blob: 376130bfba8a2c237939b115754aa538941be00e [file] [log] [blame]
// SPDX-License-Identifier: GPL-2.0+
/*
* module/drivers.c
* functions for manipulating drivers
*
* COMEDI - Linux Control and Measurement Device Interface
* Copyright (C) 1997-2000 David A. Schleef <ds@schleef.org>
* Copyright (C) 2002 Frank Mori Hess <fmhess@users.sourceforge.net>
*/
#include <linux/device.h>
#include <linux/module.h>
#include <linux/errno.h>
#include <linux/kernel.h>
#include <linux/ioport.h>
#include <linux/slab.h>
#include <linux/dma-direction.h>
#include <linux/interrupt.h>
#include <linux/firmware.h>
#include <linux/comedi/comedidev.h>
#include "comedi_internal.h"
struct comedi_driver *comedi_drivers;
/* protects access to comedi_drivers */
DEFINE_MUTEX(comedi_drivers_list_lock);
/**
* comedi_set_hw_dev() - Set hardware device associated with COMEDI device
* @dev: COMEDI device.
* @hw_dev: Hardware device.
*
* For automatically configured COMEDI devices (resulting from a call to
* comedi_auto_config() or one of its wrappers from the low-level COMEDI
* driver), comedi_set_hw_dev() is called automatically by the COMEDI core
* to associate the COMEDI device with the hardware device. It can also be
* called directly by "legacy" low-level COMEDI drivers that rely on the
* %COMEDI_DEVCONFIG ioctl to configure the hardware as long as the hardware
* has a &struct device.
*
* If @dev->hw_dev is NULL, it gets a reference to @hw_dev and sets
* @dev->hw_dev, otherwise, it does nothing. Calling it multiple times
* with the same hardware device is not considered an error. If it gets
* a reference to the hardware device, it will be automatically 'put' when
* the device is detached from COMEDI.
*
* Returns 0 if @dev->hw_dev was NULL or the same as @hw_dev, otherwise
* returns -EEXIST.
*/
int comedi_set_hw_dev(struct comedi_device *dev, struct device *hw_dev)
{
if (hw_dev == dev->hw_dev)
return 0;
if (dev->hw_dev)
return -EEXIST;
dev->hw_dev = get_device(hw_dev);
return 0;
}
EXPORT_SYMBOL_GPL(comedi_set_hw_dev);
static void comedi_clear_hw_dev(struct comedi_device *dev)
{
put_device(dev->hw_dev);
dev->hw_dev = NULL;
}
/**
* comedi_alloc_devpriv() - Allocate memory for the device private data
* @dev: COMEDI device.
* @size: Size of the memory to allocate.
*
* The allocated memory is zero-filled. @dev->private points to it on
* return. The memory will be automatically freed when the COMEDI device is
* "detached".
*
* Returns a pointer to the allocated memory, or NULL on failure.
*/
void *comedi_alloc_devpriv(struct comedi_device *dev, size_t size)
{
dev->private = kzalloc(size, GFP_KERNEL);
return dev->private;
}
EXPORT_SYMBOL_GPL(comedi_alloc_devpriv);
/**
* comedi_alloc_subdevices() - Allocate subdevices for COMEDI device
* @dev: COMEDI device.
* @num_subdevices: Number of subdevices to allocate.
*
* Allocates and initializes an array of &struct comedi_subdevice for the
* COMEDI device. If successful, sets @dev->subdevices to point to the
* first one and @dev->n_subdevices to the number.
*
* Returns 0 on success, -EINVAL if @num_subdevices is < 1, or -ENOMEM if
* failed to allocate the memory.
*/
int comedi_alloc_subdevices(struct comedi_device *dev, int num_subdevices)
{
struct comedi_subdevice *s;
int i;
if (num_subdevices < 1)
return -EINVAL;
s = kcalloc(num_subdevices, sizeof(*s), GFP_KERNEL);
if (!s)
return -ENOMEM;
dev->subdevices = s;
dev->n_subdevices = num_subdevices;
for (i = 0; i < num_subdevices; ++i) {
s = &dev->subdevices[i];
s->device = dev;
s->index = i;
s->async_dma_dir = DMA_NONE;
spin_lock_init(&s->spin_lock);
s->minor = -1;
}
return 0;
}
EXPORT_SYMBOL_GPL(comedi_alloc_subdevices);
/**
* comedi_alloc_subdev_readback() - Allocate memory for the subdevice readback
* @s: COMEDI subdevice.
*
* This is called by low-level COMEDI drivers to allocate an array to record
* the last values written to a subdevice's analog output channels (at least
* by the %INSN_WRITE instruction), to allow them to be read back by an
* %INSN_READ instruction. It also provides a default handler for the
* %INSN_READ instruction unless one has already been set.
