--- /dev/null
+/*
+ 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);
projects / GitHub / MotorolaMobilityLLC / kernel-slsi.git / commitdiff