Staging: comedi: add mite comedi pci driver

Hardware driver for NI Mite PCI interface chip

From: David Schleef <ds@schleef.org>
Cc: Frank Mori Hess <fmhess@users.sourceforge.net>
Cc: Ian Abbott <abbotti@mev.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

3 files changed, 1265 insertions, 0 deletions

diff --git a/drivers/staging/comedi/drivers/Makefile b/drivers/staging/comedi/drivers/Makefile
index c202ca3ecc39..9a4fb1de5e8c 100644
--- a/drivers/staging/comedi/drivers/Makefile
+++ b/drivers/staging/comedi/drivers/Makefile
@@ -3,3 +3,6 @@
 
 # Comedi "helper" modules
 obj-$(CONFIG_COMEDI)			+= comedi_fc.o
+
+# Comedi PCI drivers
+obj-$(CONFIG_COMEDI_PCI_DRIVERS)	+= mite.o
diff --git a/drivers/staging/comedi/drivers/mite.c b/drivers/staging/comedi/drivers/mite.c
new file mode 100644
index 000000000000..9cc527424d04
--- /dev/null
+++ b/drivers/staging/comedi/drivers/mite.c
@@ -0,0 +1,809 @@
+/*
+    comedi/drivers/mite.c
+    Hardware driver for NI Mite PCI interface chip
+
+    COMEDI - Linux Control and Measurement Device Interface
+    Copyright (C) 1997-2002 David A. Schleef <ds@schleef.org>
+
+    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., 675 Mass Ave, Cambridge, MA 02139, USA.
+
+*/
+
+/*
+	The PCI-MIO E series driver was originally written by
+	Tomasz Motylewski <...>, and ported to comedi by ds.
+
+	References for specifications:
+
+	   321747b.pdf  Register Level Programmer Manual (obsolete)
+	   321747c.pdf  Register Level Programmer Manual (new)
+	   DAQ-STC reference manual
+
+	Other possibly relevant info:
+
+	   320517c.pdf  User manual (obsolete)
+	   320517f.pdf  User manual (new)
+	   320889a.pdf  delete
+	   320906c.pdf  maximum signal ratings
+	   321066a.pdf  about 16x
+	   321791a.pdf  discontinuation of at-mio-16e-10 rev. c
+	   321808a.pdf  about at-mio-16e-10 rev P
+	   321837a.pdf  discontinuation of at-mio-16de-10 rev d
+	   321838a.pdf  about at-mio-16de-10 rev N
+
+	ISSUES:
+
+*/
+
+//#define USE_KMALLOC
+
+#include "mite.h"
+
+#include "comedi_fc.h"
+#include "comedi_pci.h"
+#include "../comedidev.h"
+
+#include <asm/system.h>
+
+#define PCI_MITE_SIZE		4096
+#define PCI_DAQ_SIZE		4096
+#define PCI_DAQ_SIZE_660X       8192
+
+MODULE_LICENSE("GPL");
+
+struct mite_struct *mite_devices = NULL;
+
+#define TOP_OF_PAGE(x) ((x)|(~(PAGE_MASK)))
+
+void mite_init(void)
+{
+	struct pci_dev *pcidev;
+	struct mite_struct *mite;
+
+	for (pcidev = pci_get_device(PCI_ANY_ID, PCI_ANY_ID, NULL);
+		pcidev != NULL;
+		pcidev = pci_get_device(PCI_ANY_ID, PCI_ANY_ID, pcidev)) {
+		if (pcidev->vendor == PCI_VENDOR_ID_NATINST) {
+			unsigned i;
+
+			mite = kzalloc(sizeof(*mite), GFP_KERNEL);
+			if (!mite) {
+				printk("mite: allocation failed\n");
+				pci_dev_put(pcidev);
+				return;
+			}
+			spin_lock_init(&mite->lock);
+			mite->pcidev = pci_dev_get(pcidev);
+			for (i = 0; i < MAX_MITE_DMA_CHANNELS; ++i) {
+				mite->channels[i].mite = mite;
+				mite->channels[i].channel = i;
+				mite->channels[i].done = 1;
+			}
+			mite->next = mite_devices;
+			mite_devices = mite;
+		}
+	}
+}
+
+static void dump_chip_signature(u32 csigr_bits)
+{
+	printk("mite: version = %i, type = %i, mite mode = %i, interface mode = %i\n", mite_csigr_version(csigr_bits), mite_csigr_type(csigr_bits), mite_csigr_mmode(csigr_bits), mite_csigr_imode(csigr_bits));
+	printk("mite: num channels = %i, write post fifo depth = %i, wins = %i, iowins = %i\n", mite_csigr_dmac(csigr_bits), mite_csigr_wpdep(csigr_bits), mite_csigr_wins(csigr_bits), mite_csigr_iowins(csigr_bits));
+}
+
+unsigned mite_fifo_size(struct mite_struct * mite, unsigned channel)
+{
+	unsigned fcr_bits = readl(mite->mite_io_addr +
+		MITE_FCR(channel));
+	unsigned empty_count = (fcr_bits >> 16) & 0xff;
+	unsigned full_count = fcr_bits & 0xff;
+	return empty_count + full_count;
+}
+
+int mite_setup2(struct mite_struct *mite, unsigned use_iodwbsr_1)
+{
+	unsigned long length;
+	resource_size_t addr;
+	int i;
+	u32 csigr_bits;
+	unsigned unknown_dma_burst_bits;
+
+	if (comedi_pci_enable(mite->pcidev, "mite")) {
+		printk("error enabling mite and requesting io regions\n");
+		return -EIO;
+	}
+	pci_set_master(mite->pcidev);
+
+	addr = pci_resource_start(mite->pcidev, 0);
+	mite->mite_phys_addr = addr;
+	mite->mite_io_addr = ioremap(addr, PCI_MITE_SIZE);
+	if (!mite->mite_io_addr) {
+		printk("failed to remap mite io memory address\n");
+		return -ENOMEM;
+	}
+	printk("MITE:0x%08llx mapped to %p ",
+		(unsigned long long)mite->mite_phys_addr, mite->mite_io_addr);
+
+	addr = pci_resource_start(mite->pcidev, 1);
+	mite->daq_phys_addr = addr;
+	length = pci_resource_len(mite->pcidev, 1);
+	// In case of a 660x board, DAQ size is 8k instead of 4k (see as shown by lspci output)
+	mite->daq_io_addr = ioremap(mite->daq_phys_addr, length);
+	if (!mite->daq_io_addr) {
+		printk("failed to remap daq io memory address\n");
+		return -ENOMEM;
+	}
+	printk("DAQ:0x%08llx mapped to %p\n",
+		(unsigned long long)mite->daq_phys_addr, mite->daq_io_addr);
+
+	if (use_iodwbsr_1) {
+		writel(0, mite->mite_io_addr + MITE_IODWBSR);
+		printk("mite: using I/O Window Base Size register 1\n");
+		writel(mite->
+			daq_phys_addr | WENAB |
+			MITE_IODWBSR_1_WSIZE_bits(length),
+			mite->mite_io_addr + MITE_IODWBSR_1);
+		writel(0, mite->mite_io_addr + MITE_IODWCR_1);
+	} else {
+		writel(mite->daq_phys_addr | WENAB,
+			mite->mite_io_addr + MITE_IODWBSR);
+	}
+	/* make sure dma bursts work.  I got this from running a bus analyzer
+	   on a pxi-6281 and a pxi-6713.  6713 powered up with register value
+	   of 0x61f and bursts worked.  6281 powered up with register value of
+	   0x1f and bursts didn't work.  The NI windows driver reads the register,
+	   then does a bitwise-or of 0x600 with it and writes it back.
