Adding upstream version 6.6.15.upstream/6.6.15

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 779 insertions, 0 deletions

diff --git a/drivers/gpu/host1x/dev.c b/drivers/gpu/host1x/dev.c
new file mode 100644
index 0000000000..7c6699aed7
--- /dev/null
+++ b/drivers/gpu/host1x/dev.c
@@ -0,0 +1,779 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Tegra host1x driver
+ *
+ * Copyright (c) 2010-2013, NVIDIA Corporation.
+ */
+
+#include <linux/clk.h>
+#include <linux/delay.h>
+#include <linux/dma-mapping.h>
+#include <linux/io.h>
+#include <linux/list.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/of_platform.h>
+#include <linux/platform_device.h>
+#include <linux/pm_runtime.h>
+#include <linux/slab.h>
+
+#include <soc/tegra/common.h>
+
+#define CREATE_TRACE_POINTS
+#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 "context.h"
+#include "debug.h"
+#include "dev.h"
+#include "intr.h"
+
+#include "hw/host1x01.h"
+#include "hw/host1x02.h"
+#include "hw/host1x04.h"
+#include "hw/host1x05.h"
+#include "hw/host1x06.h"
+#include "hw/host1x07.h"
+#include "hw/host1x08.h"
+
+void host1x_common_writel(struct host1x *host1x, u32 v, u32 r)
+{
+	writel(v, host1x->common_regs + r);
+}
+
+void host1x_hypervisor_writel(struct host1x *host1x, u32 v, u32 r)
+{
+	writel(v, host1x->hv_regs + r);
+}
+
+u32 host1x_hypervisor_readl(struct host1x *host1x, u32 r)
+{
+	return readl(host1x->hv_regs + r);
+}
+
+void host1x_sync_writel(struct host1x *host1x, u32 v, u32 r)
+{
+	void __iomem *sync_regs = host1x->regs + host1x->info->sync_offset;
+
+	writel(v, sync_regs + r);
+}
+
+u32 host1x_sync_readl(struct host1x *host1x, u32 r)
+{
+	void __iomem *sync_regs = host1x->regs + host1x->info->sync_offset;
+
+	return readl(sync_regs + r);
+}
+
+void host1x_ch_writel(struct host1x_channel *ch, u32 v, u32 r)
+{
+	writel(v, ch->regs + r);
+}
+
+u32 host1x_ch_readl(struct host1x_channel *ch, u32 r)
+{
+	return readl(ch->regs + r);
+}
+
+static const struct host1x_info host1x01_info = {
+	.nb_channels = 8,
+	.nb_pts = 32,
+	.nb_mlocks = 16,
+	.nb_bases = 8,
+	.init = host1x01_init,
+	.sync_offset = 0x3000,
+	.dma_mask = DMA_BIT_MASK(32),
+	.has_wide_gather = false,
+	.has_hypervisor = false,
+	.num_sid_entries = 0,
+	.sid_table = NULL,
+	.reserve_vblank_syncpts = true,
+};
+
+static const struct host1x_info host1x02_info = {
+	.nb_channels = 9,
+	.nb_pts = 32,
+	.nb_mlocks = 16,
+	.nb_bases = 12,
+	.init = host1x02_init,
+	.sync_offset = 0x3000,
+	.dma_mask = DMA_BIT_MASK(32),
+	.has_wide_gather = false,
+	.has_hypervisor = false,
+	.num_sid_entries = 0,
+	.sid_table = NULL,
+	.reserve_vblank_syncpts = true,
+};
+
+static const struct host1x_info host1x04_info = {
+	.nb_channels = 12,
+	.nb_pts = 192,
+	.nb_mlocks = 16,
+	.nb_bases = 64,
+	.init = host1x04_init,
+	.sync_offset = 0x2100,
+	.dma_mask = DMA_BIT_MASK(34),
+	.has_wide_gather = false,
+	.has_hypervisor = false,
+	.num_sid_entries = 0,
+	.sid_table = NULL,
+	.reserve_vblank_syncpts = false,
+};
+
+static const struct host1x_info host1x05_info = {
+	.nb_channels = 14,
+	.nb_pts = 192,
+	.nb_mlocks = 16,
+	.nb_bases = 64,
+	.init = host1x05_init,
