cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
Log | Files | Refs | README | LICENSE | sfeed.txt

gpio-logicvc.c (4230B)

      1// SPDX-License-Identifier: GPL-2.0+
      2/*
      3 * Copyright (C) 2019 Bootlin
      4 * Author: Paul Kocialkowski <paul.kocialkowski@bootlin.com>
      5 */
      6
      7#include <linux/err.h>
      8#include <linux/gpio/driver.h>
      9#include <linux/module.h>
     10#include <linux/of.h>
     11#include <linux/of_device.h>
     12#include <linux/of_address.h>
     13#include <linux/platform_device.h>
     14#include <linux/regmap.h>
     15#include <linux/mfd/syscon.h>
     16
     17#define LOGICVC_CTRL_REG		0x40
     18#define LOGICVC_CTRL_GPIO_SHIFT		11
     19#define LOGICVC_CTRL_GPIO_BITS		5
     20
     21#define LOGICVC_POWER_CTRL_REG		0x78
     22#define LOGICVC_POWER_CTRL_GPIO_SHIFT	0
     23#define LOGICVC_POWER_CTRL_GPIO_BITS	4
     24
     25struct logicvc_gpio {
     26	struct gpio_chip chip;
     27	struct regmap *regmap;
     28};
     29
     30static void logicvc_gpio_offset(struct logicvc_gpio *logicvc, unsigned offset,
     31				unsigned int *reg, unsigned int *bit)
     32{
     33	if (offset >= LOGICVC_CTRL_GPIO_BITS) {
     34		*reg = LOGICVC_POWER_CTRL_REG;
     35
     36		/* To the (virtual) power ctrl offset. */
     37		offset -= LOGICVC_CTRL_GPIO_BITS;
     38		/* To the actual bit offset in reg. */
     39		offset += LOGICVC_POWER_CTRL_GPIO_SHIFT;
     40	} else {
     41		*reg = LOGICVC_CTRL_REG;
     42
     43		/* To the actual bit offset in reg. */
     44		offset += LOGICVC_CTRL_GPIO_SHIFT;
     45	}
     46
     47	*bit = BIT(offset);
     48}
     49
     50static int logicvc_gpio_get(struct gpio_chip *chip, unsigned offset)
     51{
     52	struct logicvc_gpio *logicvc = gpiochip_get_data(chip);
     53	unsigned int reg, bit, value;
     54	int ret;
     55
     56	logicvc_gpio_offset(logicvc, offset, &reg, &bit);
     57
     58	ret = regmap_read(logicvc->regmap, reg, &value);
     59	if (ret)
     60		return ret;
     61
     62	return !!(value & bit);
     63}
     64
     65static void logicvc_gpio_set(struct gpio_chip *chip, unsigned offset, int value)
     66{
     67	struct logicvc_gpio *logicvc = gpiochip_get_data(chip);
     68	unsigned int reg, bit;
     69
     70	logicvc_gpio_offset(logicvc, offset, &reg, &bit);
     71
     72	regmap_update_bits(logicvc->regmap, reg, bit, value ? bit : 0);
     73}
     74
     75static int logicvc_gpio_direction_output(struct gpio_chip *chip,
     76					 unsigned offset, int value)
     77{
     78	/* Pins are always configured as output, so just set the value. */
     79	logicvc_gpio_set(chip, offset, value);
     80
     81	return 0;
     82}
     83
     84static struct regmap_config logicvc_gpio_regmap_config = {
     85	.reg_bits	= 32,
     86	.val_bits	= 32,
     87	.reg_stride	= 4,
     88	.name		= "logicvc-gpio",
     89};
     90
     91static int logicvc_gpio_probe(struct platform_device *pdev)
     92{
     93	struct device *dev = &pdev->dev;
     94	struct device_node *of_node = dev->of_node;
     95	struct logicvc_gpio *logicvc;
     96	int ret;
     97
     98	logicvc = devm_kzalloc(dev, sizeof(*logicvc), GFP_KERNEL);
     99	if (!logicvc)
    100		return -ENOMEM;
    101
    102	/* Try to get regmap from parent first. */
    103	logicvc->regmap = syscon_node_to_regmap(of_node->parent);
    104
    105	/* Grab our own regmap if that fails. */
    106	if (IS_ERR(logicvc->regmap)) {
    107		struct resource res;
    108		void __iomem *base;
    109
    110		ret = of_address_to_resource(of_node, 0, &res);
    111		if (ret) {
    112			dev_err(dev, "Failed to get resource from address\n");
    113			return ret;
    114		}
    115
    116		base = devm_ioremap_resource(dev, &res);
    117		if (IS_ERR(base))
    118			return PTR_ERR(base);
    119
    120		logicvc_gpio_regmap_config.max_register = resource_size(&res) -
    121			logicvc_gpio_regmap_config.reg_stride;
    122
    123		logicvc->regmap =
    124			devm_regmap_init_mmio(dev, base,
    125					      &logicvc_gpio_regmap_config);
    126		if (IS_ERR(logicvc->regmap)) {
    127			dev_err(dev, "Failed to create regmap for I/O\n");
    128			return PTR_ERR(logicvc->regmap);
    129		}
    130	}
    131
    132	logicvc->chip.parent = dev;
    133	logicvc->chip.owner = THIS_MODULE;
    134	logicvc->chip.label = dev_name(dev);
    135	logicvc->chip.base = -1;
    136	logicvc->chip.ngpio = LOGICVC_CTRL_GPIO_BITS +
    137			      LOGICVC_POWER_CTRL_GPIO_BITS;
    138	logicvc->chip.get = logicvc_gpio_get;
    139	logicvc->chip.set = logicvc_gpio_set;
    140	logicvc->chip.direction_output = logicvc_gpio_direction_output;
    141
    142	platform_set_drvdata(pdev, logicvc);
    143
    144	return devm_gpiochip_add_data(dev, &logicvc->chip, logicvc);
    145}
    146
    147static const struct of_device_id logicivc_gpio_of_table[] = {
    148	{
    149		.compatible	= "xylon,logicvc-3.02.a-gpio",
    150	},
    151	{ }
    152};
    153
    154MODULE_DEVICE_TABLE(of, logicivc_gpio_of_table);
    155
    156static struct platform_driver logicvc_gpio_driver = {
    157	.driver	= {
    158		.name		= "gpio-logicvc",
    159		.of_match_table	= logicivc_gpio_of_table,
    160	},
    161	.probe	= logicvc_gpio_probe,
    162};
    163
    164module_platform_driver(logicvc_gpio_driver);
    165
    166MODULE_AUTHOR("Paul Kocialkowski <paul.kocialkowski@bootlin.com>");
    167MODULE_DESCRIPTION("Xylon LogiCVC GPIO driver");
    168MODULE_LICENSE("GPL");