+	 */
+	unknown_dma_burst_bits =
+		readl(mite->mite_io_addr + MITE_UNKNOWN_DMA_BURST_REG);
+	unknown_dma_burst_bits |= UNKNOWN_DMA_BURST_ENABLE_BITS;
+	writel(unknown_dma_burst_bits,
+		mite->mite_io_addr + MITE_UNKNOWN_DMA_BURST_REG);
+
+	csigr_bits = readl(mite->mite_io_addr + MITE_CSIGR);
+	mite->num_channels = mite_csigr_dmac(csigr_bits);
+	if (mite->num_channels > MAX_MITE_DMA_CHANNELS) {
+		printk("mite: bug? chip claims to have %i dma channels.  Setting to %i.\n", mite->num_channels, MAX_MITE_DMA_CHANNELS);
+		mite->num_channels = MAX_MITE_DMA_CHANNELS;
+	}
+	dump_chip_signature(csigr_bits);
+	for (i = 0; i < mite->num_channels; i++) {
+		writel(CHOR_DMARESET, mite->mite_io_addr + MITE_CHOR(i));
+		/* disable interrupts */
+		writel(CHCR_CLR_DMA_IE | CHCR_CLR_LINKP_IE | CHCR_CLR_SAR_IE |
+			CHCR_CLR_DONE_IE | CHCR_CLR_MRDY_IE | CHCR_CLR_DRDY_IE |
+			CHCR_CLR_LC_IE | CHCR_CLR_CONT_RB_IE,
+			mite->mite_io_addr + MITE_CHCR(i));
+	}
+	mite->fifo_size = mite_fifo_size(mite, 0);
+	printk("mite: fifo size is %i.\n", mite->fifo_size);
+	mite->used = 1;
+
+	return 0;
+}
+
+int mite_setup(struct mite_struct *mite)
+{
+	return mite_setup2(mite, 0);
+}
+
+void mite_cleanup(void)
+{
+	struct mite_struct *mite, *next;
+
+	for (mite = mite_devices; mite; mite = next) {
+		pci_dev_put(mite->pcidev);
+		next = mite->next;
+		kfree(mite);
+	}
+}
+
+void mite_unsetup(struct mite_struct *mite)
+{
+	//unsigned long offset, start, length;
+
+	if (!mite)
+		return;
+
+	if (mite->mite_io_addr) {
+		iounmap(mite->mite_io_addr);
+		mite->mite_io_addr = NULL;
+	}
+	if (mite->daq_io_addr) {
+		iounmap(mite->daq_io_addr);
+		mite->daq_io_addr = NULL;
+	}
+	if (mite->mite_phys_addr) {
+		comedi_pci_disable(mite->pcidev);
+		mite->mite_phys_addr = 0;
+	}
+
+	mite->used = 0;
+}
+
+void mite_list_devices(void)
+{
+	struct mite_struct *mite, *next;
+
+	printk("Available NI device IDs:");
+	if (mite_devices)
+		for (mite = mite_devices; mite; mite = next) {
+			next = mite->next;
+			printk(" 0x%04x", mite_device_id(mite));
+			if (mite->used)
+				printk("(used)");
+		}
+	printk("\n");
+
+}
+
+struct mite_channel *mite_request_channel_in_range(struct mite_struct *mite,
+	struct mite_dma_descriptor_ring *ring, unsigned min_channel,
+	unsigned max_channel)
+{
+	int i;
+	unsigned long flags;
+	struct mite_channel *channel = NULL;
+
+	// spin lock so mite_release_channel can be called safely from interrupts
+	comedi_spin_lock_irqsave(&mite->lock, flags);
+	for (i = min_channel; i <= max_channel; ++i) {
+		if (mite->channel_allocated[i] == 0) {
+			mite->channel_allocated[i] = 1;
+			channel = &mite->channels[i];
+			channel->ring = ring;
+			break;
+		}
+	}
+	comedi_spin_unlock_irqrestore(&mite->lock, flags);
+	return channel;
+}
+
+void mite_release_channel(struct mite_channel *mite_chan)
+{
+	struct mite_struct *mite = mite_chan->mite;
+	unsigned long flags;
+
+	// spin lock to prevent races with mite_request_channel
+	comedi_spin_lock_irqsave(&mite->lock, flags);
+	if (mite->channel_allocated[mite_chan->channel]) {
+		mite_dma_disarm(mite_chan);
+		mite_dma_reset(mite_chan);
+/* disable all channel's interrupts (do it after disarm/reset so
+MITE_CHCR reg isn't changed while dma is still active!) */
+		writel(CHCR_CLR_DMA_IE | CHCR_CLR_LINKP_IE |
+			CHCR_CLR_SAR_IE | CHCR_CLR_DONE_IE |
+			CHCR_CLR_MRDY_IE | CHCR_CLR_DRDY_IE |
+			CHCR_CLR_LC_IE | CHCR_CLR_CONT_RB_IE,
+			mite->mite_io_addr + MITE_CHCR(mite_chan->channel));
+		mite->channel_allocated[mite_chan->channel] = 0;
+		mite_chan->ring = NULL;
+		mmiowb();
+	}
+	comedi_spin_unlock_irqrestore(&mite->lock, flags);
+}
+
+void mite_dma_arm(struct mite_channel *mite_chan)
+{
+	struct mite_struct *mite = mite_chan->mite;
+	int chor;
+	unsigned long flags;
+
+	MDPRINTK("mite_dma_arm ch%i\n", channel);
+	/* memory barrier is intended to insure any twiddling with the buffer
+	   is done before writing to the mite to arm dma transfer */
+	smp_mb();
+	/* arm */
+	chor = CHOR_START;
+	comedi_spin_lock_irqsave(&mite->lock, flags);
+	mite_chan->done = 0;
+	writel(chor, mite->mite_io_addr + MITE_CHOR(mite_chan->channel));
+	mmiowb();
+	comedi_spin_unlock_irqrestore(&mite->lock, flags);
+//      mite_dma_tcr(mite, channel);
+}
+
+/**************************************/
+
+int mite_buf_change(struct mite_dma_descriptor_ring *ring, comedi_async * async)
+{
+	unsigned int n_links;
+	int i;
+
+	if (ring->descriptors) {
+		dma_free_coherent(ring->hw_dev,
+			ring->n_links * sizeof(struct mite_dma_descriptor),
+			ring->descriptors, ring->descriptors_dma_addr);
+	}
+	ring->descriptors = NULL;
+	ring->descriptors_dma_addr = 0;
+	ring->n_links = 0;
+
+	if (async->prealloc_bufsz == 0) {
+		return 0;
+	}
+	n_links = async->prealloc_bufsz >> PAGE_SHIFT;
+
