[PATCH v1 1/2] gpu: host1x: Add back arm_iommu_detach_device()

[Dmitry Osipenko]

The case of CONFIG_ARM_DMA_USE_IOMMU=y was found to be broken for
host1x driver. Add back the workaround using arm_iommu_detach_device()
as a temporary solution.

Cc: stable at vger.kernel.org
Fixes: af1cbfb9bf0f ("gpu: host1x: Support DMA mapping of buffers"
Signed-off-by: Dmitry Osipenko <digetx at gmail.com>
---
 drivers/gpu/host1x/dev.c | 15 +++++++++++++++
 1 file changed, 15 insertions(+)

diff --git a/drivers/gpu/host1x/dev.c b/drivers/gpu/host1x/dev.c
index d0ebb70e2fdd..a2c09dca4eef 100644
--- a/drivers/gpu/host1x/dev.c
+++ b/drivers/gpu/host1x/dev.c
@@ -18,6 +18,10 @@
 #include <trace/events/host1x.h>
 #undef CREATE_TRACE_POINTS
 
+#if IS_ENABLED(CONFIG_ARM_DMA_USE_IOMMU)
+#include <asm/dma-iommu.h>
+#endif
+
 #include "bus.h"
 #include "channel.h"
 #include "debug.h"
@@ -232,6 +236,17 @@ static struct iommu_domain *host1x_iommu_attach(struct host1x *host)
 	struct iommu_domain *domain = iommu_get_domain_for_dev(host->dev);
 	int err;
 
+#if IS_ENABLED(CONFIG_ARM_DMA_USE_IOMMU)
+	if (host->dev->archdata.mapping) {
+		struct dma_iommu_mapping *mapping =
+				to_dma_iommu_mapping(host->dev);
+		arm_iommu_detach_device(host->dev);
+		arm_iommu_release_mapping(mapping);
+
+		domain = iommu_get_domain_for_dev(host->dev);
+	}
+#endif
+
 	/*
 	 * We may not always want to enable IOMMU support (for example if the
 	 * host1x firewall is already enabled and we don't support addressing
-- 
2.30.2