drm/imagination/pvr_vm.c

// SPDX-License-Identifier: GPL-2.0-only OR MIT
/* Copyright (c) 2023 Imagination Technologies Ltd. */

#include "pvr_vm.h"

#include "pvr_device.h"
#include "pvr_drv.h"
#include "pvr_gem.h"
#include "pvr_mmu.h"
#include "pvr_rogue_fwif.h"
#include "pvr_rogue_heap_config.h"

#include <drm/drm_exec.h>
#include <drm/drm_gem.h>
#include <drm/drm_gpuvm.h>

#include <linux/bug.h>
#include <linux/container_of.h>
#include <linux/err.h>
#include <linux/errno.h>
#include <linux/gfp_types.h>
#include <linux/kref.h>
#include <linux/mutex.h>
#include <linux/stddef.h>

/**
 * DOC: Memory context
 *
 * This is the "top level" datatype in the VM code. It's exposed in the public
 * API as an opaque handle.
 */

/**
 * struct pvr_vm_context - Context type used to represent a single VM.
 */
struct pvr_vm_context {
	/**
	 * @pvr_dev: The PowerVR device to which this context is bound.
	 * This binding is immutable for the life of the context.
	 */
	struct pvr_device *pvr_dev;

	/** @mmu_ctx: The context for binding to physical memory. */
	struct pvr_mmu_context *mmu_ctx;

	/** @gpuvm_mgr: GPUVM object associated with this context. */
	struct drm_gpuvm gpuvm_mgr;

	/** @lock: Global lock on this VM. */
	struct mutex lock;

	/**
	 * @fw_mem_ctx_obj: Firmware object representing firmware memory
	 * context.
	 */
	struct pvr_fw_object *fw_mem_ctx_obj;

	/** @ref_count: Reference count of object. */
	struct kref ref_count;

	/**
	 * @dummy_gem: GEM object to enable VM reservation. All private BOs
	 * should use the @dummy_gem.resv and not their own _resv field.
	 */
	struct drm_gem_object dummy_gem;
};

static inline
struct pvr_vm_context *to_pvr_vm_context(struct drm_gpuvm *gpuvm)
{
	return container_of(gpuvm, struct pvr_vm_context, gpuvm_mgr);
}

struct pvr_vm_context *pvr_vm_context_get(struct pvr_vm_context *vm_ctx)
{
	if (vm_ctx)
		kref_get(&vm_ctx->ref_count);

	return vm_ctx;
}

/**
 * pvr_vm_get_page_table_root_addr() - Get the DMA address of the root of the
 *                                     page table structure behind a VM context.
 * @vm_ctx: Target VM context.
 */
dma_addr_t pvr_vm_get_page_table_root_addr(struct pvr_vm_context *vm_ctx)
{
	return pvr_mmu_get_root_table_dma_addr(vm_ctx->mmu_ctx);
}

/**
 * pvr_vm_get_dma_resv() - Expose the dma_resv owned by the VM context.
 * @vm_ctx: Target VM context.
 *
 * This is used to allow private BOs to share a dma_resv for faster fence
 * updates.
 *
 * Returns: The dma_resv pointer.
 */
struct dma_resv *pvr_vm_get_dma_resv(struct pvr_vm_context *vm_ctx)
{
	return vm_ctx->dummy_gem.resv;
}

/**
 * DOC: Memory mappings
 */

/**
 * struct pvr_vm_gpuva - Wrapper type representing a single VM mapping.
 */
struct pvr_vm_gpuva {
	/** @base: The wrapped drm_gpuva object. */
	struct drm_gpuva base;
};

#define to_pvr_vm_gpuva(va) container_of_const(va, struct pvr_vm_gpuva, base)

enum pvr_vm_bind_type {
	PVR_VM_BIND_TYPE_MAP,
	PVR_VM_BIND_TYPE_UNMAP,
};

/**
 * struct pvr_vm_bind_op - Context of a map/unmap operation.
 */
struct pvr_vm_bind_op {
	/** @type: Map or unmap. */
	enum pvr_vm_bind_type type;

	/** @pvr_obj: Object associated with mapping (map only). */
	struct pvr_gem_object *pvr_obj;

	/**
	 * @vm_ctx: VM context where the mapping will be created or destroyed.
	 */
	struct pvr_vm_context *vm_ctx;

