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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fpi-bus.c (2141B)

      1// SPDX-License-Identifier: GPL-2.0-only
      2/*
      3 *
      4 *  Copyright (C) 2011-2015 John Crispin <blogic@phrozen.org>
      5 *  Copyright (C) 2015 Martin Blumenstingl <martin.blumenstingl@googlemail.com>
      6 *  Copyright (C) 2017 Hauke Mehrtens <hauke@hauke-m.de>
      7 */
      8
      9#include <linux/device.h>
     10#include <linux/err.h>
     11#include <linux/mfd/syscon.h>
     12#include <linux/module.h>
     13#include <linux/of.h>
     14#include <linux/of_platform.h>
     15#include <linux/platform_device.h>
     16#include <linux/property.h>
     17#include <linux/regmap.h>
     18
     19#include <lantiq_soc.h>
     20
     21#define XBAR_ALWAYS_LAST	0x430
     22#define XBAR_FPI_BURST_EN	BIT(1)
     23#define XBAR_AHB_BURST_EN	BIT(2)
     24
     25#define RCU_VR9_BE_AHB1S	0x00000008
     26
     27static int ltq_fpi_probe(struct platform_device *pdev)
     28{
     29	struct device *dev = &pdev->dev;
     30	struct device_node *np = dev->of_node;
     31	struct regmap *rcu_regmap;
     32	void __iomem *xbar_membase;
     33	u32 rcu_ahb_endianness_reg_offset;
     34	int ret;
     35
     36	xbar_membase = devm_platform_ioremap_resource(pdev, 0);
     37	if (IS_ERR(xbar_membase))
     38		return PTR_ERR(xbar_membase);
     39
     40	/* RCU configuration is optional */
     41	rcu_regmap = syscon_regmap_lookup_by_phandle(np, "lantiq,rcu");
     42	if (IS_ERR(rcu_regmap))
     43		return PTR_ERR(rcu_regmap);
     44
     45	ret = device_property_read_u32(dev, "lantiq,offset-endianness",
     46				       &rcu_ahb_endianness_reg_offset);
     47	if (ret) {
     48		dev_err(&pdev->dev, "Failed to get RCU reg offset\n");
     49		return ret;
     50	}
     51
     52	ret = regmap_update_bits(rcu_regmap, rcu_ahb_endianness_reg_offset,
     53				 RCU_VR9_BE_AHB1S, RCU_VR9_BE_AHB1S);
     54	if (ret) {
     55		dev_warn(&pdev->dev,
     56			 "Failed to configure RCU AHB endianness\n");
     57		return ret;
     58	}
     59
     60	/* disable fpi burst */
     61	ltq_w32_mask(XBAR_FPI_BURST_EN, 0, xbar_membase + XBAR_ALWAYS_LAST);
     62
     63	return of_platform_populate(dev->of_node, NULL, NULL, dev);
     64}
     65
     66static const struct of_device_id ltq_fpi_match[] = {
     67	{ .compatible = "lantiq,xrx200-fpi" },
     68	{},
     69};
     70MODULE_DEVICE_TABLE(of, ltq_fpi_match);
     71
     72static struct platform_driver ltq_fpi_driver = {
     73	.probe = ltq_fpi_probe,
     74	.driver = {
     75		.name = "fpi-xway",
     76		.of_match_table = ltq_fpi_match,
     77	},
     78};
     79
     80module_platform_driver(ltq_fpi_driver);
     81
     82MODULE_DESCRIPTION("Lantiq FPI bus driver");
     83MODULE_LICENSE("GPL");