drivers/soc/fujitsu/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
  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");