*
* On success, @s->readback points to the first element of the array, which
* is zero-filled. The low-level driver is responsible for updating its
* contents. @s->insn_read will be set to comedi_readback_insn_read()
* unless it is already non-NULL.
*
* Returns 0 on success, -EINVAL if the subdevice has no channels, or
* -ENOMEM on allocation failure.
*/
int comedi_alloc_subdev_readback(struct comedi_subdevice *s)
{
if (!s->n_chan)
return -EINVAL;
s->readback = kcalloc(s->n_chan, sizeof(*s->readback), GFP_KERNEL);
if (!s->readback)
return -ENOMEM;
if (!s->insn_read)
s->insn_read = comedi_readback_insn_read;
return 0;
}
EXPORT_SYMBOL_GPL(comedi_alloc_subdev_readback);
static void comedi_device_detach_cleanup(struct comedi_device *dev)
{
int i;
struct comedi_subdevice *s;
lockdep_assert_held(&dev->attach_lock);
lockdep_assert_held(&dev->mutex);
if (dev->subdevices) {
for (i = 0; i < dev->n_subdevices; i++) {
s = &dev->subdevices[i];
if (comedi_can_auto_free_spriv(s))
kfree(s->private);
comedi_free_subdevice_minor(s);
if (s->async) {
comedi_buf_alloc(dev, s, 0);
kfree(s->async);
}
kfree(s->readback);
}
kfree(dev->subdevices);
dev->subdevices = NULL;
dev->n_subdevices = 0;
}
kfree(dev->private);
if (!IS_ERR(dev->pacer))
kfree(dev->pacer);
dev->private = NULL;
dev->pacer = NULL;
dev->driver = NULL;
dev->board_name = NULL;
dev->board_ptr = NULL;
dev->mmio = NULL;
dev->iobase = 0;
dev->iolen = 0;
dev->ioenabled = false;
dev->irq = 0;
dev->read_subdev = NULL;
dev->write_subdev = NULL;
dev->open = NULL;
dev->close = NULL;
comedi_clear_hw_dev(dev);
}
void comedi_device_detach(struct comedi_device *dev)
{
lockdep_assert_held(&dev->mutex);
comedi_device_cancel_all(dev);
down_write(&dev->attach_lock);
dev->attached = false;
dev->detach_count++;
if (dev->driver)
dev->driver->detach(dev);
comedi_device_detach_cleanup(dev);
up_write(&dev->attach_lock);
}
static int poll_invalid(struct comedi_device *dev, struct comedi_subdevice *s)
{
return -EINVAL;
}
static int insn_device_inval(struct comedi_device *dev,
struct comedi_insn *insn, unsigned int *data)
{
return -EINVAL;
}
static unsigned int get_zero_valid_routes(struct comedi_device *dev,
unsigned int n_pairs,
unsigned int *pair_data)
{
return 0;
}
int insn_inval(struct comedi_device *dev, struct comedi_subdevice *s,
struct comedi_insn *insn, unsigned int *data)
{
return -EINVAL;
}
/**
* comedi_readback_insn_read() - A generic (*insn_read) for subdevice readback.
* @dev: COMEDI device.
* @s: COMEDI subdevice.
* @insn: COMEDI instruction.
* @data: Pointer to return the readback data.
*
* Handles the %INSN_READ instruction for subdevices that use the readback
* array allocated by comedi_alloc_subdev_readback(). It may be used
* directly as the subdevice's handler (@s->insn_read) or called via a
* wrapper.
*
* @insn->n is normally 1, which will read a single value. If higher, the
* same element of the readback array will be read multiple times.
*
* Returns @insn->n on success, or -EINVAL if @s->readback is NULL.
*/
int comedi_readback_insn_read(struct comedi_device *dev,
struct comedi_subdevice *s,
struct comedi_insn *insn,
unsigned int *data)
{
unsigned int chan = CR_CHAN(insn->chanspec);
int i;
if (!s->readback)
return -EINVAL;
for (i = 0; i < insn->n; i++)
data[i] = s->readback[chan];
return insn->n;
}
EXPORT_SYMBOL_GPL(comedi_readback_insn_read);
/**
* comedi_timeout() - Busy-wait for a driver condition to occur
* @dev: COMEDI device.
* @s: COMEDI subdevice.
* @insn: COMEDI instruction.
* @cb: Callback to check for the condition.
* @context: Private context from the driver.
*
* Busy-waits for up to a second (%COMEDI_TIMEOUT_MS) for the condition or
* some error (other than -EBUSY) to occur. The parameters @dev, @s, @insn,
* and @context are passed to the callback function, which returns -EBUSY to
* continue waiting or some other value to stop waiting (generally 0 if the
* condition occurred, or some error value).
*
* Returns -ETIMEDOUT if timed out, otherwise the return value from the
* callback function.
