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         static int req_count;
  17
  18         cd = device_create(dca_class, dca->cd, MKDEV(0, slot + 1), NULL,
  19                            "requester%d", req_count++);
  20         if (IS_ERR(cd))
  21                 return PTR_ERR(cd);
  22         return 0;
  23 }
  24
  25 void dca_sysfs_remove_req(struct dca_provider *dca, int slot)
  26 {
  27         device_destroy(dca_class, MKDEV(0, slot + 1));
  28 }
  29
  30 int dca_sysfs_add_provider(struct dca_provider *dca, struct device *dev)
  31 {
  32         struct device *cd;
  33         int err = 0;
  34
  35 idr_try_again:
  36         if (!idr_pre_get(&dca_idr, GFP_KERNEL))
  37                 return -ENOMEM;
  38         spin_lock(&dca_idr_lock);
  39         err = idr_get_new(&dca_idr, dca, &dca->id);
  40         spin_unlock(&dca_idr_lock);
  41         switch (err) {
  42         case 0:
  43                 break;
  44         case -EAGAIN:
  45                 goto idr_try_again;
  46         default:
  47                 return err;
  48         }
  49
  50         cd = device_create(dca_class, dev, MKDEV(0, 0), NULL, "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         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