1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Ampere Computing SoC's SMpro Misc Driver
4 *
5 * Copyright (c) 2022, Ampere Computing LLC
6 */
7#include <linux/mod_devicetable.h>
8#include <linux/module.h>
9#include <linux/platform_device.h>
10#include <linux/regmap.h>
11
12/* Boot Stage/Progress Registers */
13#define BOOTSTAGE 0xB0
14#define BOOTSTAGE_LO 0xB1
15#define CUR_BOOTSTAGE 0xB2
16#define BOOTSTAGE_HI 0xB3
17
18/* SOC State Registers */
19#define SOC_POWER_LIMIT 0xE5
20
21struct smpro_misc {
22 struct regmap *regmap;
23};
24
25static ssize_t boot_progress_show(struct device *dev, struct device_attribute *da, char *buf)
26{
27 struct smpro_misc *misc = dev_get_drvdata(dev);
28 u16 boot_progress[3] = { 0 };
29 u32 bootstage;
30 u8 boot_stage;
31 u8 cur_stage;
32 u32 reg_lo;
33 u32 reg;
34 int ret;
35
36 /* Read current boot stage */
37 ret = regmap_read(map: misc->regmap, CUR_BOOTSTAGE, val: &reg);
38 if (ret)
39 return ret;
40
41 cur_stage = reg & 0xff;
42
43 ret = regmap_read(map: misc->regmap, BOOTSTAGE, val: &bootstage);
44 if (ret)
45 return ret;
46
47 boot_stage = (bootstage >> 8) & 0xff;
48
49 if (boot_stage > cur_stage)
50 return -EINVAL;
51
52 ret = regmap_read(map: misc->regmap, BOOTSTAGE_LO, val: &reg_lo);
53 if (!ret)
54 ret = regmap_read(map: misc->regmap, BOOTSTAGE_HI, val: &reg);
55 if (ret)
56 return ret;
57
58 /* Firmware to report new boot stage next time */
59 if (boot_stage < cur_stage) {
60 ret = regmap_write(map: misc->regmap, BOOTSTAGE, val: ((bootstage & 0xff00) | 0x1));
61 if (ret)
62 return ret;
63 }
64
65 boot_progress[0] = bootstage;
66 boot_progress[1] = swab16(reg);
67 boot_progress[2] = swab16(reg_lo);
68
69 return sysfs_emit(buf, fmt: "%*phN\n", (int)sizeof(boot_progress), boot_progress);
70}
71
72static DEVICE_ATTR_RO(boot_progress);
73
74static ssize_t soc_power_limit_show(struct device *dev, struct device_attribute *da, char *buf)
75{
76 struct smpro_misc *misc = dev_get_drvdata(dev);
77 unsigned int value;
78 int ret;
79
80 ret = regmap_read(map: misc->regmap, SOC_POWER_LIMIT, val: &value);
81 if (ret)
82 return ret;
83
84 return sysfs_emit(buf, fmt: "%d\n", value);
85}
86
87static ssize_t soc_power_limit_store(struct device *dev, struct device_attribute *da,
88 const char *buf, size_t count)
89{
90 struct smpro_misc *misc = dev_get_drvdata(dev);
91 unsigned long val;
92 s32 ret;
93
94 ret = kstrtoul(s: buf, base: 0, res: &val);
95 if (ret)
96 return ret;
97
98 ret = regmap_write(map: misc->regmap, SOC_POWER_LIMIT, val: (unsigned int)val);
99 if (ret)
100 return -EPROTO;
101
102 return count;
103}
104
105static DEVICE_ATTR_RW(soc_power_limit);
106
107static struct attribute *smpro_misc_attrs[] = {
108 &dev_attr_boot_progress.attr,
109 &dev_attr_soc_power_limit.attr,
110 NULL
111};
112
113ATTRIBUTE_GROUPS(smpro_misc);
114
115static int smpro_misc_probe(struct platform_device *pdev)
116{
117 struct smpro_misc *misc;
118
119 misc = devm_kzalloc(dev: &pdev->dev, size: sizeof(struct smpro_misc), GFP_KERNEL);
120 if (!misc)
121 return -ENOMEM;
122
123 platform_set_drvdata(pdev, data: misc);
124
125 misc->regmap = dev_get_regmap(dev: pdev->dev.parent, NULL);
126 if (!misc->regmap)
127 return -ENODEV;
128
129 return 0;
130}
131
132static struct platform_driver smpro_misc_driver = {
133 .probe = smpro_misc_probe,
134 .driver = {
135 .name = "smpro-misc",
136 .dev_groups = smpro_misc_groups,
137 },
138};
139
140module_platform_driver(smpro_misc_driver);
141
142MODULE_AUTHOR("Tung Nguyen <tungnguyen@os.amperecomputing.com>");
143MODULE_AUTHOR("Quan Nguyen <quan@os.amperecomputing.com>");
144MODULE_DESCRIPTION("Ampere Altra SMpro Misc driver");
145MODULE_LICENSE("GPL");
146

source code of linux/drivers/misc/smpro-misc.c