/* * Allwinner SoCs Reset Controller driver * * Copyright 2013 Maxime Ripard * * Maxime Ripard <maxime.ripard@free-electrons.com> * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation; either version 2 of the License, or * (at your option) any later version. */ #include <linux/err.h> #include <linux/io.h> #include <linux/module.h> #include <linux/of.h> #include <linux/of_address.h> #include <linux/platform_device.h> #include <linux/reset-controller.h> #include <linux/slab.h> #include <linux/spinlock.h> #include <linux/types.h> struct sunxi_reset_data { spinlock_t lock; void __iomem *membase; struct reset_controller_dev rcdev; }; static int sunxi_reset_assert(struct reset_controller_dev *rcdev, unsigned long id) { struct sunxi_reset_data *data = container_of(rcdev, struct sunxi_reset_data, rcdev); int bank = id / BITS_PER_LONG; int offset = id % BITS_PER_LONG; unsigned long flags; u32 reg; spin_lock_irqsave(&data->lock, flags); reg = readl(data->membase + (bank * 4)); writel(reg & ~BIT(offset), data->membase + (bank * 4)); spin_unlock_irqrestore(&data->lock, flags); return 0; } static int sunxi_reset_deassert(struct reset_controller_dev *rcdev, unsigned long id) { struct sunxi_reset_data *data = container_of(rcdev, struct sunxi_reset_data, rcdev); int bank = id / BITS_PER_LONG; int offset = id % BITS_PER_LONG; unsigned long flags; u32 reg; spin_lock_irqsave(&data->lock, flags); reg = readl(data->membase + (bank * 4)); writel(reg | BIT(offset), data->membase + (bank * 4)); spin_unlock_irqrestore(&data->lock, flags); return 0; } static struct reset_control_ops sunxi_reset_ops = { .assert = sunxi_reset_assert, .deassert = sunxi_reset_deassert, }; static int sunxi_reset_init(struct device_node *np) { struct sunxi_reset_data *data; struct resource res; resource_size_t size; int ret; data = kzalloc(sizeof(*data), GFP_KERNEL); if (!data) return -ENOMEM; ret = of_address_to_resource(np, 0, &res); if (ret) goto err_alloc; size = resource_size(&res); if (!request_mem_region(res.start, size, np->name)) { ret = -EBUSY; goto err_alloc; } data->membase = ioremap(res.start, size); if (!data->membase) { ret = -ENOMEM; goto err_alloc; } spin_lock_init(&data->lock); data->rcdev.owner = THIS_MODULE; data->rcdev.nr_resets = size * 32; data->rcdev.ops = &sunxi_reset_ops; data->rcdev.of_node = np; reset_controller_register(&data->rcdev); return 0; err_alloc: kfree(data); return ret; }; /* * These are the reset controller we need to initialize early on in * our system, before we can even think of using a regular device * driver for it. */ static const struct of_device_id sunxi_early_reset_dt_ids[] __initdata = { { .compatible = "allwinner,sun6i-a31-ahb1-reset", }, { /* sentinel */ }, }; void __init sun6i_reset_init(void) { struct device_node *np; for_each_matching_node(np, sunxi_early_reset_dt_ids) sunxi_reset_init(np); } /* * And these are the controllers we can register through the regular * device model. */ static const struct of_device_id sunxi_reset_dt_ids[] = { { .compatible = "allwinner,sun6i-a31-clock-reset", }, { /* sentinel */ }, }; MODULE_DEVICE_TABLE(of, sunxi_reset_dt_ids); static int sunxi_reset_probe(struct platform_device *pdev) { struct sunxi_reset_data *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->membase = devm_ioremap_resource(&pdev->dev, res); if (IS_ERR(data->membase)) return PTR_ERR(data->membase); spin_lock_init(&data->lock); data->rcdev.owner = THIS_MODULE; data->rcdev.nr_resets = resource_size(res) * 32; data->rcdev.ops = &sunxi_reset_ops; data->rcdev.of_node = pdev->dev.of_node; return reset_controller_register(&data->rcdev); } static int sunxi_reset_remove(struct platform_device *pdev) { struct sunxi_reset_data *data = platform_get_drvdata(pdev); reset_controller_unregister(&data->rcdev); return 0; } static struct platform_driver sunxi_reset_driver = { .probe = sunxi_reset_probe, .remove = sunxi_reset_remove, .driver = { .name = "sunxi-reset", .of_match_table = sunxi_reset_dt_ids, }, }; module_platform_driver(sunxi_reset_driver); MODULE_AUTHOR("Maxime Ripard <maxime.ripard@free-electrons.com"); MODULE_DESCRIPTION("Allwinner SoCs Reset Controller Driver"); MODULE_LICENSE("GPL");