soc: fujitsu: Add A64FX diagnostic interrupt driver

Register the NMI/IRQ corresponding to the A64FX's device definition
dedicated to diagnostic interrupts, so that when this interrupt is
sent using the BMC, it causes a panic. This can be used to obtain
a kernel dump.

Signed-off-by: Hitomi Hasegawa <hasegawa-hitomi@fujitsu.com>
Link: https://lore.kernel.org/r/20220520074119.3574753-2-hasegawa-hitomi@fujitsu.com'
Signed-off-by: Arnd Bergmann <arnd@arndb.de>

diff --git a/MAINTAINERS b/MAINTAINERS
index 2ef5b11cd81304abac5271ec0e815ed5eba8b48c..49cb2d39c4216157032b7ab11076cd448487b572 100644 (file)
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -242,6 +242,11 @@ F: include/trace/events/9p.h
 F:     include/uapi/linux/virtio_9p.h
 F:     net/9p/
 
+A64FX DIAG DRIVER
+M:     Hitomi Hasegawa <hasegawa-hitomi@fujitsu.com>
+S:     Supported
+F:     drivers/soc/fujitsu/a64fx-diag.c
+
 A8293 MEDIA DRIVER
 M:     Antti Palosaari <crope@iki.fi>
 L:     linux-media@vger.kernel.org

diff --git a/drivers/soc/Kconfig b/drivers/soc/Kconfig
index 86ccf5970bc1bea94d4323967e238af5ab5dedb7..e461c071189b48b61ba15ff428d390b3e40ea8b9 100644 (file)
--- a/drivers/soc/Kconfig
+++ b/drivers/soc/Kconfig
@@ -9,6 +9,7 @@ source "drivers/soc/atmel/Kconfig"
 source "drivers/soc/bcm/Kconfig"
 source "drivers/soc/canaan/Kconfig"
 source "drivers/soc/fsl/Kconfig"
+source "drivers/soc/fujitsu/Kconfig"
 source "drivers/soc/imx/Kconfig"
 source "drivers/soc/ixp4xx/Kconfig"
 source "drivers/soc/litex/Kconfig"

diff --git a/drivers/soc/Makefile b/drivers/soc/Makefile
index 919716e0e7001f645355f6a9d36c722545bf5165..69ba6508cf2c17229ef32afcb79137b53f969d09 100644 (file)
--- a/drivers/soc/Makefile
+++ b/drivers/soc/Makefile
@@ -12,6 +12,7 @@ obj-$(CONFIG_SOC_CANAAN)      += canaan/
 obj-$(CONFIG_ARCH_DOVE)                += dove/
 obj-$(CONFIG_MACH_DOVE)                += dove/
 obj-y                          += fsl/
+obj-y                          += fujitsu/
 obj-$(CONFIG_ARCH_GEMINI)      += gemini/
 obj-y                          += imx/
 obj-y                          += ixp4xx/

diff --git a/drivers/soc/fujitsu/Kconfig b/drivers/soc/fujitsu/Kconfig
new file mode 100644 (file)
index 0000000..56275b4
--- /dev/null
+++ b/drivers/soc/fujitsu/Kconfig
@@ -0,0 +1,16 @@
+# SPDX-License-Identifier: GPL-2.0-only
+menu "fujitsu SoC drivers"
+
+config A64FX_DIAG
+       tristate "A64FX diag driver"
+       depends on ARM64
+       depends on ACPI
+       help
+         Say Y here if you want to enable diag interrupt on Fujitsu A64FX.
+         This driver enables BMC's diagnostic requests and enables
+         A64FX-specific interrupts. This allows administrators to obtain
+         kernel dumps via diagnostic requests using ipmitool, etc.
+
+         If unsure, say N.
+
+endmenu

diff --git a/drivers/soc/fujitsu/Makefile b/drivers/soc/fujitsu/Makefile
new file mode 100644 (file)
index 0000000..945bc1c
--- /dev/null
+++ b/drivers/soc/fujitsu/Makefile
@@ -0,0 +1,3 @@
+# SPDX-License-Identifier: GPL-2.0
+
+obj-$(CONFIG_A64FX_DIAG)       += a64fx-diag.o

