a64fx-diag.c

  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 = 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");