	/** @mmu_op_ctx: MMU op context. */
	struct pvr_mmu_op_context *mmu_op_ctx;

	/** @gpuvm_bo: Prealloced wrapped BO for attaching to the gpuvm. */
	struct drm_gpuvm_bo *gpuvm_bo;

	/**
	 * @new_va: Prealloced VA mapping object (init in callback).
	 * Used when creating a mapping.
	 */
	struct pvr_vm_gpuva *new_va;

	/**
	 * @prev_va: Prealloced VA mapping object (init in callback).
	 * Used when a mapping or unmapping operation overlaps an existing
	 * mapping and splits away the beginning into a new mapping.
	 */
	struct pvr_vm_gpuva *prev_va;

	/**
	 * @next_va: Prealloced VA mapping object (init in callback).
	 * Used when a mapping or unmapping operation overlaps an existing
	 * mapping and splits away the end into a new mapping.
	 */
	struct pvr_vm_gpuva *next_va;

	/** @offset: Offset into @pvr_obj to begin mapping from. */
	u64 offset;

	/** @device_addr: Device-virtual address at the start of the mapping. */
	u64 device_addr;

	/** @size: Size of the desired mapping. */
	u64 size;
};

/**
 * pvr_vm_bind_op_exec() - Execute a single bind op.
 * @bind_op: Bind op context.
 *
 * Returns:
 *  * 0 on success,
 *  * Any error code returned by drm_gpuva_sm_map(), drm_gpuva_sm_unmap(), or
 *    a callback function.
 */
static int pvr_vm_bind_op_exec(struct pvr_vm_bind_op *bind_op)
{
	switch (bind_op->type) {
	case PVR_VM_BIND_TYPE_MAP:
		return drm_gpuvm_sm_map(&bind_op->vm_ctx->gpuvm_mgr,
					bind_op, bind_op->device_addr,
					bind_op->size,
					gem_from_pvr_gem(bind_op->pvr_obj),
					bind_op->offset);

	case PVR_VM_BIND_TYPE_UNMAP:
		return drm_gpuvm_sm_unmap(&bind_op->vm_ctx->gpuvm_mgr,
					  bind_op, bind_op->device_addr,
					  bind_op->size);
	}

	/*
	 * This shouldn't happen unless something went wrong
	 * in drm_sched.
	 */
	WARN_ON(1);
	return -EINVAL;
}

static void pvr_vm_bind_op_fini(struct pvr_vm_bind_op *bind_op)
{
	drm_gpuvm_bo_put(bind_op->gpuvm_bo);

	kfree(bind_op->new_va);
	kfree(bind_op->prev_va);
	kfree(bind_op->next_va);

	if (bind_op->pvr_obj)
		pvr_gem_object_put(bind_op->pvr_obj);

	if (bind_op->mmu_op_ctx)
		pvr_mmu_op_context_destroy(bind_op->mmu_op_ctx);
}

static int
pvr_vm_bind_op_map_init(struct pvr_vm_bind_op *bind_op,
			struct pvr_vm_context *vm_ctx,
			struct pvr_gem_object *pvr_obj, u64 offset,
			u64 device_addr, u64 size)
{
	struct drm_gem_object *obj = gem_from_pvr_gem(pvr_obj);
	const bool is_user = vm_ctx != vm_ctx->pvr_dev->kernel_vm_ctx;
	const u64 pvr_obj_size = pvr_gem_object_size(pvr_obj);
	struct sg_table *sgt;
	u64 offset_plus_size;
	int err;

	if (check_add_overflow(offset, size, &offset_plus_size))
		return -EINVAL;

	if (is_user &&
	    !pvr_find_heap_containing(vm_ctx->pvr_dev, device_addr, size)) {
		return -EINVAL;
	}

	if (!pvr_device_addr_and_size_are_valid(vm_ctx, device_addr, size) ||
	    offset & ~PAGE_MASK || size & ~PAGE_MASK ||
	    offset >= pvr_obj_size || offset_plus_size > pvr_obj_size)
		return -EINVAL;

	bind_op->type = PVR_VM_BIND_TYPE_MAP;

