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
a64fx_diag_handler_nmi(int irq,void * dev_id)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
a64fx_diag_handler_irq(int irq,void * dev_id)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
a64fx_diag_interrupt_clear(struct a64fx_diag_priv * priv)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
a64fx_diag_interrupt_enable(struct a64fx_diag_priv * priv)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
a64fx_diag_interrupt_disable(struct a64fx_diag_priv * priv)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
a64fx_diag_probe(struct platform_device * pdev)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
a64fx_diag_remove(struct platform_device * pdev)119 static int 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 return 0;
132 }
133
134 static const struct acpi_device_id a64fx_diag_acpi_match[] = {
135 { "FUJI2007", 0 },
136 { },
137 };
138 MODULE_DEVICE_TABLE(acpi, a64fx_diag_acpi_match);
139
140
141 static struct platform_driver a64fx_diag_driver = {
142 .driver = {
143 .name = "a64fx_diag_driver",
144 .acpi_match_table = ACPI_PTR(a64fx_diag_acpi_match),
145 },
146 .probe = a64fx_diag_probe,
147 .remove = a64fx_diag_remove,
148 };
149
150 module_platform_driver(a64fx_diag_driver);
151
152 MODULE_AUTHOR("Hitomi Hasegawa <hasegawa-hitomi@fujitsu.com>");
153 MODULE_DESCRIPTION("A64FX diag driver");
154
