[PATCH v8 4/7] powernv/iommu: add support for IOMMU default DMA mode build options

[Zhen Lei <thunder.leizhen@xxxxxxxxxx>]

The default DMA mode is PASSTHROUGH on powernv, this patch make it can be
set to STRICT at build time. It can be overridden by boot option.

There is no functional change.

Signed-off-by: Zhen Lei <thunder.leizhen@xxxxxxxxxx>
---
 arch/powerpc/platforms/powernv/pci-ioda.c | 3 ++-
 drivers/iommu/Kconfig                     | 2 ++
 2 files changed, 4 insertions(+), 1 deletion(-)

diff --git a/arch/powerpc/platforms/powernv/pci-ioda.c b/arch/powerpc/platforms/powernv/pci-ioda.c
index 126602b4e39972d..40208b9019be890 100644
--- a/arch/powerpc/platforms/powernv/pci-ioda.c
+++ b/arch/powerpc/platforms/powernv/pci-ioda.c
@@ -85,7 +85,8 @@ void pe_level_printk(const struct pnv_ioda_pe *pe, const char *level,
 	va_end(args);
 }
 
-static bool pnv_iommu_bypass_disabled __read_mostly;
+static bool pnv_iommu_bypass_disabled __read_mostly =
+			!IS_ENABLED(CONFIG_IOMMU_DEFAULT_PASSTHROUGH);
 static bool pci_reset_phbs __read_mostly;
 
 static int __init iommu_setup(char *str)
diff --git a/drivers/iommu/Kconfig b/drivers/iommu/Kconfig
index 9b48c2fc20e14d3..b5af859956c4fda 100644
--- a/drivers/iommu/Kconfig
+++ b/drivers/iommu/Kconfig
@@ -78,6 +78,7 @@ config IOMMU_DEBUGFS
 choice
 	prompt "IOMMU default DMA mode"
 	depends on IOMMU_API
+	default IOMMU_DEFAULT_PASSTHROUGH if (PPC_POWERNV && PCI)
 	default IOMMU_DEFAULT_LAZY if S390_IOMMU
 	default IOMMU_DEFAULT_STRICT
 	help
@@ -98,6 +99,7 @@ config IOMMU_DEFAULT_PASSTHROUGH
 
 config IOMMU_DEFAULT_LAZY
 	bool "lazy"
+	depends on !PPC_POWERNV
 	help
 	  Support lazy mode, where for every IOMMU DMA unmap operation, the
 	  flush operation of IOTLB and the free operation of IOVA are deferred.
-- 
1.8.3