Staging: comedi: add comedi_bond driver

This adds the comedi_bond driver to the kernel tree

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>

2 files changed, 523 insertions, 0 deletions

diff --git a/drivers/staging/comedi/drivers/Makefile b/drivers/staging/comedi/drivers/Makefile
index 541141a1f096..39b12913e32a 100644
--- a/drivers/staging/comedi/drivers/Makefile
+++ b/drivers/staging/comedi/drivers/Makefile
@@ -3,6 +3,7 @@
 
 # Comedi "helper" modules
 obj-$(CONFIG_COMEDI)			+= comedi_fc.o
+obj-$(CONFIG_COMEDI)			+= comedi_bond.o
 
 # Comedi PCI drivers
 obj-$(CONFIG_COMEDI_PCI_DRIVERS)	+= mite.o
diff --git a/drivers/staging/comedi/drivers/comedi_bond.c b/drivers/staging/comedi/drivers/comedi_bond.c
new file mode 100644
index 000000000000..3a65f0316fc9
--- /dev/null
+++ b/drivers/staging/comedi/drivers/comedi_bond.c
@@ -0,0 +1,522 @@
+/*
+    comedi/drivers/comedi_bond.c
+    A Comedi driver to 'bond' or merge multiple drivers and devices as one.
+
+    COMEDI - Linux Control and Measurement Device Interface
+    Copyright (C) 2000 David A. Schleef <ds@schleef.org>
+    Copyright (C) 2005 Calin A. Culianu <calin@ajvar.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.
+
+*/
+/*
+Driver: comedi_bond
+Description: A driver to 'bond' (merge) multiple subdevices from multiple devices together as one.
+Devices:
+Author: ds
+Updated: Mon, 10 Oct 00:18:25 -0500
+Status: works
+
+This driver allows you to 'bond' (merge) multiple comedi subdevices
+(coming from possibly difference boards and/or drivers) together.  For
+example, if you had a board with 2 different DIO subdevices, and
+another with 1 DIO subdevice, you could 'bond' them with this driver
+so that they look like one big fat DIO subdevice.  This makes writing
+applications slightly easier as you don't have to worry about managing
+different subdevices in the application -- you just worry about
+indexing one linear array of channel id's.
+
+Right now only DIO subdevices are supported as that's the personal itch
+I am scratching with this driver.  If you want to add support for AI and AO
+subdevs, go right on ahead and do so!
+
+Commands aren't supported -- although it would be cool if they were.
+
+Configuration Options:
+  List of comedi-minors to bond.  All subdevices of the same type
+  within each minor will be concatenated together in the order given here.
+*/
+
+/*
+ * The previous block comment is used to automatically generate
+ * documentation in Comedi and Comedilib.  The fields:
+ *
+ * Driver: the name of the driver
+ * Description: a short phrase describing the driver.  Don't list boards.
+ * Devices: a full list of the boards that attempt to be supported by
+ *   the driver.  Format is "(manufacturer) board name [comedi name]",
+ *   where comedi_name is the name that is used to configure the board.
+ *   See the comment near board_name: in the comedi_driver structure
+ *   below.  If (manufacturer) or [comedi name] is missing, the previous
+ *   value is used.
+ * Author: you
+ * Updated: date when the _documentation_ was last updated.  Use 'date -R'
+ *   to get a value for this.
+ * Status: a one-word description of the status.  Valid values are:
+ *   works - driver works correctly on most boards supported, and
+ *     passes comedi_test.
+ *   unknown - unknown.  Usually put there by ds.
+ *   experimental - may not work in any particular release.  Author
+ *     probably wants assistance testing it.
+ *   bitrotten - driver has not been update in a long time, probably
+ *     doesn't work, and probably is missing support for significant
+ *     Comedi interface features.
+ *   untested - author probably wrote it "blind", and is believed to
+ *     work, but no confirmation.
+ *
+ * These headers should be followed by a blank line, and any comments
+ * you wish to say about the driver.  The comment area is the place
+ * to put any known bugs, limitations, unsupported features, supported
+ * command triggers, whether or not commands are supported on particular
+ * subdevices, etc.
+ *
+ * Somewhere in the comment should be information about configuration
+ * options that are used with comedi_config.
