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(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
 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(misc->regmap, SOC_POWER_LIMIT, &value);
 81	if (ret)
 82		return ret;
 83
 84	return sysfs_emit(buf, "%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(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
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(&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
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");