	dma_resv_lock(obj->resv, NULL);
	bind_op->gpuvm_bo = drm_gpuvm_bo_obtain(&vm_ctx->gpuvm_mgr, obj);
	dma_resv_unlock(obj->resv);
	if (IS_ERR(bind_op->gpuvm_bo))
		return PTR_ERR(bind_op->gpuvm_bo);

	bind_op->new_va = kzalloc(sizeof(*bind_op->new_va), GFP_KERNEL);
	bind_op->prev_va = kzalloc(sizeof(*bind_op->prev_va), GFP_KERNEL);
	bind_op->next_va = kzalloc(sizeof(*bind_op->next_va), GFP_KERNEL);
	if (!bind_op->new_va || !bind_op->prev_va || !bind_op->next_va) {
		err = -ENOMEM;
		goto err_bind_op_fini;
	}

	/* Pin pages so they're ready for use. */
	sgt = pvr_gem_object_get_pages_sgt(pvr_obj);
	err = PTR_ERR_OR_ZERO(sgt);
	if (err)
		goto err_bind_op_fini;

	bind_op->mmu_op_ctx =
		pvr_mmu_op_context_create(vm_ctx->mmu_ctx, sgt, offset, size);
	err = PTR_ERR_OR_ZERO(bind_op->mmu_op_ctx);
	if (err) {
		bind_op->mmu_op_ctx = NULL;
		goto err_bind_op_fini;
	}

	bind_op->pvr_obj = pvr_obj;
	bind_op->vm_ctx = vm_ctx;
	bind_op->device_addr = device_addr;
	bind_op->size = size;
	bind_op->offset = offset;

	return 0;

err_bind_op_fini:
	pvr_vm_bind_op_fini(bind_op);

	return err;
}

static int
pvr_vm_bind_op_unmap_init(struct pvr_vm_bind_op *bind_op,
			  struct pvr_vm_context *vm_ctx,
			  struct pvr_gem_object *pvr_obj,
			  u64 device_addr, u64 size)
{
	int err;

	if (!pvr_device_addr_and_size_are_valid(vm_ctx, device_addr, size))
		return -EINVAL;

	bind_op->type = PVR_VM_BIND_TYPE_UNMAP;

	bind_op->prev_va = kzalloc(sizeof(*bind_op->prev_va), GFP_KERNEL);
	bind_op->next_va = kzalloc(sizeof(*bind_op->next_va), GFP_KERNEL);
	if (!bind_op->prev_va || !bind_op->next_va) {
		err = -ENOMEM;
		goto err_bind_op_fini;
	}

	bind_op->mmu_op_ctx =
		pvr_mmu_op_context_create(vm_ctx->mmu_ctx, NULL, 0, 0);
	err = PTR_ERR_OR_ZERO(bind_op->mmu_op_ctx);
	if (err) {
		bind_op->mmu_op_ctx = NULL;
		goto err_bind_op_fini;
	}

	bind_op->pvr_obj = pvr_obj;
	bind_op->vm_ctx = vm_ctx;
	bind_op->device_addr = device_addr;
	bind_op->size = size;

	return 0;

err_bind_op_fini:
	pvr_vm_bind_op_fini(bind_op);

	return err;
}

/**
 * pvr_vm_gpuva_map() - Insert a mapping into a memory context.
 * @op: gpuva op containing the remap details.
 * @op_ctx: Operation context.
 *
 * Context: Called by drm_gpuvm_sm_map following a successful mapping while
 * @op_ctx.vm_ctx mutex is held.
 *
 * Return:
 *  * 0 on success, or
 *  * Any error returned by pvr_mmu_map().
 */
static int
pvr_vm_gpuva_map(struct drm_gpuva_op *op, void *op_ctx)
{
	struct pvr_gem_object *pvr_gem = gem_to_pvr_gem(op->map.gem.obj);
	struct pvr_vm_bind_op *ctx = op_ctx;
	int err;

	if ((op->map.gem.offset | op->map.va.range) & ~PVR_DEVICE_PAGE_MASK)
		return -EINVAL;

	err = pvr_mmu_map(ctx->mmu_op_ctx, op->map.va.range, pvr_gem->flags,
			  op->map.va.addr);
	if (err)
		return err;

	drm_gpuva_map(&ctx->vm_ctx->gpuvm_mgr, &ctx->new_va->base, &op->map);
	drm_gpuva_link(&ctx->new_va->base, ctx->gpuvm_bo);
	ctx->new_va = NULL;

