1/*
2 * Copyright (c) 2015 Pengutronix, Sascha Hauer <kernel@pengutronix.de>
3 *
4 * This program is free software; you can redistribute it and/or modify
5 * it under the terms of the GNU General Public License version 2 as
6 * published by the Free Software Foundation.
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#include <linux/export.h>
15#include <linux/jiffies.h>
16#include <linux/regmap.h>
17#include <linux/soc/mediatek/infracfg.h>
18#include <asm/processor.h>
19
20#define INFRA_TOPAXI_PROTECTEN		0x0220
21#define INFRA_TOPAXI_PROTECTSTA1	0x0228
22
23/**
24 * mtk_infracfg_set_bus_protection - enable bus protection
25 * @regmap: The infracfg regmap
26 * @mask: The mask containing the protection bits to be enabled.
27 *
28 * This function enables the bus protection bits for disabled power
29 * domains so that the system does not hang when some unit accesses the
30 * bus while in power down.
31 */
32int mtk_infracfg_set_bus_protection(struct regmap *infracfg, u32 mask)
33{
34	unsigned long expired;
35	u32 val;
36	int ret;
37
38	regmap_update_bits(infracfg, INFRA_TOPAXI_PROTECTEN, mask, mask);
39
40	expired = jiffies + HZ;
41
42	while (1) {
43		ret = regmap_read(infracfg, INFRA_TOPAXI_PROTECTSTA1, &val);
44		if (ret)
45			return ret;
46
47		if ((val & mask) == mask)
48			break;
49
50		cpu_relax();
51		if (time_after(jiffies, expired))
52			return -EIO;
53	}
54
55	return 0;
56}
57
58/**
59 * mtk_infracfg_clear_bus_protection - disable bus protection
60 * @regmap: The infracfg regmap
61 * @mask: The mask containing the protection bits to be disabled.
62 *
63 * This function disables the bus protection bits previously enabled with
64 * mtk_infracfg_set_bus_protection.
65 */
66int mtk_infracfg_clear_bus_protection(struct regmap *infracfg, u32 mask)
67{
68	unsigned long expired;
69	int ret;
70
71	regmap_update_bits(infracfg, INFRA_TOPAXI_PROTECTEN, mask, 0);
72
73	expired = jiffies + HZ;
74
75	while (1) {
76		u32 val;
77
78		ret = regmap_read(infracfg, INFRA_TOPAXI_PROTECTSTA1, &val);
79		if (ret)
80			return ret;
81
82		if (!(val & mask))
83			break;
84
85		cpu_relax();
86		if (time_after(jiffies, expired))
87			return -EIO;
88	}
89
90	return 0;
91}
92