iommu/sun50i: Fix R/W permission check

[ Upstream commit eac0104 ]

Because driver has enum type permissions and iommu subsystem has bitmap
type, we have to be careful how check for combined read and write
permissions is done. In such case, we have to mask both permissions and
check that both are set at the same time.

Current code just masks both flags but doesn't check that both are set.
In short, it always sets R/W permission, regardles if requested
permissions were RO, WO or RW. Fix that.

Fixes: 4100b8c ("iommu: Add Allwinner H6 IOMMU driver")
Signed-off-by: Jernej Skrabec <jernej.skrabec@gmail.com>
Link: https://lore.kernel.org/r/20221025165415.307591-4-jernej.skrabec@gmail.com
Signed-off-by: Joerg Roedel <jroedel@suse.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>

drivers/iommu/sun50i-iommu.c

@@ -271,7 +271,7 @@ static u32 sun50i_mk_pte(phys_addr_t page, int prot)
 	enum sun50i_iommu_aci aci;
 	u32 flags = 0;
 
-	if (prot & (IOMMU_READ | IOMMU_WRITE))
+	if ((prot & (IOMMU_READ | IOMMU_WRITE)) == (IOMMU_READ | IOMMU_WRITE))
 		aci = SUN50I_IOMMU_ACI_RD_WR;
 	else if (prot & IOMMU_READ)
 		aci = SUN50I_IOMMU_ACI_RD;