	return 0;
}

/**
 * pvr_vm_gpuva_unmap() - Remove a mapping from a memory context.
 * @op: gpuva op containing the unmap details.
 * @op_ctx: Operation context.
 *
 * Context: Called by drm_gpuvm_sm_unmap following a successful unmapping while
 * @op_ctx.vm_ctx mutex is held.
 *
 * Return:
 *  * 0 on success, or
 *  * Any error returned by pvr_mmu_unmap().
 */
static int
pvr_vm_gpuva_unmap(struct drm_gpuva_op *op, void *op_ctx)
{
	struct pvr_vm_bind_op *ctx = op_ctx;

	int err = pvr_mmu_unmap(ctx->mmu_op_ctx, op->unmap.va->va.addr,
				op->unmap.va->va.range);

	if (err)
		return err;

	drm_gpuva_unmap(&op->unmap);
	drm_gpuva_unlink(op->unmap.va);
	kfree(to_pvr_vm_gpuva(op->unmap.va));

	return 0;
}

/**
 * pvr_vm_gpuva_remap() - Remap a mapping within a memory context.
 * @op: gpuva op containing the remap details.
 * @op_ctx: Operation context.
 *
 * Context: Called by either drm_gpuvm_sm_map or drm_gpuvm_sm_unmap when a
 * mapping or unmapping operation causes a region to be split. The
 * @op_ctx.vm_ctx mutex is held.
 *
 * Return:
 *  * 0 on success, or
 *  * Any error returned by pvr_vm_gpuva_unmap() or pvr_vm_gpuva_unmap().
 */
static int
pvr_vm_gpuva_remap(struct drm_gpuva_op *op, void *op_ctx)
{
	struct pvr_vm_bind_op *ctx = op_ctx;
	u64 va_start = 0, va_range = 0;
	int err;

	drm_gpuva_op_remap_to_unmap_range(&op->remap, &va_start, &va_range);
	err = pvr_mmu_unmap(ctx->mmu_op_ctx, va_start, va_range);
	if (err)
		return err;

	/* No actual remap required: the page table tree depth is fixed to 3,
	 * and we use 4k page table entries only for now.
	 */
	drm_gpuva_remap(&ctx->prev_va->base, &ctx->next_va->base, &op->remap);

	if (op->remap.prev) {
		pvr_gem_object_get(gem_to_pvr_gem(ctx->prev_va->base.gem.obj));
		drm_gpuva_link(&ctx->prev_va->base, ctx->gpuvm_bo);
		ctx->prev_va = NULL;
	}

	if (op->remap.next) {
		pvr_gem_object_get(gem_to_pvr_gem(ctx->next_va->base.gem.obj));
		drm_gpuva_link(&ctx->next_va->base, ctx->gpuvm_bo);
		ctx->next_va = NULL;
	}

	drm_gpuva_unlink(op->remap.unmap->va);
	kfree(to_pvr_vm_gpuva(op->remap.unmap->va));

	return 0;
}

/*
 * Public API
 *
 * For an overview of these functions, see *DOC: Public API* in "pvr_vm.h".
 */

/**
 * pvr_device_addr_is_valid() - Tests whether a device-virtual address
 *                              is valid.
 * @device_addr: Virtual device address to test.
 *
 * Return:
 *  * %true if @device_addr is within the valid range for a device page
 *    table and is aligned to the device page size, or
 *  * %false otherwise.
 */
bool
pvr_device_addr_is_valid(u64 device_addr)
{
	return (device_addr & ~PVR_PAGE_TABLE_ADDR_MASK) == 0 &&
	       (device_addr & ~PVR_DEVICE_PAGE_MASK) == 0;
}

