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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mmio.c (3563B)

      1// SPDX-License-Identifier: GPL-2.0
      2/*
      3 * MMIO register bitfield-controlled multiplexer driver
      4 *
      5 * Copyright (C) 2017 Pengutronix, Philipp Zabel <kernel@pengutronix.de>
      6 */
      7
      8#include <linux/bitops.h>
      9#include <linux/err.h>
     10#include <linux/mfd/syscon.h>
     11#include <linux/module.h>
     12#include <linux/mux/driver.h>
     13#include <linux/of_platform.h>
     14#include <linux/platform_device.h>
     15#include <linux/property.h>
     16#include <linux/regmap.h>
     17
     18static int mux_mmio_set(struct mux_control *mux, int state)
     19{
     20	struct regmap_field **fields = mux_chip_priv(mux->chip);
     21
     22	return regmap_field_write(fields[mux_control_get_index(mux)], state);
     23}
     24
     25static const struct mux_control_ops mux_mmio_ops = {
     26	.set = mux_mmio_set,
     27};
     28
     29static const struct of_device_id mux_mmio_dt_ids[] = {
     30	{ .compatible = "mmio-mux", },
     31	{ .compatible = "reg-mux", },
     32	{ /* sentinel */ }
     33};
     34MODULE_DEVICE_TABLE(of, mux_mmio_dt_ids);
     35
     36static int mux_mmio_probe(struct platform_device *pdev)
     37{
     38	struct device *dev = &pdev->dev;
     39	struct device_node *np = dev->of_node;
     40	struct regmap_field **fields;
     41	struct mux_chip *mux_chip;
     42	struct regmap *regmap;
     43	int num_fields;
     44	int ret;
     45	int i;
     46
     47	if (of_device_is_compatible(np, "mmio-mux"))
     48		regmap = syscon_node_to_regmap(np->parent);
     49	else
     50		regmap = dev_get_regmap(dev->parent, NULL) ?: ERR_PTR(-ENODEV);
     51	if (IS_ERR(regmap)) {
     52		ret = PTR_ERR(regmap);
     53		dev_err(dev, "failed to get regmap: %d\n", ret);
     54		return ret;
     55	}
     56
     57	ret = of_property_count_u32_elems(np, "mux-reg-masks");
     58	if (ret == 0 || ret % 2)
     59		ret = -EINVAL;
     60	if (ret < 0) {
     61		dev_err(dev, "mux-reg-masks property missing or invalid: %d\n",
     62			ret);
     63		return ret;
     64	}
     65	num_fields = ret / 2;
     66
     67	mux_chip = devm_mux_chip_alloc(dev, num_fields, num_fields *
     68				       sizeof(*fields));
     69	if (IS_ERR(mux_chip))
     70		return PTR_ERR(mux_chip);
     71
     72	fields = mux_chip_priv(mux_chip);
     73
     74	for (i = 0; i < num_fields; i++) {
     75		struct mux_control *mux = &mux_chip->mux[i];
     76		struct reg_field field;
     77		s32 idle_state = MUX_IDLE_AS_IS;
     78		u32 reg, mask;
     79		int bits;
     80
     81		ret = of_property_read_u32_index(np, "mux-reg-masks",
     82						 2 * i, &reg);
     83		if (!ret)
     84			ret = of_property_read_u32_index(np, "mux-reg-masks",
     85							 2 * i + 1, &mask);
     86		if (ret < 0) {
     87			dev_err(dev, "bitfield %d: failed to read mux-reg-masks property: %d\n",
     88				i, ret);
     89			return ret;
     90		}
     91
     92		field.reg = reg;
     93		field.msb = fls(mask) - 1;
     94		field.lsb = ffs(mask) - 1;
     95
     96		if (mask != GENMASK(field.msb, field.lsb)) {
     97			dev_err(dev, "bitfield %d: invalid mask 0x%x\n",
     98				i, mask);
     99			return -EINVAL;
    100		}
    101
    102		fields[i] = devm_regmap_field_alloc(dev, regmap, field);
    103		if (IS_ERR(fields[i])) {
    104			ret = PTR_ERR(fields[i]);
    105			dev_err(dev, "bitfield %d: failed allocate: %d\n",
    106				i, ret);
    107			return ret;
    108		}
    109
    110		bits = 1 + field.msb - field.lsb;
    111		mux->states = 1 << bits;
    112
    113		of_property_read_u32_index(np, "idle-states", i,
    114					   (u32 *)&idle_state);
    115		if (idle_state != MUX_IDLE_AS_IS) {
    116			if (idle_state < 0 || idle_state >= mux->states) {
    117				dev_err(dev, "bitfield: %d: out of range idle state %d\n",
    118					i, idle_state);
    119				return -EINVAL;
    120			}
    121
    122			mux->idle_state = idle_state;
    123		}
    124	}
    125
    126	mux_chip->ops = &mux_mmio_ops;
    127
    128	return devm_mux_chip_register(dev, mux_chip);
    129}
    130
    131static struct platform_driver mux_mmio_driver = {
    132	.driver = {
    133		.name = "mmio-mux",
    134		.of_match_table	= of_match_ptr(mux_mmio_dt_ids),
    135	},
    136	.probe = mux_mmio_probe,
    137};
    138module_platform_driver(mux_mmio_driver);
    139
    140MODULE_DESCRIPTION("MMIO register bitfield-controlled multiplexer driver");
    141MODULE_AUTHOR("Philipp Zabel <p.zabel@pengutronix.de>");
    142MODULE_LICENSE("GPL v2");