patch-2.1.23 linux/drivers/sbus/audio/bounce.c

• Lines: 151
• Date: Thu Jan 1 02:00:00 1970
• Orig file: v2.1.22/linux/drivers/sbus/audio/bounce.c
• Orig date: Sun Dec 22 16:37:36 1996

diff -u --recursive --new-file v2.1.22/linux/drivers/sbus/audio/bounce.c linux/drivers/sbus/audio/bounce.c
@@ -1,150 +0,0 @@
-/*
- * drivers/sbus/audio/bounce.c
- *
- * Copyright (C) 1996 Thomas K. Dyas (tdyas@noc.rutgers.edu)
- *
- * Simple bounce buffer allocator used for allocating pages for use in
- * DMA and pseudo-DMA (byte-by-byte using an interrupt)
- * applications. For safety, we do most operations in bottom half so
- * we have some guarnatee of atomicity. System calls can do
- * "start_bh_atomic" to get some atomicity.
- */
-
-#include <linux/kernel.h>
-#include <linux/malloc.h>
-#include "bounce.h"
-
-
-static struct bounce_page *pages[NR_BOUNCE_PAGES];
-static struct bounce_page *free_list_head, *free_list_tail;
-
-/* Add a bounce page to the free list. */
-static void add_bounce_page(struct bounce_page *page)
-{
-  unsigned long flags;
-
-#ifdef DEBUG_BOUNCE
-  if (page->next) {
-    printk(KERN_DEBUG "add_bounce_page: page already on list from %p\n",
-	   __builtin_return_address(0));
-    return;
-  }
-#endif
-
-  save_flags(flags);
-  cli();
-
-  /* Case #1: Nothing on the list. */
-  if (!free_list_tail) {
-#ifdef DEBUG_BOUNCE
-    if (free_list_head) {
-      printk(KERN_DEBUG "add_bounce_page: inconsistent free list from %p\n",
-	     __builtin_return_address(0));
-      restore_flags(flags);
-      return;
-    }
-#endif
-    free_list_head = free_list_tail = page;
-  } else {
-    free_list_tail->next = page;
-    page->next = NULL;
-    free_list_tail = page;
-  }
-
-  restore_flags(flags);
-}
-
-/* Remove a bounce page from the free list. */
-static struct bounce_page *next_bounce_page(void)
-{
-  struct bounce_page *p;
-  unsigned long flags;
-
-  save_flags(flags);
-  cli();
-
-  /* If the free list is empty, return empty handed. */
-  if (!free_list_head) {
-    restore_flags(flags);
-    return NULL;
-  }
-
-  /* Remove the next available bounce page from the free list. */
-  p = free_list_head;
-
-  /* Update the free list pointers. */
-  free_list_head = free_list_head->next;
-  if (!free_list_head)
-    free_list_tail = NULL;
-
-  /* Return the page that we found. */
-  p->next = NULL;
-  restore_flags(flags);
-  return p;
-}
-
-/* Allocate the bounce buffers and the page lists. */
-int bounce_init(void)
-{
-  register int i;
-
-  /* Allocate space for all of the bounce pages. */
-  for (i = 0; i < NR_BOUNCE_PAGES; i++) {
-    pages[i] = __get_free_page(GFP_KERNEL);
-    if (!pages[i]) {
-      register int j;
-      for (j = 0; j < i; j++) free_page(pages[i]);
-      return -ENOMEM;
-    }
-  }
-
-  /* Place all of the pages onto the free list. */
-  for (i = 0; i < NR_BOUNCE_PAGES - 1; i++)
-    pages[i]->next = pages[i+1];
-  pages[NR_BOUNCE_BUFFERS-1]->next = NULL;
-
-  /* Setup pointers to the free list head and tail. */
-  free_list_head = pages[0];
-  free_list_tail = pages[NR_BOUNCE_BUFFERS-1];
-  return 0;
-}
-
-/* Allocate a bounce buffer to a process. */
-struct bounce_page * get_bounce_page(int timeout)
-{
-  struct bounce_page *p;
-  int tries;
-
-  do {
-    /* Do not allow interrupts to muck with the lists. */
-    start_bh_atomic();
-
-    /* Check to see if a bounce page is available. */
-    p = next_bounce_page();
-    if (p) {
-      end_bh_atomic();
-      return p;
-    }
-
-    /* No bounce page was available. Sleep and wait for one. */
-    end_bh_atomic();
-    current->state = TASK_INTERRUPTIBLE;
-    current->timeout = jiffies + HZ / 10;
-    schedule();
-
-    /* If we received a signal, then bail out. */
-    if (current->signal & ~current->blocked)
-      return NULL;
-    
-  } while (jiffies <= timeout);
-
-  /* We did not find anything before the timeout. */
-  return NULL;
-}
-
-/* Return a bounce buffer to the free list. */
-void put_bounce_page(struct bounce_page *page)
-{
-  add_bounce_page(page);
-}
-