_pre_get(&mmc_host_idr, GFP_KERNEL))
 104                 return -ENOMEM;
 105
 106         spin_lock(&mmc_host_lock);
 107         err = idr_get_new(&mmc_host_idr, host, &host->index);
 108         spin_unlock(&mmc_host_lock);
 109         if (err)
 110                 return err;
 111
 112         snprintf(host->class_dev.bus_id, BUS_ID_SIZE,
 113                  "mmc%d", host->index);
 114
 115         err = device_add(&host->class_dev);
 116         if (err)
 117                 return err;
 118
 119         mmc_start_host(host);
 120
 121         return 0;
 122 }
 123
 124 EXPORT_SYMBOL(mmc_add_host);
 125
 126 /**
 127  *      mmc_remove_host - remove host hardware
 128  *      @host: mmc host
 129  *
 130  *      Unregister and remove all cards associated with this host,
 131  *      and power down the MMC bus. No new requests will be issued
 132  *      after this function has returned.
 133  */
 134 void mmc_remove_host(struct mmc_host *host)
 135 {
 136         mmc_stop_host(host);
 137
 138         device_del(&host->class_dev);
 139
 140         spin_lock(&mmc_host_lock);
 141         idr_remove(&mmc_host_idr, host->index);
 142         spin_unlock(&mmc_host_lock);
 143 }
 144
 145 EXPORT_SYMBOL(mmc_remove_host);
 146
 147 /**
 148  *      mmc_free_host - free the host structure
 149  *      @host: mmc host
 150  *
 151  *      Free the host once all references to it have been dropped.
 152  */
 153 void mmc_free_host(struct mmc_host *host)
 154 {
 155         put_device(&host->class_dev);
 156 }
 157
 158 EXPORT_SYMBOL(mmc_free_host);
 159