drivers/dca/dca-sysfs.c

   1 #include <linux/kernel.h>
   2 #include <linux/spinlock.h>
   3 #include <linux/device.h>
   4 #include <linux/idr.h>
   5 #include <linux/kdev_t.h>
   6 #include <linux/err.h>
   7 #include <linux/dca.h>
   8
   9 static struct class *dca_class;
  10 static struct idr dca_idr;
  11 static spinlock_t dca_idr_lock;
  12
  13 int dca_sysfs_add_req(struct dca_provider *dca, struct device *dev, int slot)
  14 {
  15         struct device *cd;
  16
  17         cd = device_create(dca_class, dca->cd, MKDEV(0, slot + 1),
  18                            "requester%d", slot);
  19         if (IS_ERR(cd))
  20                 return PTR_ERR(cd);
  21         return 0;
  22 }
  23
  24 void dca_sysfs_remove_req(struct dca_provider *dca, int slot)
  25 {
  26         device_destroy(dca_class, MKDEV(0, slot + 1));
  27 }
  28
  29 int dca_sysfs_add_provider(struct dca_provider *dca, struct device *dev)
  30 {
  31         struct device *cd;
  32         int err = 0;
  33
  34 idr_try_again:
  35         if (!idr_pre_get(&dca_idr, GFP_KERNEL))
  36                 return -ENOMEM;
  37         spin_lock(&dca_idr_lock);
  38         err = idr_get_new(&dca_idr, dca, &dca->id);
  39         spin_unlock(&dca_idr_lock);
  40         switch (err) {
  41         case 0:
  42                 break;
  43         case -EAGAIN:
  44                 goto idr_try_again;
  45         default:
  46                 return err;
  47         }
  48
  49         cd = device_create(dca_class, dev, MKDEV(0, 0), "dca%d", dca->id);
  50         if (IS_ERR(cd)) {
  51                 spin_lock(&dca_idr_lock);
  52                 idr_remove(&dca_idr, dca->id);
  53                 spin_unlock(&dca_idr_lock);
  54                 return PTR_ERR(cd);
  55         }
  56         dca->cd = cd;
  57         return 0;
  58 }
  59
  60 void dca_sysfs_remove_provider(struct dca_provider *dca)
  61 {
  62         device_unregister(dca->cd);
  63         dca->cd = NULL;
  64         spin_lock(&dca_idr_lock);
  65         idr_remove(&dca_idr, dca->id);
  66         spin_unlock(&dca_idr_lock);
  67 }
  68
  69 int __init dca_sysfs_init(void)
  70 {
  71         idr_init(&dca_idr);
  72         spin_lock_init(&dca_idr_lock);
  73
  74         dca_class = class_create(THIS_MODULE, "dca");
  75         if (IS_ERR(dca_class)) {
  76                 idr_destroy(&dca_idr);
  77                 return PTR_ERR(dca_class);
  78         }
  79         return 0;
  80 }
  81
  82 void __exit dca_sysfs_exit(void)
  83 {
  84         class_destroy(dca_class);
  85         idr_destroy(&dca_idr);
  86 }
  87