[PATCH v7 3/7] of: Allow the iommu-map property to omit untranslated devices

[Jean-Philippe Brucker <jean-philippe.brucker@arm.com>]

In PCI root complex nodes, the iommu-map property describes the IOMMU that
translates each endpoint. On some platforms, the IOMMU itself is presented
as a PCI endpoint (e.g. AMD IOMMU and virtio-iommu). This isn't supported
by the current OF driver, which expects all endpoints to have an IOMMU.
Allow the iommu-map property to have gaps.

Relaxing of_map_rid() also allows the msi-map property to have gaps, which
is invalid since MSIs always reach an MSI controller. In that case
pci_msi_setup_msi_irqs() will return an error when attempting to find the
device's MSI domain.

Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Jean-Philippe Brucker <jean-philippe.brucker@arm.com>
---
 drivers/of/base.c | 10 +++++++---
 1 file changed, 7 insertions(+), 3 deletions(-)

diff --git a/drivers/of/base.c b/drivers/of/base.c
index 5226e898476e..4d12b1cab55f 100644
--- a/drivers/of/base.c
+++ b/drivers/of/base.c
@@ -2293,8 +2293,12 @@ int of_map_rid(struct device_node *np, u32 rid,
 		return 0;
 	}
 
-	pr_err("%pOF: Invalid %s translation - no match for rid 0x%x on %pOF\n",
-		np, map_name, rid, target && *target ? *target : NULL);
-	return -EFAULT;
+	pr_info("%pOF: no %s translation for rid 0x%x on %pOF\n", np, map_name,
+		rid, target && *target ? *target : NULL);
+
+	/* Bypasses translation */
+	if (id_out)
+		*id_out = rid;
+	return 0;
 }
 EXPORT_SYMBOL_GPL(of_map_rid);
-- 
2.19.1