+	.sync_offset = 0x2100,
+	.dma_mask = DMA_BIT_MASK(34),
+	.has_wide_gather = false,
+	.has_hypervisor = false,
+	.num_sid_entries = 0,
+	.sid_table = NULL,
+	.reserve_vblank_syncpts = false,
+};
+
+static const struct host1x_sid_entry tegra186_sid_table[] = {
+	{
+		/* VIC */
+		.base = 0x1af0,
+		.offset = 0x30,
+		.limit = 0x34
+	},
+	{
+		/* NVDEC */
+		.base = 0x1b00,
+		.offset = 0x30,
+		.limit = 0x34
+	},
+};
+
+static const struct host1x_info host1x06_info = {
+	.nb_channels = 63,
+	.nb_pts = 576,
+	.nb_mlocks = 24,
+	.nb_bases = 16,
+	.init = host1x06_init,
+	.sync_offset = 0x0,
+	.dma_mask = DMA_BIT_MASK(40),
+	.has_wide_gather = true,
+	.has_hypervisor = true,
+	.num_sid_entries = ARRAY_SIZE(tegra186_sid_table),
+	.sid_table = tegra186_sid_table,
+	.reserve_vblank_syncpts = false,
+};
+
+static const struct host1x_sid_entry tegra194_sid_table[] = {
+	{
+		/* VIC */
+		.base = 0x1af0,
+		.offset = 0x30,
+		.limit = 0x34
+	},
+	{
+		/* NVDEC */
+		.base = 0x1b00,
+		.offset = 0x30,
+		.limit = 0x34
+	},
+	{
+		/* NVDEC1 */
+		.base = 0x1bc0,
+		.offset = 0x30,
+		.limit = 0x34
+	},
+};
+
+static const struct host1x_info host1x07_info = {
+	.nb_channels = 63,
+	.nb_pts = 704,
+	.nb_mlocks = 32,
+	.nb_bases = 0,
+	.init = host1x07_init,
+	.sync_offset = 0x0,
+	.dma_mask = DMA_BIT_MASK(40),
+	.has_wide_gather = true,
+	.has_hypervisor = true,
+	.num_sid_entries = ARRAY_SIZE(tegra194_sid_table),
+	.sid_table = tegra194_sid_table,
+	.reserve_vblank_syncpts = false,
+};
+
+/*
+ * Tegra234 has two stream ID protection tables, one for setting stream IDs
+ * through the channel path via SETSTREAMID, and one for setting them via
+ * MMIO. We program each engine's data stream ID in the channel path table
+ * and firmware stream ID in the MMIO path table.
+ */
+static const struct host1x_sid_entry tegra234_sid_table[] = {
+	{
+		/* VIC channel */
+		.base = 0x17b8,
+		.offset = 0x30,
+		.limit = 0x30
+	},
+	{
+		/* VIC MMIO */
+		.base = 0x1688,
+		.offset = 0x34,
+		.limit = 0x34
+	},
+	{
+		/* NVDEC channel */
+		.base = 0x17c8,
+		.offset = 0x30,
+		.limit = 0x30,
+	},
+	{
+		/* NVDEC MMIO */
+		.base = 0x1698,
+		.offset = 0x34,
+		.limit = 0x34,
+	},
+};
+
+static const struct host1x_info host1x08_info = {
+	.nb_channels = 63,
+	.nb_pts = 1024,
+	.nb_mlocks = 24,
+	.nb_bases = 0,
+	.init = host1x08_init,
+	.sync_offset = 0x0,
+	.dma_mask = DMA_BIT_MASK(40),
+	.has_wide_gather = true,
+	.has_hypervisor = true,
+	.has_common = true,
+	.num_sid_entries = ARRAY_SIZE(tegra234_sid_table),
+	.sid_table = tegra234_sid_table,
+	.streamid_vm_table = { 0x1004, 128 },
+	.classid_vm_table = { 0x1404, 25 },
+	.mmio_vm_table = { 0x1504, 25 },
+	.reserve_vblank_syncpts = false,
+};
+
+static const struct of_device_id host1x_of_match[] = {
+	{ .compatible = "nvidia,tegra234-host1x", .data = &host1x08_info, },
+	{ .compatible = "nvidia,tegra194-host1x", .data = &host1x07_info, },
+	{ .compatible = "nvidia,tegra186-host1x", .data = &host1x06_info, },
+	{ .compatible = "nvidia,tegra210-host1x", .data = &host1x05_info, },
+	{ .compatible = "nvidia,tegra124-host1x", .data = &host1x04_info, },
+	{ .compatible = "nvidia,tegra114-host1x", .data = &host1x02_info, },