*/
int comedi_timeout(struct comedi_device *dev,
struct comedi_subdevice *s,
struct comedi_insn *insn,
int (*cb)(struct comedi_device *dev,
struct comedi_subdevice *s,
struct comedi_insn *insn,
unsigned long context),
unsigned long context)
{
unsigned long timeout = jiffies + msecs_to_jiffies(COMEDI_TIMEOUT_MS);
int ret;
while (time_before(jiffies, timeout)) {
ret = cb(dev, s, insn, context);
if (ret != -EBUSY)
return ret; /* success (0) or non EBUSY errno */
cpu_relax();
}
return -ETIMEDOUT;
}
EXPORT_SYMBOL_GPL(comedi_timeout);
/**
* comedi_dio_insn_config() - Boilerplate (*insn_config) for DIO subdevices
* @dev: COMEDI device.
* @s: COMEDI subdevice.
* @insn: COMEDI instruction.
* @data: Instruction parameters and return data.
* @mask: io_bits mask for grouped channels, or 0 for single channel.
*
* If @mask is 0, it is replaced with a single-bit mask corresponding to the
* channel number specified by @insn->chanspec. Otherwise, @mask
* corresponds to a group of channels (which should include the specified
* channel) that are always configured together as inputs or outputs.
*
* Partially handles the %INSN_CONFIG_DIO_INPUT, %INSN_CONFIG_DIO_OUTPUTS,
* and %INSN_CONFIG_DIO_QUERY instructions. The first two update
* @s->io_bits to record the directions of the masked channels. The last
* one sets @data[1] to the current direction of the group of channels
* (%COMEDI_INPUT) or %COMEDI_OUTPUT) as recorded in @s->io_bits.
*
* The caller is responsible for updating the DIO direction in the hardware
* registers if this function returns 0.
*
* Returns 0 for a %INSN_CONFIG_DIO_INPUT or %INSN_CONFIG_DIO_OUTPUT
* instruction, @insn->n (> 0) for a %INSN_CONFIG_DIO_QUERY instruction, or
* -EINVAL for some other instruction.
*/
int comedi_dio_insn_config(struct comedi_device *dev,
struct comedi_subdevice *s,
struct comedi_insn *insn,
unsigned int *data,
unsigned int mask)
{
unsigned int chan_mask = 1 << CR_CHAN(insn->chanspec);
if (!mask)
mask = chan_mask;
switch (data[0]) {
case INSN_CONFIG_DIO_INPUT:
s->io_bits &= ~mask;
break;
case INSN_CONFIG_DIO_OUTPUT:
s->io_bits |= mask;
break;
case INSN_CONFIG_DIO_QUERY:
data[1] = (s->io_bits & mask) ? COMEDI_OUTPUT : COMEDI_INPUT;
return insn->n;
default:
return -EINVAL;
}
return 0;
}
EXPORT_SYMBOL_GPL(comedi_dio_insn_config);
/**
* comedi_dio_update_state() - Update the internal state of DIO subdevices
* @s: COMEDI subdevice.
* @data: The channel mask and bits to update.
*
* Updates @s->state which holds the internal state of the outputs for DIO
* or DO subdevices (up to 32 channels). @data[0] contains a bit-mask of
* the channels to be updated. @data[1] contains a bit-mask of those
* channels to be set to '1'. The caller is responsible for updating the
* outputs in hardware according to @s->state. As a minimum, the channels
* in the returned bit-mask need to be updated.
*
* Returns @mask with non-existent channels removed.
*/
unsigned int comedi_dio_update_state(struct comedi_subdevice *s,
unsigned int *data)
{
unsigned int chanmask = (s->n_chan < 32) ? ((1 << s->n_chan) - 1)
: 0xffffffff;
unsigned int mask = data[0] & chanmask;
unsigned int bits = data[1];
if (mask) {
s->state &= ~mask;
s->state |= (bits & mask);
}
return mask;
}
EXPORT_SYMBOL_GPL(comedi_dio_update_state);
/**
* comedi_bytes_per_scan_cmd() - Get length of asynchronous command "scan" in
* bytes
* @s: COMEDI subdevice.
* @cmd: COMEDI command.
*
* Determines the overall scan length according to the subdevice type and the
* number of channels in the scan for the specified command.
*
* For digital input, output or input/output subdevices, samples for
* multiple channels are assumed to be packed into one or more unsigned
* short or unsigned int values according to the subdevice's %SDF_LSAMPL
* flag. For other types of subdevice, samples are assumed to occupy a
* whole unsigned short or unsigned int according to the %SDF_LSAMPL flag.
*
* Returns the overall scan length in bytes.