+	MDPRINTK("ring->hw_dev=%p, n_links=0x%04x\n", ring->hw_dev, n_links);
+
+	ring->descriptors =
+		dma_alloc_coherent(ring->hw_dev,
+		n_links * sizeof(struct mite_dma_descriptor),
+		&ring->descriptors_dma_addr, GFP_KERNEL);
+	if (!ring->descriptors) {
+		printk("mite: ring buffer allocation failed\n");
+		return -ENOMEM;
+	}
+	ring->n_links = n_links;
+
+	for (i = 0; i < n_links; i++) {
+		ring->descriptors[i].count = cpu_to_le32(PAGE_SIZE);
+		ring->descriptors[i].addr =
+			cpu_to_le32(async->buf_page_list[i].dma_addr);
+		ring->descriptors[i].next =
+			cpu_to_le32(ring->descriptors_dma_addr + (i +
+				1) * sizeof(struct mite_dma_descriptor));
+	}
+	ring->descriptors[n_links - 1].next =
+		cpu_to_le32(ring->descriptors_dma_addr);
+	/* barrier is meant to insure that all the writes to the dma descriptors
+	   have completed before the dma controller is commanded to read them */
+	smp_wmb();
+	return 0;
+}
+
+void mite_prep_dma(struct mite_channel *mite_chan,
+	unsigned int num_device_bits, unsigned int num_memory_bits)
+{
+	unsigned int chor, chcr, mcr, dcr, lkcr;
+	struct mite_struct *mite = mite_chan->mite;
+
+	MDPRINTK("mite_prep_dma ch%i\n", mite_chan->channel);
+
+	/* reset DMA and FIFO */
+	chor = CHOR_DMARESET | CHOR_FRESET;
+	writel(chor, mite->mite_io_addr + MITE_CHOR(mite_chan->channel));
+
+	/* short link chaining mode */
+	chcr = CHCR_SET_DMA_IE | CHCR_LINKSHORT | CHCR_SET_DONE_IE |
+		CHCR_BURSTEN;
+	/*
+	 * Link Complete Interrupt: interrupt every time a link
+	 * in MITE_RING is completed. This can generate a lot of
+	 * extra interrupts, but right now we update the values
+	 * of buf_int_ptr and buf_int_count at each interrupt.  A
+	 * better method is to poll the MITE before each user
+	 * "read()" to calculate the number of bytes available.
+	 */
+	chcr |= CHCR_SET_LC_IE;
+	if (num_memory_bits == 32 && num_device_bits == 16) {
+		/* Doing a combined 32 and 16 bit byteswap gets the 16 bit samples into the fifo in the right order.
+		   Tested doing 32 bit memory to 16 bit device transfers to the analog out of a pxi-6281,
+		   which has mite version = 1, type = 4.  This also works for dma reads from the counters
+		   on e-series boards.  */
+		chcr |= CHCR_BYTE_SWAP_DEVICE | CHCR_BYTE_SWAP_MEMORY;
+	}
+	if (mite_chan->dir == COMEDI_INPUT) {
+		chcr |= CHCR_DEV_TO_MEM;
+	}
+	writel(chcr, mite->mite_io_addr + MITE_CHCR(mite_chan->channel));
+
+	/* to/from memory */
+	mcr = CR_RL(64) | CR_ASEQUP;
+	switch (num_memory_bits) {
+	case 8:
+		mcr |= CR_PSIZE8;
+		break;
+	case 16:
+		mcr |= CR_PSIZE16;
+		break;
+	case 32:
+		mcr |= CR_PSIZE32;
+		break;
+	default:
+		rt_printk
+			("mite: bug! invalid mem bit width for dma transfer\n");
+		break;
+	}
+	writel(mcr, mite->mite_io_addr + MITE_MCR(mite_chan->channel));
+
+	/* from/to device */
+	dcr = CR_RL(64) | CR_ASEQUP;
+	dcr |= CR_PORTIO | CR_AMDEVICE | CR_REQSDRQ(mite_chan->channel);
+	switch (num_device_bits) {
+	case 8:
+		dcr |= CR_PSIZE8;
+		break;
+	case 16:
+		dcr |= CR_PSIZE16;
+		break;
+	case 32:
+		dcr |= CR_PSIZE32;
+		break;
+	default:
+		rt_printk
+			("mite: bug! invalid dev bit width for dma transfer\n");
+		break;
+	}
+	writel(dcr, mite->mite_io_addr + MITE_DCR(mite_chan->channel));
+
+	/* reset the DAR */
+	writel(0, mite->mite_io_addr + MITE_DAR(mite_chan->channel));
+
+	/* the link is 32bits */
+	lkcr = CR_RL(64) | CR_ASEQUP | CR_PSIZE32;
+	writel(lkcr, mite->mite_io_addr + MITE_LKCR(mite_chan->channel));
+
+	/* starting address for link chaining */
+	writel(mite_chan->ring->descriptors_dma_addr,
+		mite->mite_io_addr + MITE_LKAR(mite_chan->channel));
+
+	MDPRINTK("exit mite_prep_dma\n");
+}
+
+u32 mite_device_bytes_transferred(struct mite_channel *mite_chan)
+{
+	struct mite_struct *mite = mite_chan->mite;
+	return readl(mite->mite_io_addr + MITE_DAR(mite_chan->channel));
+}
+
+u32 mite_bytes_in_transit(struct mite_channel * mite_chan)
+{
+	struct mite_struct *mite = mite_chan->mite;
+	return readl(mite->mite_io_addr +
+		MITE_FCR(mite_chan->channel)) & 0x000000FF;
+}
+
+// returns lower bound for number of bytes transferred from device to memory
+u32 mite_bytes_written_to_memory_lb(struct mite_channel * mite_chan)
+{
+	u32 device_byte_count;
+
+	device_byte_count = mite_device_bytes_transferred(mite_chan);
+	return device_byte_count - mite_bytes_in_transit(mite_chan);
+}
+
+// returns upper bound for number of bytes transferred from device to memory
+u32 mite_bytes_written_to_memory_ub(struct mite_channel * mite_chan)
+{
+	u32 in_transit_count;
+
+	in_transit_count = mite_bytes_in_transit(mite_chan);
+	return mite_device_bytes_transferred(mite_chan) - in_transit_count;
+}
+
+// returns lower bound for number of bytes read from memory for transfer to device
+u32 mite_bytes_read_from_memory_lb(struct mite_channel * mite_chan)
+{
