151 lines
4.7 KiB
C
151 lines
4.7 KiB
C
/*
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* This file is provided under a dual BSD/GPLv2 license. When using or
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* redistributing this file, you may do so under either license.
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*
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* GPL LICENSE SUMMARY
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*
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* Copyright (c) 2016 BayLibre, SAS.
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* Author: Neil Armstrong <narmstrong@baylibre.com>
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* Copyright (C) 2014 Amlogic, Inc.
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of version 2 of the GNU General Public License as
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* published by the Free Software Foundation.
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*
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* This program is distributed in the hope that it will be useful, but
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* WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, see <http://www.gnu.org/licenses/>.
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* The full GNU General Public License is included in this distribution
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* in the file called COPYING.
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*
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* BSD LICENSE
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*
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* Copyright (c) 2016 BayLibre, SAS.
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* Author: Neil Armstrong <narmstrong@baylibre.com>
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* Copyright (C) 2014 Amlogic, Inc.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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*
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* * Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* * Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in
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* the documentation and/or other materials provided with the
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* distribution.
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* * Neither the name of Intel Corporation nor the names of its
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* contributors may be used to endorse or promote products derived
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* from this software without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
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* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
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* OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
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* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
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* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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#include <linux/err.h>
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#include <linux/module.h>
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#include <linux/io.h>
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#include <linux/platform_device.h>
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#include <linux/hw_random.h>
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#include <linux/slab.h>
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#include <linux/types.h>
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#include <linux/of.h>
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#include <linux/clk.h>
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#define RNG_DATA 0x00
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struct meson_rng_data {
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void __iomem *base;
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struct platform_device *pdev;
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struct hwrng rng;
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struct clk *core_clk;
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};
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static int meson_rng_read(struct hwrng *rng, void *buf, size_t max, bool wait)
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{
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struct meson_rng_data *data =
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container_of(rng, struct meson_rng_data, rng);
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*(u32 *)buf = readl_relaxed(data->base + RNG_DATA);
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return sizeof(u32);
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}
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static void meson_rng_clk_disable(void *data)
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{
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clk_disable_unprepare(data);
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}
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static int meson_rng_probe(struct platform_device *pdev)
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{
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struct device *dev = &pdev->dev;
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struct meson_rng_data *data;
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struct resource *res;
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int ret;
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data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL);
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if (!data)
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return -ENOMEM;
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data->pdev = pdev;
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res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
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data->base = devm_ioremap_resource(dev, res);
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if (IS_ERR(data->base))
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return PTR_ERR(data->base);
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data->core_clk = devm_clk_get(dev, "core");
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if (IS_ERR(data->core_clk))
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data->core_clk = NULL;
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if (data->core_clk) {
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ret = clk_prepare_enable(data->core_clk);
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if (ret)
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return ret;
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ret = devm_add_action_or_reset(dev, meson_rng_clk_disable,
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data->core_clk);
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if (ret)
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return ret;
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}
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data->rng.name = pdev->name;
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data->rng.read = meson_rng_read;
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platform_set_drvdata(pdev, data);
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return devm_hwrng_register(dev, &data->rng);
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}
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static const struct of_device_id meson_rng_of_match[] = {
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{ .compatible = "amlogic,meson-rng", },
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{},
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};
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MODULE_DEVICE_TABLE(of, meson_rng_of_match);
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static struct platform_driver meson_rng_driver = {
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.probe = meson_rng_probe,
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.driver = {
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.name = "meson-rng",
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.of_match_table = meson_rng_of_match,
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},
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};
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module_platform_driver(meson_rng_driver);
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MODULE_DESCRIPTION("Meson H/W Random Number Generator driver");
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MODULE_AUTHOR("Lawrence Mok <lawrence.mok@amlogic.com>");
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MODULE_AUTHOR("Neil Armstrong <narmstrong@baylibre.com>");
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MODULE_LICENSE("Dual BSD/GPL");
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