1 // SPDX-License-Identifier: GPL-2.0-or-later 2 /* 3 * Allwinner SoCs Reset Controller driver 4 * 5 * Copyright 2013 Maxime Ripard 6 * 7 * Maxime Ripard <maxime.ripard@free-electrons.com> 8 */ 9 10 #include <linux/err.h> 11 #include <linux/io.h> 12 #include <linux/init.h> 13 #include <linux/of.h> 14 #include <linux/of_address.h> 15 #include <linux/platform_device.h> 16 #include <linux/reset-controller.h> 17 #include <linux/reset/reset-simple.h> 18 #include <linux/reset/sunxi.h> 19 #include <linux/slab.h> 20 #include <linux/spinlock.h> 21 #include <linux/types.h> 22 23 static int sunxi_reset_init(struct device_node *np) 24 { 25 struct reset_simple_data *data; 26 struct resource res; 27 resource_size_t size; 28 int ret; 29 30 data = kzalloc(sizeof(*data), GFP_KERNEL); 31 if (!data) 32 return -ENOMEM; 33 34 ret = of_address_to_resource(np, 0, &res); 35 if (ret) 36 goto err_alloc; 37 38 size = resource_size(&res); 39 if (!request_mem_region(res.start, size, np->name)) { 40 ret = -EBUSY; 41 goto err_alloc; 42 } 43 44 data->membase = ioremap(res.start, size); 45 if (!data->membase) { 46 ret = -ENOMEM; 47 goto err_alloc; 48 } 49 50 spin_lock_init(&data->lock); 51 52 data->rcdev.owner = THIS_MODULE; 53 data->rcdev.nr_resets = size * 8; 54 data->rcdev.ops = &reset_simple_ops; 55 data->rcdev.of_node = np; 56 data->active_low = true; 57 58 return reset_controller_register(&data->rcdev); 59 60 err_alloc: 61 kfree(data); 62 return ret; 63 }; 64 65 /* 66 * These are the reset controller we need to initialize early on in 67 * our system, before we can even think of using a regular device 68 * driver for it. 69 * The controllers that we can register through the regular device 70 * model are handled by the simple reset driver directly. 71 */ 72 static const struct of_device_id sunxi_early_reset_dt_ids[] __initconst = { 73 { .compatible = "allwinner,sun6i-a31-ahb1-reset", }, 74 { /* sentinel */ }, 75 }; 76 77 void __init sun6i_reset_init(void) 78 { 79 struct device_node *np; 80 81 for_each_matching_node(np, sunxi_early_reset_dt_ids) 82 sunxi_reset_init(np); 83 } 84