+	u32 device_byte_count;
+
+	device_byte_count = mite_device_bytes_transferred(mite_chan);
+	return device_byte_count + mite_bytes_in_transit(mite_chan);
+}
+
+// returns upper bound for number of bytes read from memory for transfer to device
+u32 mite_bytes_read_from_memory_ub(struct mite_channel * mite_chan)
+{
+	u32 in_transit_count;
+
+	in_transit_count = mite_bytes_in_transit(mite_chan);
+	return mite_device_bytes_transferred(mite_chan) + in_transit_count;
+}
+
+unsigned mite_dma_tcr(struct mite_channel *mite_chan)
+{
+	struct mite_struct *mite = mite_chan->mite;
+	int tcr;
+	int lkar;
+
+	lkar = readl(mite->mite_io_addr + MITE_LKAR(mite_chan->channel));
+	tcr = readl(mite->mite_io_addr + MITE_TCR(mite_chan->channel));
+	MDPRINTK("mite_dma_tcr ch%i, lkar=0x%08x tcr=%d\n", mite_chan->channel,
+		lkar, tcr);
+
+	return tcr;
+}
+
+void mite_dma_disarm(struct mite_channel *mite_chan)
+{
+	struct mite_struct *mite = mite_chan->mite;
+	unsigned chor;
+
+	/* disarm */
+	chor = CHOR_ABORT;
+	writel(chor, mite->mite_io_addr + MITE_CHOR(mite_chan->channel));
+}
+
+int mite_sync_input_dma(struct mite_channel *mite_chan, comedi_async * async)
+{
+	int count;
+	unsigned int nbytes, old_alloc_count;
+	const unsigned bytes_per_scan = cfc_bytes_per_scan(async->subdevice);
+
+	old_alloc_count = async->buf_write_alloc_count;
+	// write alloc as much as we can
+	comedi_buf_write_alloc(async, async->prealloc_bufsz);
+
+	nbytes = mite_bytes_written_to_memory_lb(mite_chan);
+	if ((int)(mite_bytes_written_to_memory_ub(mite_chan) -
+			old_alloc_count) > 0) {
+		rt_printk("mite: DMA overwrite of free area\n");
+		async->events |= COMEDI_CB_OVERFLOW;
+		return -1;
+	}
+
+	count = nbytes - async->buf_write_count;
+	/* it's possible count will be negative due to
+	 * conservative value returned by mite_bytes_written_to_memory_lb */
+	if (count <= 0) {
+		return 0;
+	}
+	comedi_buf_write_free(async, count);
+
+	async->scan_progress += count;
+	if (async->scan_progress >= bytes_per_scan) {
+		async->scan_progress %= bytes_per_scan;
+		async->events |= COMEDI_CB_EOS;
+	}
+	async->events |= COMEDI_CB_BLOCK;
+	return 0;
+}
+
+int mite_sync_output_dma(struct mite_channel *mite_chan, comedi_async * async)
+{
+	int count;
+	u32 nbytes_ub, nbytes_lb;
+	unsigned int old_alloc_count;
+	u32 stop_count =
+		async->cmd.stop_arg * cfc_bytes_per_scan(async->subdevice);
+
+	old_alloc_count = async->buf_read_alloc_count;
+	// read alloc as much as we can
+	comedi_buf_read_alloc(async, async->prealloc_bufsz);
+	nbytes_lb = mite_bytes_read_from_memory_lb(mite_chan);
+	if (async->cmd.stop_src == TRIG_COUNT &&
+		(int)(nbytes_lb - stop_count) > 0)
+		nbytes_lb = stop_count;
+	nbytes_ub = mite_bytes_read_from_memory_ub(mite_chan);
+	if (async->cmd.stop_src == TRIG_COUNT &&
+		(int)(nbytes_ub - stop_count) > 0)
+		nbytes_ub = stop_count;
+	if ((int)(nbytes_ub - old_alloc_count) > 0) {
+		rt_printk("mite: DMA underrun\n");
+		async->events |= COMEDI_CB_OVERFLOW;
+		return -1;
+	}
+	count = nbytes_lb - async->buf_read_count;
+	if (count <= 0) {
+		return 0;
+	}
+	if (count) {
+		comedi_buf_read_free(async, count);
+		async->events |= COMEDI_CB_BLOCK;
+	}
+	return 0;
+}
+
+unsigned mite_get_status(struct mite_channel *mite_chan)
+{
+	struct mite_struct *mite = mite_chan->mite;
+	unsigned status;
+	unsigned long flags;
+
+	comedi_spin_lock_irqsave(&mite->lock, flags);
+	status = readl(mite->mite_io_addr + MITE_CHSR(mite_chan->channel));
+	if (status & CHSR_DONE) {
+		mite_chan->done = 1;
+		writel(CHOR_CLRDONE,
+			mite->mite_io_addr + MITE_CHOR(mite_chan->channel));
+	}
+	mmiowb();
+	comedi_spin_unlock_irqrestore(&mite->lock, flags);
+	return status;
+}
+
+int mite_done(struct mite_channel *mite_chan)
+{
+	struct mite_struct *mite = mite_chan->mite;
+	unsigned long flags;
+	int done;
+
+	mite_get_status(mite_chan);
+	comedi_spin_lock_irqsave(&mite->lock, flags);
+	done = mite_chan->done;
+	comedi_spin_unlock_irqrestore(&mite->lock, flags);
+	return done;
+}
+
+#ifdef DEBUG_MITE
+
+static void mite_decode(char **bit_str, unsigned int bits);
+
+/* names of bits in mite registers */
+
+static const char *const mite_CHOR_strings[] = {
+	"start", "cont", "stop", "abort",
+	"freset", "clrlc", "clrrb", "clrdone",
+	"clr_lpause", "set_lpause", "clr_send_tc",
+	"set_send_tc", "12", "13", "14",
+	"15", "16", "17", "18",
+	"19", "20", "21", "22",
+	"23", "24", "25", "26",
+	"27", "28", "29", "30",
+	"dmareset",
+};
+
+static const char *const mite_CHCR_strings[] = {
+	"continue", "ringbuff", "2", "3",
+	"4", "5", "6", "7",
+	"8", "9", "10", "11",
+	"12", "13", "bursten", "fifodis",
+	"clr_cont_rb_ie", "set_cont_rb_ie", "clr_lc_ie", "set_lc_ie",
+	"clr_drdy_ie", "set_drdy_ie", "clr_mrdy_ie", "set_mrdy_ie",
+	"clr_done_ie", "set_done_ie", "clr_sar_ie", "set_sar_ie",