+	{ .compatible = "nvidia,tegra30-host1x", .data = &host1x01_info, },
+	{ .compatible = "nvidia,tegra20-host1x", .data = &host1x01_info, },
+	{ },
+};
+MODULE_DEVICE_TABLE(of, host1x_of_match);
+
+static void host1x_setup_virtualization_tables(struct host1x *host)
+{
+	const struct host1x_info *info = host->info;
+	unsigned int i;
+
+	if (!info->has_hypervisor)
+		return;
+
+	for (i = 0; i < info->num_sid_entries; i++) {
+		const struct host1x_sid_entry *entry = &info->sid_table[i];
+
+		host1x_hypervisor_writel(host, entry->offset, entry->base);
+		host1x_hypervisor_writel(host, entry->limit, entry->base + 4);
+	}
+
+	for (i = 0; i < info->streamid_vm_table.count; i++) {
+		/* Allow access to all stream IDs to all VMs. */
+		host1x_hypervisor_writel(host, 0xff, info->streamid_vm_table.base + 4 * i);
+	}
+
+	for (i = 0; i < info->classid_vm_table.count; i++) {
+		/* Allow access to all classes to all VMs. */
+		host1x_hypervisor_writel(host, 0xff, info->classid_vm_table.base + 4 * i);
+	}
+
+	for (i = 0; i < info->mmio_vm_table.count; i++) {
+		/* Use VM1 (that's us) as originator VMID for engine MMIO accesses. */
+		host1x_hypervisor_writel(host, 0x1, info->mmio_vm_table.base + 4 * i);
+	}
+}
+
+static bool host1x_wants_iommu(struct host1x *host1x)
+{
+	/* Our IOMMU usage policy doesn't currently play well with GART */
+	if (of_machine_is_compatible("nvidia,tegra20"))
+		return false;
+
+	/*
+	 * If we support addressing a maximum of 32 bits of physical memory
+	 * and if the host1x firewall is enabled, there's no need to enable
+	 * IOMMU support. This can happen for example on Tegra20, Tegra30
+	 * and Tegra114.
+	 *
+	 * Tegra124 and later can address up to 34 bits of physical memory and
+	 * many platforms come equipped with more than 2 GiB of system memory,
+	 * which requires crossing the 4 GiB boundary. But there's a catch: on
+	 * SoCs before Tegra186 (i.e. Tegra124 and Tegra210), the host1x can
+	 * only address up to 32 bits of memory in GATHER opcodes, which means
+	 * that command buffers need to either be in the first 2 GiB of system
+	 * memory (which could quickly lead to memory exhaustion), or command
+	 * buffers need to be treated differently from other buffers (which is
+	 * not possible with the current ABI).
+	 *
+	 * A third option is to use the IOMMU in these cases to make sure all
+	 * buffers will be mapped into a 32-bit IOVA space that host1x can
+	 * address. This allows all of the system memory to be used and works
+	 * within the limitations of the host1x on these SoCs.
+	 *
+	 * In summary, default to enable IOMMU on Tegra124 and later. For any
+	 * of the earlier SoCs, only use the IOMMU for additional safety when
+	 * the host1x firewall is disabled.
+	 */
+	if (host1x->info->dma_mask <= DMA_BIT_MASK(32)) {
+		if (IS_ENABLED(CONFIG_TEGRA_HOST1X_FIREWALL))
+			return false;
+	}
+
+	return true;
+}
+
+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
+	 * more than 32 bits of physical memory), so check for that first.
+	 *
+	 * Similarly, if host1x is already attached to an IOMMU (via the DMA
+	 * API), don't try to attach again.