diff --git a/drivers/soc/fujitsu/a64fx-diag.c b/drivers/soc/fujitsu/a64fx-diag.c
new file mode 100644 (file)
index 0000000..d87f348
--- /dev/null
+++ b/drivers/soc/fujitsu/a64fx-diag.c
@@ -0,0 +1,154 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * A64FX diag driver.
+ * Copyright (c) 2022 Fujitsu Ltd.
+ */
+
+#include <linux/acpi.h>
+#include <linux/interrupt.h>
+#include <linux/irq.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+
+#define A64FX_DIAG_IRQ 1
+#define BMC_DIAG_INTERRUPT_ENABLE 0x40
+#define BMC_DIAG_INTERRUPT_STATUS 0x44
+#define BMC_DIAG_INTERRUPT_MASK BIT(31)
+
+struct a64fx_diag_priv {
+       void __iomem *mmsc_reg_base;
+       int irq;
+       bool has_nmi;
+};
+
+static irqreturn_t a64fx_diag_handler_nmi(int irq, void *dev_id)
+{
+       nmi_panic(NULL, "a64fx_diag: interrupt received\n");
+
+       return IRQ_HANDLED;
+}
+
+static irqreturn_t a64fx_diag_handler_irq(int irq, void *dev_id)
+{
+       panic("a64fx_diag: interrupt received\n");
+
+       return IRQ_HANDLED;
+}
+
+static void a64fx_diag_interrupt_clear(struct a64fx_diag_priv *priv)
+{
+       void __iomem *diag_status_reg_addr;
+       u32 mmsc;
+
+       diag_status_reg_addr = priv->mmsc_reg_base + BMC_DIAG_INTERRUPT_STATUS;
+       mmsc = readl(diag_status_reg_addr);
+       if (mmsc & BMC_DIAG_INTERRUPT_MASK)
+               writel(BMC_DIAG_INTERRUPT_MASK, diag_status_reg_addr);
+}
+
+static void a64fx_diag_interrupt_enable(struct a64fx_diag_priv *priv)
+{
+       void __iomem *diag_enable_reg_addr;
+       u32 mmsc;
+
+       diag_enable_reg_addr = priv->mmsc_reg_base + BMC_DIAG_INTERRUPT_ENABLE;
+       mmsc = readl(diag_enable_reg_addr);
+       if (!(mmsc & BMC_DIAG_INTERRUPT_MASK)) {
+               mmsc |= BMC_DIAG_INTERRUPT_MASK;
+               writel(mmsc, diag_enable_reg_addr);
+       }
+}
+
+static void a64fx_diag_interrupt_disable(struct a64fx_diag_priv *priv)
+{
+       void __iomem *diag_enable_reg_addr;
+       u32 mmsc;
+
+       diag_enable_reg_addr = priv->mmsc_reg_base + BMC_DIAG_INTERRUPT_ENABLE;
+       mmsc = readl(diag_enable_reg_addr);
+       if (mmsc & BMC_DIAG_INTERRUPT_MASK) {
+               mmsc &= ~BMC_DIAG_INTERRUPT_MASK;
+               writel(mmsc, diag_enable_reg_addr);
+       }
+}
+
+static int a64fx_diag_probe(struct platform_device *pdev)
+{
+       struct device *dev = &pdev->dev;
+       struct a64fx_diag_priv *priv;
+       unsigned long irq_flags;
+       int ret;
+
+       priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
+       if (priv == NULL)
+               return -ENOMEM;
+
+       priv->mmsc_reg_base = devm_platform_ioremap_resource(pdev, 0);
+       if (IS_ERR(priv->mmsc_reg_base))
+               return PTR_ERR(priv->mmsc_reg_base);
+
+       priv->irq = platform_get_irq(pdev, A64FX_DIAG_IRQ);
+       if (priv->irq < 0)
+               return priv->irq;
+
+       platform_set_drvdata(pdev, priv);
+
+       irq_flags = IRQF_PERCPU | IRQF_NOBALANCING | IRQF_NO_AUTOEN |
+                  IRQF_NO_THREAD;
+       ret = request_nmi(priv->irq, &a64fx_diag_handler_nmi, irq_flags,
+                       "a64fx_diag_nmi", NULL);
+       if (ret) {
+               ret = request_irq(priv->irq, &a64fx_diag_handler_irq,
+                               irq_flags, "a64fx_diag_irq", NULL);
+               if (ret) {
+                       dev_err(dev, "cannot register IRQ %d\n", ret);
+                       return ret;
+               }
+               enable_irq(priv->irq);
+       } else {
+               enable_nmi(priv->irq);
+               priv->has_nmi = true;
+       }
+
+       a64fx_diag_interrupt_clear(priv);
+       a64fx_diag_interrupt_enable(priv);
+
+       return 0;
+}
+
+static int a64fx_diag_remove(struct platform_device *pdev)
+{
+       struct a64fx_diag_priv *priv = platform_get_drvdata(pdev);
+
+       a64fx_diag_interrupt_disable(priv);
+       a64fx_diag_interrupt_clear(priv);
+
+       if (priv->has_nmi)
+               free_nmi(priv->irq, NULL);
+       else
+               free_irq(priv->irq, NULL);
+
+       return 0;
+}
+
+static const struct acpi_device_id a64fx_diag_acpi_match[] = {
+       { "FUJI2007", 0 },
+       { },
+};
+MODULE_DEVICE_TABLE(acpi, a64fx_diag_acpi_match);
+
+
+static struct platform_driver a64fx_diag_driver = {
+       .driver = {
+               .name = "a64fx_diag_driver",
+               .acpi_match_table = ACPI_PTR(a64fx_diag_acpi_match),
+       },
+       .probe = a64fx_diag_probe,
+       .remove = a64fx_diag_remove,
+};
+
+module_platform_driver(a64fx_diag_driver);
+
+MODULE_LICENSE("GPL v2");
+MODULE_AUTHOR("Hitomi Hasegawa <hasegawa-hitomi@fujitsu.com>");
+MODULE_DESCRIPTION("A64FX diag driver");