+	"clr_linkp_ie", "set_linkp_ie", "clr_dma_ie", "set_dma_ie",
+};
+
+static const char *const mite_MCR_strings[] = {
+	"amdevice", "1", "2", "3",
+	"4", "5", "portio", "portvxi",
+	"psizebyte", "psizehalf (byte & half = word)", "aseqxp1", "11",
+	"12", "13", "blocken", "berhand",
+	"reqsintlim/reqs0", "reqs1", "reqs2", "rd32",
+	"rd512", "rl1", "rl2", "rl8",
+	"24", "25", "26", "27",
+	"28", "29", "30", "stopen",
+};
+
+static const char *const mite_DCR_strings[] = {
+	"amdevice", "1", "2", "3",
+	"4", "5", "portio", "portvxi",
+	"psizebyte", "psizehalf (byte & half = word)", "aseqxp1", "aseqxp2",
+	"aseqxp8", "13", "blocken", "berhand",
+	"reqsintlim", "reqs1", "reqs2", "rd32",
+	"rd512", "rl1", "rl2", "rl8",
+	"23", "24", "25", "27",
+	"28", "wsdevc", "wsdevs", "rwdevpack",
+};
+
+static const char *const mite_LKCR_strings[] = {
+	"amdevice", "1", "2", "3",
+	"4", "5", "portio", "portvxi",
+	"psizebyte", "psizehalf (byte & half = word)", "asequp", "aseqdown",
+	"12", "13", "14", "berhand",
+	"16", "17", "18", "rd32",
+	"rd512", "rl1", "rl2", "rl8",
+	"24", "25", "26", "27",
+	"28", "29", "30", "chngend",
+};
+
+static const char *const mite_CHSR_strings[] = {
+	"d.err0", "d.err1", "m.err0", "m.err1",
+	"l.err0", "l.err1", "drq0", "drq1",
+	"end", "xferr", "operr0", "operr1",
+	"stops", "habort", "sabort", "error",
+	"16", "conts_rb", "18", "linkc",
+	"20", "drdy", "22", "mrdy",
+	"24", "done", "26", "sars",
+	"28", "lpauses", "30", "int",
+};
+
+void mite_dump_regs(struct mite_channel *mite_chan)
+{
+	unsigned long mite_io_addr =
+		(unsigned long)mite_chan->mite->mite_io_addr;
+	unsigned long addr = 0;
+	unsigned long temp = 0;
+
+	printk("mite_dump_regs ch%i\n", mite_chan->channel);
+	printk("mite address is  =0x%08lx\n", mite_io_addr);
+
+	addr = mite_io_addr + MITE_CHOR(channel);
+	printk("mite status[CHOR]at 0x%08lx =0x%08lx\n", addr, temp =
+		readl(addr));
+	mite_decode(mite_CHOR_strings, temp);
+	addr = mite_io_addr + MITE_CHCR(channel);
+	printk("mite status[CHCR]at 0x%08lx =0x%08lx\n", addr, temp =
+		readl(addr));
+	mite_decode(mite_CHCR_strings, temp);
+	addr = mite_io_addr + MITE_TCR(channel);
+	printk("mite status[TCR] at 0x%08lx =0x%08x\n", addr, readl(addr));
+	addr = mite_io_addr + MITE_MCR(channel);
+	printk("mite status[MCR] at 0x%08lx =0x%08lx\n", addr, temp =
+		readl(addr));
+	mite_decode(mite_MCR_strings, temp);
+
+	addr = mite_io_addr + MITE_MAR(channel);
+	printk("mite status[MAR] at 0x%08lx =0x%08x\n", addr, readl(addr));
+	addr = mite_io_addr + MITE_DCR(channel);
+	printk("mite status[DCR] at 0x%08lx =0x%08lx\n", addr, temp =
+		readl(addr));
+	mite_decode(mite_DCR_strings, temp);
+	addr = mite_io_addr + MITE_DAR(channel);
+	printk("mite status[DAR] at 0x%08lx =0x%08x\n", addr, readl(addr));
+	addr = mite_io_addr + MITE_LKCR(channel);
+	printk("mite status[LKCR]at 0x%08lx =0x%08lx\n", addr, temp =
+		readl(addr));
+	mite_decode(mite_LKCR_strings, temp);
+	addr = mite_io_addr + MITE_LKAR(channel);
+	printk("mite status[LKAR]at 0x%08lx =0x%08x\n", addr, readl(addr));
+
+	addr = mite_io_addr + MITE_CHSR(channel);
+	printk("mite status[CHSR]at 0x%08lx =0x%08lx\n", addr, temp =
+		readl(addr));
+	mite_decode(mite_CHSR_strings, temp);
+	addr = mite_io_addr + MITE_FCR(channel);
+	printk("mite status[FCR] at 0x%08lx =0x%08x\n\n", addr, readl(addr));
+}
+
+static void mite_decode(char **bit_str, unsigned int bits)
+{
+	int i;
+
+	for (i = 31; i >= 0; i--) {
+		if (bits & (1 << i)) {
+			printk(" %s", bit_str[i]);
+		}
+	}
+	printk("\n");
+}
+#endif
+
+#ifdef MODULE
+int __init init_module(void)
+{
+	mite_init();
+	mite_list_devices();
+
+	return 0;
+}
+
+void __exit cleanup_module(void)
+{
+	mite_cleanup();
+}
+
+EXPORT_SYMBOL(mite_dma_tcr);
+EXPORT_SYMBOL(mite_dma_arm);
+EXPORT_SYMBOL(mite_dma_disarm);
+EXPORT_SYMBOL(mite_sync_input_dma);
+EXPORT_SYMBOL(mite_sync_output_dma);
+EXPORT_SYMBOL(mite_setup);
+EXPORT_SYMBOL(mite_setup2);
+EXPORT_SYMBOL(mite_unsetup);
+#if 0
+EXPORT_SYMBOL(mite_kvmem_segment_load);
+EXPORT_SYMBOL(mite_ll_from_kvmem);
+EXPORT_SYMBOL(mite_setregs);
+#endif
+EXPORT_SYMBOL(mite_devices);
+EXPORT_SYMBOL(mite_list_devices);
+EXPORT_SYMBOL(mite_request_channel_in_range);
+EXPORT_SYMBOL(mite_release_channel);
+EXPORT_SYMBOL(mite_prep_dma);
+EXPORT_SYMBOL(mite_buf_change);
+EXPORT_SYMBOL(mite_bytes_written_to_memory_lb);
+EXPORT_SYMBOL(mite_bytes_written_to_memory_ub);
+EXPORT_SYMBOL(mite_bytes_read_from_memory_lb);
+EXPORT_SYMBOL(mite_bytes_read_from_memory_ub);
+EXPORT_SYMBOL(mite_bytes_in_transit);
+EXPORT_SYMBOL(mite_get_status);
+EXPORT_SYMBOL(mite_done);
+#ifdef DEBUG_MITE
+EXPORT_SYMBOL(mite_decode);
+EXPORT_SYMBOL(mite_dump_regs);
+#endif
+
+#endif
diff --git a/drivers/staging/comedi/drivers/mite.h b/drivers/staging/comedi/drivers/mite.h