*/
unsigned int comedi_bytes_per_scan_cmd(struct comedi_subdevice *s,
struct comedi_cmd *cmd)
{
unsigned int num_samples;
unsigned int bits_per_sample;
switch (s->type) {
case COMEDI_SUBD_DI:
case COMEDI_SUBD_DO:
case COMEDI_SUBD_DIO:
bits_per_sample = 8 * comedi_bytes_per_sample(s);
num_samples = DIV_ROUND_UP(cmd->scan_end_arg, bits_per_sample);
break;
default:
num_samples = cmd->scan_end_arg;
break;
}
return comedi_samples_to_bytes(s, num_samples);
}
EXPORT_SYMBOL_GPL(comedi_bytes_per_scan_cmd);
/**
* comedi_bytes_per_scan() - Get length of asynchronous command "scan" in bytes
* @s: COMEDI subdevice.
*
* Determines the overall scan length according to the subdevice type and the
* number of channels in the scan for the current command.
*
* For digital input, output or input/output subdevices, samples for
* multiple channels are assumed to be packed into one or more unsigned
* short or unsigned int values according to the subdevice's %SDF_LSAMPL
* flag. For other types of subdevice, samples are assumed to occupy a
* whole unsigned short or unsigned int according to the %SDF_LSAMPL flag.
*
* Returns the overall scan length in bytes.
*/
unsigned int comedi_bytes_per_scan(struct comedi_subdevice *s)
{
struct comedi_cmd *cmd = &s->async->cmd;
return comedi_bytes_per_scan_cmd(s, cmd);
}
EXPORT_SYMBOL_GPL(comedi_bytes_per_scan);
static unsigned int __comedi_nscans_left(struct comedi_subdevice *s,
unsigned int nscans)
{
struct comedi_async *async = s->async;
struct comedi_cmd *cmd = &async->cmd;
if (cmd->stop_src == TRIG_COUNT) {
unsigned int scans_left = 0;
if (async->scans_done < cmd->stop_arg)
scans_left = cmd->stop_arg - async->scans_done;
if (nscans > scans_left)
nscans = scans_left;
}
return nscans;
}
/**
* comedi_nscans_left() - Return the number of scans left in the command
* @s: COMEDI subdevice.
* @nscans: The expected number of scans or 0 for all available scans.
*
* If @nscans is 0, it is set to the number of scans available in the
* async buffer.
*
* If the async command has a stop_src of %TRIG_COUNT, the @nscans will be
* checked against the number of scans remaining to complete the command.
*
* The return value will then be either the expected number of scans or the
* number of scans remaining to complete the command, whichever is fewer.
*/
unsigned int comedi_nscans_left(struct comedi_subdevice *s,
unsigned int nscans)
{
if (nscans == 0) {
unsigned int nbytes = comedi_buf_read_n_available(s);
nscans = nbytes / comedi_bytes_per_scan(s);
}
return __comedi_nscans_left(s, nscans);
}
EXPORT_SYMBOL_GPL(comedi_nscans_left);
/**
* comedi_nsamples_left() - Return the number of samples left in the command
* @s: COMEDI subdevice.
* @nsamples: The expected number of samples.
*
* Returns the number of samples remaining to complete the command, or the
* specified expected number of samples (@nsamples), whichever is fewer.
*/
unsigned int comedi_nsamples_left(struct comedi_subdevice *s,
unsigned int nsamples)
{
struct comedi_async *async = s->async;
struct comedi_cmd *cmd = &async->cmd;
unsigned long long scans_left;
unsigned long long samples_left;
if (cmd->stop_src != TRIG_COUNT)
return nsamples;
scans_left = __comedi_nscans_left(s, cmd->stop_arg);
if (!scans_left)
return 0;
samples_left = scans_left * cmd->scan_end_arg -
comedi_bytes_to_samples(s, async->scan_progress);
if (samples_left < nsamples)
return samples_left;
return nsamples;
}
EXPORT_SYMBOL_GPL(comedi_nsamples_left);
/**
* comedi_inc_scan_progress() - Update scan progress in asynchronous command
* @s: COMEDI subdevice.
* @num_bytes: Amount of data in bytes to increment scan progress.
*
* Increments the scan progress by the number of bytes specified by @num_bytes.
* If the scan progress reaches or exceeds the scan length in bytes, reduce
* it modulo the scan length in bytes and set the "end of scan" asynchronous
* event flag (%COMEDI_CB_EOS) to be processed later.
