[PATCH] xen/iommu: smmu: Rework how the SMMU version is detected

[Julien Grall <julien@xxxxxxx>]

From: Julien Grall <jgrall@xxxxxxxxxx>

Clang 11 will throw the following error:

smmu.c:2284:18: error: cast to smaller integer type 'enum 
arm_smmu_arch_version' from 'const void *' [-Werror,-Wvoid-pointer-to-enum-cast]
        smmu->version = (enum arm_smmu_arch_version)of_id->data;
                        ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

The error can be prevented by introduce static variable for each SMMU
version and store a pointer for each of them.

Signed-off-by: Julien Grall <jgrall@xxxxxxxxxx>

---

Only build tested
---
 xen/drivers/passthrough/arm/smmu.c | 15 +++++++++------
 1 file changed, 9 insertions(+), 6 deletions(-)

diff --git a/xen/drivers/passthrough/arm/smmu.c 
b/xen/drivers/passthrough/arm/smmu.c
index ed04d85e05e9..4a507d7aff64 100644
--- a/xen/drivers/passthrough/arm/smmu.c
+++ b/xen/drivers/passthrough/arm/smmu.c
@@ -2249,12 +2249,15 @@ static int arm_smmu_device_cfg_probe(struct 
arm_smmu_device *smmu)
        return 0;
 }
 
+static const enum arm_smmu_arch_version smmu_v1_version = ARM_SMMU_V1;
+static const enum arm_smmu_arch_version smmu_v2_version = ARM_SMMU_V2;
+
 static const struct of_device_id arm_smmu_of_match[] = {
-       { .compatible = "arm,smmu-v1", .data = (void *)ARM_SMMU_V1 },
-       { .compatible = "arm,smmu-v2", .data = (void *)ARM_SMMU_V2 },
-       { .compatible = "arm,mmu-400", .data = (void *)ARM_SMMU_V1 },
-       { .compatible = "arm,mmu-401", .data = (void *)ARM_SMMU_V1 },
-       { .compatible = "arm,mmu-500", .data = (void *)ARM_SMMU_V2 },
+       { .compatible = "arm,smmu-v1", .data = &smmu_v1_version },
+       { .compatible = "arm,smmu-v2", .data = &smmu_v2_version },
+       { .compatible = "arm,mmu-400", .data = &smmu_v1_version },
+       { .compatible = "arm,mmu-401", .data = &smmu_v1_version },
+       { .compatible = "arm,mmu-500", .data = &smmu_v2_version },
        { },
 };
 MODULE_DEVICE_TABLE(of, arm_smmu_of_match);
@@ -2281,7 +2284,7 @@ static int arm_smmu_device_dt_probe(struct 
platform_device *pdev)
        smmu->dev = dev;
 
        of_id = of_match_node(arm_smmu_of_match, dev->of_node);
-       smmu->version = (enum arm_smmu_arch_version)of_id->data;
+       smmu->version = *(enum arm_smmu_arch_version *)of_id->data;
 
        res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
        smmu->base = devm_ioremap_resource(dev, res);
-- 
2.17.1