new file mode 100644
index 000000000000..90a656b5c5b7
--- /dev/null
+++ b/drivers/staging/comedi/drivers/mite.h
@@ -0,0 +1,453 @@
+/*
+    module/mite.h
+    Hardware driver for NI Mite PCI interface chip
+
+    COMEDI - Linux Control and Measurement Device Interface
+    Copyright (C) 1999 David A. Schleef <ds@schleef.org>
+
+    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., 675 Mass Ave, Cambridge, MA 02139, USA.
+
+*/
+
+#ifndef _MITE_H_
+#define _MITE_H_
+
+#include "../comedidev.h"
+#include "../pci.h"
+
+#define PCI_VENDOR_ID_NATINST		0x1093
+
+// #define DEBUG_MITE
+#define PCIMIO_COMPAT
+
+#ifdef DEBUG_MITE
+#define MDPRINTK(format,args...)	printk(format , ## args )
+#else
+#define MDPRINTK(format,args...)
+#endif
+
+#define MAX_MITE_DMA_CHANNELS 8
+
+struct mite_dma_descriptor {
+	u32 count;
+	u32 addr;
+	u32 next;
+	u32 dar;
+};
+
+struct mite_dma_descriptor_ring {
+	struct device *hw_dev;
+	unsigned int n_links;
+	struct mite_dma_descriptor *descriptors;
+	dma_addr_t descriptors_dma_addr;
+};
+
+struct mite_channel {
+	struct mite_struct *mite;
+	unsigned channel;
+	int dir;
+	int done;
+	struct mite_dma_descriptor_ring *ring;
+};
+
+struct mite_struct {
+	struct mite_struct *next;
+	int used;
+
+	struct pci_dev *pcidev;
+	resource_size_t mite_phys_addr;
+	void *mite_io_addr;
+	resource_size_t daq_phys_addr;
+	void *daq_io_addr;
+
+	struct mite_channel channels[MAX_MITE_DMA_CHANNELS];
+	short channel_allocated[MAX_MITE_DMA_CHANNELS];
+	int num_channels;
+	unsigned fifo_size;
+	spinlock_t lock;
+};
+
+static inline struct mite_dma_descriptor_ring *mite_alloc_ring(struct
+	mite_struct *mite)
+{
+	struct mite_dma_descriptor_ring *ring =
+		kmalloc(sizeof(struct mite_dma_descriptor_ring), GFP_KERNEL);
+	if (ring == NULL)
+		return ring;
+	ring->hw_dev = get_device(&mite->pcidev->dev);
+	if (ring->hw_dev == NULL) {
+		kfree(ring);
+		return NULL;
+	}
+	ring->n_links = 0;
+	ring->descriptors = NULL;
+	ring->descriptors_dma_addr = 0;
+	return ring;
+};
+
+static inline void mite_free_ring(struct mite_dma_descriptor_ring *ring)
+{
+	if (ring) {
+		if (ring->descriptors) {
+			dma_free_coherent(ring->hw_dev,
+				ring->n_links *
+				sizeof(struct mite_dma_descriptor),
+				ring->descriptors, ring->descriptors_dma_addr);
+		}
+		put_device(ring->hw_dev);
+		kfree(ring);
+	}
+};
+
+extern struct mite_struct *mite_devices;
+
+static inline unsigned int mite_irq(struct mite_struct *mite)
+{
+	return mite->pcidev->irq;
+};
+static inline unsigned int mite_device_id(struct mite_struct *mite)
+{
+	return mite->pcidev->device;
+};
+
+void mite_init(void);
+void mite_cleanup(void);
+int mite_setup(struct mite_struct *mite);
+int mite_setup2(struct mite_struct *mite, unsigned use_iodwbsr_1);
+void mite_unsetup(struct mite_struct *mite);
+void mite_list_devices(void);
+struct mite_channel *mite_request_channel_in_range(struct mite_struct *mite,
+	struct mite_dma_descriptor_ring *ring, unsigned min_channel,
+	unsigned max_channel);
+static inline struct mite_channel *mite_request_channel(struct mite_struct
+	*mite, struct mite_dma_descriptor_ring *ring)
+{
+	return mite_request_channel_in_range(mite, ring, 0,
+		mite->num_channels - 1);
+}
+void mite_release_channel(struct mite_channel *mite_chan);
+
+unsigned mite_dma_tcr(struct mite_channel *mite_chan);
+void mite_dma_arm(struct mite_channel *mite_chan);
+void mite_dma_disarm(struct mite_channel *mite_chan);
+int mite_sync_input_dma(struct mite_channel *mite_chan, comedi_async * async);
+int mite_sync_output_dma(struct mite_channel *mite_chan, comedi_async * async);
+u32 mite_bytes_written_to_memory_lb(struct mite_channel *mite_chan);
+u32 mite_bytes_written_to_memory_ub(struct mite_channel *mite_chan);
+u32 mite_bytes_read_from_memory_lb(struct mite_channel *mite_chan);
+u32 mite_bytes_read_from_memory_ub(struct mite_channel *mite_chan);
+u32 mite_bytes_in_transit(struct mite_channel *mite_chan);
+unsigned mite_get_status(struct mite_channel *mite_chan);
+int mite_done(struct mite_channel *mite_chan);
+
+#if 0
+unsigned long mite_ll_from_kvmem(struct mite_struct *mite, comedi_async * async,
+	int len);
+void mite_setregs(struct mite_struct *mite, unsigned long ll_start, int chan,
+	int dir);
+#endif
+
+void mite_prep_dma(struct mite_channel *mite_chan,
+	unsigned int num_device_bits, unsigned int num_memory_bits);
+int mite_buf_change(struct mite_dma_descriptor_ring *ring,
+	comedi_async * async);
+
+#ifdef DEBUG_MITE
+void mite_print_chsr(unsigned int chsr);
+void mite_dump_regs(struct mite_channel *mite_chan);
+#endif
+
+static inline int CHAN_OFFSET(int channel)
+{
+	return 0x500 + 0x100 * channel;
+};
+
+enum mite_registers {
+	/* The bits 0x90180700 in MITE_UNKNOWN_DMA_BURST_REG can be
+	   written and read back.  The bits 0x1f always read as 1.
