xref: /openbmc/linux/drivers/misc/smpro-misc.c (revision 763dc90e)
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 
21 struct smpro_misc {
22 	struct regmap *regmap;
23 };
24 
boot_progress_show(struct device * dev,struct device_attribute * da,char * buf)25 static 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(misc->regmap, CUR_BOOTSTAGE, &reg);
38 	if (ret)
39 		return ret;
40 
41 	cur_stage = reg & 0xff;
42 
43 	ret = regmap_read(misc->regmap, BOOTSTAGE, &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(misc->regmap,	BOOTSTAGE_LO, &reg_lo);
53 	if (!ret)
54 		ret = regmap_read(misc->regmap, BOOTSTAGE_HI, &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(misc->regmap, BOOTSTAGE, ((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, "%*phN\n", (int)sizeof(boot_progress), boot_progress);
70 }
71 
72 static DEVICE_ATTR_RO(boot_progress);
73 
soc_power_limit_show(struct device * dev,struct device_attribute * da,char * buf)74 static 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(misc->regmap, SOC_POWER_LIMIT, &value);
81 	if (ret)
82 		return ret;
83 
84 	return sysfs_emit(buf, "%d\n", value);
85 }
86 
soc_power_limit_store(struct device * dev,struct device_attribute * da,const char * buf,size_t count)87 static 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(buf, 0, &val);
95 	if (ret)
96 		return ret;
97 
98 	ret = regmap_write(misc->regmap, SOC_POWER_LIMIT, (unsigned int)val);
99 	if (ret)
100 		return -EPROTO;
101 
102 	return count;
103 }
104 
105 static DEVICE_ATTR_RW(soc_power_limit);
106 
107 static struct attribute *smpro_misc_attrs[] = {
108 	&dev_attr_boot_progress.attr,
109 	&dev_attr_soc_power_limit.attr,
110 	NULL
111 };
112 
113 ATTRIBUTE_GROUPS(smpro_misc);
114 
smpro_misc_probe(struct platform_device * pdev)115 static int smpro_misc_probe(struct platform_device *pdev)
116 {
117 	struct smpro_misc *misc;
118 
119 	misc = devm_kzalloc(&pdev->dev, sizeof(struct smpro_misc), GFP_KERNEL);
120 	if (!misc)
121 		return -ENOMEM;
122 
123 	platform_set_drvdata(pdev, misc);
124 
125 	misc->regmap = dev_get_regmap(pdev->dev.parent, NULL);
126 	if (!misc->regmap)
127 		return -ENODEV;
128 
129 	return 0;
130 }
131 
132 static 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 
140 module_platform_driver(smpro_misc_driver);
141 
142 MODULE_AUTHOR("Tung Nguyen <tungnguyen@os.amperecomputing.com>");
143 MODULE_AUTHOR("Quan Nguyen <quan@os.amperecomputing.com>");
144 MODULE_DESCRIPTION("Ampere Altra SMpro Misc driver");
145 MODULE_LICENSE("GPL");
146