+ */
+
+#include "../comedilib.h"
+#include "../comedidev.h"
+#include <linux/string.h>
+
+/* The maxiumum number of channels per subdevice. */
+#define MAX_CHANS 256
+
+#define MODULE_NAME "comedi_bond"
+#ifdef MODULE_LICENSE
+MODULE_LICENSE("GPL");
+#endif
+#ifndef STR
+#  define STR1(x) #x
+#  define STR(x) STR1(x)
+#endif
+
+int debug = 0;
+module_param(debug, int, 0644);
+MODULE_PARM_DESC(debug,
+	"If true, print extra cryptic debugging output useful only to developers probably.");
+
+#define LOG_MSG(x...) printk(KERN_INFO MODULE_NAME": "x)
+#define DEBUG(x...)  do { if(debug) printk(KERN_DEBUG MODULE_NAME": DEBUG: "x); } while(0)
+#define WARNING(x...)  printk(KERN_WARNING MODULE_NAME ": WARNING: "x)
+#define ERROR(x...)  printk(KERN_ERR MODULE_NAME ": INTERNAL ERROR: "x)
+MODULE_AUTHOR("Calin A. Culianu");
+MODULE_DESCRIPTION(MODULE_NAME
+	": A driver for COMEDI to bond multiple COMEDI devices together as one.  In the words of John Lennon: 'And the world will live as one...'");
+
+/*
+ * Board descriptions for two imaginary boards.  Describing the
+ * boards in this way is optional, and completely driver-dependent.
+ * Some drivers use arrays such as this, other do not.
+ */
+struct BondingBoard {
+	const char *name;
+};
+typedef struct BondingBoard BondingBoard;
+
+static const BondingBoard bondingBoards[] = {
+	{
+	      name:	MODULE_NAME,
+		},
+};
+
+/*
+ * Useful for shorthand access to the particular board structure
+ */
+#define thisboard ((const BondingBoard *)dev->board_ptr)
+
+struct BondedDevice {
+	comedi_t *dev;
+	unsigned minor;
+	unsigned subdev;
+	unsigned subdev_type;
+	unsigned nchans;
+	unsigned chanid_offset;	/* The offset into our unified linear channel-id's
+				   of chanid 0 on this subdevice. */
+};
+typedef struct BondedDevice BondedDevice;
+
+/* this structure is for data unique to this hardware driver.  If
+   several hardware drivers keep similar information in this structure,
+   feel free to suggest moving the variable to the comedi_device struct.  */
+struct Private {
+# define MAX_BOARD_NAME 256
+	char name[MAX_BOARD_NAME];
+	struct BondedDevice **devs;
+	unsigned ndevs;
+	struct BondedDevice *chanIdDevMap[MAX_CHANS];
+	unsigned nchans;
+};
+typedef struct Private Private;
+
+/*
+ * most drivers define the following macro to make it easy to
+ * access the private structure.
+ */
+#define devpriv ((Private *)dev->private)
+
+/*
+ * The comedi_driver structure tells the Comedi core module
+ * which functions to call to configure/deconfigure (attach/detach)
+ * the board, and also about the kernel module that contains
+ * the device code.
+ */
+static int bonding_attach(comedi_device * dev, comedi_devconfig * it);
+static int bonding_detach(comedi_device * dev);
+/** Build Private array of all devices.. */
+static int doDevConfig(comedi_device * dev, comedi_devconfig * it);
+static void doDevUnconfig(comedi_device * dev);
+/* Ugly implementation of realloc that always copies memory around -- I'm lazy, what can I say?  I like to do wasteful memcopies.. :) */
+static void *Realloc(const void *ptr, size_t len, size_t old_len);
+
+static comedi_driver driver_bonding = {
+      driver_name:MODULE_NAME,
+      module:THIS_MODULE,
+      attach:bonding_attach,
+      detach:bonding_detach,
+	/* It is not necessary to implement the following members if you are
+	 * writing a driver for a ISA PnP or PCI card */
+	/* Most drivers will support multiple types of boards by
+	 * having an array of board structures.  These were defined
+	 * in skel_boards[] above.  Note that the element 'name'
+	 * was first in the structure -- Comedi uses this fact to
+	 * extract the name of the board without knowing any details
+	 * about the structure except for its length.