+	   The rest always read as zero. */
+	MITE_UNKNOWN_DMA_BURST_REG = 0x28,
+	MITE_IODWBSR = 0xc0,	//IO Device Window Base Size Register
+	MITE_IODWBSR_1 = 0xc4,	// IO Device Window Base Size Register 1
+	MITE_IODWCR_1 = 0xf4,
+	MITE_PCI_CONFIG_OFFSET = 0x300,
+	MITE_CSIGR = 0x460	//chip signature
+};
+static inline int MITE_CHOR(int channel)	// channel operation
+{
+	return CHAN_OFFSET(channel) + 0x0;
+};
+static inline int MITE_CHCR(int channel)	// channel control
+{
+	return CHAN_OFFSET(channel) + 0x4;
+};
+static inline int MITE_TCR(int channel)	// transfer count
+{
+	return CHAN_OFFSET(channel) + 0x8;
+};
+static inline int MITE_MCR(int channel)	// memory configuration
+{
+	return CHAN_OFFSET(channel) + 0xc;
+};
+static inline int MITE_MAR(int channel)	// memory address
+{
+	return CHAN_OFFSET(channel) + 0x10;
+};
+static inline int MITE_DCR(int channel)	// device configuration
+{
+	return CHAN_OFFSET(channel) + 0x14;
+};
+static inline int MITE_DAR(int channel)	// device address
+{
+	return CHAN_OFFSET(channel) + 0x18;
+};
+static inline int MITE_LKCR(int channel)	// link configuration
+{
+	return CHAN_OFFSET(channel) + 0x1c;
+};
+static inline int MITE_LKAR(int channel)	// link address
+{
+	return CHAN_OFFSET(channel) + 0x20;
+};
+static inline int MITE_LLKAR(int channel)	// see mite section of tnt5002 manual
+{
+	return CHAN_OFFSET(channel) + 0x24;
+};
+static inline int MITE_BAR(int channel)	// base address
+{
+	return CHAN_OFFSET(channel) + 0x28;
+};
+static inline int MITE_BCR(int channel)	// base count
+{
+	return CHAN_OFFSET(channel) + 0x2c;
+};
+static inline int MITE_SAR(int channel)	// ? address
+{
+	return CHAN_OFFSET(channel) + 0x30;
+};
+static inline int MITE_WSCR(int channel)	// ?
+{
+	return CHAN_OFFSET(channel) + 0x34;
+};
+static inline int MITE_WSER(int channel)	// ?
+{
+	return CHAN_OFFSET(channel) + 0x38;
+};
+static inline int MITE_CHSR(int channel)	// channel status
+{
+	return CHAN_OFFSET(channel) + 0x3c;
+};
+static inline int MITE_FCR(int channel)	// fifo count
+{
+	return CHAN_OFFSET(channel) + 0x40;
+};
+
+enum MITE_IODWBSR_bits {
+	WENAB = 0x80,		// window enable
+};
+
+static inline unsigned MITE_IODWBSR_1_WSIZE_bits(unsigned size)
+{
+	unsigned order = 0;
+	while (size >>= 1)
+		++order;
+	BUG_ON(order < 1);
+	return (order - 1) & 0x1f;
+}
+
+enum MITE_UNKNOWN_DMA_BURST_bits {
+	UNKNOWN_DMA_BURST_ENABLE_BITS = 0x600
+};
+
+static inline int mite_csigr_version(u32 csigr_bits)
+{
+	return csigr_bits & 0xf;
+};
+static inline int mite_csigr_type(u32 csigr_bits)
+{				// original mite = 0, minimite = 1
+	return (csigr_bits >> 4) & 0xf;
+};
+static inline int mite_csigr_mmode(u32 csigr_bits)
+{				// mite mode, minimite = 1
+	return (csigr_bits >> 8) & 0x3;
+};
+static inline int mite_csigr_imode(u32 csigr_bits)
+{				// cpu port interface mode, pci = 0x3
+	return (csigr_bits >> 12) & 0x3;
+};
+static inline int mite_csigr_dmac(u32 csigr_bits)
+{				// number of dma channels
+	return (csigr_bits >> 16) & 0xf;
+};
+static inline int mite_csigr_wpdep(u32 csigr_bits)
+{				// write post fifo depth
+	unsigned int wpdep_bits = (csigr_bits >> 20) & 0x7;
+	if (wpdep_bits == 0)
+		return 0;
+	else
+		return 1 << (wpdep_bits - 1);
+};
+static inline int mite_csigr_wins(u32 csigr_bits)
+{
+	return (csigr_bits >> 24) & 0x1f;
+};
+static inline int mite_csigr_iowins(u32 csigr_bits)
+{				// number of io windows
+	return (csigr_bits >> 29) & 0x7;
+};
+
+enum MITE_MCR_bits {
+	MCRPON = 0,
+};
+
+enum MITE_DCR_bits {
+	DCR_NORMAL = (1 << 29),
+	DCRPON = 0,
+};
+
