cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
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cio-dac.c (3623B)

      1// SPDX-License-Identifier: GPL-2.0-only
      2/*
      3 * IIO driver for the Measurement Computing CIO-DAC
      4 * Copyright (C) 2016 William Breathitt Gray
      5 *
      6 * This driver supports the following Measurement Computing devices: CIO-DAC16,
      7 * CIO-DAC06, and PC104-DAC06.
      8 */
      9#include <linux/bitops.h>
     10#include <linux/device.h>
     11#include <linux/errno.h>
     12#include <linux/iio/iio.h>
     13#include <linux/iio/types.h>
     14#include <linux/io.h>
     15#include <linux/ioport.h>
     16#include <linux/isa.h>
     17#include <linux/module.h>
     18#include <linux/moduleparam.h>
     19
     20#define CIO_DAC_NUM_CHAN 16
     21
     22#define CIO_DAC_CHAN(chan) {				\
     23	.type = IIO_VOLTAGE,				\
     24	.channel = chan,				\
     25	.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),	\
     26	.indexed = 1,					\
     27	.output = 1					\
     28}
     29
     30#define CIO_DAC_EXTENT 32
     31
     32static unsigned int base[max_num_isa_dev(CIO_DAC_EXTENT)];
     33static unsigned int num_cio_dac;
     34module_param_hw_array(base, uint, ioport, &num_cio_dac, 0);
     35MODULE_PARM_DESC(base, "Measurement Computing CIO-DAC base addresses");
     36
     37/**
     38 * struct cio_dac_iio - IIO device private data structure
     39 * @chan_out_states:	channels' output states
     40 * @base:		base port address of the IIO device
     41 */
     42struct cio_dac_iio {
     43	int chan_out_states[CIO_DAC_NUM_CHAN];
     44	unsigned int base;
     45};
     46
     47static int cio_dac_read_raw(struct iio_dev *indio_dev,
     48	struct iio_chan_spec const *chan, int *val, int *val2, long mask)
     49{
     50	struct cio_dac_iio *const priv = iio_priv(indio_dev);
     51
     52	if (mask != IIO_CHAN_INFO_RAW)
     53		return -EINVAL;
     54
     55	*val = priv->chan_out_states[chan->channel];
     56
     57	return IIO_VAL_INT;
     58}
     59
     60static int cio_dac_write_raw(struct iio_dev *indio_dev,
     61	struct iio_chan_spec const *chan, int val, int val2, long mask)
     62{
     63	struct cio_dac_iio *const priv = iio_priv(indio_dev);
     64	const unsigned int chan_addr_offset = 2 * chan->channel;
     65
     66	if (mask != IIO_CHAN_INFO_RAW)
     67		return -EINVAL;
     68
     69	/* DAC can only accept up to a 16-bit value */
     70	if ((unsigned int)val > 65535)
     71		return -EINVAL;
     72
     73	priv->chan_out_states[chan->channel] = val;
     74	outw(val, priv->base + chan_addr_offset);
     75
     76	return 0;
     77}
     78
     79static const struct iio_info cio_dac_info = {
     80	.read_raw = cio_dac_read_raw,
     81	.write_raw = cio_dac_write_raw
     82};
     83
     84static const struct iio_chan_spec cio_dac_channels[CIO_DAC_NUM_CHAN] = {
     85	CIO_DAC_CHAN(0), CIO_DAC_CHAN(1), CIO_DAC_CHAN(2), CIO_DAC_CHAN(3),
     86	CIO_DAC_CHAN(4), CIO_DAC_CHAN(5), CIO_DAC_CHAN(6), CIO_DAC_CHAN(7),
     87	CIO_DAC_CHAN(8), CIO_DAC_CHAN(9), CIO_DAC_CHAN(10), CIO_DAC_CHAN(11),
     88	CIO_DAC_CHAN(12), CIO_DAC_CHAN(13), CIO_DAC_CHAN(14), CIO_DAC_CHAN(15)
     89};
     90
     91static int cio_dac_probe(struct device *dev, unsigned int id)
     92{
     93	struct iio_dev *indio_dev;
     94	struct cio_dac_iio *priv;
     95	unsigned int i;
     96
     97	indio_dev = devm_iio_device_alloc(dev, sizeof(*priv));
     98	if (!indio_dev)
     99		return -ENOMEM;
    100
    101	if (!devm_request_region(dev, base[id], CIO_DAC_EXTENT,
    102		dev_name(dev))) {
    103		dev_err(dev, "Unable to request port addresses (0x%X-0x%X)\n",
    104			base[id], base[id] + CIO_DAC_EXTENT);
    105		return -EBUSY;
    106	}
    107
    108	indio_dev->info = &cio_dac_info;
    109	indio_dev->modes = INDIO_DIRECT_MODE;
    110	indio_dev->channels = cio_dac_channels;
    111	indio_dev->num_channels = CIO_DAC_NUM_CHAN;
    112	indio_dev->name = dev_name(dev);
    113
    114	priv = iio_priv(indio_dev);
    115	priv->base = base[id];
    116
    117	/* initialize DAC outputs to 0V */
    118	for (i = 0; i < 32; i += 2)
    119		outw(0, base[id] + i);
    120
    121	return devm_iio_device_register(dev, indio_dev);
    122}
    123
    124static struct isa_driver cio_dac_driver = {
    125	.probe = cio_dac_probe,
    126	.driver = {
    127		.name = "cio-dac"
    128	}
    129};
    130
    131module_isa_driver(cio_dac_driver, num_cio_dac);
    132
    133MODULE_AUTHOR("William Breathitt Gray <vilhelm.gray@gmail.com>");
    134MODULE_DESCRIPTION("Measurement Computing CIO-DAC IIO driver");
    135MODULE_LICENSE("GPL v2");