+	 * When a device is attached (by comedi_config), the name
+	 * of the device is given to Comedi, and Comedi tries to
+	 * match it by going through the list of board names.  If
+	 * there is a match, the address of the pointer is put
+	 * into dev->board_ptr and driver->attach() is called.
+	 *
+	 * Note that these are not necessary if you can determine
+	 * the type of board in software.  ISA PnP, PCI, and PCMCIA
+	 * devices are such boards.
+	 */
+      board_name:&bondingBoards[0].name,
+      offset:sizeof(BondingBoard),
+      num_names:sizeof(bondingBoards) / sizeof(BondingBoard),
+};
+
+static int bonding_dio_insn_bits(comedi_device * dev, comedi_subdevice * s,
+	comedi_insn * insn, lsampl_t * data);
+static int bonding_dio_insn_config(comedi_device * dev, comedi_subdevice * s,
+	comedi_insn * insn, lsampl_t * data);
+
+/*
+ * Attach is called by the Comedi core to configure the driver
+ * for a particular board.  If you specified a board_name array
+ * in the driver structure, dev->board_ptr contains that
+ * address.
+ */
+static int bonding_attach(comedi_device * dev, comedi_devconfig * it)
+{
+	comedi_subdevice *s;
+
+	LOG_MSG("comedi%d\n", dev->minor);
+
+/*
+ * Allocate the private structure area.  alloc_private() is a
+ * convenient macro defined in comedidev.h.
+ */
+	if (alloc_private(dev, sizeof(Private)) < 0)
+		return -ENOMEM;
+
+/*
+ * Setup our bonding from config params.. sets up our Private struct..
+ */
+	if (!doDevConfig(dev, it))
+		return -EINVAL;
+
+/*
+ * Initialize dev->board_name.  Note that we can use the "thisboard"
+ * macro now, since we just initialized it in the last line.
+ */
+	dev->board_name = devpriv->name;
+
+/*
+ * Allocate the subdevice structures.  alloc_subdevice() is a
+ * convenient macro defined in comedidev.h.
+ */
+	if (alloc_subdevices(dev, 1) < 0)
+		return -ENOMEM;
+
+	s = dev->subdevices + 0;
+	s->type = COMEDI_SUBD_DIO;
+	s->subdev_flags = SDF_READABLE | SDF_WRITABLE;
+	s->n_chan = devpriv->nchans;
+	s->maxdata = 1;
+	s->range_table = &range_digital;
+	s->insn_bits = bonding_dio_insn_bits;
+	s->insn_config = bonding_dio_insn_config;
+
+	LOG_MSG("attached with %u DIO channels coming from %u different subdevices all bonded together.  John Lennon would be proud!\n", devpriv->nchans, devpriv->ndevs);
+
+	return 1;
+}
+
+/*
+ * _detach is called to deconfigure a device.  It should deallocate
+ * resources.
+ * This function is also called when _attach() fails, so it should be
+ * careful not to release resources that were not necessarily
+ * allocated by _attach().  dev->private and dev->subdevices are
+ * deallocated automatically by the core.
+ */
+static int bonding_detach(comedi_device * dev)
+{
+	LOG_MSG("comedi%d: remove\n", dev->minor);
+	doDevUnconfig(dev);
+	return 0;
+}
+
+/* DIO devices are slightly special.  Although it is possible to
+ * implement the insn_read/insn_write interface, it is much more
+ * useful to applications if you implement the insn_bits interface.