*/
void comedi_inc_scan_progress(struct comedi_subdevice *s,
unsigned int num_bytes)
{
struct comedi_async *async = s->async;
struct comedi_cmd *cmd = &async->cmd;
unsigned int scan_length = comedi_bytes_per_scan(s);
/* track the 'cur_chan' for non-SDF_PACKED subdevices */
if (!(s->subdev_flags & SDF_PACKED)) {
async->cur_chan += comedi_bytes_to_samples(s, num_bytes);
async->cur_chan %= cmd->chanlist_len;
}
async->scan_progress += num_bytes;
if (async->scan_progress >= scan_length) {
unsigned int nscans = async->scan_progress / scan_length;
if (async->scans_done < (UINT_MAX - nscans))
async->scans_done += nscans;
else
async->scans_done = UINT_MAX;
async->scan_progress %= scan_length;
async->events |= COMEDI_CB_EOS;
}
}
EXPORT_SYMBOL_GPL(comedi_inc_scan_progress);
/**
* comedi_handle_events() - Handle events and possibly stop acquisition
* @dev: COMEDI device.
* @s: COMEDI subdevice.
*
* Handles outstanding asynchronous acquisition event flags associated
* with the subdevice. Call the subdevice's @s->cancel() handler if the
* "end of acquisition", "error" or "overflow" event flags are set in order
* to stop the acquisition at the driver level.
*
* Calls comedi_event() to further process the event flags, which may mark
* the asynchronous command as no longer running, possibly terminated with
* an error, and may wake up tasks.
*
* Return a bit-mask of the handled events.
*/
unsigned int comedi_handle_events(struct comedi_device *dev,
struct comedi_subdevice *s)
{
unsigned int events = s->async->events;
if (events == 0)
return events;
if ((events & COMEDI_CB_CANCEL_MASK) && s->cancel)
s->cancel(dev, s);
comedi_event(dev, s);
return events;
}
EXPORT_SYMBOL_GPL(comedi_handle_events);
static int insn_rw_emulate_bits(struct comedi_device *dev,
struct comedi_subdevice *s,
struct comedi_insn *insn,
unsigned int *data)
{
struct comedi_insn _insn;
unsigned int chan = CR_CHAN(insn->chanspec);
unsigned int base_chan = (chan < 32) ? 0 : chan;
unsigned int _data[2];
int ret;
memset(_data, 0, sizeof(_data));
memset(&_insn, 0, sizeof(_insn));
_insn.insn = INSN_BITS;
_insn.chanspec = base_chan;
_insn.n = 2;
_insn.subdev = insn->subdev;
if (insn->insn == INSN_WRITE) {
if (!(s->subdev_flags & SDF_WRITABLE))
return -EINVAL;
_data[0] = 1 << (chan - base_chan); /* mask */
_data[1] = data[0] ? (1 << (chan - base_chan)) : 0; /* bits */
}
ret = s->insn_bits(dev, s, &_insn, _data);
if (ret < 0)
return ret;
if (insn->insn == INSN_READ)
data[0] = (_data[1] >> (chan - base_chan)) & 1;
return 1;
}
static int __comedi_device_postconfig_async(struct comedi_device *dev,
struct comedi_subdevice *s)
{
struct comedi_async *async;
unsigned int buf_size;
int ret;
lockdep_assert_held(&dev->mutex);
if ((s->subdev_flags & (SDF_CMD_READ | SDF_CMD_WRITE)) == 0) {
dev_warn(dev->class_dev,
"async subdevices must support SDF_CMD_READ or SDF_CMD_WRITE\n");
return -EINVAL;
}
if (!s->do_cmdtest) {
dev_warn(dev->class_dev,
"async subdevices must have a do_cmdtest() function\n");
return -EINVAL;
}
if (!s->cancel)
dev_warn(dev->class_dev,
"async subdevices should have a cancel() function\n");
async = kzalloc(sizeof(*async), GFP_KERNEL);
if (!async)
return -ENOMEM;
init_waitqueue_head(&async->wait_head);
s->async = async;
async->max_bufsize = comedi_default_buf_maxsize_kb * 1024;
buf_size = comedi_default_buf_size_kb * 1024;
if (buf_size > async->max_bufsize)
buf_size = async->max_bufsize;
if (comedi_buf_alloc(dev, s, buf_size) < 0) {
dev_warn(dev->class_dev, "Buffer allocation failed\n");
return -ENOMEM;
}
if (s->buf_change) {
ret = s->buf_change(dev, s);
if (ret < 0)
return ret;
}
comedi_alloc_subdevice_minor(s);
return 0;
}
static int __comedi_device_postconfig(struct comedi_device *dev)
{
struct comedi_subdevice *s;
int ret;
int i;
lockdep_assert_held(&dev->mutex);
if (!dev->insn_device_config)
dev->insn_device_config = insn_device_inval;
if (!dev->get_valid_routes)
dev->get_valid_routes = get_zero_valid_routes;
for (i = 0; i < dev->n_subdevices; i++) {
s = &dev->subdevices[i];
if (s->type == COMEDI_SUBD_UNUSED)
continue;
if (s->type == COMEDI_SUBD_DO) {
if (s->n_chan < 32)
s->io_bits = (1 << s->n_chan) - 1;
else
s->io_bits = 0xffffffff;
}
if (s->len_chanlist == 0)
s->len_chanlist = 1;
if (s->do_cmd) {
ret = __comedi_device_postconfig_async(dev, s);
if (ret)
return ret;
}
if (!s->range_table && !s->range_table_list)
s->range_table = &range_unknown;
if (!s->insn_read && s->insn_bits)
s->insn_read = insn_rw_emulate_bits;
if (!s->insn_write && s->insn_bits)
s->insn_write = insn_rw_emulate_bits;
if (!s->insn_read)
s->insn_read = insn_inval;
if (!s->insn_write)
s->insn_write = insn_inval;
if (!s->insn_bits)
s->insn_bits = insn_inval;
if (!s->insn_config)
s->insn_config = insn_inval;
if (!s->poll)
s->poll = poll_invalid;
}
return 0;
}
/* do a little post-config cleanup */
static int comedi_device_postconfig(struct comedi_device *dev)
{
int ret;
lockdep_assert_held(&dev->mutex);
ret = __comedi_device_postconfig(dev);
if (ret < 0)
return ret;
down_write(&dev->attach_lock);
dev->attached = true;
up_write(&dev->attach_lock);
return 0;
}
/*
* Generic recognize function for drivers that register their supported
* board names.
