| /* |
| * Copyright (c) 2021 Arm Limited. All rights reserved. |
| * |
| * This program is free software and is provided to you under the terms of the |
| * GNU General Public License version 2 as published by the Free Software |
| * Foundation, and any use by you of this program is subject to the terms |
| * of such GNU licence. |
| * |
| * 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, you can access it online at |
| * http://www.gnu.org/licenses/gpl-2.0.html. |
| * |
| * SPDX-License-Identifier: GPL-2.0-only |
| */ |
| |
| #include <linux/io.h> |
| #include <linux/kernel.h> |
| #include <linux/module.h> |
| #include <linux/of.h> |
| #include <linux/of_device.h> |
| #include <linux/platform_device.h> |
| #include <linux/reset-controller.h> |
| |
| #define ETHOSU_BRIDGE_RESET_DRIVER_VERSION "0.0.1" |
| |
| struct ethosu_reset { |
| struct reset_controller_dev rst; |
| struct device *dev; |
| void __iomem *base; |
| }; |
| |
| #define ETHOSU_BRIDGE_ID(base) (base) |
| #define ETHOSU_BRIDGE_CTRL(base) ((base) + 0x100) |
| |
| #define ETHOSU_BRIDGE_WAIT_ENABLE (0x2) |
| #define ETHOSU_BRIDGE_RESET (0x1) |
| |
| static void __iomem *bridge_verify_and_remap(struct device *dev, |
| struct resource *res) |
| { |
| void __iomem *base = devm_ioremap_resource(dev, res); |
| u32 id; |
| u16 magic; |
| u8 minor; |
| u8 major; |
| |
| if (IS_ERR(base)) |
| return base; |
| |
| id = readl(ETHOSU_BRIDGE_ID(base)); |
| magic = id & 0x0000ffff; |
| minor = (id & 0x00ff0000) >> 16; |
| major = (id & 0xff000000) >> 24; |
| |
| dev_dbg(dev, "verifying bridge %d.%d", major, minor); |
| |
| if (magic != 0xBD9E) |
| return IOMEM_ERR_PTR(-EINVAL); |
| |
| return base; |
| } |
| |
| int ethosu_bridge_assert(struct reset_controller_dev *rcdev, |
| unsigned long id) |
| { |
| struct ethosu_reset *ethosu = container_of(rcdev, struct ethosu_reset, |
| rst); |
| |
| /* pull reset */ |
| dev_dbg(ethosu->dev, "Asserting reset"); |
| |
| /* set wait and reset */ |
| writel(ETHOSU_BRIDGE_WAIT_ENABLE | ETHOSU_BRIDGE_RESET, |
| ETHOSU_BRIDGE_CTRL(ethosu->base)); |
| |
| return 0; |
| } |
| |
| int ethosu_bridge_deassert(struct reset_controller_dev *rcdev, |
| unsigned long id) |
| { |
| struct ethosu_reset *ethosu = container_of(rcdev, struct ethosu_reset, |
| rst); |
| |
| /* release reset */ |
| dev_dbg(ethosu->dev, "Deasserting reset"); |
| writel(~ETHOSU_BRIDGE_WAIT_ENABLE & ETHOSU_BRIDGE_RESET, |
| ETHOSU_BRIDGE_CTRL(ethosu->base)); |
| |
| return 0; |
| } |
| |
| static struct reset_control_ops ethosu_reset_bridge_ops = { |
| .assert = ethosu_bridge_assert, |
| .deassert = ethosu_bridge_deassert, |
| }; |
| |
| static const struct of_device_id ethosu_reset_match[] = { |
| { .compatible = "arm,ethosu-bridge-reset", .data = 0 }, |
| { /* sentinel */ }, |
| }; |
| |
| static int ethosu_bridge_reset_probe(struct platform_device *pdev) |
| { |
| struct device *dev = &pdev->dev; |
| struct ethosu_reset *ethosu; |
| struct resource *res; |
| |
| ethosu = devm_kzalloc(&pdev->dev, sizeof(*ethosu), GFP_KERNEL); |
| if (!ethosu) |
| return -ENOMEM; |
| |
| res = platform_get_resource(pdev, IORESOURCE_MEM, 0); |
| |
| ethosu->base = bridge_verify_and_remap(dev, res); |
| ethosu->dev = dev; |
| |
| if (IS_ERR(ethosu->base)) |
| return PTR_ERR(ethosu->base); |
| |
| platform_set_drvdata(pdev, ethosu); |
| |
| ethosu->rst.owner = THIS_MODULE; |
| ethosu->rst.nr_resets = 1; |
| ethosu->rst.ops = ðosu_reset_bridge_ops; |
| ethosu->rst.of_node = pdev->dev.of_node; |
| |
| dev_dbg(dev, "registering to reset controller core"); |
| |
| return devm_reset_controller_register(dev, ðosu->rst); |
| } |
| |
| static int ethosu_bridge_reset_remove(struct platform_device *pdev) |
| { |
| return 0; |
| } |
| |
| static struct platform_driver ethosu_reset_driver = { |
| .probe = ethosu_bridge_reset_probe, |
| .remove = ethosu_bridge_reset_remove, |
| .driver = { |
| .name = "ethosu-bridge-reset", |
| .of_match_table = of_match_ptr(ethosu_reset_match), |
| }, |
| }; |
| |
| module_platform_driver(ethosu_reset_driver); |
| |
| MODULE_LICENSE("GPL v2"); |
| MODULE_AUTHOR("Arm Ltd"); |
| MODULE_DESCRIPTION("Arm Ethos-U NPU Bridge Reset Driver"); |
| MODULE_VERSION(ETHOSU_BRIDGE_RESET_DRIVER_VERSION); |