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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reset-bcm6345.c (3549B)

      1// SPDX-License-Identifier: GPL-2.0-or-later
      2/*
      3 * BCM6345 Reset Controller Driver
      4 *
      5 * Copyright (C) 2020 Álvaro Fernández Rojas <noltari@gmail.com>
      6 */
      7
      8#include <linux/delay.h>
      9#include <linux/init.h>
     10#include <linux/io.h>
     11#include <linux/mod_devicetable.h>
     12#include <linux/platform_device.h>
     13#include <linux/reset-controller.h>
     14
     15#define BCM6345_RESET_NUM		32
     16#define BCM6345_RESET_SLEEP_MIN_US	10000
     17#define BCM6345_RESET_SLEEP_MAX_US	20000
     18
     19struct bcm6345_reset {
     20	struct reset_controller_dev rcdev;
     21	void __iomem *base;
     22	spinlock_t lock;
     23};
     24
     25static inline struct bcm6345_reset *
     26to_bcm6345_reset(struct reset_controller_dev *rcdev)
     27{
     28	return container_of(rcdev, struct bcm6345_reset, rcdev);
     29}
     30
     31static int bcm6345_reset_update(struct reset_controller_dev *rcdev,
     32				unsigned long id, bool assert)
     33{
     34	struct bcm6345_reset *bcm6345_reset = to_bcm6345_reset(rcdev);
     35	unsigned long flags;
     36	uint32_t val;
     37
     38	spin_lock_irqsave(&bcm6345_reset->lock, flags);
     39	val = __raw_readl(bcm6345_reset->base);
     40	if (assert)
     41		val &= ~BIT(id);
     42	else
     43		val |= BIT(id);
     44	__raw_writel(val, bcm6345_reset->base);
     45	spin_unlock_irqrestore(&bcm6345_reset->lock, flags);
     46
     47	return 0;
     48}
     49
     50static int bcm6345_reset_assert(struct reset_controller_dev *rcdev,
     51				unsigned long id)
     52{
     53	return bcm6345_reset_update(rcdev, id, true);
     54}
     55
     56static int bcm6345_reset_deassert(struct reset_controller_dev *rcdev,
     57				  unsigned long id)
     58{
     59	return bcm6345_reset_update(rcdev, id, false);
     60}
     61
     62static int bcm6345_reset_reset(struct reset_controller_dev *rcdev,
     63			       unsigned long id)
     64{
     65	bcm6345_reset_update(rcdev, id, true);
     66	usleep_range(BCM6345_RESET_SLEEP_MIN_US,
     67		     BCM6345_RESET_SLEEP_MAX_US);
     68
     69	bcm6345_reset_update(rcdev, id, false);
     70	/*
     71	 * Ensure component is taken out reset state by sleeping also after
     72	 * deasserting the reset. Otherwise, the component may not be ready
     73	 * for operation.
     74	 */
     75	usleep_range(BCM6345_RESET_SLEEP_MIN_US,
     76		     BCM6345_RESET_SLEEP_MAX_US);
     77
     78	return 0;
     79}
     80
     81static int bcm6345_reset_status(struct reset_controller_dev *rcdev,
     82				unsigned long id)
     83{
     84	struct bcm6345_reset *bcm6345_reset = to_bcm6345_reset(rcdev);
     85
     86	return !(__raw_readl(bcm6345_reset->base) & BIT(id));
     87}
     88
     89static const struct reset_control_ops bcm6345_reset_ops = {
     90	.assert = bcm6345_reset_assert,
     91	.deassert = bcm6345_reset_deassert,
     92	.reset = bcm6345_reset_reset,
     93	.status = bcm6345_reset_status,
     94};
     95
     96static int bcm6345_reset_probe(struct platform_device *pdev)
     97{
     98	struct bcm6345_reset *bcm6345_reset;
     99
    100	bcm6345_reset = devm_kzalloc(&pdev->dev,
    101				     sizeof(*bcm6345_reset), GFP_KERNEL);
    102	if (!bcm6345_reset)
    103		return -ENOMEM;
    104
    105	platform_set_drvdata(pdev, bcm6345_reset);
    106
    107	bcm6345_reset->base = devm_platform_ioremap_resource(pdev, 0);
    108	if (IS_ERR(bcm6345_reset->base))
    109		return PTR_ERR(bcm6345_reset->base);
    110
    111	spin_lock_init(&bcm6345_reset->lock);
    112	bcm6345_reset->rcdev.ops = &bcm6345_reset_ops;
    113	bcm6345_reset->rcdev.owner = THIS_MODULE;
    114	bcm6345_reset->rcdev.of_node = pdev->dev.of_node;
    115	bcm6345_reset->rcdev.of_reset_n_cells = 1;
    116	bcm6345_reset->rcdev.nr_resets = BCM6345_RESET_NUM;
    117
    118	return devm_reset_controller_register(&pdev->dev,
    119					      &bcm6345_reset->rcdev);
    120}
    121
    122static const struct of_device_id bcm6345_reset_of_match[] = {
    123	{ .compatible = "brcm,bcm6345-reset" },
    124	{ /* sentinel */ },
    125};
    126
    127static struct platform_driver bcm6345_reset_driver = {
    128	.probe = bcm6345_reset_probe,
    129	.driver	= {
    130		.name = "bcm6345-reset",
    131		.of_match_table = bcm6345_reset_of_match,
    132		.suppress_bind_attrs = true,
    133	},
    134};
    135builtin_platform_driver(bcm6345_reset_driver);