/**
 * pvr_device_addr_and_size_are_valid() - Tests whether a device-virtual
 * address and associated size are both valid.
 * @vm_ctx: Target VM context.
 * @device_addr: Virtual device address to test.
 * @size: Size of the range based at @device_addr to test.
 *
 * Calling pvr_device_addr_is_valid() twice (once on @size, and again on
 * @device_addr + @size) to verify a device-virtual address range initially
 * seems intuitive, but it produces a false-negative when the address range
 * is right at the end of device-virtual address space.
 *
 * This function catches that corner case, as well as checking that
 * @size is non-zero.
 *
 * Return:
 *  * %true if @device_addr is device page aligned; @size is device page
 *    aligned; the range specified by @device_addr and @size is within the
 *    bounds of the device-virtual address space, and @size is non-zero, or
 *  * %false otherwise.
 */
bool
pvr_device_addr_and_size_are_valid(struct pvr_vm_context *vm_ctx,
				   u64 device_addr, u64 size)
{
	return pvr_device_addr_is_valid(device_addr) &&
	       drm_gpuvm_range_valid(&vm_ctx->gpuvm_mgr, device_addr, size) &&
	       size != 0 && (size & ~PVR_DEVICE_PAGE_MASK) == 0 &&
	       (device_addr + size <= PVR_PAGE_TABLE_ADDR_SPACE_SIZE);
}

static void pvr_gpuvm_free(struct drm_gpuvm *gpuvm)
{
	kfree(to_pvr_vm_context(gpuvm));
}

static const struct drm_gpuvm_ops pvr_vm_gpuva_ops = {
	.vm_free = pvr_gpuvm_free,
	.sm_step_map = pvr_vm_gpuva_map,
	.sm_step_remap = pvr_vm_gpuva_remap,
	.sm_step_unmap = pvr_vm_gpuva_unmap,
};

static void
fw_mem_context_init(void *cpu_ptr, void *priv)
{
	struct rogue_fwif_fwmemcontext *fw_mem_ctx = cpu_ptr;
	struct pvr_vm_context *vm_ctx = priv;

	fw_mem_ctx->pc_dev_paddr = pvr_vm_get_page_table_root_addr(vm_ctx);
	fw_mem_ctx->page_cat_base_reg_set = ROGUE_FW_BIF_INVALID_PCSET;
}

/**
 * pvr_vm_create_context() - Create a new VM context.
 * @pvr_dev: Target PowerVR device.
 * @is_userspace_context: %true if this context is for userspace. This will
 *                        create a firmware memory context for the VM context
 *                        and disable warnings when tearing down mappings.
 *
 * Return:
 *  * A handle to the newly-minted VM context on success,
 *  * -%EINVAL if the feature "virtual address space bits" on @pvr_dev is
 *    missing or has an unsupported value,
 *  * -%ENOMEM if allocation of the structure behind the opaque handle fails,
 *    or
 *  * Any error encountered while setting up internal structures.
 */
struct pvr_vm_context *
pvr_vm_create_context(struct pvr_device *pvr_dev, bool is_userspace_context)
{
	struct drm_device *drm_dev = from_pvr_device(pvr_dev);

	struct pvr_vm_context *vm_ctx;
	u16 device_addr_bits;

	int err;

	err = PVR_FEATURE_VALUE(pvr_dev, virtual_address_space_bits,
				&device_addr_bits);
	if (err) {
		drm_err(drm_dev,
			"Failed to get device virtual address space bits\n");
		return ERR_PTR(err);
	}

	if (device_addr_bits != PVR_PAGE_TABLE_ADDR_BITS) {
		drm_err(drm_dev,
			"Device has unsupported virtual address space size\n");
		return ERR_PTR(-EINVAL);
	}

	vm_ctx = kzalloc(sizeof(*vm_ctx), GFP_KERNEL);
	if (!vm_ctx)
		return ERR_PTR(-ENOMEM);

	vm_ctx->pvr_dev = pvr_dev;

	vm_ctx->mmu_ctx = pvr_mmu_context_create(pvr_dev);
	err = PTR_ERR_OR_ZERO(vm_ctx->mmu_ctx);
	if (err)
		goto err_free;

	if (is_userspace_context) {
		err = pvr_fw_object_create(pvr_dev, sizeof(struct rogue_fwif_fwmemcontext),
					   PVR_BO_FW_FLAGS_DEVICE_UNCACHED,
					   fw_mem_context_init, vm_ctx, &vm_ctx->fw_mem_ctx_obj);

		if (err)
			goto err_page_table_destroy;
	}

	drm_gem_private_object_init(&pvr_dev->base, &vm_ctx->dummy_gem, 0);
	drm_gpuvm_init(&vm_ctx->gpuvm_mgr,
		       is_userspace_context ? "PowerVR-user-VM" : "PowerVR-FW-VM",
		       0, &pvr_dev->base, &vm_ctx->dummy_gem,
		       0, 1ULL << device_addr_bits, 0, 0, &pvr_vm_gpuva_ops);

