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 = kmalloc(sizeof(struct mmc_host) + extra, GFP_KERNEL);
  62         if (!host)
  63                 return NULL;
  64
  65         memset(host, 0, sizeof(struct mmc_host) + extra);
  66
  67         host->parent = dev;
  68         host->class_dev.parent = dev;
  69         host->class_dev.class = &mmc_host_class;
  70         device_initialize(&host->class_dev);
  71
  72         spin_lock_init(&host->lock);
  73         init_waitqueue_head(&host->wq);
  74         INIT_DELAYED_WORK(&host->detect, mmc_rescan);
  75
  76         /*
  77          * By default, hosts do not support SGIO or large requests.
  78          * They have to set these according to their abilities.
  79          */
  80         host->max_hw_segs = 1;
  81         host->max_phys_segs = 1;
  82         host->max_seg_size = PAGE_CACHE_SIZE;
  83
  84         host->max_req_size = PAGE_CACHE_SIZE;
  85         host->max_blk_size = 512;
  86         host->max_blk_count = PAGE_CACHE_SIZE / 512;
  87
  88         return host;
  89 }
  90
  91 EXPORT_SYMBOL(mmc_alloc_host);
  92
  93 /**
  94  *      mmc_add_host - initialise host hardware
  95  *      @host: mmc host
  96  *
  97  *      Register the host with the driver model. The host must be
  98  *      prepared to start servicing requests before this function
  99  *      completes.
 100  */
 101 int mmc_add_host(struct mmc_host *host)
 102 {
 103         int err;
 104
 105         if (!idr_pre_get(&mmc_host_idr, GFP_KERNEL))
 106                 return -ENOMEM;
 107
 108         spin_lock(&mmc_host_lock);
 109         err = idr_get_new(&mmc_host_idr, host, &host->index);
 110         spin_unlock(&mmc_host_lock);
 111         if (err)
 112                 return err;
 113
 114         snprintf(host->class_dev.bus_id, BUS_ID_SIZE,
 115                  "mmc%d", host->index);
 116
 117         err = device_add(&host->class_dev);
 118         if (err)
 119                 return err;
 120
 121         mmc_start_host(host);
 122
 123         return 0;
 124 }
 125
 126 EXPORT_SYMBOL(mmc_add_host);
 127
 128 /**
 129  *      mmc_remove_host - remove host hardware
 130  *      @host: mmc host
 131  *
 132  *      Unregister and remove all cards associated with this host,
 133  *      and power down the MMC bus. No new requests will be issued
 134  *      after this function has returned.
 135  */
 136 void mmc_remove_host(struct mmc_host *host)
 137 {
 138         mmc_stop_host(host);
 139
 140         device_del(&host->class_dev);
 141
 142         spin_lock(&mmc_host_lock);
 143         idr_remove(&mmc_host_idr, host->index);
 144         spin_unlock(&mmc_host_lock);
 145 }
 146
 147 EXPORT_SYMBOL(mmc_remove_host);
 148
 149 /**
 150  *      mmc_free_host - free the host structure
 151  *      @host: mmc host
 152  *
 153  *      Free the host once all references to it have been dropped.
 154  */
 155 void mmc_free_host(struct mmc_host *host)
 156 {
 157         put_device(&host->class_dev);
 158 }
 159
 160 EXPORT_SYMBOL(mmc_free_host);
 161