mirror of https://gitee.com/openkylin/linux.git
131 lines
3.2 KiB
C
131 lines
3.2 KiB
C
/*
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* Copyright (C) 1997 Claus-Justus Heine
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 2, or (at your option)
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any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program; see the file COPYING. If not, write to
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the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.
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*
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* $Source: /homes/cvs/ftape-stacked/ftape/lowlevel/ftape-buffer.c,v $
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* $Revision: 1.3 $
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* $Date: 1997/10/16 23:33:11 $
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*
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* This file contains the allocator/dealloctor for ftape's dynamic dma
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* buffer.
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*/
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#include <linux/slab.h>
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#include <linux/mm.h>
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#include <linux/mman.h>
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#include <asm/dma.h>
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#include <linux/ftape.h>
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#include "../lowlevel/ftape-rw.h"
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#include "../lowlevel/ftape-read.h"
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#include "../lowlevel/ftape-tracing.h"
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#include "../lowlevel/ftape-buffer.h"
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/* DMA'able memory allocation stuff.
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*/
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static inline void *dmaalloc(size_t size)
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{
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unsigned long addr;
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if (size == 0) {
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return NULL;
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}
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addr = __get_dma_pages(GFP_KERNEL, get_order(size));
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if (addr) {
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struct page *page;
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for (page = virt_to_page(addr); page < virt_to_page(addr+size); page++)
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SetPageReserved(page);
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}
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return (void *)addr;
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}
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static inline void dmafree(void *addr, size_t size)
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{
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if (size > 0) {
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struct page *page;
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for (page = virt_to_page((unsigned long)addr);
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page < virt_to_page((unsigned long)addr+size); page++)
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ClearPageReserved(page);
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free_pages((unsigned long) addr, get_order(size));
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}
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}
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static int add_one_buffer(void)
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{
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TRACE_FUN(ft_t_flow);
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if (ft_nr_buffers >= FT_MAX_NR_BUFFERS) {
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TRACE_EXIT -ENOMEM;
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}
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ft_buffer[ft_nr_buffers] = kmalloc(sizeof(buffer_struct), GFP_KERNEL);
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if (ft_buffer[ft_nr_buffers] == NULL) {
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TRACE_EXIT -ENOMEM;
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}
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memset(ft_buffer[ft_nr_buffers], 0, sizeof(buffer_struct));
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ft_buffer[ft_nr_buffers]->address = dmaalloc(FT_BUFF_SIZE);
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if (ft_buffer[ft_nr_buffers]->address == NULL) {
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kfree(ft_buffer[ft_nr_buffers]);
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ft_buffer[ft_nr_buffers] = NULL;
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TRACE_EXIT -ENOMEM;
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}
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ft_nr_buffers ++;
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TRACE(ft_t_info, "buffer nr #%d @ %p, dma area @ %p",
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ft_nr_buffers,
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ft_buffer[ft_nr_buffers-1],
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ft_buffer[ft_nr_buffers-1]->address);
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TRACE_EXIT 0;
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}
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static void del_one_buffer(void)
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{
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TRACE_FUN(ft_t_flow);
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if (ft_nr_buffers > 0) {
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TRACE(ft_t_info, "releasing buffer nr #%d @ %p, dma area @ %p",
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ft_nr_buffers,
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ft_buffer[ft_nr_buffers-1],
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ft_buffer[ft_nr_buffers-1]->address);
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ft_nr_buffers --;
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dmafree(ft_buffer[ft_nr_buffers]->address, FT_BUFF_SIZE);
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kfree(ft_buffer[ft_nr_buffers]);
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ft_buffer[ft_nr_buffers] = NULL;
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}
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TRACE_EXIT;
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}
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int ftape_set_nr_buffers(int cnt)
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{
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int delta = cnt - ft_nr_buffers;
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TRACE_FUN(ft_t_flow);
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if (delta > 0) {
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while (delta--) {
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if (add_one_buffer() < 0) {
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TRACE_EXIT -ENOMEM;
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}
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}
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} else if (delta < 0) {
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while (delta++) {
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del_one_buffer();
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}
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}
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ftape_zap_read_buffers();
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TRACE_EXIT 0;
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}
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