1// SPDX-License-Identifier: GPL-2.0
  2/* Copyright (c) 2020, Broadcom */
  3
  4#include <linux/clk.h>
  5#include <linux/dma-mapping.h>
  6#include <linux/err.h>
  7#include <linux/kernel.h>
  8#include <linux/io.h>
  9#include <linux/module.h>
 10#include <linux/platform_device.h>
 11#include <linux/usb.h>
 12#include <linux/usb/hcd.h>
 13#include <linux/iopoll.h>
 14
 15#include "ehci.h"
 16
 17#define hcd_to_ehci_priv(h) ((struct brcm_priv *)hcd_to_ehci(h)->priv)
 18
 19struct brcm_priv {
 20	struct clk *clk;
 21};
 22
 23/*
 24 * ehci_brcm_wait_for_sof
 25 * Wait for start of next microframe, then wait extra delay microseconds
 26 */
 27static inline void ehci_brcm_wait_for_sof(struct ehci_hcd *ehci, u32 delay)
 28{
 29	u32 frame_idx = ehci_readl(ehci, &ehci->regs->frame_index);
 30	u32 val;
 31	int res;
 32
 33	/* Wait for next microframe (every 125 usecs) */
 34	res = readl_relaxed_poll_timeout(&ehci->regs->frame_index, val,
 35					 val != frame_idx, 1, 130);
 36	if (res)
 37		ehci_err(ehci, "Error waiting for SOF\n");
 38	udelay(delay);
 39}
 40
 41/*
 42 * ehci_brcm_hub_control
 43 * The EHCI controller has a bug where it can violate the SOF
 44 * interval between the first two SOF's transmitted after resume
 45 * if the resume occurs near the end of the microframe. This causees
 46 * the controller to detect babble on the suspended port and
 47 * will eventually cause the controller to reset the port.
 48 * The fix is to Intercept the echi-hcd request to complete RESUME and
 49 * align it to the start of the next microframe.
 50 * See SWLINUX-1909 for more details
 51 */
 52static int ehci_brcm_hub_control(
 53	struct usb_hcd	*hcd,
 54	u16		typeReq,
 55	u16		wValue,
 56	u16		wIndex,
 57	char		*buf,
 58	u16		wLength)
 59{
 60	struct ehci_hcd	*ehci = hcd_to_ehci(hcd);
 61	int		ports = HCS_N_PORTS(ehci->hcs_params);
 62	u32 __iomem	*status_reg;
 63	unsigned long flags;
 64	int retval, irq_disabled = 0;
 65
 66	status_reg = &ehci->regs->port_status[(wIndex & 0xff) - 1];
 67
 68	/*
 69	 * RESUME is cleared when GetPortStatus() is called 20ms after start
 70	 * of RESUME
 71	 */
 72	if ((typeReq == GetPortStatus) &&
 73	    (wIndex && wIndex <= ports) &&
 74	    ehci->reset_done[wIndex-1] &&
 75	    time_after_eq(jiffies, ehci->reset_done[wIndex-1]) &&
 76	    (ehci_readl(ehci, status_reg) & PORT_RESUME)) {
 77
 78		/*
 79		 * to make sure we are not interrupted until RESUME bit
 80		 * is cleared, disable interrupts on current CPU
 81		 */
 82		ehci_dbg(ehci, "SOF alignment workaround\n");
 83		irq_disabled = 1;
 84		local_irq_save(flags);
 85		ehci_brcm_wait_for_sof(ehci, 5);
 86	}
 87	retval = ehci_hub_control(hcd, typeReq, wValue, wIndex, buf, wLength);
 88	if (irq_disabled)
 89		local_irq_restore(flags);
 90	return retval;
 91}
 92
 93static int ehci_brcm_reset(struct usb_hcd *hcd)
 94{
 95	struct ehci_hcd *ehci = hcd_to_ehci(hcd);
 96	int len;
 97
 98	ehci->big_endian_mmio = 1;
 99
100	ehci->caps = (void __iomem *)hcd->regs;
101	len = HC_LENGTH(ehci, ehci_readl(ehci, &ehci->caps->hc_capbase));
102	ehci->regs = (void __iomem *)(hcd->regs + len);
103
104	/* This fixes the lockup during reboot due to prior interrupts */
105	ehci_writel(ehci, CMD_RESET, &ehci->regs->command);
106	mdelay(10);
107
108	/*
109	 * SWLINUX-1705: Avoid OUT packet underflows during high memory
110	 *   bus usage
111	 * port_status[0x0f] = Broadcom-proprietary USB_EHCI_INSNREG00 @ 0x90
112	 */
113	ehci_writel(ehci, 0x00800040, &ehci->regs->port_status[0x10]);
114	ehci_writel(ehci, 0x00000001, &ehci->regs->port_status[0x12]);
115
116	return ehci_setup(hcd);
117}
118
119static struct hc_driver __read_mostly ehci_brcm_hc_driver;
120
121static const struct ehci_driver_overrides brcm_overrides __initconst = {
122	.reset = ehci_brcm_reset,
123	.extra_priv_size = sizeof(struct brcm_priv),
124};
125
126static int ehci_brcm_probe(struct platform_device *pdev)
127{
128	struct device *dev = &pdev->dev;
