Quelle  hpios.c   Sprache: C

// SPDX-License-Identifier: GPL-2.0-only
/******************************************************************************

    AudioScience HPI driver
    Copyright (C) 1997-2012  AudioScience Inc. <support@audioscience.com>


HPI Operating System function implementation for Linux

(C) Copyright AudioScience Inc. 1997-2003
******************************************************************************/
#define SOURCEFILE_NAME "hpios.c"
#include "hpi_internal.h"
#include "hpidebug.h"
#include <linux/delay.h>
#include <linux/sched.h>

void hpios_delay_micro_seconds(u32 num_micro_sec)
{
 if ((usecs_to_jiffies(num_micro_sec) > 1) && !in_interrupt()) {
  /* MUST NOT SCHEDULE IN INTERRUPT CONTEXT! */
  schedule_timeout_uninterruptible(usecs_to_jiffies
   (num_micro_sec));
 } else if (num_micro_sec <= 2000)
  udelay(num_micro_sec);
 else
  mdelay(num_micro_sec / 1000);

}

/** Allocate an area of locked memory for bus master DMA operations.

If allocation fails, return 1, and *pMemArea.size = 0
*/
u16 hpios_locked_mem_alloc(struct consistent_dma_area *p_mem_area, u32 size,
 struct pci_dev *pdev)
{
 /*?? any benefit in using managed dmam_alloc_coherent? */
 p_mem_area->vaddr =
  dma_alloc_coherent(&pdev->dev, size, &p_mem_area->dma_handle,
  GFP_KERNEL);

 if (p_mem_area->vaddr) {
  HPI_DEBUG_LOG(DEBUG, "allocated %d bytes, dma 0x%x vma %p\n",
   size, (unsigned int)p_mem_area->dma_handle,
   p_mem_area->vaddr);
  p_mem_area->pdev = &pdev->dev;
  p_mem_area->size = size;
  return 0;
 } else {
  HPI_DEBUG_LOG(WARNING,
   "failed to allocate %d bytes locked memory\n", size);
  p_mem_area->size = 0;
  return 1;
 }
}

u16 hpios_locked_mem_free(struct consistent_dma_area *p_mem_area)
{
 if (p_mem_area->size) {
  dma_free_coherent(p_mem_area->pdev, p_mem_area->size,
   p_mem_area->vaddr, p_mem_area->dma_handle);
  HPI_DEBUG_LOG(DEBUG, "freed %lu bytes, dma 0x%x vma %p\n",
   (unsigned long)p_mem_area->size,
   (unsigned int)p_mem_area->dma_handle,
   p_mem_area->vaddr);
  p_mem_area->size = 0;
  return 0;
 } else {
  return 1;
 }
}