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1a59d1b8e0
Based on 1 normalized pattern(s): this program is free software you can redistribute it and or modify it under the terms of the gnu general public license as published by the free software foundation either version 2 of the license or at your option any later version this program is distributed in the hope that it will be useful but without any warranty without even the implied warranty of merchantability or fitness for a particular purpose see the gnu general public license for more details you should have received a copy of the gnu general public license along with this program if not write to the free software foundation inc 59 temple place suite 330 boston ma 02111 1307 usa extracted by the scancode license scanner the SPDX license identifier GPL-2.0-or-later has been chosen to replace the boilerplate/reference in 1334 file(s). Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Allison Randal <allison@lohutok.net> Reviewed-by: Richard Fontana <rfontana@redhat.com> Cc: linux-spdx@vger.kernel.org Link: https://lkml.kernel.org/r/20190527070033.113240726@linutronix.de Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
100 lines
2.3 KiB
C
100 lines
2.3 KiB
C
// SPDX-License-Identifier: GPL-2.0-or-later
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/*
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* ISA DMA support functions
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* Copyright (c) by Jaroslav Kysela <perex@perex.cz>
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*/
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/*
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* Defining following add some delay. Maybe this helps for some broken
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* ISA DMA controllers.
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*/
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#undef HAVE_REALLY_SLOW_DMA_CONTROLLER
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#include <linux/export.h>
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#include <sound/core.h>
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#include <asm/dma.h>
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/**
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* snd_dma_program - program an ISA DMA transfer
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* @dma: the dma number
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* @addr: the physical address of the buffer
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* @size: the DMA transfer size
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* @mode: the DMA transfer mode, DMA_MODE_XXX
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*
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* Programs an ISA DMA transfer for the given buffer.
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*/
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void snd_dma_program(unsigned long dma,
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unsigned long addr, unsigned int size,
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unsigned short mode)
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{
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unsigned long flags;
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flags = claim_dma_lock();
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disable_dma(dma);
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clear_dma_ff(dma);
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set_dma_mode(dma, mode);
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set_dma_addr(dma, addr);
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set_dma_count(dma, size);
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if (!(mode & DMA_MODE_NO_ENABLE))
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enable_dma(dma);
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release_dma_lock(flags);
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}
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EXPORT_SYMBOL(snd_dma_program);
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/**
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* snd_dma_disable - stop the ISA DMA transfer
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* @dma: the dma number
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*
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* Stops the ISA DMA transfer.
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*/
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void snd_dma_disable(unsigned long dma)
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{
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unsigned long flags;
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flags = claim_dma_lock();
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clear_dma_ff(dma);
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disable_dma(dma);
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release_dma_lock(flags);
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}
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EXPORT_SYMBOL(snd_dma_disable);
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/**
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* snd_dma_pointer - return the current pointer to DMA transfer buffer in bytes
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* @dma: the dma number
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* @size: the dma transfer size
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*
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* Return: The current pointer in DMA transfer buffer in bytes.
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*/
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unsigned int snd_dma_pointer(unsigned long dma, unsigned int size)
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{
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unsigned long flags;
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unsigned int result, result1;
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flags = claim_dma_lock();
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clear_dma_ff(dma);
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if (!isa_dma_bridge_buggy)
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disable_dma(dma);
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result = get_dma_residue(dma);
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/*
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* HACK - read the counter again and choose higher value in order to
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* avoid reading during counter lower byte roll over if the
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* isa_dma_bridge_buggy is set.
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*/
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result1 = get_dma_residue(dma);
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if (!isa_dma_bridge_buggy)
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enable_dma(dma);
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release_dma_lock(flags);
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if (unlikely(result < result1))
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result = result1;
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#ifdef CONFIG_SND_DEBUG
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if (result > size)
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pr_err("ALSA: pointer (0x%x) for DMA #%ld is greater than transfer size (0x%x)\n", result, dma, size);
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#endif
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if (result >= size || result == 0)
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return 0;
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else
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return size - result;
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}
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EXPORT_SYMBOL(snd_dma_pointer);
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