+ * This allows packed reading/writing of the DIO channels.  The
+ * comedi core can convert between insn_bits and insn_read/write */
+static int bonding_dio_insn_bits(comedi_device * dev, comedi_subdevice * s,
+	comedi_insn * insn, lsampl_t * data)
+{
+#define LSAMPL_BITS (sizeof(lsampl_t)*8)
+	unsigned nchans = LSAMPL_BITS, num_done = 0, i;
+	if (insn->n != 2)
+		return -EINVAL;
+
+	if (devpriv->nchans < nchans)
+		nchans = devpriv->nchans;
+
+	/* The insn data is a mask in data[0] and the new data
+	 * in data[1], each channel cooresponding to a bit. */
+	for (i = 0; num_done < nchans && i < devpriv->ndevs; ++i) {
+		BondedDevice *bdev = devpriv->devs[i];
+		/* Grab the channel mask and data of only the bits corresponding
+		   to this subdevice.. need to shift them to zero position of
+		   course. */
+		lsampl_t subdevMask = ((1 << bdev->nchans) - 1);	/* Bits corresponding
+									   to this subdev. */
+		lsampl_t writeMask, dataBits;
+
+		/* Argh, we have >= LSAMPL_BITS chans.. take all bits */
+		if (bdev->nchans >= LSAMPL_BITS)
+			subdevMask = (lsampl_t) (-1);
+
+		writeMask = (data[0] >> num_done) & subdevMask;
+		dataBits = (data[1] >> num_done) & subdevMask;
+
+		/* Read/Write the new digital lines */
+		if (comedi_dio_bitfield(bdev->dev, bdev->subdev, writeMask,
+				&dataBits) != 2)
+			return -EINVAL;
+
+		/* Make room for the new bits in data[1], the return value */
+		data[1] &= ~(subdevMask << num_done);
+		/* Put the bits in the return value */
+		data[1] |= (dataBits & subdevMask) << num_done;
+		/* Save the new bits to the saved state.. */
+		s->state = data[1];
+
+		num_done += bdev->nchans;
+	}
+
+	return insn->n;
+}
+
+static int bonding_dio_insn_config(comedi_device * dev, comedi_subdevice * s,
+	comedi_insn * insn, lsampl_t * data)
+{
+	int chan = CR_CHAN(insn->chanspec), ret, io_bits = s->io_bits;
+	unsigned int io;
+	BondedDevice *bdev;
+
+	if (chan < 0 || chan >= devpriv->nchans)
+		return -EINVAL;
+	bdev = devpriv->chanIdDevMap[chan];
+
+	/* The input or output configuration of each digital line is
+	 * configured by a special insn_config instruction.  chanspec
+	 * contains the channel to be changed, and data[0] contains the
+	 * value COMEDI_INPUT or COMEDI_OUTPUT. */
+	switch (data[0]) {
+	case INSN_CONFIG_DIO_OUTPUT:
+		io = COMEDI_OUTPUT;	/* is this really necessary? */
+		io_bits |= 1 << chan;
+		break;
+	case INSN_CONFIG_DIO_INPUT:
+		io = COMEDI_INPUT;	/* is this really necessary? */
+		io_bits &= ~(1 << chan);
+		break;
+	case INSN_CONFIG_DIO_QUERY:
+		data[1] =
+			(io_bits & (1 << chan)) ? COMEDI_OUTPUT : COMEDI_INPUT;
+		return insn->n;
+		break;
+	default:
+		return -EINVAL;
+		break;
+	}
+	chan -= bdev->chanid_offset;	/* 'real' channel id for this subdev.. */
+	ret = comedi_dio_config(bdev->dev, bdev->subdev, chan, io);
+	if (ret != 1)
+		return -EINVAL;
+	/* Finally, save the new io_bits values since we didn't get
+	   an error above. */
+	s->io_bits = io_bits;
+	return insn->n;
+}
+
+static void *Realloc(const void *oldmem, size_t newlen, size_t oldlen)
+{
+#define MIN(a,b) (a < b ? a : b)
+	void *newmem = kmalloc(newlen, GFP_KERNEL);
+	if (newmem && oldmem)
+		memcpy(newmem, oldmem, MIN(oldlen, newlen));
+	if (oldmem)
+		kfree(oldmem);
+	return newmem;
+}
+
+static int doDevConfig(comedi_device * dev, comedi_devconfig * it)
