1/**
  2 * dwc3-keystone.c - Keystone Specific Glue layer
  3 *
  4 * Copyright (C) 2010-2013 Texas Instruments Incorporated - http://www.ti.com
  5 *
  6 * Author: WingMan Kwok <w-kwok2@ti.com>
  7 *
  8 * This program is free software: you can redistribute it and/or modify
  9 * it under the terms of the GNU General Public License version 2  of
 10 * the License as published by the Free Software Foundation.
 11 *
 12 * This program is distributed in the hope that it will be useful,
 13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 15 * GNU General Public License for more details.
 16 */
 17
 18#include <linux/clk.h>
 19#include <linux/module.h>
 20#include <linux/kernel.h>
 21#include <linux/interrupt.h>
 22#include <linux/platform_device.h>
 23#include <linux/dma-mapping.h>
 24#include <linux/io.h>
 25#include <linux/of_platform.h>
 26
 27/* USBSS register offsets */
 28#define USBSS_REVISION		0x0000
 29#define USBSS_SYSCONFIG		0x0010
 30#define USBSS_IRQ_EOI		0x0018
 31#define USBSS_IRQSTATUS_RAW_0	0x0020
 32#define USBSS_IRQSTATUS_0	0x0024
 33#define USBSS_IRQENABLE_SET_0	0x0028
 34#define USBSS_IRQENABLE_CLR_0	0x002c
 35
 36/* IRQ register bits */
 37#define USBSS_IRQ_EOI_LINE(n)	BIT(n)
 38#define USBSS_IRQ_EVENT_ST	BIT(0)
 39#define USBSS_IRQ_COREIRQ_EN	BIT(0)
 40#define USBSS_IRQ_COREIRQ_CLR	BIT(0)
 41
 42struct dwc3_keystone {
 43	struct device			*dev;
 44	struct clk			*clk;
 45	void __iomem			*usbss;
 46};
 47
 48static inline u32 kdwc3_readl(void __iomem *base, u32 offset)
 49{
 50	return readl(base + offset);
 51}
 52
 53static inline void kdwc3_writel(void __iomem *base, u32 offset, u32 value)
 54{
 55	writel(value, base + offset);
 56}
 57
 58static void kdwc3_enable_irqs(struct dwc3_keystone *kdwc)
 59{
 60	u32 val;
 61
 62	val = kdwc3_readl(kdwc->usbss, USBSS_IRQENABLE_SET_0);
 63	val |= USBSS_IRQ_COREIRQ_EN;
 64	kdwc3_writel(kdwc->usbss, USBSS_IRQENABLE_SET_0, val);
 65}
 66
 67static void kdwc3_disable_irqs(struct dwc3_keystone *kdwc)
 68{
 69	u32 val;
 70
 71	val = kdwc3_readl(kdwc->usbss, USBSS_IRQENABLE_SET_0);
 72	val &= ~USBSS_IRQ_COREIRQ_EN;
 73	kdwc3_writel(kdwc->usbss, USBSS_IRQENABLE_SET_0, val);
 74}
 75
 76static irqreturn_t dwc3_keystone_interrupt(int irq, void *_kdwc)
 77{
 78	struct dwc3_keystone	*kdwc = _kdwc;
 79
 80	kdwc3_writel(kdwc->usbss, USBSS_IRQENABLE_CLR_0, USBSS_IRQ_COREIRQ_CLR);
 81	kdwc3_writel(kdwc->usbss, USBSS_IRQSTATUS_0, USBSS_IRQ_EVENT_ST);
 82	kdwc3_writel(kdwc->usbss, USBSS_IRQENABLE_SET_0, USBSS_IRQ_COREIRQ_EN);
 83	kdwc3_writel(kdwc->usbss, USBSS_IRQ_EOI, USBSS_IRQ_EOI_LINE(0));
 84
 85	return IRQ_HANDLED;
 86}
 87
 88static int kdwc3_probe(struct platform_device *pdev)
 89{
 90	struct device		*dev = &pdev->dev;
 91	struct device_node	*node = pdev->dev.of_node;
 92	struct dwc3_keystone	*kdwc;
 93	struct resource		*res;
 94	int			error, irq;
 95
 96	kdwc = devm_kzalloc(dev, sizeof(*kdwc), GFP_KERNEL);
 97	if (!kdwc)
 98		return -ENOMEM;
 99
100	platform_set_drvdata(pdev, kdwc);
101
102	kdwc->dev = dev;
103
104	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
105	kdwc->usbss = devm_ioremap_resource(dev, res);
106	if (IS_ERR(kdwc->usbss))
107		return PTR_ERR(kdwc->usbss);
108
109	kdwc->clk = devm_clk_get(kdwc->dev, "usb");
110
111	error = clk_prepare_enable(kdwc->clk);
112	if (error < 0) {
113		dev_err(kdwc->dev, "unable to enable usb clock, error %d\n",
114			error);
115		return error;
116	}
117
118	irq = platform_get_irq(pdev, 0);
119	if (irq < 0) {
120		dev_err(&pdev->dev, "missing irq\n");
121		error = irq;
122		goto err_irq;
123	}
124
125	error = devm_request_irq(dev, irq, dwc3_keystone_interrupt, IRQF_SHARED,
126			dev_name(dev), kdwc);
127	if (error) {
128		dev_err(dev, "failed to request IRQ #%d --> %d\n",
129				irq, error);
130		goto err_irq;
131	}
132
133	kdwc3_enable_irqs(kdwc);
134
135	error = of_platform_populate(node, NULL, NULL, dev);
136	if (error) {
137		dev_err(&pdev->dev, "failed to create dwc3 core\n");
138		goto err_core;
139	}
140
141	return 0;
142
143err_core:
144	kdwc3_disable_irqs(kdwc);
145err_irq:
146	clk_disable_unprepare(kdwc->clk);
147
148	return error;
149}
150
151static int kdwc3_remove_core(struct device *dev, void *c)
152{
153	struct platform_device *pdev = to_platform_device(dev);
154
155	platform_device_unregister(pdev);
156
157	return 0;
158}
159
160static int kdwc3_remove(struct platform_device *pdev)
161{
162	struct dwc3_keystone *kdwc = platform_get_drvdata(pdev);
163
164	kdwc3_disable_irqs(kdwc);
165	device_for_each_child(&pdev->dev, NULL, kdwc3_remove_core);
166	clk_disable_unprepare(kdwc->clk);
167	platform_set_drvdata(pdev, NULL);
168
169	return 0;
170}
171
172static const struct of_device_id kdwc3_of_match[] = {
173	{ .compatible = "ti,keystone-dwc3", },
174	{},
175};
176MODULE_DEVICE_TABLE(of, kdwc3_of_match);
177
178static struct platform_driver kdwc3_driver = {
179	.probe		= kdwc3_probe,
180	.remove		= kdwc3_remove,
181	.driver		= {
182		.name	= "keystone-dwc3",
183		.of_match_table	= kdwc3_of_match,
184	},
185};
186
187module_platform_driver(kdwc3_driver);
188
189MODULE_ALIAS("platform:keystone-dwc3");
190MODULE_AUTHOR("WingMan Kwok <w-kwok2@ti.com>");
191MODULE_LICENSE("GPL v2");
192MODULE_DESCRIPTION("DesignWare USB3 KEYSTONE Glue Layer");