1/*
 2 * Copyright (C) 2011 Google, Inc.
 3 *
 4 * This software is licensed under the terms of the GNU General Public
 5 * License version 2, as published by the Free Software Foundation, and
 6 * may be copied, distributed, and modified under those terms.
 7 *
 8 * This program is distributed in the hope that it will be useful,
 9 * but WITHOUT ANY WARRANTY; without even the implied warranty of
10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
11 * GNU General Public License for more details.
12 *
13 */
14
15#include <linux/kernel.h>
16#include <linux/usb.h>
17#include <linux/io.h>
18#include <linux/usb/otg.h>
19#include <linux/usb/ulpi.h>
20
21#define ULPI_VIEW_WAKEUP	(1 << 31)
22#define ULPI_VIEW_RUN		(1 << 30)
23#define ULPI_VIEW_WRITE		(1 << 29)
24#define ULPI_VIEW_READ		(0 << 29)
25#define ULPI_VIEW_ADDR(x)	(((x) & 0xff) << 16)
26#define ULPI_VIEW_DATA_READ(x)	(((x) >> 8) & 0xff)
27#define ULPI_VIEW_DATA_WRITE(x)	((x) & 0xff)
28
29static int ulpi_viewport_wait(void __iomem *view, u32 mask)
30{
31	unsigned long usec = 2000;
32
33	while (usec--) {
34		if (!(readl(view) & mask))
35			return 0;
36
37		udelay(1);
38	};
39
40	return -ETIMEDOUT;
41}
42
43static int ulpi_viewport_read(struct otg_transceiver *otg, u32 reg)
44{
45	int ret;
46	void __iomem *view = otg->io_priv;
47
48	writel(ULPI_VIEW_WAKEUP | ULPI_VIEW_WRITE, view);
49	ret = ulpi_viewport_wait(view, ULPI_VIEW_WAKEUP);
50	if (ret)
51		return ret;
52
53	writel(ULPI_VIEW_RUN | ULPI_VIEW_READ | ULPI_VIEW_ADDR(reg), view);
54	ret = ulpi_viewport_wait(view, ULPI_VIEW_RUN);
55	if (ret)
56		return ret;
57
58	return ULPI_VIEW_DATA_READ(readl(view));
59}
60
61static int ulpi_viewport_write(struct otg_transceiver *otg, u32 val, u32 reg)
62{
63	int ret;
64	void __iomem *view = otg->io_priv;
65
66	writel(ULPI_VIEW_WAKEUP | ULPI_VIEW_WRITE, view);
67	ret = ulpi_viewport_wait(view, ULPI_VIEW_WAKEUP);
68	if (ret)
69		return ret;
70
71	writel(ULPI_VIEW_RUN | ULPI_VIEW_WRITE | ULPI_VIEW_DATA_WRITE(val) |
72						 ULPI_VIEW_ADDR(reg), view);
73
74	return ulpi_viewport_wait(view, ULPI_VIEW_RUN);
75}
76
77struct otg_io_access_ops ulpi_viewport_access_ops = {
78	.read	= ulpi_viewport_read,
79	.write	= ulpi_viewport_write,
80};