1 files changed, 157 insertions, 0 deletions

diff --git a/drivers/staging/media/tegra-vde/iommu.c b/drivers/staging/media/tegra-vde/iommu.c
new file mode 100644
index 000000000000..6af863d92123
--- /dev/null
+++ b/drivers/staging/media/tegra-vde/iommu.c
@@ -0,0 +1,157 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * NVIDIA Tegra Video decoder driver
+ *
+ * Copyright (C) 2016-2019 GRATE-DRIVER project
+ */
+
+#include <linux/iommu.h>
+#include <linux/iova.h>
+#include <linux/kernel.h>
+#include <linux/platform_device.h>
+
+#if IS_ENABLED(CONFIG_ARM_DMA_USE_IOMMU)
+#include <asm/dma-iommu.h>
+#endif
+
+#include "vde.h"
+
+int tegra_vde_iommu_map(struct tegra_vde *vde,
+			struct sg_table *sgt,
+			struct iova **iovap,
+			size_t size)
+{
+	struct iova *iova;
+	unsigned long shift;
+	unsigned long end;
+	dma_addr_t addr;
+
+	end = vde->domain->geometry.aperture_end;
+	size = iova_align(&vde->iova, size);
+	shift = iova_shift(&vde->iova);
+
+	iova = alloc_iova(&vde->iova, size >> shift, end >> shift, true);
+	if (!iova)
+		return -ENOMEM;
+
+	addr = iova_dma_addr(&vde->iova, iova);
+
+	size = iommu_map_sg(vde->domain, addr, sgt->sgl, sgt->nents,
+			    IOMMU_READ | IOMMU_WRITE);
+	if (!size) {
+		__free_iova(&vde->iova, iova);
+		return -ENXIO;
+	}
+
+	*iovap = iova;
+
+	return 0;
+}
+
+void tegra_vde_iommu_unmap(struct tegra_vde *vde, struct iova *iova)
+{
+	unsigned long shift = iova_shift(&vde->iova);
+	unsigned long size = iova_size(iova) << shift;
+	dma_addr_t addr = iova_dma_addr(&vde->iova, iova);
+
+	iommu_unmap(vde->domain, addr, size);
+	__free_iova(&vde->iova, iova);
+}
+
+int tegra_vde_iommu_init(struct tegra_vde *vde)
+{
+	struct device *dev = vde->miscdev.parent;
+	struct iova *iova;
+	unsigned long order;
+	unsigned long shift;
+	int err;
+
+	vde->group = iommu_group_get(dev);
+	if (!vde->group)
+		return 0;
+
+#if IS_ENABLED(CONFIG_ARM_DMA_USE_IOMMU)
+	if (dev->archdata.mapping) {
+		struct dma_iommu_mapping *mapping = to_dma_iommu_mapping(dev);
+
+		arm_iommu_detach_device(dev);
+		arm_iommu_release_mapping(mapping);
+	}
+#endif
+	vde->domain = iommu_domain_alloc(&platform_bus_type);
+	if (!vde->domain) {
+		err = -ENOMEM;
+		goto put_group;
+	}
+
+	err = iova_cache_get();
+	if (err)
+		goto free_domain;
+
+	order = __ffs(vde->domain->pgsize_bitmap);
+	init_iova_domain(&vde->iova, 1UL << order, 0);
+
+	err = iommu_attach_group(vde->domain, vde->group);
+	if (err)
+		goto put_iova;
+
+	/*
+	 * We're using some static addresses that are not accessible by VDE
+	 * to trap invalid memory accesses.
+	 */
+	shift = iova_shift(&vde->iova);
+	iova = reserve_iova(&vde->iova, 0x60000000 >> shift,
+			    0x70000000 >> shift);
+	if (!iova) {
+		err = -ENOMEM;
+		goto detach_group;
+	}
+
+	vde->iova_resv_static_addresses = iova;
+
+	/*
+	 * BSEV's end-address wraps around due to integer overflow during
+	 * of hardware context preparation if IOVA is allocated at the end
+	 * of address space and VDE can't handle that. Hence simply reserve
+	 * the last page to avoid the problem.
+	 */
+	iova = reserve_iova(&vde->iova, 0xffffffff >> shift,
+			    (0xffffffff >> shift) + 1);
+	if (!iova) {
+		err = -ENOMEM;
+		goto unreserve_iova;
+	}
+
+	vde->iova_resv_last_page = iova;
+
+	return 0;
+
+unreserve_iova:
+	__free_iova(&vde->iova, vde->iova_resv_static_addresses);
+detach_group:
+	iommu_detach_group(vde->domain, vde->group);
+put_iova:
+	put_iova_domain(&vde->iova);
+	iova_cache_put();
+free_domain:
+	iommu_domain_free(vde->domain);
+put_group:
+	iommu_group_put(vde->group);
+
+	return err;
+}
+
+void tegra_vde_iommu_deinit(struct tegra_vde *vde)
+{
+	if (vde->domain) {
+		__free_iova(&vde->iova, vde->iova_resv_last_page);
+		__free_iova(&vde->iova, vde->iova_resv_static_addresses);
+		iommu_detach_group(vde->domain, vde->group);
+		put_iova_domain(&vde->iova);
+		iova_cache_put();
+		iommu_domain_free(vde->domain);
+		iommu_group_put(vde->group);
+
+		vde->domain = NULL;
+	}
+}