[PATCH 7/7] irqchip/al-msi: Add ACPI support

[Hanna Hawa <hhhawa@amazon.com>]

This patch adds ACPI support for AL-MSIx driver.

The AL-MSIx controller is not standard, is not included in the UEFI
specification, and will not be added. The driver ACPI binding is
performed when the following conditions are true:
- OEM ID is AMAZON
- MADT table type is 0x80 (part of the OEM reserved range).

Signed-off-by: Hanna Hawa <hhhawa@amazon.com>
Co-developed-by: Vladimir Aerov <vaerov@amazon.com>
Signed-off-by: Vladimir Aerov <vaerov@amazon.com>
---
 drivers/irqchip/irq-al-msi.c | 118 ++++++++++++++++++++++++++++++++++++++++---
 1 file changed, 111 insertions(+), 7 deletions(-)

diff --git a/drivers/irqchip/irq-al-msi.c b/drivers/irqchip/irq-al-msi.c
index ec27455..cb80c1e 100644
--- a/drivers/irqchip/irq-al-msi.c
+++ b/drivers/irqchip/irq-al-msi.c
@@ -9,6 +9,7 @@
 
 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
 
+#include <linux/acpi.h>
 #include <linux/dma-iommu.h>
 #include <linux/irqchip.h>
 #include <linux/irqchip/arm-gic.h>
@@ -126,14 +127,20 @@ static int al_msix_gic_domain_alloc(struct irq_domain *domain,
 	struct irq_data *d;
 	int ret;
 
-	if (!is_of_node(domain->parent->fwnode))
+	if (is_of_node(domain->parent->fwnode)) {
+		fwspec.fwnode = domain->parent->fwnode;
+		fwspec.param_count = 3;
+		fwspec.param[0] = 0;
+		fwspec.param[1] = spi;
+		fwspec.param[2] = IRQ_TYPE_EDGE_RISING;
+	} else if (is_fwnode_irqchip(domain->parent->fwnode)) {
+		fwspec.fwnode = domain->parent->fwnode;
+		fwspec.param_count = 2;
+		fwspec.param[0] = spi + 32;
+		fwspec.param[1] = IRQ_TYPE_EDGE_RISING;
+	} else {
 		return -EINVAL;
-
-	fwspec.fwnode = domain->parent->fwnode;
-	fwspec.param_count = 3;
-	fwspec.param[0] = 0;
-	fwspec.param[1] = spi;
-	fwspec.param[2] = IRQ_TYPE_EDGE_RISING;
+	}
 
 	ret = irq_domain_alloc_irqs_parent(domain, virq, 1, &fwspec);
 	if (ret)
@@ -304,3 +311,100 @@ static int al_msix_init(struct device_node *node, struct device_node *parent)
 }
 IRQCHIP_DECLARE(alpine_msix, "al,alpine-msix", al_msix_init);
 IRQCHIP_DECLARE(al_msix, "amazon,al-msix", al_msix_init);
+
+#ifdef CONFIG_ACPI
+static struct al_msix_data *priv;
+
+#define ACPI_AMZN_MADT_OEM_TYPE		0x80
+#define ACPI_AMZN_OEM_ID		"AMAZON"
+
+struct acpi_madt_msix_oem_frame {
+	struct acpi_subtable_header header;
+	u64 base_address;
+	u32 base_address_len;
+	u16 spi_count;
+	u16 spi_base;
+};
+
+static struct fwnode_handle *al_msi_get_fwnode(struct device *dev)
+{
+	return priv->msi_domain_handle;
+}
+
+static int __init al_msix_acpi_probe(struct acpi_subtable_header *header,
+				     const unsigned long end)
+{
+	struct irq_domain *gic_domain;
+	struct fwnode_handle *gic_domain_handle;
+	struct acpi_madt_msix_oem_frame *m;
+	int ret;
+
+	m = container_of(header, struct acpi_madt_msix_oem_frame, header);
+	if (BAD_MADT_ENTRY(m, end))
+		return -EINVAL;
+
+	gic_domain_handle = acpi_get_gsi_domain_id();
+	if (!gic_domain_handle) {
+		pr_err("Failed to find the GIC domain handle\n");
+		return -ENXIO;
+	}
+
+	gic_domain = irq_find_matching_fwnode(gic_domain_handle,
+					      DOMAIN_BUS_ANY);
+	if (!gic_domain) {
+		pr_err("Failed to find the GIC domain\n");
+		return -ENXIO;
+	}
+
+	priv = kzalloc(sizeof(*priv), GFP_KERNEL);
+	if (!priv)
+		return -ENOMEM;
+
+	priv->spi_first = m->spi_base;
+	priv->num_spis = m->spi_count;
+
+	priv->msi_domain_handle = irq_domain_alloc_fwnode((void *)
+							  m->base_address);
+	if (!priv->msi_domain_handle) {
+		pr_err("Unable to allocate msi domain token\n");
+		ret = -EINVAL;
+		goto err_acpi_priv;
+	}
+
+	ret = al_msix_init_common(priv, m->base_address);
+	if (ret)
+		goto err_acpi_priv;
+
+	ret = al_msix_init_domains(priv, gic_domain);
+	if (ret)
+		goto err_acpi_map;
+
+	pci_msi_register_fwnode_provider(&al_msi_get_fwnode);
+
+	return 0;
+
+err_acpi_map:
+	kfree(priv->msi_map);
+err_acpi_priv:
+	kfree(priv);
+	return ret;
+}
+
+static int __init al_msix_acpi_init(void)
+{
+	static struct acpi_table_madt *madt;
+	acpi_status status;
+
+	/* if ACPI MADT table is not Amazon defined return */
+	status = acpi_get_table(ACPI_SIG_MADT, 0,
+				(struct acpi_table_header **)&madt);
+	if (ACPI_FAILURE(status) || (madt && memcmp(madt->header.oem_id,
+						    ACPI_AMZN_OEM_ID,
+						    ACPI_OEM_ID_SIZE)))
+		return -ENODEV;
+
+	return acpi_table_parse_madt(ACPI_AMZN_MADT_OEM_TYPE,
+				     al_msix_acpi_probe, 0);
+}
+early_initcall(al_msix_acpi_init);
+#endif /* CONFIG_ACPI */
-- 
2.7.4