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-rw-r--r--sound/core/isadma.c117
1 files changed, 117 insertions, 0 deletions
diff --git a/sound/core/isadma.c b/sound/core/isadma.c
new file mode 100644
index 000000000..31e8544d7
--- /dev/null
+++ b/sound/core/isadma.c
@@ -0,0 +1,117 @@
+/*
+ * ISA DMA support functions
+ * Copyright (c) by Jaroslav Kysela <perex@perex.cz>
+ *
+ *
+ * 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
+ *
+ */
+
+/*
+ * Defining following add some delay. Maybe this helps for some broken
+ * ISA DMA controllers.
+ */
+
+#undef HAVE_REALLY_SLOW_DMA_CONTROLLER
+
+#include <linux/export.h>
+#include <sound/core.h>
+#include <asm/dma.h>
+
+/**
+ * snd_dma_program - program an ISA DMA transfer
+ * @dma: the dma number
+ * @addr: the physical address of the buffer
+ * @size: the DMA transfer size
+ * @mode: the DMA transfer mode, DMA_MODE_XXX
+ *
+ * Programs an ISA DMA transfer for the given buffer.
+ */
+void snd_dma_program(unsigned long dma,
+ unsigned long addr, unsigned int size,
+ unsigned short mode)
+{
+ unsigned long flags;
+
+ flags = claim_dma_lock();
+ disable_dma(dma);
+ clear_dma_ff(dma);
+ set_dma_mode(dma, mode);
+ set_dma_addr(dma, addr);
+ set_dma_count(dma, size);
+ if (!(mode & DMA_MODE_NO_ENABLE))
+ enable_dma(dma);
+ release_dma_lock(flags);
+}
+
+EXPORT_SYMBOL(snd_dma_program);
+
+/**
+ * snd_dma_disable - stop the ISA DMA transfer
+ * @dma: the dma number
+ *
+ * Stops the ISA DMA transfer.
+ */
+void snd_dma_disable(unsigned long dma)
+{
+ unsigned long flags;
+
+ flags = claim_dma_lock();
+ clear_dma_ff(dma);
+ disable_dma(dma);
+ release_dma_lock(flags);
+}
+
+EXPORT_SYMBOL(snd_dma_disable);
+
+/**
+ * snd_dma_pointer - return the current pointer to DMA transfer buffer in bytes
+ * @dma: the dma number
+ * @size: the dma transfer size
+ *
+ * Return: The current pointer in DMA transfer buffer in bytes.
+ */
+unsigned int snd_dma_pointer(unsigned long dma, unsigned int size)
+{
+ unsigned long flags;
+ unsigned int result, result1;
+
+ flags = claim_dma_lock();
+ clear_dma_ff(dma);
+ if (!isa_dma_bridge_buggy)
+ disable_dma(dma);
+ result = get_dma_residue(dma);
+ /*
+ * HACK - read the counter again and choose higher value in order to
+ * avoid reading during counter lower byte roll over if the
+ * isa_dma_bridge_buggy is set.
+ */
+ result1 = get_dma_residue(dma);
+ if (!isa_dma_bridge_buggy)
+ enable_dma(dma);
+ release_dma_lock(flags);
+ if (unlikely(result < result1))
+ result = result1;
+#ifdef CONFIG_SND_DEBUG
+ if (result > size)
+ pr_err("ALSA: pointer (0x%x) for DMA #%ld is greater than transfer size (0x%x)\n", result, dma, size);
+#endif
+ if (result >= size || result == 0)
+ return 0;
+ else
+ return size - result;
+}
+
+EXPORT_SYMBOL(snd_dma_pointer);