*
* 'driv->board_name' points to a 'const char *' member within the
* zeroth element of an array of some private board information
* structure, say 'struct foo_board' containing a member 'const char
* *board_name' that is initialized to point to a board name string that
* is one of the candidates matched against this function's 'name'
* parameter.
*
* 'driv->offset' is the size of the private board information
* structure, say 'sizeof(struct foo_board)', and 'driv->num_names' is
* the length of the array of private board information structures.
*
* If one of the board names in the array of private board information
* structures matches the name supplied to this function, the function
* returns a pointer to the pointer to the board name, otherwise it
* returns NULL. The return value ends up in the 'board_ptr' member of
* a 'struct comedi_device' that the low-level comedi driver's
* 'attach()' hook can convert to a point to a particular element of its
* array of private board information structures by subtracting the
* offset of the member that points to the board name. (No subtraction
* is required if the board name pointer is the first member of the
* private board information structure, which is generally the case.)
*/
static void *comedi_recognize(struct comedi_driver *driv, const char *name)
{
char **name_ptr = (char **)driv->board_name;
int i;
for (i = 0; i < driv->num_names; i++) {
if (strcmp(*name_ptr, name) == 0)
return name_ptr;
name_ptr = (void *)name_ptr + driv->offset;
}
return NULL;
}
static void comedi_report_boards(struct comedi_driver *driv)
{
unsigned int i;
const char *const *name_ptr;
pr_info("comedi: valid board names for %s driver are:\n",
driv->driver_name);
name_ptr = driv->board_name;
for (i = 0; i < driv->num_names; i++) {
pr_info(" %s\n", *name_ptr);
name_ptr = (const char **)((char *)name_ptr + driv->offset);
}
if (driv->num_names == 0)
pr_info(" %s\n", driv->driver_name);
}
/**
* comedi_load_firmware() - Request and load firmware for a device
* @dev: COMEDI device.
* @device: Hardware device.
* @name: The name of the firmware image.
* @cb: Callback to the upload the firmware image.
* @context: Private context from the driver.
*
* Sends a firmware request for the hardware device and waits for it. Calls
* the callback function to upload the firmware to the device, them releases
* the firmware.
*
* Returns 0 on success, -EINVAL if @cb is NULL, or a negative error number
* from the firmware request or the callback function.
*/
int comedi_load_firmware(struct comedi_device *dev,
struct device *device,
const char *name,
int (*cb)(struct comedi_device *dev,
const u8 *data, size_t size,
unsigned long context),
unsigned long context)
{
const struct firmware *fw;
int ret;
if (!cb)
return -EINVAL;
ret = request_firmware(&fw, name, device);
if (ret == 0) {
ret = cb(dev, fw->data, fw->size, context);
release_firmware(fw);
}
return min(ret, 0);
}
EXPORT_SYMBOL_GPL(comedi_load_firmware);
/**
* __comedi_request_region() - Request an I/O region for a legacy driver
* @dev: COMEDI device.
* @start: Base address of the I/O region.
* @len: Length of the I/O region.
*
* Requests the specified I/O port region which must start at a non-zero
* address.
*
* Returns 0 on success, -EINVAL if @start is 0, or -EIO if the request
* fails.