+	 */
+	if (!host1x_wants_iommu(host) || domain)
+		return domain;
+
+	host->group = iommu_group_get(host->dev);
+	if (host->group) {
+		struct iommu_domain_geometry *geometry;
+		dma_addr_t start, end;
+		unsigned long order;
+
+		err = iova_cache_get();
+		if (err < 0)
+			goto put_group;
+
+		host->domain = iommu_domain_alloc(&platform_bus_type);
+		if (!host->domain) {
+			err = -ENOMEM;
+			goto put_cache;
+		}
+
+		err = iommu_attach_group(host->domain, host->group);
+		if (err) {
+			if (err == -ENODEV)
+				err = 0;
+
+			goto free_domain;
+		}
+
+		geometry = &host->domain->geometry;
+		start = geometry->aperture_start & host->info->dma_mask;
+		end = geometry->aperture_end & host->info->dma_mask;
+
+		order = __ffs(host->domain->pgsize_bitmap);
+		init_iova_domain(&host->iova, 1UL << order, start >> order);
+		host->iova_end = end;
+
+		domain = host->domain;
+	}
+
+	return domain;
+
+free_domain:
+	iommu_domain_free(host->domain);
+	host->domain = NULL;
+put_cache:
+	iova_cache_put();
+put_group:
+	iommu_group_put(host->group);
+	host->group = NULL;
+
+	return ERR_PTR(err);
+}
+
+static int host1x_iommu_init(struct host1x *host)
+{
+	u64 mask = host->info->dma_mask;
+	struct iommu_domain *domain;
+	int err;
+
+	domain = host1x_iommu_attach(host);
+	if (IS_ERR(domain)) {
+		err = PTR_ERR(domain);
+		dev_err(host->dev, "failed to attach to IOMMU: %d\n", err);
+		return err;
+	}
+
+	/*
+	 * If we're not behind an IOMMU make sure we don't get push buffers
+	 * that are allocated outside of the range addressable by the GATHER
+	 * opcode.
+	 *
+	 * Newer generations of Tegra (Tegra186 and later) support a wide
+	 * variant of the GATHER opcode that allows addressing more bits.
+	 */
+	if (!domain && !host->info->has_wide_gather)
+		mask = DMA_BIT_MASK(32);
+
+	err = dma_coerce_mask_and_coherent(host->dev, mask);
+	if (err < 0) {
+		dev_err(host->dev, "failed to set DMA mask: %d\n", err);
+		return err;
+	}
+
+	return 0;
+}
+
+static void host1x_iommu_exit(struct host1x *host)
+{
+	if (host->domain) {
+		put_iova_domain(&host->iova);
+		iommu_detach_group(host->domain, host->group);
+
+		iommu_domain_free(host->domain);
+		host->domain = NULL;
+
+		iova_cache_put();
+
+		iommu_group_put(host->group);
+		host->group = NULL;
+	}
+}
+
+static int host1x_get_resets(struct host1x *host)
+{
+	int err;
+
+	host->resets[0].id = "mc";
+	host->resets[1].id = "host1x";
+	host->nresets = ARRAY_SIZE(host->resets);
+
+	err = devm_reset_control_bulk_get_optional_exclusive_released(
+				host->dev, host->nresets, host->resets);
+	if (err) {
+		dev_err(host->dev, "failed to get reset: %d\n", err);
+		return err;
+	}
+
+	return 0;
+}
+
+static int host1x_probe(struct platform_device *pdev)
+{
+	struct host1x *host;
+	int err;
+
+	host = devm_kzalloc(&pdev->dev, sizeof(*host), GFP_KERNEL);
+	if (!host)
+		return -ENOMEM;
+
+	host->info = of_device_get_match_data(&pdev->dev);
+
+	if (host->info->has_hypervisor) {
+		host->regs = devm_platform_ioremap_resource_byname(pdev, "vm");
+		if (IS_ERR(host->regs))
+			return PTR_ERR(host->regs);
+
+		host->hv_regs = devm_platform_ioremap_resource_byname(pdev, "hypervisor");
+		if (IS_ERR(host->hv_regs))
+			return PTR_ERR(host->hv_regs);
