1// SPDX-License-Identifier: GPL-2.0+
2/*
3 * Copyright (c) 2017 Intel Corporation
4 */
5#include <common.h>
6#include <dm.h>
7#include <regmap.h>
8#include <syscon.h>
9#include <asm/cpu.h>
10#include <asm/pmu.h>
11#include <linux/delay.h>
12#include <linux/errno.h>
13#include <linux/io.h>
14
15/* Registers */
16struct pmu_regs {
17	u32	sts;
18	u32	cmd;
19	u32	ics;
20	u32	reserved;
21	u32	wkc[4];
22	u32	wks[4];
23	u32	ssc[4];
24	u32	sss[4];
25};
26
27/* Bits in PMU_REGS_STS */
28#define PMU_REGS_STS_BUSY		(1 << 8)
29
30struct pmu_mid {
31	struct pmu_regs *regs;
32};
33
34static int pmu_read_status(struct pmu_regs *regs)
35{
36	int retry = 500000;
37	u32 val;
38
39	do {
40		val = readl(&regs->sts);
41		if (!(val & PMU_REGS_STS_BUSY))
42			return 0;
43
44		udelay(1);
45	} while (--retry);
46
47	printf("WARNING: PMU still busy\n");
48	return -EBUSY;
49}
50
51static int pmu_power_lss(struct pmu_regs *regs, unsigned int lss, bool on)
52{
53	unsigned int offset = (lss * 2) / 32;
54	unsigned int shift = (lss * 2) % 32;
55	u32 ssc;
56	int ret;
57
58	/* Check PMU status */
59	ret = pmu_read_status(regs);
60	if (ret)
61		return ret;
62
63	/* Read PMU values */
64	ssc = readl(&regs->sss[offset]);
65
66	/* Modify PMU values */
67	if (on)
68		ssc &= ~(0x3 << shift);		/* D0 */
69	else
70		ssc |= 0x3 << shift;		/* D3hot */
71
72	/* Write modified PMU values */
73	writel(ssc, &regs->ssc[offset]);
74
75	/* Update modified PMU values */
76	writel(0x00002201, &regs->cmd);
77
78	/* Check PMU status */
79	return pmu_read_status(regs);
80}
81
82int pmu_turn_power(unsigned int lss, bool on)
83{
84	struct pmu_mid *pmu;
85	struct udevice *dev;
86	int ret;
87
88	ret = syscon_get_by_driver_data(X86_SYSCON_PMU, &dev);
89	if (ret)
90		return ret;
91
92	pmu = dev_get_priv(dev);
93
94	return pmu_power_lss(pmu->regs, lss, on);
95}
96
97static int pmu_mid_probe(struct udevice *dev)
98{
99	struct pmu_mid *pmu = dev_get_priv(dev);
100
101	pmu->regs = syscon_get_first_range(X86_SYSCON_PMU);
102
103	return 0;
104}
105
106static const struct udevice_id pmu_mid_match[] = {
107	{ .compatible = "intel,pmu-mid", .data = X86_SYSCON_PMU },
108	{ /* sentinel */ }
109};
110
111U_BOOT_DRIVER(intel_mid_pmu) = {
112	.name		= "pmu_mid",
113	.id		= UCLASS_SYSCON,
114	.of_match	= pmu_mid_match,
115	.probe		= pmu_mid_probe,
116	.priv_auto	= sizeof(struct pmu_mid),
117};
118