*/
int __comedi_request_region(struct comedi_device *dev,
unsigned long start, unsigned long len)
{
if (!start) {
dev_warn(dev->class_dev,
"%s: a I/O base address must be specified\n",
dev->board_name);
return -EINVAL;
}
if (!request_region(start, len, dev->board_name)) {
dev_warn(dev->class_dev, "%s: I/O port conflict (%#lx,%lu)\n",
dev->board_name, start, len);
return -EIO;
}
return 0;
}
EXPORT_SYMBOL_GPL(__comedi_request_region);
/**
* comedi_request_region() - Request an I/O region for a legacy driver
* @dev: COMEDI device.
* @start: Base address of the I/O region.
* @len: Length of the I/O region.
*
* Requests the specified I/O port region which must start at a non-zero
* address.
*
* On success, @dev->iobase is set to the base address of the region and
* @dev->iolen is set to its length.
*
* Returns 0 on success, -EINVAL if @start is 0, or -EIO if the request
* fails.
*/
int comedi_request_region(struct comedi_device *dev,
unsigned long start, unsigned long len)
{
int ret;
ret = __comedi_request_region(dev, start, len);
if (ret == 0) {
dev->iobase = start;
dev->iolen = len;
}
return ret;
}
EXPORT_SYMBOL_GPL(comedi_request_region);
/**
* comedi_legacy_detach() - A generic (*detach) function for legacy drivers
* @dev: COMEDI device.
*
* This is a simple, generic 'detach' handler for legacy COMEDI devices that
* just use a single I/O port region and possibly an IRQ and that don't need
* any special clean-up for their private device or subdevice storage. It
* can also be called by a driver-specific 'detach' handler.
*
* If @dev->irq is non-zero, the IRQ will be freed. If @dev->iobase and
* @dev->iolen are both non-zero, the I/O port region will be released.
*/
void comedi_legacy_detach(struct comedi_device *dev)
{
if (dev->irq) {
free_irq(dev->irq, dev);
dev->irq = 0;
}
if (dev->iobase && dev->iolen) {
release_region(dev->iobase, dev->iolen);
dev->iobase = 0;
dev->iolen = 0;
}
}
EXPORT_SYMBOL_GPL(comedi_legacy_detach);
int comedi_device_attach(struct comedi_device *dev, struct comedi_devconfig *it)
{
struct comedi_driver *driv;
int ret;
lockdep_assert_held(&dev->mutex);
if (dev->attached)
return -EBUSY;
mutex_lock(&comedi_drivers_list_lock);
for (driv = comedi_drivers; driv; driv = driv->next) {
if (!try_module_get(driv->module))
continue;
if (driv->num_names) {
dev->board_ptr = comedi_recognize(driv, it->board_name);
if (dev->board_ptr)
break;
} else if (strcmp(driv->driver_name, it->board_name) == 0) {
break;
}
module_put(driv->module);
}
if (!driv) {
/* recognize has failed if we get here */
/* report valid board names before returning error */
for (driv = comedi_drivers; driv; driv = driv->next) {
if (!try_module_get(driv->module))
continue;
comedi_report_boards(driv);
module_put(driv->module);
}
ret = -EIO;
goto out;
}
if (!driv->attach) {
/* driver does not support manual configuration */
dev_warn(dev->class_dev,
"driver '%s' does not support attach using comedi_config\n",
driv->driver_name);
module_put(driv->module);
ret = -EIO;
goto out;
}
dev->driver = driv;
dev->board_name = dev->board_ptr ? *(const char **)dev->board_ptr
: dev->driver->driver_name;
ret = driv->attach(dev, it);
if (ret >= 0)
ret = comedi_device_postconfig(dev);
if (ret < 0) {
comedi_device_detach(dev);
module_put(driv->module);
}
/* On success, the driver module count has been incremented. */
out:
mutex_unlock(&comedi_drivers_list_lock);
return ret;
}
/**
* comedi_auto_config() - Create a COMEDI device for a hardware device
* @hardware_device: Hardware device.
* @driver: COMEDI low-level driver for the hardware device.
* @context: Driver context for the auto_attach handler.
*
* Allocates a new COMEDI device for the hardware device and calls the
* low-level driver's 'auto_attach' handler to set-up the hardware and
* allocate the COMEDI subdevices. Additional "post-configuration" setting
* up is performed on successful return from the 'auto_attach' handler.
* If the 'auto_attach' handler fails, the low-level driver's 'detach'
* handler will be called as part of the clean-up.
*
* This is usually called from a wrapper function in a bus-specific COMEDI
* module, which in turn is usually called from a bus device 'probe'
* function in the low-level driver.
*
* Returns 0 on success, -EINVAL if the parameters are invalid or the
* post-configuration determines the driver has set the COMEDI device up
* incorrectly, -ENOMEM if failed to allocate memory, -EBUSY if run out of
* COMEDI minor device numbers, or some negative error number returned by
* the driver's 'auto_attach' handler.
