[PATCH] iommu/arm-smmu-v3: Fix compilation when CONFIG_CMA=n

[Will Deacon]

When compiling a kernel without support for CMA, CONFIG_CMA_ALIGNMENT
is not defined which results in the following build failure:

In file included from ./include/linux/list.h:9:0
                 from ./include/linux/kobject.h:19,
                 from ./include/linux/of.h:17
                 from ./include/linux/irqdomain.h:35,
                 from ./include/linux/acpi.h:13,
                 from drivers/iommu/arm-smmu-v3.c:12:
drivers/iommu/arm-smmu-v3.c: In function âarm_smmu_device_hw_probeâ:
drivers/iommu/arm-smmu-v3.c:194:40: error: âCONFIG_CMA_ALIGNMENTâ undeclared (first use in this function)
 #define Q_MAX_SZ_SHIFT   (PAGE_SHIFT + CONFIG_CMA_ALIGNMENT)

Fix the breakage by capping the maximum queue size based on MAX_ORDER
when CMA is not enabled.

Reported-by: Zhangshaokun <zhangshaokun@xxxxxxxxxxxxx>
Signed-off-by: Will Deacon <will@xxxxxxxxxx>
---
 drivers/iommu/arm-smmu-v3.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/drivers/iommu/arm-smmu-v3.c b/drivers/iommu/arm-smmu-v3.c
index 57fb4e080d6b..8e73a7615bf5 100644
--- a/drivers/iommu/arm-smmu-v3.c
+++ b/drivers/iommu/arm-smmu-v3.c
@@ -191,7 +191,13 @@
 #define Q_BASE_RWA			(1UL << 62)
 #define Q_BASE_ADDR_MASK		GENMASK_ULL(51, 5)
 #define Q_BASE_LOG2SIZE			GENMASK(4, 0)
+
+/* Ensure DMA allocations are naturally aligned */
+#ifdef CONFIG_CMA_ALIGNMENT
 #define Q_MAX_SZ_SHIFT			(PAGE_SHIFT + CONFIG_CMA_ALIGNMENT)
+#else
+#define Q_MAX_SZ_SHIFT			(PAGE_SHIFT + MAX_ORDER - 1)
+#endif
 
 /*
  * Stream table.
-- 
2.11.0