+
+		if (host->info->has_common) {
+			host->common_regs = devm_platform_ioremap_resource_byname(pdev, "common");
+			if (IS_ERR(host->common_regs))
+				return PTR_ERR(host->common_regs);
+		}
+	} else {
+		host->regs = devm_platform_ioremap_resource(pdev, 0);
+		if (IS_ERR(host->regs))
+			return PTR_ERR(host->regs);
+	}
+
+	host->syncpt_irq = platform_get_irq(pdev, 0);
+	if (host->syncpt_irq < 0)
+		return host->syncpt_irq;
+
+	mutex_init(&host->devices_lock);
+	INIT_LIST_HEAD(&host->devices);
+	INIT_LIST_HEAD(&host->list);
+	host->dev = &pdev->dev;
+
+	/* set common host1x device data */
+	platform_set_drvdata(pdev, host);
+
+	host->dev->dma_parms = &host->dma_parms;
+	dma_set_max_seg_size(host->dev, UINT_MAX);
+
+	if (host->info->init) {
+		err = host->info->init(host);
+		if (err)
+			return err;
+	}
+
+	host->clk = devm_clk_get(&pdev->dev, NULL);
+	if (IS_ERR(host->clk)) {
+		err = PTR_ERR(host->clk);
+
+		if (err != -EPROBE_DEFER)
+			dev_err(&pdev->dev, "failed to get clock: %d\n", err);
+
+		return err;
+	}
+
+	err = host1x_get_resets(host);
+	if (err)
+		return err;
+
+	host1x_bo_cache_init(&host->cache);
+
+	err = host1x_iommu_init(host);
+	if (err < 0) {
+		dev_err(&pdev->dev, "failed to setup IOMMU: %d\n", err);
+		goto destroy_cache;
+	}
+
+	err = host1x_channel_list_init(&host->channel_list,
+				       host->info->nb_channels);
+	if (err) {
+		dev_err(&pdev->dev, "failed to initialize channel list\n");
+		goto iommu_exit;
+	}
+
+	err = host1x_memory_context_list_init(host);
+	if (err) {
+		dev_err(&pdev->dev, "failed to initialize context list\n");
+		goto free_channels;
+	}
+
+	err = host1x_syncpt_init(host);
+	if (err) {
+		dev_err(&pdev->dev, "failed to initialize syncpts\n");
+		goto free_contexts;
+	}
+
+	err = host1x_intr_init(host);
+	if (err) {
+		dev_err(&pdev->dev, "failed to initialize interrupts\n");
+		goto deinit_syncpt;
+	}
+
+	pm_runtime_enable(&pdev->dev);
+
+	err = devm_tegra_core_dev_init_opp_table_common(&pdev->dev);
+	if (err)
+		goto pm_disable;
+
+	/* the driver's code isn't ready yet for the dynamic RPM */
+	err = pm_runtime_resume_and_get(&pdev->dev);
+	if (err)
+		goto pm_disable;
+
+	host1x_debug_init(host);
+
+	err = host1x_register(host);
+	if (err < 0)
+		goto deinit_debugfs;
+
+	err = devm_of_platform_populate(&pdev->dev);
+	if (err < 0)
+		goto unregister;
+
+	return 0;
+
+unregister:
+	host1x_unregister(host);
+deinit_debugfs:
+	host1x_debug_deinit(host);
+
+	pm_runtime_put_sync_suspend(&pdev->dev);
+pm_disable:
+	pm_runtime_disable(&pdev->dev);
+
+	host1x_intr_deinit(host);
+deinit_syncpt:
+	host1x_syncpt_deinit(host);
+free_contexts:
+	host1x_memory_context_list_free(&host->context_list);
+free_channels:
+	host1x_channel_list_free(&host->channel_list);
+iommu_exit:
+	host1x_iommu_exit(host);
+destroy_cache:
+	host1x_bo_cache_destroy(&host->cache);
+
+	return err;
+}
+
+static int host1x_remove(struct platform_device *pdev)
+{
+	struct host1x *host = platform_get_drvdata(pdev);
+
+	host1x_unregister(host);
+	host1x_debug_deinit(host);
+
+	pm_runtime_force_suspend(&pdev->dev);
+
+	host1x_intr_deinit(host);
+	host1x_syncpt_deinit(host);
+	host1x_memory_context_list_free(&host->context_list);
