ACPI: AGDI: Add interrupt signaling mode support

AGDI has two types of signaling modes: SDEI and interrupt.
Currently, the AGDI driver only supports SDEI.
Therefore, add support for interrupt signaling mode.
The interrupt vector is retrieved from the AGDI table, and call panic
function when an interrupt occurs.

Acked-by: Hanjun Guo <guohanjun@huawei.com>
Reviewed-by: Ilkka Koskinen <ilkka@os.amperecomputing.com>
Signed-off-by: Kazuhiro Abe <fj1078ii@aa.jp.fujitsu.com>
Signed-off-by: Will Deacon <will@kernel.org>

Author: Kazuhiro-Abe-fj

drivers/acpi/arm64/agdi.c

@@ -16,7 +16,11 @@
 #include "init.h"
 
 struct agdi_data {
+	unsigned char flags; /* AGDI Signaling Mode */
 	int sdei_event;
+	unsigned int gsiv;
+	bool use_nmi;
+	int irq;
 };
 
 static int agdi_sdei_handler(u32 sdei_event, struct pt_regs *regs, void *arg)
@@ -48,19 +52,73 @@ static int agdi_sdei_probe(struct platform_device *pdev,
 	return 0;
 }
 
+static irqreturn_t agdi_interrupt_handler_nmi(int irq, void *dev_id)
+{
+	nmi_panic(NULL, "Arm Generic Diagnostic Dump and Reset NMI Interrupt event issued\n");
+	return IRQ_HANDLED;
+}
+
+static irqreturn_t agdi_interrupt_handler_irq(int irq, void *dev_id)
+{
+	panic("Arm Generic Diagnostic Dump and Reset Interrupt event issued\n");
+	return IRQ_HANDLED;
+}
+
+static int agdi_interrupt_probe(struct platform_device *pdev,
+				struct agdi_data *adata)
+{
+	unsigned long irq_flags;
+	int ret;
+	int irq;
+
+	irq = acpi_register_gsi(NULL, adata->gsiv, ACPI_EDGE_SENSITIVE, ACPI_ACTIVE_HIGH);
+	if (irq < 0) {
+		dev_err(&pdev->dev, "cannot register GSI#%d (%d)\n", adata->gsiv, irq);
+		return irq;
+	}
+
+	irq_flags = IRQF_PERCPU | IRQF_NOBALANCING | IRQF_NO_AUTOEN |
+		    IRQF_NO_THREAD;
+	/* try NMI first */
+	ret = request_nmi(irq, &agdi_interrupt_handler_nmi, irq_flags,
+			  "agdi_interrupt_nmi", NULL);
+	if (!ret) {
+		enable_nmi(irq);
+		adata->irq = irq;
+		adata->use_nmi = true;
+		return 0;
+	}
+
+	/* Then try normal interrupt */
+	ret = request_irq(irq, &agdi_interrupt_handler_irq,
+			  irq_flags, "agdi_interrupt_irq", NULL);
+	if (ret) {
+		dev_err(&pdev->dev, "cannot register IRQ %d\n", ret);
+		acpi_unregister_gsi(adata->gsiv);
+		return ret;
+	}
+	enable_irq(irq);
+	adata->irq = irq;
+
+	return 0;
+}
+
 static int agdi_probe(struct platform_device *pdev)
 {
 	struct agdi_data *adata = dev_get_platdata(&pdev->dev);
 
 	if (!adata)
 		return -EINVAL;
 
-	return agdi_sdei_probe(pdev, adata);
+	if (adata->flags & ACPI_AGDI_SIGNALING_MODE)
+		return agdi_interrupt_probe(pdev, adata);
+	else
+		return agdi_sdei_probe(pdev, adata);
 }
 
-static void agdi_remove(struct platform_device *pdev)
+static void agdi_sdei_remove(struct platform_device *pdev,
+			     struct agdi_data *adata)
 {
-	struct agdi_data *adata = dev_get_platdata(&pdev->dev);
 	int err, i;
 
 	err = sdei_event_disable(adata->sdei_event);
@@ -83,6 +141,30 @@ static void agdi_remove(struct platform_device *pdev)
 			adata->sdei_event, ERR_PTR(err));
 }
 
+static void agdi_interrupt_remove(struct platform_device *pdev,
+				  struct agdi_data *adata)
+{
+	if (adata->irq == -1)
+		return;
+
+	if (adata->use_nmi)
+		free_nmi(adata->irq, NULL);
+	else
+		free_irq(adata->irq, NULL);
+
+	acpi_unregister_gsi(adata->gsiv);
+}
+
+static void agdi_remove(struct platform_device *pdev)
+{
+	struct agdi_data *adata = dev_get_platdata(&pdev->dev);
+
+	if (adata->flags & ACPI_AGDI_SIGNALING_MODE)
+		agdi_interrupt_remove(pdev, adata);
+	else
+		agdi_sdei_remove(pdev, adata);
+}
+
 static struct platform_driver agdi_driver = {
 	.driver = {
 		.name = "agdi",
@@ -94,7 +176,7 @@ static struct platform_driver agdi_driver = {
 void __init acpi_agdi_init(void)
 {
 	struct acpi_table_agdi *agdi_table;
-	struct agdi_data pdata;
+	struct agdi_data pdata = { 0 };
 	struct platform_device *pdev;
 	acpi_status status;
 
@@ -103,12 +185,13 @@ void __init acpi_agdi_init(void)
 	if (ACPI_FAILURE(status))
 		return;
 
-	if (agdi_table->flags & ACPI_AGDI_SIGNALING_MODE) {
-		pr_warn("Interrupt signaling is not supported");
-		goto err_put_table;
-	}
+	if (agdi_table->flags & ACPI_AGDI_SIGNALING_MODE)
+		pdata.gsiv = agdi_table->gsiv;
+	else
+		pdata.sdei_event = agdi_table->sdei_event;
 
-	pdata.sdei_event = agdi_table->sdei_event;
+	pdata.irq = -1;
+	pdata.flags = agdi_table->flags;
 
 	pdev = platform_device_register_data(NULL, "agdi", 0, &pdata, sizeof(pdata));
 	if (IS_ERR(pdev))