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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meson-efuse.c (2854B)

      1// SPDX-License-Identifier: GPL-2.0-only
      2/*
      3 * Amlogic Meson GX eFuse Driver
      4 *
      5 * Copyright (c) 2016 Endless Computers, Inc.
      6 * Author: Carlo Caione <carlo@endlessm.com>
      7 */
      8
      9#include <linux/clk.h>
     10#include <linux/module.h>
     11#include <linux/nvmem-provider.h>
     12#include <linux/of.h>
     13#include <linux/platform_device.h>
     14
     15#include <linux/firmware/meson/meson_sm.h>
     16
     17static int meson_efuse_read(void *context, unsigned int offset,
     18			    void *val, size_t bytes)
     19{
     20	struct meson_sm_firmware *fw = context;
     21
     22	return meson_sm_call_read(fw, (u8 *)val, bytes, SM_EFUSE_READ, offset,
     23				  bytes, 0, 0, 0);
     24}
     25
     26static int meson_efuse_write(void *context, unsigned int offset,
     27			     void *val, size_t bytes)
     28{
     29	struct meson_sm_firmware *fw = context;
     30
     31	return meson_sm_call_write(fw, (u8 *)val, bytes, SM_EFUSE_WRITE, offset,
     32				   bytes, 0, 0, 0);
     33}
     34
     35static const struct of_device_id meson_efuse_match[] = {
     36	{ .compatible = "amlogic,meson-gxbb-efuse", },
     37	{ /* sentinel */ },
     38};
     39MODULE_DEVICE_TABLE(of, meson_efuse_match);
     40
     41static int meson_efuse_probe(struct platform_device *pdev)
     42{
     43	struct device *dev = &pdev->dev;
     44	struct meson_sm_firmware *fw;
     45	struct device_node *sm_np;
     46	struct nvmem_device *nvmem;
     47	struct nvmem_config *econfig;
     48	struct clk *clk;
     49	unsigned int size;
     50	int ret;
     51
     52	sm_np = of_parse_phandle(pdev->dev.of_node, "secure-monitor", 0);
     53	if (!sm_np) {
     54		dev_err(&pdev->dev, "no secure-monitor node\n");
     55		return -ENODEV;
     56	}
     57
     58	fw = meson_sm_get(sm_np);
     59	of_node_put(sm_np);
     60	if (!fw)
     61		return -EPROBE_DEFER;
     62
     63	clk = devm_clk_get(dev, NULL);
     64	if (IS_ERR(clk)) {
     65		ret = PTR_ERR(clk);
     66		if (ret != -EPROBE_DEFER)
     67			dev_err(dev, "failed to get efuse gate");
     68		return ret;
     69	}
     70
     71	ret = clk_prepare_enable(clk);
     72	if (ret) {
     73		dev_err(dev, "failed to enable gate");
     74		return ret;
     75	}
     76
     77	ret = devm_add_action_or_reset(dev,
     78				       (void(*)(void *))clk_disable_unprepare,
     79				       clk);
     80	if (ret) {
     81		dev_err(dev, "failed to add disable callback");
     82		return ret;
     83	}
     84
     85	if (meson_sm_call(fw, SM_EFUSE_USER_MAX, &size, 0, 0, 0, 0, 0) < 0) {
     86		dev_err(dev, "failed to get max user");
     87		return -EINVAL;
     88	}
     89
     90	econfig = devm_kzalloc(dev, sizeof(*econfig), GFP_KERNEL);
     91	if (!econfig)
     92		return -ENOMEM;
     93
     94	econfig->dev = dev;
     95	econfig->name = dev_name(dev);
     96	econfig->stride = 1;
     97	econfig->word_size = 1;
     98	econfig->reg_read = meson_efuse_read;
     99	econfig->reg_write = meson_efuse_write;
    100	econfig->size = size;
    101	econfig->priv = fw;
    102
    103	nvmem = devm_nvmem_register(&pdev->dev, econfig);
    104
    105	return PTR_ERR_OR_ZERO(nvmem);
    106}
    107
    108static struct platform_driver meson_efuse_driver = {
    109	.probe = meson_efuse_probe,
    110	.driver = {
    111		.name = "meson-efuse",
    112		.of_match_table = meson_efuse_match,
    113	},
    114};
    115
    116module_platform_driver(meson_efuse_driver);
    117
    118MODULE_AUTHOR("Carlo Caione <carlo@endlessm.com>");
    119MODULE_DESCRIPTION("Amlogic Meson GX NVMEM driver");
    120MODULE_LICENSE("GPL v2");