*/
int comedi_auto_config(struct device *hardware_device,
struct comedi_driver *driver, unsigned long context)
{
struct comedi_device *dev;
int ret;
if (!hardware_device) {
pr_warn("BUG! %s called with NULL hardware_device\n", __func__);
return -EINVAL;
}
if (!driver) {
dev_warn(hardware_device,
"BUG! %s called with NULL comedi driver\n", __func__);
return -EINVAL;
}
if (!driver->auto_attach) {
dev_warn(hardware_device,
"BUG! comedi driver '%s' has no auto_attach handler\n",
driver->driver_name);
return -EINVAL;
}
dev = comedi_alloc_board_minor(hardware_device);
if (IS_ERR(dev)) {
dev_warn(hardware_device,
"driver '%s' could not create device.\n",
driver->driver_name);
return PTR_ERR(dev);
}
/* Note: comedi_alloc_board_minor() locked dev->mutex. */
lockdep_assert_held(&dev->mutex);
dev->driver = driver;
dev->board_name = dev->driver->driver_name;
ret = driver->auto_attach(dev, context);
if (ret >= 0)
ret = comedi_device_postconfig(dev);
if (ret < 0) {
dev_warn(hardware_device,
"driver '%s' failed to auto-configure device.\n",
driver->driver_name);
mutex_unlock(&dev->mutex);
comedi_release_hardware_device(hardware_device);
} else {
/*
* class_dev should be set properly here
* after a successful auto config
*/
dev_info(dev->class_dev,
"driver '%s' has successfully auto-configured '%s'.\n",
driver->driver_name, dev->board_name);
mutex_unlock(&dev->mutex);
}
return ret;
}
EXPORT_SYMBOL_GPL(comedi_auto_config);
/**
* comedi_auto_unconfig() - Unconfigure auto-allocated COMEDI device
* @hardware_device: Hardware device previously passed to
* comedi_auto_config().
*
* Cleans up and eventually destroys the COMEDI device allocated by
* comedi_auto_config() for the same hardware device. As part of this
* clean-up, the low-level COMEDI driver's 'detach' handler will be called.
* (The COMEDI device itself will persist in an unattached state if it is
* still open, until it is released, and any mmapped buffers will persist
* until they are munmapped.)
*
* This is usually called from a wrapper module in a bus-specific COMEDI
* module, which in turn is usually set as the bus device 'remove' function
* in the low-level COMEDI driver.
*/
void comedi_auto_unconfig(struct device *hardware_device)
{
if (!hardware_device)
return;
comedi_release_hardware_device(hardware_device);
}
EXPORT_SYMBOL_GPL(comedi_auto_unconfig);
/**
* comedi_driver_register() - Register a low-level COMEDI driver
* @driver: Low-level COMEDI driver.
*
* The low-level COMEDI driver is added to the list of registered COMEDI
* drivers. This is used by the handler for the "/proc/comedi" file and is
* also used by the handler for the %COMEDI_DEVCONFIG ioctl to configure
* "legacy" COMEDI devices (for those low-level drivers that support it).
*
* Returns 0.
*/
int comedi_driver_register(struct comedi_driver *driver)
{
mutex_lock(&comedi_drivers_list_lock);
driver->next = comedi_drivers;
comedi_drivers = driver;
mutex_unlock(&comedi_drivers_list_lock);
return 0;
}
EXPORT_SYMBOL_GPL(comedi_driver_register);
/**
* comedi_driver_unregister() - Unregister a low-level COMEDI driver
* @driver: Low-level COMEDI driver.
*
* The low-level COMEDI driver is removed from the list of registered COMEDI
* drivers. Detaches any COMEDI devices attached to the driver, which will
* result in the low-level driver's 'detach' handler being called for those
* devices before this function returns.
*/
void comedi_driver_unregister(struct comedi_driver *driver)
{
struct comedi_driver *prev;
int i;
/* unlink the driver */
mutex_lock(&comedi_drivers_list_lock);
if (comedi_drivers == driver) {
comedi_drivers = driver->next;
} else {
for (prev = comedi_drivers; prev->next; prev = prev->next) {
if (prev->next == driver) {
prev->next = driver->next;
break;
}
}
}
mutex_unlock(&comedi_drivers_list_lock);
/* check for devices using this driver */
for (i = 0; i < COMEDI_NUM_BOARD_MINORS; i++) {
struct comedi_device *dev = comedi_dev_get_from_minor(i);
if (!dev)
continue;
mutex_lock(&dev->mutex);
if (dev->attached && dev->driver == driver) {
if (dev->use_count)
dev_warn(dev->class_dev,
"BUG! detaching device with use_count=%d\n",
dev->use_count);
comedi_device_detach(dev);
}
mutex_unlock(&dev->mutex);
comedi_dev_put(dev);
}
}
EXPORT_SYMBOL_GPL(comedi_driver_unregister);