129	struct resource *res_mem;
130	struct brcm_priv *priv;
131	struct usb_hcd *hcd;
132	int irq;
133	int err;
134
135	err = dma_set_mask_and_coherent(dev, DMA_BIT_MASK(32));
136	if (err)
137		return err;
138
139	irq = platform_get_irq(pdev, 0);
140	if (irq <= 0)
141		return irq ? irq : -EINVAL;
142
143	/* Hook the hub control routine to work around a bug */
144	ehci_brcm_hc_driver.hub_control = ehci_brcm_hub_control;
145
146	/* initialize hcd */
147	hcd = usb_create_hcd(&ehci_brcm_hc_driver, dev, dev_name(dev));
148	if (!hcd)
149		return -ENOMEM;
150
151	platform_set_drvdata(pdev, hcd);
152	priv = hcd_to_ehci_priv(hcd);
153
154	priv->clk = devm_clk_get_optional(dev, NULL);
155	if (IS_ERR(priv->clk)) {
156		err = PTR_ERR(priv->clk);
157		goto err_hcd;
158	}
159
160	err = clk_prepare_enable(priv->clk);
161	if (err)
162		goto err_hcd;
163
164	hcd->regs = devm_platform_get_and_ioremap_resource(pdev, 0, &res_mem);
165	if (IS_ERR(hcd->regs)) {
166		err = PTR_ERR(hcd->regs);
167		goto err_clk;
168	}
169	hcd->rsrc_start = res_mem->start;
170	hcd->rsrc_len = resource_size(res_mem);
171	err = usb_add_hcd(hcd, irq, IRQF_SHARED);
172	if (err)
173		goto err_clk;
174
175	device_wakeup_enable(hcd->self.controller);
176	device_enable_async_suspend(hcd->self.controller);
177
178	return 0;
179
180err_clk:
181	clk_disable_unprepare(priv->clk);
182err_hcd:
183	usb_put_hcd(hcd);
184
185	return err;
186}
187
188static int ehci_brcm_remove(struct platform_device *dev)
189{
190	struct usb_hcd *hcd = platform_get_drvdata(dev);
191	struct brcm_priv *priv = hcd_to_ehci_priv(hcd);
192
193	usb_remove_hcd(hcd);
194	clk_disable_unprepare(priv->clk);
195	usb_put_hcd(hcd);
196	return 0;
197}
198
199static int __maybe_unused ehci_brcm_suspend(struct device *dev)
200{
201	int ret;
202	struct usb_hcd *hcd = dev_get_drvdata(dev);
203	struct brcm_priv *priv = hcd_to_ehci_priv(hcd);
204	bool do_wakeup = device_may_wakeup(dev);
205
206	ret = ehci_suspend(hcd, do_wakeup);
207	if (ret)
208		return ret;
209	clk_disable_unprepare(priv->clk);
210	return 0;
211}
212
213static int __maybe_unused ehci_brcm_resume(struct device *dev)
214{
215	struct usb_hcd *hcd = dev_get_drvdata(dev);
216	struct ehci_hcd *ehci = hcd_to_ehci(hcd);
217	struct brcm_priv *priv = hcd_to_ehci_priv(hcd);
218	int err;
219
220	err = clk_prepare_enable(priv->clk);
221	if (err)
222		return err;
223	/*
224	 * SWLINUX-1705: Avoid OUT packet underflows during high memory
225	 *   bus usage
226	 * port_status[0x0f] = Broadcom-proprietary USB_EHCI_INSNREG00
227	 * @ 0x90
228	 */
229	ehci_writel(ehci, 0x00800040, &ehci->regs->port_status[0x10]);
230	ehci_writel(ehci, 0x00000001, &ehci->regs->port_status[0x12]);
231
232	ehci_resume(hcd, false);
233
234	pm_runtime_disable(dev);
235	pm_runtime_set_active(dev);
236	pm_runtime_enable(dev);
237
238	return 0;
239}
240
241static SIMPLE_DEV_PM_OPS(ehci_brcm_pm_ops, ehci_brcm_suspend,
242		ehci_brcm_resume);
243
244static const struct of_device_id brcm_ehci_of_match[] = {
245	{ .compatible = "brcm,ehci-brcm-v2", },
246	{ .compatible = "brcm,bcm7445-ehci", },
247	{}
248};
249
250static struct platform_driver ehci_brcm_driver = {
251	.probe		= ehci_brcm_probe,
252	.remove		= ehci_brcm_remove,
253	.shutdown	= usb_hcd_platform_shutdown,
254	.driver		= {
255		.name	= "ehci-brcm",
256		.pm	= &ehci_brcm_pm_ops,
257		.of_match_table = brcm_ehci_of_match,
258	}
259};
260
261static int __init ehci_brcm_init(void)
262{
263	if (usb_disabled())
264		return -ENODEV;
265
266	ehci_init_driver(&ehci_brcm_hc_driver, &brcm_overrides);
267	return platform_driver_register(&ehci_brcm_driver);
268}
269module_init(ehci_brcm_init);
270
271static void __exit ehci_brcm_exit(void)
272{
273	platform_driver_unregister(&ehci_brcm_driver);
274}
275module_exit(ehci_brcm_exit);
276
277MODULE_ALIAS("platform:ehci-brcm");
278MODULE_DESCRIPTION("EHCI Broadcom STB driver");
279MODULE_AUTHOR("Al Cooper");
280MODULE_LICENSE("GPL");