diff options
Diffstat (limited to 'drivers/char/hw_random/meson-rng.c')
| -rw-r--r-- | drivers/char/hw_random/meson-rng.c | 150 |
1 files changed, 150 insertions, 0 deletions
diff --git a/drivers/char/hw_random/meson-rng.c b/drivers/char/hw_random/meson-rng.c new file mode 100644 index 000000000..2e23be802 --- /dev/null +++ b/drivers/char/hw_random/meson-rng.c @@ -0,0 +1,150 @@ +/* + * This file is provided under a dual BSD/GPLv2 license. When using or + * redistributing this file, you may do so under either license. + * + * GPL LICENSE SUMMARY + * + * Copyright (c) 2016 BayLibre, SAS. + * Author: Neil Armstrong <narmstrong@baylibre.com> + * Copyright (C) 2014 Amlogic, Inc. + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of version 2 of the GNU General Public License as + * published by the Free Software Foundation. + * + * This program is distributed in the hope that it will be useful, but + * WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + * General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, see <http://www.gnu.org/licenses/>. + * The full GNU General Public License is included in this distribution + * in the file called COPYING. + * + * BSD LICENSE + * + * Copyright (c) 2016 BayLibre, SAS. + * Author: Neil Armstrong <narmstrong@baylibre.com> + * Copyright (C) 2014 Amlogic, Inc. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * + * * Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * * Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in + * the documentation and/or other materials provided with the + * distribution. + * * Neither the name of Intel Corporation nor the names of its + * contributors may be used to endorse or promote products derived + * from this software without specific prior written permission. + * + * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS + * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT + * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR + * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT + * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, + * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT + * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, + * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY + * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT + * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE + * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. + */ +#include <linux/err.h> +#include <linux/module.h> +#include <linux/io.h> +#include <linux/platform_device.h> +#include <linux/hw_random.h> +#include <linux/slab.h> +#include <linux/types.h> +#include <linux/of.h> +#include <linux/clk.h> + +#define RNG_DATA 0x00 + +struct meson_rng_data { + void __iomem *base; + struct platform_device *pdev; + struct hwrng rng; + struct clk *core_clk; +}; + +static int meson_rng_read(struct hwrng *rng, void *buf, size_t max, bool wait) +{ + struct meson_rng_data *data = + container_of(rng, struct meson_rng_data, rng); + + *(u32 *)buf = readl_relaxed(data->base + RNG_DATA); + + return sizeof(u32); +} + +static void meson_rng_clk_disable(void *data) +{ + clk_disable_unprepare(data); +} + +static int meson_rng_probe(struct platform_device *pdev) +{ + struct device *dev = &pdev->dev; + struct meson_rng_data *data; + struct resource *res; + int ret; + + data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL); + if (!data) + return -ENOMEM; + + data->pdev = pdev; + + res = platform_get_resource(pdev, IORESOURCE_MEM, 0); + data->base = devm_ioremap_resource(dev, res); + if (IS_ERR(data->base)) + return PTR_ERR(data->base); + + data->core_clk = devm_clk_get(dev, "core"); + if (IS_ERR(data->core_clk)) + data->core_clk = NULL; + + if (data->core_clk) { + ret = clk_prepare_enable(data->core_clk); + if (ret) + return ret; + ret = devm_add_action_or_reset(dev, meson_rng_clk_disable, + data->core_clk); + if (ret) + return ret; + } + + data->rng.name = pdev->name; + data->rng.read = meson_rng_read; + + platform_set_drvdata(pdev, data); + + return devm_hwrng_register(dev, &data->rng); +} + +static const struct of_device_id meson_rng_of_match[] = { + { .compatible = "amlogic,meson-rng", }, + {}, +}; +MODULE_DEVICE_TABLE(of, meson_rng_of_match); + +static struct platform_driver meson_rng_driver = { + .probe = meson_rng_probe, + .driver = { + .name = "meson-rng", + .of_match_table = meson_rng_of_match, + }, +}; + +module_platform_driver(meson_rng_driver); + +MODULE_DESCRIPTION("Meson H/W Random Number Generator driver"); +MODULE_AUTHOR("Lawrence Mok <lawrence.mok@amlogic.com>"); +MODULE_AUTHOR("Neil Armstrong <narmstrong@baylibre.com>"); +MODULE_LICENSE("Dual BSD/GPL"); |