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 #include <linux/export.h>
  31
  32 static struct class *dca_class;
  33 static struct idr dca_idr;
  34 static spinlock_t dca_idr_lock;
  35
  36 int dca_sysfs_add_req(struct dca_provider *dca, struct device *dev, int slot)
  37 {
  38         struct device *cd;
  39         static int req_count;
  40
  41         cd = device_create(dca_class, dca->cd, MKDEV(0, slot + 1), NULL,
  42                            "requester%d", req_count++);
  43         if (IS_ERR(cd))
  44                 return PTR_ERR(cd);
  45         return 0;
  46 }
  47
  48 void dca_sysfs_remove_req(struct dca_provider *dca, int slot)
  49 {
  50         device_destroy(dca_class, MKDEV(0, slot + 1));
  51 }
  52
  53 int dca_sysfs_add_provider(struct dca_provider *dca, struct device *dev)
  54 {
  55         struct device *cd;
  56         int err = 0;
  57
  58 idr_try_again:
  59         if (!idr_pre_get(&dca_idr, GFP_KERNEL))
  60                 return -ENOMEM;
  61         spin_lock(&dca_idr_lock);
  62         err = idr_get_new(&dca_idr, dca, &dca->id);
  63         spin_unlock(&dca_idr_lock);
  64         switch (err) {
  65         case 0:
  66                 break;
  67         case -EAGAIN:
  68                 goto idr_try_again;
  69         default:
  70                 return err;
  71         }
  72
  73         cd = device_create(dca_class, dev, MKDEV(0, 0), NULL, "dca%d", dca->id);
  74         if (IS_ERR(cd)) {
  75                 spin_lock(&dca_idr_lock);
  76                 idr_remove(&dca_idr, dca->id);
  77                 spin_unlock(&dca_idr_lock);
  78                 return PTR_ERR(cd);
  79         }
  80         dca->cd = cd;
  81         return 0;
  82 }
  83
  84 void dca_sysfs_remove_provider(struct dca_provider *dca)
  85 {
  86         device_unregister(dca->cd);
  87         dca->cd = NULL;
  88         spin_lock(&dca_idr_lock);
  89         idr_remove(&dca_idr, dca->id);
  90         spin_unlock(&dca_idr_lock);
  91 }
  92
  93 int __init dca_sysfs_init(void)
  94 {
  95         idr_init(&dca_idr);
  96         spin_lock_init(&dca_idr_lock);
  97
  98         dca_class = class_create(THIS_MODULE, "dca");
  99         if (IS_ERR(dca_class)) {
 100                 idr_destroy(&dca_idr);
 101                 return PTR_ERR(dca_class);
 102         }
 103         return 0;
 104 }
 105
 106 void __exit dca_sysfs_exit(void)
 107 {
 108         class_destroy(dca_class);
 109         idr_destroy(&dca_idr);
 110 }
 111