[PATCH v4 21/23] irqchip/riscv-rpmi-sysmsi: Add ACPI support

[Anup Patel <apatel@ventanamicro.com>]

From: Sunil V L <sunilvl@ventanamicro.com>

Add ACPI support for the RISC-V RPMI system MSI based irqchip driver.

Signed-off-by: Sunil V L <sunilvl@ventanamicro.com>
Signed-off-by: Anup Patel <apatel@ventanamicro.com>
---
 drivers/irqchip/Kconfig                 |  2 +-
 drivers/irqchip/irq-riscv-rpmi-sysmsi.c | 48 ++++++++++++++++++++++---
 2 files changed, 45 insertions(+), 5 deletions(-)

diff --git a/drivers/irqchip/Kconfig b/drivers/irqchip/Kconfig
index 83700fc2ddc9..132e56a596fc 100644
--- a/drivers/irqchip/Kconfig
+++ b/drivers/irqchip/Kconfig
@@ -614,7 +614,7 @@ config RISCV_IMSIC
 
 config RISCV_RPMI_SYSMSI
 	bool
-	depends on MAILBOX
+	depends on RISCV && MAILBOX
 	select IRQ_DOMAIN_HIERARCHY
 	select GENERIC_MSI_IRQ
 	default RISCV
diff --git a/drivers/irqchip/irq-riscv-rpmi-sysmsi.c b/drivers/irqchip/irq-riscv-rpmi-sysmsi.c
index d7b19fb7bf4e..6d27c036928a 100644
--- a/drivers/irqchip/irq-riscv-rpmi-sysmsi.c
+++ b/drivers/irqchip/irq-riscv-rpmi-sysmsi.c
@@ -1,9 +1,11 @@
 // SPDX-License-Identifier: GPL-2.0
 /* Copyright (C) 2025 Ventana Micro Systems Inc. */
 
+#include <linux/acpi.h>
 #include <linux/device.h>
 #include <linux/dev_printk.h>
 #include <linux/irq.h>
+#include <linux/irqchip/riscv-imsic.h>
 #include <linux/irqdomain.h>
 #include <linux/mailbox_client.h>
 #include <linux/mailbox/riscv-rpmi-message.h>
@@ -209,6 +211,9 @@ static int rpmi_sysmsi_probe(struct platform_device *pdev)
 {
 	struct device *dev = &pdev->dev;
 	struct rpmi_sysmsi_priv *priv;
+	struct irq_domain *msi_domain;
+	struct fwnode_handle *fwnode;
+	u32 id;
 	int rc;
 
 	priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
@@ -240,6 +245,22 @@ static int rpmi_sysmsi_probe(struct platform_device *pdev)
 	}
 	priv->nr_irqs = rc;
 
+	fwnode = dev_fwnode(dev);
+	if (is_acpi_node(fwnode)) {
+		u32 nr_irqs;
+
+		rc = riscv_acpi_get_gsi_info(fwnode, &priv->gsi_base, &id,
+					     &nr_irqs, NULL);
+		if (rc) {
+			dev_err(dev, "failed to find GSI mapping\n");
+			return rc;
+		}
+
+		/* Update with actual GSI range */
+		if (nr_irqs != priv->nr_irqs)
+			riscv_acpi_update_gsi_range(priv->gsi_base, priv->nr_irqs);
+	}
+
 	/* Set the device MSI domain if not available */
 	if (!dev_get_msi_domain(dev)) {
 		/*
@@ -249,8 +270,13 @@ static int rpmi_sysmsi_probe(struct platform_device *pdev)
 		 * then we need to set it explicitly before using any platform
 		 * MSI functions.
 		 */
-		if (is_of_node(dev_fwnode(dev)))
-			of_msi_configure(dev, to_of_node(dev_fwnode(dev)));
+		if (is_of_node(fwnode)) {
+			of_msi_configure(dev, to_of_node(fwnode));
+		} else if (is_acpi_device_node(fwnode)) {
+			msi_domain = irq_find_matching_fwnode(imsic_acpi_get_fwnode(dev),
+							      DOMAIN_BUS_PLATFORM_MSI);
+			dev_set_msi_domain(dev, msi_domain);
+		}
 
 		if (!dev_get_msi_domain(dev)) {
 			mbox_free_channel(priv->chan);
@@ -265,6 +291,13 @@ static int rpmi_sysmsi_probe(struct platform_device *pdev)
 		return dev_err_probe(dev, -ENOMEM, "failed to create MSI irq domain\n");
 	}
 
+#ifdef CONFIG_ACPI
+	struct acpi_device *adev = ACPI_COMPANION(dev);
+
+	if (adev)
+		acpi_dev_clear_dependencies(adev);
+#endif
+
 	dev_info(dev, "%u system MSIs registered\n", priv->nr_irqs);
 	return 0;
 }
@@ -274,10 +307,17 @@ static const struct of_device_id rpmi_sysmsi_match[] = {
 	{}
 };
 
+static const struct acpi_device_id acpi_rpmi_sysmsi_match[] = {
+	{ "RSCV0006" },
+	{}
+};
+MODULE_DEVICE_TABLE(acpi, acpi_rpmi_sysmsi_match);
+
 static struct platform_driver rpmi_sysmsi_driver = {
 	.driver = {
-		.name		= "rpmi-sysmsi",
-		.of_match_table	= rpmi_sysmsi_match,
+		.name			= "rpmi-sysmsi",
+		.of_match_table		= rpmi_sysmsi_match,
+		.acpi_match_table	= acpi_rpmi_sysmsi_match,
 	},
 	.probe = rpmi_sysmsi_probe,
 };
-- 
2.43.0