	mutex_init(&vm_ctx->lock);
	kref_init(&vm_ctx->ref_count);

	return vm_ctx;

err_page_table_destroy:
	pvr_mmu_context_destroy(vm_ctx->mmu_ctx);

err_free:
	kfree(vm_ctx);

	return ERR_PTR(err);
}

/**
 * pvr_vm_context_release() - Teardown a VM context.
 * @ref_count: Pointer to reference counter of the VM context.
 *
 * This function also ensures that no mappings are left dangling by calling
 * pvr_vm_unmap_all.
 */
static void
pvr_vm_context_release(struct kref *ref_count)
{
	struct pvr_vm_context *vm_ctx =
		container_of(ref_count, struct pvr_vm_context, ref_count);

	if (vm_ctx->fw_mem_ctx_obj)
		pvr_fw_object_destroy(vm_ctx->fw_mem_ctx_obj);

	pvr_vm_unmap_all(vm_ctx);

	pvr_mmu_context_destroy(vm_ctx->mmu_ctx);
	drm_gem_private_object_fini(&vm_ctx->dummy_gem);
	mutex_destroy(&vm_ctx->lock);

	drm_gpuvm_put(&vm_ctx->gpuvm_mgr);
}

/**
 * pvr_vm_context_lookup() - Look up VM context from handle
 * @pvr_file: Pointer to pvr_file structure.
 * @handle: Object handle.
 *
 * Takes reference on VM context object. Call pvr_vm_context_put() to release.
 *
 * Returns:
 *  * The requested object on success, or
 *  * %NULL on failure (object does not exist in list, or is not a VM context)
 */
struct pvr_vm_context *
pvr_vm_context_lookup(struct pvr_file *pvr_file, u32 handle)
{
	struct pvr_vm_context *vm_ctx;

	xa_lock(&pvr_file->vm_ctx_handles);
	vm_ctx = xa_load(&pvr_file->vm_ctx_handles, handle);
	pvr_vm_context_get(vm_ctx);
	xa_unlock(&pvr_file->vm_ctx_handles);

	return vm_ctx;
}

/**
 * pvr_vm_context_put() - Release a reference on a VM context
 * @vm_ctx: Target VM context.
 *
 * Returns:
 *  * %true if the VM context was destroyed, or
 *  * %false if there are any references still remaining.
 */
bool
pvr_vm_context_put(struct pvr_vm_context *vm_ctx)
{
	if (vm_ctx)
		return kref_put(&vm_ctx->ref_count, pvr_vm_context_release);

	return true;
}

/**
 * pvr_destroy_vm_contexts_for_file: Destroy any VM contexts associated with the
 * given file.
 * @pvr_file: Pointer to pvr_file structure.
 *
 * Removes all vm_contexts associated with @pvr_file from the device VM context
 * list and drops initial references. vm_contexts will then be destroyed once
 * all outstanding references are dropped.
 */
void pvr_destroy_vm_contexts_for_file(struct pvr_file *pvr_file)
{
	struct pvr_vm_context *vm_ctx;
	unsigned long handle;

	xa_for_each(&pvr_file->vm_ctx_handles, handle, vm_ctx) {
		/* vm_ctx is not used here because that would create a race with xa_erase */
		pvr_vm_context_put(xa_erase(&pvr_file->vm_ctx_handles, handle));
	}
}

static int
pvr_vm_lock_extra(struct drm_gpuvm_exec *vm_exec)
{
	struct pvr_vm_bind_op *bind_op = vm_exec->extra.priv;
	struct pvr_gem_object *pvr_obj = bind_op->pvr_obj;

	/* Acquire lock on the GEM object being mapped/unmapped. */
	return drm_exec_lock_obj(&vm_exec->exec, gem_from_pvr_gem(pvr_obj));
}

