1// SPDX-License-Identifier: GPL-2.0
 2/*
 3 * Copyright (C) 2011 Google, Inc.
 4 */
 5
 6#include <linux/export.h>
 7#include <linux/kernel.h>
 8#include <linux/usb.h>
 9#include <linux/io.h>
10#include <linux/iopoll.h>
11#include <linux/usb/otg.h>
12#include <linux/usb/ulpi.h>
13
14#define ULPI_VIEW_WAKEUP	(1 << 31)
15#define ULPI_VIEW_RUN		(1 << 30)
16#define ULPI_VIEW_WRITE		(1 << 29)
17#define ULPI_VIEW_READ		(0 << 29)
18#define ULPI_VIEW_ADDR(x)	(((x) & 0xff) << 16)
19#define ULPI_VIEW_DATA_READ(x)	(((x) >> 8) & 0xff)
20#define ULPI_VIEW_DATA_WRITE(x)	((x) & 0xff)
21
22static int ulpi_viewport_wait(void __iomem *view, u32 mask)
23{
24	u32 val;
25
26	return readl_poll_timeout_atomic(view, val, !(val & mask), 1, 2000);
27}
28
29static int ulpi_viewport_read(struct usb_phy *otg, u32 reg)
30{
31	int ret;
32	void __iomem *view = otg->io_priv;
33
34	writel(ULPI_VIEW_WAKEUP | ULPI_VIEW_WRITE, view);
35	ret = ulpi_viewport_wait(view, ULPI_VIEW_WAKEUP);
36	if (ret)
37		return ret;
38
39	writel(ULPI_VIEW_RUN | ULPI_VIEW_READ | ULPI_VIEW_ADDR(reg), view);
40	ret = ulpi_viewport_wait(view, ULPI_VIEW_RUN);
41	if (ret)
42		return ret;
43
44	return ULPI_VIEW_DATA_READ(readl(view));
45}
46
47static int ulpi_viewport_write(struct usb_phy *otg, u32 val, u32 reg)
48{
49	int ret;
50	void __iomem *view = otg->io_priv;
51
52	writel(ULPI_VIEW_WAKEUP | ULPI_VIEW_WRITE, view);
53	ret = ulpi_viewport_wait(view, ULPI_VIEW_WAKEUP);
54	if (ret)
55		return ret;
56
57	writel(ULPI_VIEW_RUN | ULPI_VIEW_WRITE | ULPI_VIEW_DATA_WRITE(val) |
58						 ULPI_VIEW_ADDR(reg), view);
59
60	return ulpi_viewport_wait(view, ULPI_VIEW_RUN);
61}
62
63struct usb_phy_io_ops ulpi_viewport_access_ops = {
64	.read	= ulpi_viewport_read,
65	.write	= ulpi_viewport_write,
66};
67EXPORT_SYMBOL_GPL(ulpi_viewport_access_ops);