+{
+	int i;
+	comedi_t *devs_opened[COMEDI_NUM_BOARD_MINORS];
+
+	memset(devs_opened, 0, sizeof(devs_opened));
+	devpriv->name[0] = 0;;
+	/* Loop through all comedi devices specified on the command-line,
+	   building our device list */
+	for (i = 0; i < COMEDI_NDEVCONFOPTS && (!i || it->options[i]); ++i) {
+		char file[] = "/dev/comediXXXXXX";
+		int minor = it->options[i];
+		comedi_t *d;
+		int sdev = -1, nchans, tmp;
+		BondedDevice *bdev = 0;
+
+		if (minor < 0 || minor > COMEDI_NUM_BOARD_MINORS) {
+			ERROR("Minor %d is invalid!\n", minor);
+			return 0;
+		}
+		if (minor == dev->minor) {
+			ERROR("Cannot bond this driver to itself!\n");
+			return 0;
+		}
+		if (devs_opened[minor]) {
+			ERROR("Minor %d specified more than once!\n", minor);
+			return 0;
+		}
+
+		snprintf(file, sizeof(file), "/dev/comedi%u", minor);
+		file[sizeof(file) - 1] = 0;
+
+		d = devs_opened[minor] = comedi_open(file);
+
+		if (!d) {
+			ERROR("Minor %u could not be opened\n", minor);
+			return 0;
+		}
+
+		/* Do DIO, as that's all we support now.. */
+		while ((sdev = comedi_find_subdevice_by_type(d, COMEDI_SUBD_DIO,
+					sdev + 1)) > -1) {
+			if ((nchans = comedi_get_n_channels(d, sdev)) <= 0) {
+				ERROR("comedi_get_n_channels() returned %d on minor %u subdev %d!\n", nchans, minor, sdev);
+				return 0;
+			}
+			bdev = kmalloc(sizeof(*bdev), GFP_KERNEL);
+			if (!bdev) {
+				ERROR("Out of memory.\n");
+				return 0;
+			}
+			bdev->dev = d;
+			bdev->minor = minor;
+			bdev->subdev = sdev;
+			bdev->subdev_type = COMEDI_SUBD_DIO;
+			bdev->nchans = nchans;
+			bdev->chanid_offset = devpriv->nchans;
+
+			/* map channel id's to BondedDevice * pointer.. */
+			while (nchans--)
+				devpriv->chanIdDevMap[devpriv->nchans++] = bdev;
+
+			/* Now put bdev pointer at end of devpriv->devs array list.. */
+
+			/* ergh.. ugly.. we need to realloc :(  */
+			tmp = devpriv->ndevs * sizeof(bdev);
+			devpriv->devs =
+				Realloc(devpriv->devs,
+				++devpriv->ndevs * sizeof(bdev), tmp);
+			if (!devpriv->devs) {
+				ERROR("Could not allocate memory. Out of memory?");
+				return 0;
+			}
+
+			devpriv->devs[devpriv->ndevs - 1] = bdev;
+			{
+	/** Append dev:subdev to devpriv->name */
+				char buf[20];
+				int left =
+					MAX_BOARD_NAME - strlen(devpriv->name) -
+					1;
+				snprintf(buf, sizeof(buf), "%d:%d ", dev->minor,
+					bdev->subdev);
+				buf[sizeof(buf) - 1] = 0;
+				strncat(devpriv->name, buf, left);
+			}
+
+		}
+	}
+
+	if (!devpriv->nchans) {
+		ERROR("No channels found!\n");
+		return 0;
+	}
+
+	return 1;
+}
+
+static void doDevUnconfig(comedi_device * dev)
+{
+	unsigned long devs_closed = 0;
+
+	if (devpriv) {
+		while (devpriv->ndevs-- && devpriv->devs) {
+			BondedDevice *bdev = devpriv->devs[devpriv->ndevs];
+			if (!bdev)
+				continue;
+			if (!(devs_closed & (0x1 << bdev->minor))) {
+				comedi_close(bdev->dev);
+				devs_closed |= (0x1 << bdev->minor);
+			}
+			kfree(bdev);
+		}
+		if (devpriv->devs) {
+			kfree(devpriv->devs);
+			devpriv->devs = 0;
+		}
+		kfree(devpriv);
+		dev->private = 0;
+	}
+}
+
+int __init init(void)
+{
+	return comedi_driver_register(&driver_bonding);
+}
+
+void __exit cleanup(void)
+{
+	comedi_driver_unregister(&driver_bonding);
+}
+
+module_init(init);
+module_exit(cleanup);