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 #include <linux/gfp.h>
  30
  31 static struct class *dca_class;
  32 static struct idr dca_idr;
  33 static spinlock_t dca_idr_lock;
  34
  35 int dca_sysfs_add_req(struct dca_provider *dca, struct device *dev, int slot)
  36 {
  37         struct device *cd;
  38         static int req_count;
  39
  40         cd = device_create(dca_class, dca->cd, MKDEV(0, slot + 1), NULL,
  41                            "requester%d", req_count++);
  42         if (IS_ERR(cd))
  43                 return PTR_ERR(cd);
  44         return 0;
  45 }
  46
  47 void dca_sysfs_remove_req(struct dca_provider *dca, int slot)
  48 {
  49         device_destroy(dca_class, MKDEV(0, slot + 1));
  50 }
  51
  52 int dca_sysfs_add_provider(struct dca_provider *dca, struct device *dev)
  53 {
  54         struct device *cd;
  55         int err = 0;
  56
  57 idr_try_again:
  58         if (!idr_pre_get(&dca_idr, GFP_KERNEL))
  59                 return -ENOMEM;
  60         spin_lock(&dca_idr_lock);
  61         err = idr_get_new(&dca_idr, dca, &dca->id);
  62         spin_unlock(&dca_idr_lock);
  63         switch (err) {
  64         case 0:
  65                 break;
  66         case -EAGAIN:
  67                 goto idr_try_again;
  68         default:
  69                 return err;
  70         }
  71
  72         cd = device_create(dca_class, dev, MKDEV(0, 0), NULL, "dca%d", dca->id);
  73         if (IS_ERR(cd)) {
  74                 spin_lock(&dca_idr_lock);
  75                 idr_remove(&dca_idr, dca->id);
  76                 spin_unlock(&dca_idr_lock);
  77                 return PTR_ERR(cd);
  78         }
  79         dca->cd = cd;
  80         return 0;
  81 }
  82
  83 void dca_sysfs_remove_provider(struct dca_provider *dca)
  84 {
  85         device_unregister(dca->cd);
  86         dca->cd = NULL;
  87         spin_lock(&dca_idr_lock);
  88         idr_remove(&dca_idr, dca->id);
  89         spin_unlock(&dca_idr_lock);
  90 }
  91
  92 int __init dca_sysfs_init(void)
  93 {
  94         idr_init(&dca_idr);
  95         spin_lock_init(&dca_idr_lock);
  96
  97         dca_class = class_create(THIS_MODULE, "dca");
  98         if (IS_ERR(dca_class)) {
  99                 idr_destroy(&dca_idr);
 100                 return PTR_ERR(dca_class);
 101         }
 102         return 0;
 103 }
 104
 105 void __exit dca_sysfs_exit(void)
 106 {
 107         class_destroy(dca_class);
 108         idr_destroy(&dca_idr);
 109 }
 110