[RFC 03/13] ACPI/IORT: Allow registration of external tables

[Jean-Philippe Brucker <jean-philippe@xxxxxxxxxx>]

Add a function to register an IORT table from an external source.

Signed-off-by: Jean-Philippe Brucker <jean-philippe@xxxxxxxxxx>
---
 drivers/acpi/iort.c       | 22 ++++++++++++++++++++--
 include/linux/acpi_iort.h | 10 ++++++++++
 2 files changed, 30 insertions(+), 2 deletions(-)

diff --git a/drivers/acpi/iort.c b/drivers/acpi/iort.c
index d62a9ea26fae..9c6c91e06f8f 100644
--- a/drivers/acpi/iort.c
+++ b/drivers/acpi/iort.c
@@ -144,6 +144,7 @@ typedef acpi_status (*iort_find_node_callback)
 
 /* Root pointer to the mapped IORT table */
 static struct acpi_table_header *iort_table;
+static enum iort_table_source iort_table_source;
 
 static LIST_HEAD(iort_msi_chip_list);
 static DEFINE_SPINLOCK(iort_msi_chip_lock);
@@ -1617,11 +1618,28 @@ static void __init iort_init_platform_devices(void)
 	}
 }
 
+void __init acpi_iort_register_table(struct acpi_table_header *table,
+				     enum iort_table_source source)
+{
+	/*
+	 * Firmware or hypervisor should know better than give us two IORT
+	 * tables.
+	 */
+	if (WARN_ON(iort_table))
+		return;
+
+	iort_table = table;
+	iort_table_source = source;
+
+	iort_init_platform_devices();
+}
+
 void __init acpi_iort_init(void)
 {
 	acpi_status status;
+	static struct acpi_table_header *table;
 
-	status = acpi_get_table(ACPI_SIG_IORT, 0, &iort_table);
+	status = acpi_get_table(ACPI_SIG_IORT, 0, &table);
 	if (ACPI_FAILURE(status)) {
 		if (status != AE_NOT_FOUND) {
 			const char *msg = acpi_format_exception(status);
@@ -1632,5 +1650,5 @@ void __init acpi_iort_init(void)
 		return;
 	}
 
-	iort_init_platform_devices();
+	acpi_iort_register_table(table, IORT_SOURCE_IORT);
 }
diff --git a/include/linux/acpi_iort.h b/include/linux/acpi_iort.h
index 8e7e2ec37f1b..f4db5fff07cf 100644
--- a/include/linux/acpi_iort.h
+++ b/include/linux/acpi_iort.h
@@ -11,6 +11,11 @@
 #include <linux/fwnode.h>
 #include <linux/irqdomain.h>
 
+enum iort_table_source {
+	IORT_SOURCE_IORT,	/* The Real Thing */
+	IORT_SOURCE_VIOT,	/* Paravirtual extensions */
+};
+
 #define IORT_IRQ_MASK(irq)		(irq & 0xffffffffULL)
 #define IORT_IRQ_TRIGGER_MASK(irq)	((irq >> 32) & 0xffffffffULL)
 
@@ -27,6 +32,8 @@ int iort_register_domain_token(int trans_id, phys_addr_t base,
 void iort_deregister_domain_token(int trans_id);
 struct fwnode_handle *iort_find_domain_token(int trans_id);
 #ifdef CONFIG_ACPI_IORT
+void acpi_iort_register_table(struct acpi_table_header *table,
+			      enum iort_table_source source);
 void acpi_iort_init(void);
 u32 iort_msi_map_rid(struct device *dev, u32 req_id);
 struct irq_domain *iort_get_device_domain(struct device *dev, u32 req_id);
@@ -37,6 +44,9 @@ void iort_dma_setup(struct device *dev, u64 *dma_addr, u64 *size);
 const struct iommu_ops *iort_iommu_configure(struct device *dev);
 int iort_iommu_msi_get_resv_regions(struct device *dev, struct list_head *head);
 #else
+static void acpi_iort_register_table(struct acpi_table_header *table,
+				     enum iort_table_source source)
+{ }
 static inline void acpi_iort_init(void) { }
 static inline u32 iort_msi_map_rid(struct device *dev, u32 req_id)
 { return req_id; }
-- 
2.24.0