[PATCH] ACPI/IORT: Update SMMUv3 DeviceID support

[Robin Murphy]

IORT E.e now allows SMMUv3 nodes to describe the DeviceID for MSIs
independently of wired GSIVs, where the previous oddly-restrictive
definition meant that an SMMU without PRI support had to provide a
DeviceID even if it didn't support MSIs either. Support this, with
the usual temporary flag definition while the real one is making
its way through ACPICA.

Signed-off-by: Robin Murphy <robin.murphy at arm.com>
---
 drivers/acpi/arm64/iort.c | 16 ++++++++++++----
 1 file changed, 12 insertions(+), 4 deletions(-)

diff --git a/drivers/acpi/arm64/iort.c b/drivers/acpi/arm64/iort.c
index ca2aed86b540..51bc3c1d8d42 100644
--- a/drivers/acpi/arm64/iort.c
+++ b/drivers/acpi/arm64/iort.c
@@ -402,6 +402,10 @@ static struct acpi_iort_node *iort_node_get_id(struct acpi_iort_node *node,
 	return NULL;
 }
 
+#ifndef ACPI_IORT_SMMU_V3_DEVICEID_VALID
+#define ACPI_IORT_SMMU_V3_DEVICEID_VALID (1 << 4)
+#endif
+
 static int iort_get_id_mapping_index(struct acpi_iort_node *node)
 {
 	struct acpi_iort_smmu_v3 *smmu;
@@ -418,12 +422,16 @@ static int iort_get_id_mapping_index(struct acpi_iort_node *node)
 
 		smmu = (struct acpi_iort_smmu_v3 *)node->node_data;
 		/*
-		 * ID mapping index is only ignored if all interrupts are
-		 * GSIV based
+		 * Until IORT E.e (node rev. 5), the ID mapping index was
+		 * defined to be valid unless all interrupts are GSIV-based.
 		 */
-		if (smmu->event_gsiv && smmu->pri_gsiv && smmu->gerr_gsiv
-		    && smmu->sync_gsiv)
+		if (node->revision < 5) {
+			if (smmu->event_gsiv && smmu->pri_gsiv &&
+			    smmu->gerr_gsiv && smmu->sync_gsiv)
+				return -EINVAL;
+		} else if (!(smmu->flags & ACPI_IORT_SMMU_V3_DEVICEID_VALID)) {
 			return -EINVAL;
+		}
 
 		if (smmu->id_mapping_index >= node->mapping_count) {
 			pr_err(FW_BUG "[node %p type %d] ID mapping index overflows valid mappings\n",
-- 
2.36.1.dirty