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 class_device *cd;
  16
  17         cd = class_device_create(dca_class, dca->cd, MKDEV(0, slot + 1),
  18                                  dev, "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         class_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 class_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 = class_device_create(dca_class, NULL, MKDEV(0, 0),
  50                                  dev, "dca%d", dca->id);
  51         if (IS_ERR(cd)) {
  52                 spin_lock(&dca_idr_lock);
  53                 idr_remove(&dca_idr, dca->id);
  54                 spin_unlock(&dca_idr_lock);
  55                 return PTR_ERR(cd);
  56         }
  57         dca->cd = cd;
  58         return 0;
  59 }
  60
  61 void dca_sysfs_remove_provider(struct dca_provider *dca)
  62 {
  63         class_device_unregister(dca->cd);
  64         dca->cd = NULL;
  65         spin_lock(&dca_idr_lock);
  66         idr_remove(&dca_idr, dca->id);
  67         spin_unlock(&dca_idr_lock);
  68 }
  69
  70 int __init dca_sysfs_init(void)
  71 {
  72         idr_init(&dca_idr);
  73         spin_lock_init(&dca_idr_lock);
  74
  75         dca_class = class_create(THIS_MODULE, "dca");
  76         if (IS_ERR(dca_class)) {
  77                 idr_destroy(&dca_idr);
  78                 return PTR_ERR(dca_class);
  79         }
  80         return 0;
  81 }
  82
  83 void __exit dca_sysfs_exit(void)
  84 {
  85         class_destroy(dca_class);
  86         idr_destroy(&dca_idr);
  87 }
  88