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_drvdata(dca_class, dca->cd,
  18                                    MKDEV(0, slot + 1), NULL,
  19                                    "requester%d", slot);
  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_drvdata(dca_class, dev, MKDEV(0, 0), NULL,
  51                                    "dca%d", dca->id);
  52         if (IS_ERR(cd)) {
  53                 spin_lock(&dca_idr_lock);
  54                 idr_remove(&dca_idr, dca->id);
  55                 spin_unlock(&dca_idr_lock);
  56                 return PTR_ERR(cd);
  57         }
  58         dca->cd = cd;
  59         return 0;
  60 }
  61
  62 void dca_sysfs_remove_provider(struct dca_provider *dca)
  63 {
  64         device_unregister(dca->cd);
  65         dca->cd = NULL;
  66         spin_lock(&dca_idr_lock);
  67         idr_remove(&dca_idr, dca->id);
  68         spin_unlock(&dca_idr_lock);
  69 }
  70
  71 int __init dca_sysfs_init(void)
  72 {
  73         idr_init(&dca_idr);
  74         spin_lock_init(&dca_idr_lock);
  75
  76         dca_class = class_create(THIS_MODULE, "dca");
  77         if (IS_ERR(dca_class)) {
  78                 idr_destroy(&dca_idr);
  79                 return PTR_ERR(dca_class);
  80         }
  81         return 0;
  82 }
  83
  84 void __exit dca_sysfs_exit(void)
  85 {
  86         class_destroy(dca_class);
  87         idr_destroy(&dca_idr);
  88 }
  89