/**
 * pvr_vm_map() - Map a section of physical memory into a section of
 * device-virtual memory.
 * @vm_ctx: Target VM context.
 * @pvr_obj: Target PowerVR memory object.
 * @pvr_obj_offset: Offset into @pvr_obj to map from.
 * @device_addr: Virtual device address at the start of the requested mapping.
 * @size: Size of the requested mapping.
 *
 * No handle is returned to represent the mapping. Instead, callers should
 * remember @device_addr and use that as a handle.
 *
 * Return:
 *  * 0 on success,
 *  * -%EINVAL if @device_addr is not a valid page-aligned device-virtual
 *    address; the region specified by @pvr_obj_offset and @size does not fall
 *    entirely within @pvr_obj, or any part of the specified region of @pvr_obj
 *    is not device-virtual page-aligned,
 *  * Any error encountered while performing internal operations required to
 *    destroy the mapping (returned from pvr_vm_gpuva_map or
 *    pvr_vm_gpuva_remap).
 */
int
pvr_vm_map(struct pvr_vm_context *vm_ctx, struct pvr_gem_object *pvr_obj,
	   u64 pvr_obj_offset, u64 device_addr, u64 size)
{
	struct pvr_vm_bind_op bind_op = {0};
	struct drm_gpuvm_exec vm_exec = {
		.vm = &vm_ctx->gpuvm_mgr,
		.flags = DRM_EXEC_INTERRUPTIBLE_WAIT |
			 DRM_EXEC_IGNORE_DUPLICATES,
		.extra = {
			.fn = pvr_vm_lock_extra,
			.priv = &bind_op,
		},
	};

	int err = pvr_vm_bind_op_map_init(&bind_op, vm_ctx, pvr_obj,
					  pvr_obj_offset, device_addr,
					  size);

	if (err)
		return err;

	pvr_gem_object_get(pvr_obj);

	err = drm_gpuvm_exec_lock(&vm_exec);
	if (err)
		goto err_cleanup;

	err = pvr_vm_bind_op_exec(&bind_op);

	drm_gpuvm_exec_unlock(&vm_exec);

err_cleanup:
	pvr_vm_bind_op_fini(&bind_op);

	return err;
}

/**
 * pvr_vm_unmap_obj_locked() - Unmap an already mapped section of device-virtual
 * memory.
 * @vm_ctx: Target VM context.
 * @pvr_obj: Target PowerVR memory object.
 * @device_addr: Virtual device address at the start of the target mapping.
 * @size: Size of the target mapping.
 *
 * Return:
 *  * 0 on success,
 *  * -%EINVAL if @device_addr is not a valid page-aligned device-virtual
 *    address,
 *  * Any error encountered while performing internal operations required to
 *    destroy the mapping (returned from pvr_vm_gpuva_unmap or
 *    pvr_vm_gpuva_remap).
 *
 * The vm_ctx->lock must be held when calling this function.
 */
static int
pvr_vm_unmap_obj_locked(struct pvr_vm_context *vm_ctx,
			struct pvr_gem_object *pvr_obj,
			u64 device_addr, u64 size)
{
	struct pvr_vm_bind_op bind_op = {0};
	struct drm_gpuvm_exec vm_exec = {
		.vm = &vm_ctx->gpuvm_mgr,
		.flags = DRM_EXEC_INTERRUPTIBLE_WAIT |
			 DRM_EXEC_IGNORE_DUPLICATES,
		.extra = {
			.fn = pvr_vm_lock_extra,
			.priv = &bind_op,
		},
	};

	int err = pvr_vm_bind_op_unmap_init(&bind_op, vm_ctx, pvr_obj,
					    device_addr, size);
	if (err)
		return err;

	pvr_gem_object_get(pvr_obj);

	err = drm_gpuvm_exec_lock(&vm_exec);
	if (err)
		goto err_cleanup;

	err = pvr_vm_bind_op_exec(&bind_op);

	drm_gpuvm_exec_unlock(&vm_exec);

err_cleanup:
	pvr_vm_bind_op_fini(&bind_op);

	return err;
}

/**
 * pvr_vm_unmap_obj() - Unmap an already mapped section of device-virtual
 * memory.
 * @vm_ctx: Target VM context.
 * @pvr_obj: Target PowerVR memory object.
 * @device_addr: Virtual device address at the start of the target mapping.
 * @size: Size of the target mapping.
 *
 * Return:
 *  * 0 on success,
 *  * Any error encountered by pvr_vm_unmap_obj_locked.
 */
int
pvr_vm_unmap_obj(struct pvr_vm_context *vm_ctx, struct pvr_gem_object *pvr_obj,
		 u64 device_addr, u64 size)
{
	int err;

