source: mainline/uspace/drv/uhci/callback.c@ d956aa5

#include <errno.h>
#include <mem.h>

#include "callback.h"
int callback_init(callback_t *instance, device_t *dev,
  void *buffer, size_t size, usbhc_iface_transfer_in_callback_t func_in,
  usbhc_iface_transfer_out_callback_t func_out, void *arg)
{
        assert(instance);
        assert(func_in == NULL || func_out == NULL);
        if (size > 0) {
                instance->new_buffer = malloc32(size);
                if (!instance->new_buffer) {
                        uhci_print_error("Failed to allocate device acessible buffer.\n");
                        return ENOMEM;
                }
                if (func_out)
                        memcpy(instance->new_buffer, buffer, size);
        } else {
                instance->new_buffer = NULL;
        }


        instance->callback_out = func_out;
        instance->callback_in = func_in;
        instance->old_buffer = buffer;
        instance->buffer_size = size;
        instance->dev = dev;
        instance->arg = arg;
        return EOK;
}
/*----------------------------------------------------------------------------*/
void callback_run(
callback_t *instance, usb_transaction_outcome_t outcome, size_t act_size)
{
        assert(instance);

        /* update the old buffer */
        if (instance->new_buffer &&
          (instance->new_buffer != instance->old_buffer)) {
                memcpy(instance->old_buffer, instance->new_buffer, instance->buffer_size);
                free32(instance->new_buffer);
                instance->new_buffer = NULL;
        }

        if (instance->callback_in) {
                assert(instance->callback_out == NULL);
                uhci_print_verbose("Callback in: %p %x %d.\n",
                  instance->callback_in, outcome, act_size);
                instance->callback_in(
                  instance->dev, act_size, outcome, instance->arg);
        } else {
                assert(instance->callback_out);
                assert(instance->callback_in == NULL);
                uhci_print_verbose("Callback out: %p %p %x %p .\n",
                 instance->callback_out, instance->dev, outcome, instance->arg);
                instance->callback_out(
                  instance->dev, outcome, instance->arg);
        }
}