/* * Amlogic Meson Reset Controller driver * * 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> * * 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> * * 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/init.h> #include <linux/io.h> #include <linux/of.h> #include <linux/platform_device.h> #include <linux/reset-controller.h> #include <linux/slab.h> #include <linux/types.h> #include <linux/of_device.h> #define REG_COUNT 8 #define BITS_PER_REG 32 #define LEVEL_OFFSET 0x7c struct meson_reset { void __iomem *reg_base; struct reset_controller_dev rcdev; spinlock_t lock; }; static int meson_reset_reset(struct reset_controller_dev *rcdev, unsigned long id) { struct meson_reset *data = container_of(rcdev, struct meson_reset, rcdev); unsigned int bank = id / BITS_PER_REG; unsigned int offset = id % BITS_PER_REG; void __iomem *reg_addr = data->reg_base + (bank << 2); writel(BIT(offset), reg_addr); return 0; } static int meson_reset_level(struct reset_controller_dev *rcdev, unsigned long id, bool assert) { struct meson_reset *data = container_of(rcdev, struct meson_reset, rcdev); unsigned int bank = id / BITS_PER_REG; unsigned int offset = id % BITS_PER_REG; void __iomem *reg_addr = data->reg_base + LEVEL_OFFSET + (bank << 2); unsigned long flags; u32 reg; spin_lock_irqsave(&data->lock, flags); reg = readl(reg_addr); if (assert) writel(reg & ~BIT(offset), reg_addr); else writel(reg | BIT(offset), reg_addr); spin_unlock_irqrestore(&data->lock, flags); return 0; } static int meson_reset_assert(struct reset_controller_dev *rcdev, unsigned long id) { return meson_reset_level(rcdev, id, true); } static int meson_reset_deassert(struct reset_controller_dev *rcdev, unsigned long id) { return meson_reset_level(rcdev, id, false); } static const struct reset_control_ops meson_reset_ops = { .reset = meson_reset_reset, .assert = meson_reset_assert, .deassert = meson_reset_deassert, }; static const struct of_device_id meson_reset_dt_ids[] = { { .compatible = "amlogic,meson8b-reset" }, { .compatible = "amlogic,meson-gxbb-reset" }, { .compatible = "amlogic,meson-axg-reset" }, { /* sentinel */ }, }; static int meson_reset_probe(struct platform_device *pdev) { struct meson_reset *data; struct resource *res; data = devm_kzalloc(&pdev->dev, sizeof(*data), GFP_KERNEL); if (!data) return -ENOMEM; res = platform_get_resource(pdev, IORESOURCE_MEM, 0); data->reg_base = devm_ioremap_resource(&pdev->dev, res); if (IS_ERR(data->reg_base)) return PTR_ERR(data->reg_base); platform_set_drvdata(pdev, data); spin_lock_init(&data->lock); data->rcdev.owner = THIS_MODULE; data->rcdev.nr_resets = REG_COUNT * BITS_PER_REG; data->rcdev.ops = &meson_reset_ops; data->rcdev.of_node = pdev->dev.of_node; return devm_reset_controller_register(&pdev->dev, &data->rcdev); } static struct platform_driver meson_reset_driver = { .probe = meson_reset_probe, .driver = { .name = "meson_reset", .of_match_table = meson_reset_dt_ids, }, }; builtin_platform_driver(meson_reset_driver);