+	host1x_channel_list_free(&host->channel_list);
+	host1x_iommu_exit(host);
+	host1x_bo_cache_destroy(&host->cache);
+
+	return 0;
+}
+
+static int __maybe_unused host1x_runtime_suspend(struct device *dev)
+{
+	struct host1x *host = dev_get_drvdata(dev);
+	int err;
+
+	host1x_intr_stop(host);
+	host1x_syncpt_save(host);
+
+	err = reset_control_bulk_assert(host->nresets, host->resets);
+	if (err) {
+		dev_err(dev, "failed to assert reset: %d\n", err);
+		goto resume_host1x;
+	}
+
+	usleep_range(1000, 2000);
+
+	clk_disable_unprepare(host->clk);
+	reset_control_bulk_release(host->nresets, host->resets);
+
+	return 0;
+
+resume_host1x:
+	host1x_setup_virtualization_tables(host);
+	host1x_syncpt_restore(host);
+	host1x_intr_start(host);
+
+	return err;
+}
+
+static int __maybe_unused host1x_runtime_resume(struct device *dev)
+{
+	struct host1x *host = dev_get_drvdata(dev);
+	int err;
+
+	err = reset_control_bulk_acquire(host->nresets, host->resets);
+	if (err) {
+		dev_err(dev, "failed to acquire reset: %d\n", err);
+		return err;
+	}
+
+	err = clk_prepare_enable(host->clk);
+	if (err) {
+		dev_err(dev, "failed to enable clock: %d\n", err);
+		goto release_reset;
+	}
+
+	err = reset_control_bulk_deassert(host->nresets, host->resets);
+	if (err < 0) {
+		dev_err(dev, "failed to deassert reset: %d\n", err);
+		goto disable_clk;
+	}
+
+	host1x_setup_virtualization_tables(host);
+	host1x_syncpt_restore(host);
+	host1x_intr_start(host);
+
+	return 0;
+
+disable_clk:
+	clk_disable_unprepare(host->clk);
+release_reset:
+	reset_control_bulk_release(host->nresets, host->resets);
+
+	return err;
+}
+
+static const struct dev_pm_ops host1x_pm_ops = {
+	SET_RUNTIME_PM_OPS(host1x_runtime_suspend, host1x_runtime_resume,
+			   NULL)
+	/* TODO: add system suspend-resume once driver will be ready for that */
+};
+
+static struct platform_driver tegra_host1x_driver = {
+	.driver = {
+		.name = "tegra-host1x",
+		.of_match_table = host1x_of_match,
+		.pm = &host1x_pm_ops,
+	},
+	.probe = host1x_probe,
+	.remove = host1x_remove,
+};
+
+static struct platform_driver * const drivers[] = {
+	&tegra_host1x_driver,
+	&tegra_mipi_driver,
+};
+
+static int __init tegra_host1x_init(void)
+{
+	int err;
+
+	err = bus_register(&host1x_bus_type);
+	if (err < 0)
+		return err;
+
+	err = platform_register_drivers(drivers, ARRAY_SIZE(drivers));
+	if (err < 0)
+		bus_unregister(&host1x_bus_type);
+
+	return err;
+}
+module_init(tegra_host1x_init);
+
+static void __exit tegra_host1x_exit(void)
+{
+	platform_unregister_drivers(drivers, ARRAY_SIZE(drivers));
+	bus_unregister(&host1x_bus_type);
+}
+module_exit(tegra_host1x_exit);
+
+/**
+ * host1x_get_dma_mask() - query the supported DMA mask for host1x
+ * @host1x: host1x instance
+ *
+ * Note that this returns the supported DMA mask for host1x, which can be
+ * different from the applicable DMA mask under certain circumstances.
+ */
+u64 host1x_get_dma_mask(struct host1x *host1x)
+{
+	return host1x->info->dma_mask;
+}
+EXPORT_SYMBOL(host1x_get_dma_mask);
+
+MODULE_AUTHOR("Thierry Reding <thierry.reding@avionic-design.de>");
+MODULE_AUTHOR("Terje Bergstrom <tbergstrom@nvidia.com>");
+MODULE_DESCRIPTION("Host1x driver for Tegra products");
+MODULE_LICENSE("GPL");