1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * A64FX diag driver.
4 * Copyright (c) 2022 Fujitsu Ltd.
5 */
6
7#include <linux/acpi.h>
8#include <linux/interrupt.h>
9#include <linux/irq.h>
10#include <linux/module.h>
11#include <linux/platform_device.h>
12
13#define A64FX_DIAG_IRQ 1
14#define BMC_DIAG_INTERRUPT_ENABLE 0x40
15#define BMC_DIAG_INTERRUPT_STATUS 0x44
16#define BMC_DIAG_INTERRUPT_MASK BIT(31)
17
18struct a64fx_diag_priv {
19	void __iomem *mmsc_reg_base;
20	int irq;
21	bool has_nmi;
22};
23
24static irqreturn_t a64fx_diag_handler_nmi(int irq, void *dev_id)
25{
26	nmi_panic(NULL, "a64fx_diag: interrupt received\n");
27
28	return IRQ_HANDLED;
29}
30
31static irqreturn_t a64fx_diag_handler_irq(int irq, void *dev_id)
32{
33	panic("a64fx_diag: interrupt received\n");
34
35	return IRQ_HANDLED;
36}
37
38static void a64fx_diag_interrupt_clear(struct a64fx_diag_priv *priv)
39{
40	void __iomem *diag_status_reg_addr;
41	u32 mmsc;
42
43	diag_status_reg_addr = priv->mmsc_reg_base + BMC_DIAG_INTERRUPT_STATUS;
44	mmsc = readl(diag_status_reg_addr);
45	if (mmsc & BMC_DIAG_INTERRUPT_MASK)
46		writel(BMC_DIAG_INTERRUPT_MASK, diag_status_reg_addr);
47}
48
49static void a64fx_diag_interrupt_enable(struct a64fx_diag_priv *priv)
50{
51	void __iomem *diag_enable_reg_addr;
52	u32 mmsc;
53
54	diag_enable_reg_addr = priv->mmsc_reg_base + BMC_DIAG_INTERRUPT_ENABLE;
55	mmsc = readl(diag_enable_reg_addr);
56	if (!(mmsc & BMC_DIAG_INTERRUPT_MASK)) {
57		mmsc |= BMC_DIAG_INTERRUPT_MASK;
58		writel(mmsc, diag_enable_reg_addr);
59	}
60}
61
62static void a64fx_diag_interrupt_disable(struct a64fx_diag_priv *priv)
63{
64	void __iomem *diag_enable_reg_addr;
65	u32 mmsc;
66
67	diag_enable_reg_addr = priv->mmsc_reg_base + BMC_DIAG_INTERRUPT_ENABLE;
68	mmsc = readl(diag_enable_reg_addr);
69	if (mmsc & BMC_DIAG_INTERRUPT_MASK) {
70		mmsc &= ~BMC_DIAG_INTERRUPT_MASK;
71		writel(mmsc, diag_enable_reg_addr);
72	}
73}
74
75static int a64fx_diag_probe(struct platform_device *pdev)
76{
77	struct device *dev = &pdev->dev;
78	struct a64fx_diag_priv *priv;
79	unsigned long irq_flags;
80	int ret;
81
82	priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
83	if (priv == NULL)
84		return -ENOMEM;
85
86	priv->mmsc_reg_base = devm_platform_ioremap_resource(pdev, 0);
87	if (IS_ERR(priv->mmsc_reg_base))
88		return PTR_ERR(priv->mmsc_reg_base);
89
90	priv->irq = platform_get_irq(pdev, A64FX_DIAG_IRQ);
91	if (priv->irq < 0)
92		return priv->irq;
93
94	platform_set_drvdata(pdev, priv);
95
96	irq_flags = IRQF_PERCPU | IRQF_NOBALANCING | IRQF_NO_AUTOEN |
97		   IRQF_NO_THREAD;
98	ret = request_nmi(priv->irq, &a64fx_diag_handler_nmi, irq_flags,
99			"a64fx_diag_nmi", NULL);
100	if (ret) {
101		ret = request_irq(priv->irq, &a64fx_diag_handler_irq,
102				irq_flags, "a64fx_diag_irq", NULL);
103		if (ret) {
104			dev_err(dev, "cannot register IRQ %d\n", ret);
105			return ret;
106		}
107		enable_irq(priv->irq);
108	} else {
109		enable_nmi(priv->irq);
110		priv->has_nmi = true;
111	}
112
113	a64fx_diag_interrupt_clear(priv);
114	a64fx_diag_interrupt_enable(priv);
115
116	return 0;
117}
118
119static void a64fx_diag_remove(struct platform_device *pdev)
120{
121	struct a64fx_diag_priv *priv = platform_get_drvdata(pdev);
122
123	a64fx_diag_interrupt_disable(priv);
124	a64fx_diag_interrupt_clear(priv);
125
126	if (priv->has_nmi)
127		free_nmi(priv->irq, NULL);
128	else
129		free_irq(priv->irq, NULL);
130}
131
132static const struct acpi_device_id a64fx_diag_acpi_match[] = {
133	{ "FUJI2007", 0 },
134	{ },
135};
136MODULE_DEVICE_TABLE(acpi, a64fx_diag_acpi_match);
137
138
139static struct platform_driver a64fx_diag_driver = {
140	.driver = {
141		.name = "a64fx_diag_driver",
142		.acpi_match_table = ACPI_PTR(a64fx_diag_acpi_match),
143	},
144	.probe = a64fx_diag_probe,
145	.remove_new = a64fx_diag_remove,
146};
147
148module_platform_driver(a64fx_diag_driver);
149
150MODULE_AUTHOR("Hitomi Hasegawa <hasegawa-hitomi@fujitsu.com>");
151MODULE_DESCRIPTION("A64FX diag driver");
152