comedi: Move "comedi_isadma.h" to <linux/comedi/comedi_isadma.h>

Some of the header files in "drivers/comedi/drivers/" are common enough
to be useful to out-of-tree comedi driver modules.  Using them for
out-of-tree module builds is hampered by the headers being outside the
"include/" directory so it is desirable to move them.

There are about a half a dozen or so Comedi device drivers that use the
"comedi_isadma" module to add ISA DMA support.  The macros and
declarations to use that module are in the "comedi_isadma.h" header file
in the comedi "drivers" directory.  Move it into
"include/linux/comedi/".

Signed-off-by: Ian Abbott <abbotti@mev.co.uk>
Link: https://lore.kernel.org/r/20211117120604.117740-6-abbotti@mev.co.uk
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 114 insertions, 0 deletions

diff --git a/include/linux/comedi/comedi_isadma.h b/include/linux/comedi/comedi_isadma.h
new file mode 100644
index 000000000000..9d2b12db7e6e
--- /dev/null
+++ b/include/linux/comedi/comedi_isadma.h
@@ -0,0 +1,114 @@
+/* SPDX-License-Identifier: GPL-2.0+ */
+/*
+ * COMEDI ISA DMA support functions
+ * Copyright (c) 2014 H Hartley Sweeten <hsweeten@visionengravers.com>
+ */
+
+#ifndef _COMEDI_ISADMA_H
+#define _COMEDI_ISADMA_H
+
+#include <linux/types.h>
+
+struct comedi_device;
+struct device;
+
+/*
+ * These are used to avoid issues when <asm/dma.h> and the DMA_MODE_
+ * defines are not available.
+ */
+#define COMEDI_ISADMA_READ	0
+#define COMEDI_ISADMA_WRITE	1
+
+/**
+ * struct comedi_isadma_desc - cookie for ISA DMA
+ * @virt_addr:	virtual address of buffer
+ * @hw_addr:	hardware (bus) address of buffer
+ * @chan:	DMA channel
+ * @maxsize:	allocated size of buffer (in bytes)
+ * @size:	transfer size (in bytes)
+ * @mode:	DMA_MODE_READ or DMA_MODE_WRITE
+ */
+struct comedi_isadma_desc {
+	void *virt_addr;
+	dma_addr_t hw_addr;
+	unsigned int chan;
+	unsigned int maxsize;
+	unsigned int size;
+	char mode;
+};
+
+/**
+ * struct comedi_isadma - ISA DMA data
+ * @dev:	device to allocate non-coherent memory for
+ * @desc:	cookie for each DMA buffer
+ * @n_desc:	the number of cookies
+ * @cur_dma:	the current cookie in use
+ * @chan:	the first DMA channel requested
+ * @chan2:	the second DMA channel requested
+ */
+struct comedi_isadma {
+	struct device *dev;
+	struct comedi_isadma_desc *desc;
+	int n_desc;
+	int cur_dma;
+	unsigned int chan;
+	unsigned int chan2;
+};
+
+#if IS_ENABLED(CONFIG_ISA_DMA_API)
+
+void comedi_isadma_program(struct comedi_isadma_desc *desc);
+unsigned int comedi_isadma_disable(unsigned int dma_chan);
+unsigned int comedi_isadma_disable_on_sample(unsigned int dma_chan,
+					     unsigned int size);
+unsigned int comedi_isadma_poll(struct comedi_isadma *dma);
+void comedi_isadma_set_mode(struct comedi_isadma_desc *desc, char dma_dir);
+
+struct comedi_isadma *comedi_isadma_alloc(struct comedi_device *dev,
+					  int n_desc, unsigned int dma_chan1,
+					  unsigned int dma_chan2,
+					  unsigned int maxsize, char dma_dir);
+void comedi_isadma_free(struct comedi_isadma *dma);
+
+#else	/* !IS_ENABLED(CONFIG_ISA_DMA_API) */
+
+static inline void comedi_isadma_program(struct comedi_isadma_desc *desc)
+{
+}
+
+static inline unsigned int comedi_isadma_disable(unsigned int dma_chan)
+{
+	return 0;
+}
+
+static inline unsigned int
+comedi_isadma_disable_on_sample(unsigned int dma_chan, unsigned int size)
+{
+	return 0;
+}
+
+static inline unsigned int comedi_isadma_poll(struct comedi_isadma *dma)
+{
+	return 0;
+}
+
+static inline void comedi_isadma_set_mode(struct comedi_isadma_desc *desc,
+					  char dma_dir)
+{
+}
+
+static inline struct comedi_isadma *
+comedi_isadma_alloc(struct comedi_device *dev, int n_desc,
+		    unsigned int dma_chan1, unsigned int dma_chan2,
+		    unsigned int maxsize, char dma_dir)
+{
+	return NULL;
+}
+
+static inline void comedi_isadma_free(struct comedi_isadma *dma)
+{
+}
+
+#endif	/* !IS_ENABLED(CONFIG_ISA_DMA_API) */
+
+#endif	/* #ifndef _COMEDI_ISADMA_H */