drivers/dca/dca-sysfs.c

   1 /*
   2  * Copyright(c) 2007 - 2009 Intel Corporation. All rights reserved.
   3  *
   4  * This program is free software; you can redistribute it and/or modify it
   5  * under the terms of the GNU General Public License as published by the Free
   6  * Software Foundation; either version 2 of the License, or (at your option)
   7  * any later version.
   8  *
   9  * This program is distributed in the hope that it will be useful, but WITHOUT
  10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
  12  * more details.
  13  *
  14  * You should have received a copy of the GNU General Public License along with
  15  * this program; if not, write to the Free Software Foundation, Inc., 59
  16  * Temple Place - Suite 330, Boston, MA  02111-1307, USA.
  17  *
  18  * The full GNU General Public License is included in this distribution in the
  19  * file called COPYING.
  20  */
  21
  22 #include <linux/kernel.h>
  23 #include <linux/spinlock.h>
  24 #include <linux/device.h>
  25 #include <linux/idr.h>
  26 #include <linux/kdev_t.h>
  27 #include <linux/err.h>
  28 #include <linux/dca.h>
  29
  30 static struct class *dca_class;
  31 static struct idr dca_idr;
  32 static spinlock_t dca_idr_lock;
  33
  34 int dca_sysfs_add_req(struct dca_provider *dca, struct device *dev, int slot)
  35 {
  36         struct device *cd;
  37         static int req_count;
  38
  39         cd = device_create(dca_class, dca->cd, MKDEV(0, slot + 1), NULL,
  40                            "requester%d", req_count++);
  41         if (IS_ERR(cd))
  42                 return PTR_ERR(cd);
  43         return 0;
  44 }
  45
  46 void dca_sysfs_remove_req(struct dca_provider *dca, int slot)
  47 {
  48         device_destroy(dca_class, MKDEV(0, slot + 1));
  49 }
  50
  51 int dca_sysfs_add_provider(struct dca_provider *dca, struct device *dev)
  52 {
  53         struct device *cd;
  54         int err = 0;
  55
  56 idr_try_again:
  57         if (!idr_pre_get(&dca_idr, GFP_KERNEL))
  58                 return -ENOMEM;
  59         spin_lock(&dca_idr_lock);
  60         err = idr_get_new(&dca_idr, dca, &dca->id);
  61         spin_unlock(&dca_idr_lock);
  62         switch (err) {
  63         case 0:
  64                 break;
  65         case -EAGAIN:
  66                 goto idr_try_again;
  67         default:
  68                 return err;
  69         }
  70
  71         cd = device_create(dca_class, dev, MKDEV(0, 0), NULL, "dca%d", dca->id);
  72         if (IS_ERR(cd)) {
  73                 spin_lock(&dca_idr_lock);
  74                 idr_remove(&dca_idr, dca->id);
  75                 spin_unlock(&dca_idr_lock);
  76                 return PTR_ERR(cd);
  77         }
  78         dca->cd = cd;
  79         return 0;
  80 }
  81
  82 void dca_sysfs_remove_provider(struct dca_provider *dca)
  83 {
  84         device_unregister(dca->cd);
  85         dca->cd = NULL;
  86         spin_lock(&dca_idr_lock);
  87         idr_remove(&dca_idr, dca->id);
  88         spin_unlock(&dca_idr_lock);
  89 }
  90
  91 int __init dca_sysfs_init(void)
  92 {
  93         idr_init(&dca_idr);
  94         spin_lock_init(&dca_idr_lock);
  95
  96         dca_class = class_create(THIS_MODULE, "dca");
  97         if (IS_ERR(dca_class)) {
  98                 idr_destroy(&dca_idr);
  99                 return PTR_ERR(dca_class);
 100         }
 101         return 0;
 102 }
 103
 104 void __exit dca_sysfs_exit(void)
 105 {
 106         class_destroy(dca_class);
 107         idr_destroy(&dca_idr);
 108 }
 109