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authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-07 18:49:45 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-07 18:49:45 +0000
commit2c3c1048746a4622d8c89a29670120dc8fab93c4 (patch)
tree848558de17fb3008cdf4d861b01ac7781903ce39 /drivers/gpu/host1x/dev.c
parentInitial commit. (diff)
downloadlinux-upstream.tar.xz
linux-upstream.zip
Adding upstream version 6.1.76.upstream/6.1.76upstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to '')
-rw-r--r--drivers/gpu/host1x/dev.c767
1 files changed, 767 insertions, 0 deletions
diff --git a/drivers/gpu/host1x/dev.c b/drivers/gpu/host1x/dev.c
new file mode 100644
index 000000000..f60ea24db
--- /dev/null
+++ b/drivers/gpu/host1x/dev.c
@@ -0,0 +1,767 @@
+// 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_device.h>
+#include <linux/of.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
+ },
+};
+
+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 syncpt_irq;
+ 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);
+ }
+
+ syncpt_irq = platform_get_irq(pdev, 0);
+ if (syncpt_irq < 0)
+ return 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, syncpt_irq);
+ 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");