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-raspberrypi.c (3152B)

      1// SPDX-License-Identifier: GPL-2.0
      2/*
      3 * Raspberry Pi 4 firmware reset driver
      4 *
      5 * Copyright (C) 2020 Nicolas Saenz Julienne <nsaenzjulienne@suse.de>
      6 */
      7#include <linux/delay.h>
      8#include <linux/device.h>
      9#include <linux/module.h>
     10#include <linux/of.h>
     11#include <linux/platform_device.h>
     12#include <linux/reset-controller.h>
     13#include <soc/bcm2835/raspberrypi-firmware.h>
     14#include <dt-bindings/reset/raspberrypi,firmware-reset.h>
     15
     16struct rpi_reset {
     17	struct reset_controller_dev rcdev;
     18	struct rpi_firmware *fw;
     19};
     20
     21static inline struct rpi_reset *to_rpi(struct reset_controller_dev *rcdev)
     22{
     23	return container_of(rcdev, struct rpi_reset, rcdev);
     24}
     25
     26static int rpi_reset_reset(struct reset_controller_dev *rcdev, unsigned long id)
     27{
     28	struct rpi_reset *priv = to_rpi(rcdev);
     29	u32 dev_addr;
     30	int ret;
     31
     32	switch (id) {
     33	case RASPBERRYPI_FIRMWARE_RESET_ID_USB:
     34		/*
     35		 * The Raspberry Pi 4 gets its USB functionality from VL805, a
     36		 * PCIe chip that implements xHCI. After a PCI reset, VL805's
     37		 * firmware may either be loaded directly from an EEPROM or, if
     38		 * not present, by the SoC's co-processor, VideoCore. rpi's
     39		 * VideoCore OS contains both the non public firmware load
     40		 * logic and the VL805 firmware blob. This triggers the
     41		 * aforementioned process.
     42		 *
     43		 * The pci device address is expected is expected by the
     44		 * firmware encoded like this:
     45		 *
     46		 *	PCI_BUS << 20 | PCI_SLOT << 15 | PCI_FUNC << 12
     47		 *
     48		 * But since rpi's PCIe is hardwired, we know the address in
     49		 * advance.
     50		 */
     51		dev_addr = 0x100000;
     52		ret = rpi_firmware_property(priv->fw, RPI_FIRMWARE_NOTIFY_XHCI_RESET,
     53					    &dev_addr, sizeof(dev_addr));
     54		if (ret)
     55			return ret;
     56
     57		/* Wait for vl805 to startup */
     58		usleep_range(200, 1000);
     59		break;
     60
     61	default:
     62		return -EINVAL;
     63	}
     64
     65	return 0;
     66}
     67
     68static const struct reset_control_ops rpi_reset_ops = {
     69	.reset	= rpi_reset_reset,
     70};
     71
     72static int rpi_reset_probe(struct platform_device *pdev)
     73{
     74	struct device *dev = &pdev->dev;
     75	struct rpi_firmware *fw;
     76	struct device_node *np;
     77	struct rpi_reset *priv;
     78
     79	np = of_get_parent(dev->of_node);
     80	if (!np) {
     81		dev_err(dev, "Missing firmware node\n");
     82		return -ENOENT;
     83	}
     84
     85	fw = devm_rpi_firmware_get(&pdev->dev, np);
     86	of_node_put(np);
     87	if (!fw)
     88		return -EPROBE_DEFER;
     89
     90	priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
     91	if (!priv)
     92		return -ENOMEM;
     93
     94	dev_set_drvdata(dev, priv);
     95
     96	priv->fw = fw;
     97	priv->rcdev.owner = THIS_MODULE;
     98	priv->rcdev.nr_resets = RASPBERRYPI_FIRMWARE_RESET_NUM_IDS;
     99	priv->rcdev.ops = &rpi_reset_ops;
    100	priv->rcdev.of_node = dev->of_node;
    101
    102	return devm_reset_controller_register(dev, &priv->rcdev);
    103}
    104
    105static const struct of_device_id rpi_reset_of_match[] = {
    106	{ .compatible = "raspberrypi,firmware-reset" },
    107	{ /* sentinel */ }
    108};
    109MODULE_DEVICE_TABLE(of, rpi_reset_of_match);
    110
    111static struct platform_driver rpi_reset_driver = {
    112	.probe	= rpi_reset_probe,
    113	.driver	= {
    114		.name = "raspberrypi-reset",
    115		.of_match_table = rpi_reset_of_match,
    116	},
    117};
    118module_platform_driver(rpi_reset_driver);
    119
    120MODULE_AUTHOR("Nicolas Saenz Julienne <nsaenzjulienne@suse.de>");
    121MODULE_DESCRIPTION("Raspberry Pi 4 firmware reset driver");
    122MODULE_LICENSE("GPL");