xref: /linux/drivers/soc/fujitsu/a64fx-diag.c (revision c5dbf04160005e07e8ca7232a7faa77ab1547ae0)
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 
18 struct a64fx_diag_priv {
19 	void __iomem *mmsc_reg_base;
20 	int irq;
21 	bool has_nmi;
22 };
23 
24 static 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 
31 static 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 
38 static 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 
49 static 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 
62 static 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 
75 static 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 
119 static 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 
132 static const struct acpi_device_id a64fx_diag_acpi_match[] = {
133 	{ "FUJI2007", 0 },
134 	{ },
135 };
136 MODULE_DEVICE_TABLE(acpi, a64fx_diag_acpi_match);
137 
138 
139 static 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 
148 module_platform_driver(a64fx_diag_driver);
149 
150 MODULE_AUTHOR("Hitomi Hasegawa <hasegawa-hitomi@fujitsu.com>");
151 MODULE_DESCRIPTION("A64FX diag driver");
152