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_drvdata(dca_class, dca->cd,
  19                                    MKDEV(0, slot + 1), NULL,
  20                                    "requester%d", req_count++);
  21         if (IS_ERR(cd))
  22                 return PTR_ERR(cd);
  23         return 0;
  24 }
  25
  26 void dca_sysfs_remove_req(struct dca_provider *dca, int slot)
  27 {
  28         device_destroy(dca_class, MKDEV(0, slot + 1));
  29 }
  30
  31 int dca_sysfs_add_provider(struct dca_provider *dca, struct device *dev)
  32 {
  33         struct device *cd;
  34         int err = 0;
  35
  36 idr_try_again:
  37         if (!idr_pre_get(&dca_idr, GFP_KERNEL))
  38                 return -ENOMEM;
  39         spin_lock(&dca_idr_lock);
  40         err = idr_get_new(&dca_idr, dca, &dca->id);
  41         spin_unlock(&dca_idr_lock);
  42         switch (err) {
  43         case 0:
  44                 break;
  45         case -EAGAIN:
  46                 goto idr_try_again;
  47         default:
  48                 return err;
  49         }
  50
  51         cd = device_create_drvdata(dca_class, dev, MKDEV(0, 0), NULL,
  52                                    "dca%d", dca->id);
  53         if (IS_ERR(cd)) {
  54                 spin_lock(&dca_idr_lock);
  55                 idr_remove(&dca_idr, dca->id);
  56                 spin_unlock(&dca_idr_lock);
  57                 return PTR_ERR(cd);
  58         }
  59         dca->cd = cd;
  60         return 0;
  61 }
  62
  63 void dca_sysfs_remove_provider(struct dca_provider *dca)
  64 {
  65         device_unregister(dca->cd);
  66         dca->cd = NULL;
  67         spin_lock(&dca_idr_lock);
  68         idr_remove(&dca_idr, dca->id);
  69         spin_unlock(&dca_idr_lock);
  70 }
  71
  72 int __init dca_sysfs_init(void)
  73 {
  74         idr_init(&dca_idr);
  75         spin_lock_init(&dca_idr_lock);
  76
  77         dca_class = class_create(THIS_MODULE, "dca");
  78         if (IS_ERR(dca_class)) {
  79                 idr_destroy(&dca_idr);
  80                 return PTR_ERR(dca_class);
  81         }
  82         return 0;
  83 }
  84
  85 void __exit dca_sysfs_exit(void)
  86 {
  87         class_destroy(dca_class);
  88         idr_destroy(&dca_idr);
  89 }
  90