+enum MITE_CHOR_bits {
+	CHOR_DMARESET = (1 << 31),
+	CHOR_SET_SEND_TC = (1 << 11),
+	CHOR_CLR_SEND_TC = (1 << 10),
+	CHOR_SET_LPAUSE = (1 << 9),
+	CHOR_CLR_LPAUSE = (1 << 8),
+	CHOR_CLRDONE = (1 << 7),
+	CHOR_CLRRB = (1 << 6),
+	CHOR_CLRLC = (1 << 5),
+	CHOR_FRESET = (1 << 4),
+	CHOR_ABORT = (1 << 3),	/* stop without emptying fifo */
+	CHOR_STOP = (1 << 2),	/* stop after emptying fifo */
+	CHOR_CONT = (1 << 1),
+	CHOR_START = (1 << 0),
+	CHOR_PON = (CHOR_CLR_SEND_TC | CHOR_CLR_LPAUSE),
+};
+
+enum MITE_CHCR_bits {
+	CHCR_SET_DMA_IE = (1 << 31),
+	CHCR_CLR_DMA_IE = (1 << 30),
+	CHCR_SET_LINKP_IE = (1 << 29),
+	CHCR_CLR_LINKP_IE = (1 << 28),
+	CHCR_SET_SAR_IE = (1 << 27),
+	CHCR_CLR_SAR_IE = (1 << 26),
+	CHCR_SET_DONE_IE = (1 << 25),
+	CHCR_CLR_DONE_IE = (1 << 24),
+	CHCR_SET_MRDY_IE = (1 << 23),
+	CHCR_CLR_MRDY_IE = (1 << 22),
+	CHCR_SET_DRDY_IE = (1 << 21),
+	CHCR_CLR_DRDY_IE = (1 << 20),
+	CHCR_SET_LC_IE = (1 << 19),
+	CHCR_CLR_LC_IE = (1 << 18),
+	CHCR_SET_CONT_RB_IE = (1 << 17),
+	CHCR_CLR_CONT_RB_IE = (1 << 16),
+	CHCR_FIFODIS = (1 << 15),
+	CHCR_FIFO_ON = 0,
+	CHCR_BURSTEN = (1 << 14),
+	CHCR_NO_BURSTEN = 0,
+	CHCR_BYTE_SWAP_DEVICE = (1 << 6),
+	CHCR_BYTE_SWAP_MEMORY = (1 << 4),
+	CHCR_DIR = (1 << 3),
+	CHCR_DEV_TO_MEM = CHCR_DIR,
+	CHCR_MEM_TO_DEV = 0,
+	CHCR_NORMAL = (0 << 0),
+	CHCR_CONTINUE = (1 << 0),
+	CHCR_RINGBUFF = (2 << 0),
+	CHCR_LINKSHORT = (4 << 0),
+	CHCR_LINKLONG = (5 << 0),
+	CHCRPON =
+		(CHCR_CLR_DMA_IE | CHCR_CLR_LINKP_IE | CHCR_CLR_SAR_IE |
+		CHCR_CLR_DONE_IE | CHCR_CLR_MRDY_IE | CHCR_CLR_DRDY_IE |
+		CHCR_CLR_LC_IE | CHCR_CLR_CONT_RB_IE),
+};
+
+enum ConfigRegister_bits {
+	CR_REQS_MASK = 0x7 << 16,
+	CR_ASEQDONT = 0x0 << 10,
+	CR_ASEQUP = 0x1 << 10,
+	CR_ASEQDOWN = 0x2 << 10,
+	CR_ASEQ_MASK = 0x3 << 10,
+	CR_PSIZE8 = (1 << 8),
+	CR_PSIZE16 = (2 << 8),
+	CR_PSIZE32 = (3 << 8),
+	CR_PORTCPU = (0 << 6),
+	CR_PORTIO = (1 << 6),
+	CR_PORTVXI = (2 << 6),
+	CR_PORTMXI = (3 << 6),
+	CR_AMDEVICE = (1 << 0),
+};
+static inline int CR_REQS(int source)
+{
+	return (source & 0x7) << 16;
+};
+static inline int CR_REQSDRQ(unsigned drq_line)
+{
+	/* This also works on m-series when
+	   using channels (drq_line) 4 or 5. */
+	return CR_REQS((drq_line & 0x3) | 0x4);
+}
+static inline int CR_RL(unsigned int retry_limit)
+{
+	int value = 0;
+
+	while (retry_limit) {
+		retry_limit >>= 1;
+		value++;
+	}
+	if (value > 0x7)
+		rt_printk("comedi: bug! retry_limit too large\n");
+	return (value & 0x7) << 21;
+}
+
+enum CHSR_bits {
+	CHSR_INT = (1 << 31),
+	CHSR_LPAUSES = (1 << 29),
+	CHSR_SARS = (1 << 27),
+	CHSR_DONE = (1 << 25),
+	CHSR_MRDY = (1 << 23),
+	CHSR_DRDY = (1 << 21),
+	CHSR_LINKC = (1 << 19),
+	CHSR_CONTS_RB = (1 << 17),
+	CHSR_ERROR = (1 << 15),
+	CHSR_SABORT = (1 << 14),
+	CHSR_HABORT = (1 << 13),
+	CHSR_STOPS = (1 << 12),
+	CHSR_OPERR_mask = (3 << 10),
+	CHSR_OPERR_NOERROR = (0 << 10),
+	CHSR_OPERR_FIFOERROR = (1 << 10),
+	CHSR_OPERR_LINKERROR = (1 << 10),	/* ??? */
+	CHSR_XFERR = (1 << 9),
+	CHSR_END = (1 << 8),
+	CHSR_DRQ1 = (1 << 7),
+	CHSR_DRQ0 = (1 << 6),
+	CHSR_LxERR_mask = (3 << 4),
+	CHSR_LBERR = (1 << 4),
+	CHSR_LRERR = (2 << 4),
+	CHSR_LOERR = (3 << 4),
+	CHSR_MxERR_mask = (3 << 2),
+	CHSR_MBERR = (1 << 2),
+	CHSR_MRERR = (2 << 2),
+	CHSR_MOERR = (3 << 2),
+	CHSR_DxERR_mask = (3 << 0),
+	CHSR_DBERR = (1 << 0),
+	CHSR_DRERR = (2 << 0),
+	CHSR_DOERR = (3 << 0),
+};
+
+static inline void mite_dma_reset(struct mite_channel *mite_chan)
+{
+	writel(CHOR_DMARESET | CHOR_FRESET,
+		mite_chan->mite->mite_io_addr + MITE_CHOR(mite_chan->channel));
+};
+
+#endif