	mutex_lock(&vm_ctx->lock);
	err = pvr_vm_unmap_obj_locked(vm_ctx, pvr_obj, device_addr, size);
	mutex_unlock(&vm_ctx->lock);

	return err;
}

/**
 * pvr_vm_unmap() - Unmap an already mapped section of device-virtual memory.
 * @vm_ctx: Target VM context.
 * @device_addr: Virtual device address at the start of the target mapping.
 * @size: Size of the target mapping.
 *
 * Return:
 *  * 0 on success,
 *  * Any error encountered by drm_gpuva_find,
 *  * Any error encountered by pvr_vm_unmap_obj_locked.
 */
int
pvr_vm_unmap(struct pvr_vm_context *vm_ctx, u64 device_addr, u64 size)
{
	struct pvr_gem_object *pvr_obj;
	struct drm_gpuva *va;
	int err;

	mutex_lock(&vm_ctx->lock);

	va = drm_gpuva_find(&vm_ctx->gpuvm_mgr, device_addr, size);
	if (va) {
		pvr_obj = gem_to_pvr_gem(va->gem.obj);
		err = pvr_vm_unmap_obj_locked(vm_ctx, pvr_obj,
					      va->va.addr, va->va.range);
	} else {
		err = -ENOENT;
	}

	mutex_unlock(&vm_ctx->lock);

	return err;
}

/**
 * pvr_vm_unmap_all() - Unmap all mappings associated with a VM context.
 * @vm_ctx: Target VM context.
 *
 * This function ensures that no mappings are left dangling by unmapping them
 * all in order of ascending device-virtual address.
 */
void
pvr_vm_unmap_all(struct pvr_vm_context *vm_ctx)
{
	mutex_lock(&vm_ctx->lock);

	for (;;) {
		struct pvr_gem_object *pvr_obj;
		struct drm_gpuva *va;

		va = drm_gpuva_find_first(&vm_ctx->gpuvm_mgr,
					  vm_ctx->gpuvm_mgr.mm_start,
					  vm_ctx->gpuvm_mgr.mm_range);
		if (!va)
			break;

		pvr_obj = gem_to_pvr_gem(va->gem.obj);

		WARN_ON(pvr_vm_unmap_obj_locked(vm_ctx, pvr_obj,
						va->va.addr, va->va.range));
	}

	mutex_unlock(&vm_ctx->lock);
}

/* Static data areas are determined by firmware. */
static const struct drm_pvr_static_data_area static_data_areas[] = {
	{
		.area_usage = DRM_PVR_STATIC_DATA_AREA_FENCE,
		.location_heap_id = DRM_PVR_HEAP_GENERAL,
		.offset = 0,
		.size = 128,
	},
	{
		.area_usage = DRM_PVR_STATIC_DATA_AREA_YUV_CSC,
		.location_heap_id = DRM_PVR_HEAP_GENERAL,
		.offset = 128,
		.size = 1024,
	},
	{
		.area_usage = DRM_PVR_STATIC_DATA_AREA_VDM_SYNC,
		.location_heap_id = DRM_PVR_HEAP_PDS_CODE_DATA,
		.offset = 0,
		.size = 128,
	},
	{
		.area_usage = DRM_PVR_STATIC_DATA_AREA_EOT,
		.location_heap_id = DRM_PVR_HEAP_PDS_CODE_DATA,
		.offset = 128,
		.size = 128,
	},
	{
		.area_usage = DRM_PVR_STATIC_DATA_AREA_VDM_SYNC,
		.location_heap_id = DRM_PVR_HEAP_USC_CODE,
		.offset = 0,
		.size = 128,
	},
};

#define GET_RESERVED_SIZE(last_offset, last_size) round_up((last_offset) + (last_size), PAGE_SIZE)

/*
 * The values given to GET_RESERVED_SIZE() are taken from the last entry in the corresponding
 * static data area for each heap.
 */
static const struct drm_pvr_heap pvr_heaps[] = {
	[DRM_PVR_HEAP_GENERAL] = {
		.base = ROGUE_GENERAL_HEAP_BASE,
		.size = ROGUE_GENERAL_HEAP_SIZE,
		.flags = 0,
		.page_size_log2 = PVR_DEVICE_PAGE_SHIFT,
	},
	[DRM_PVR_HEAP_PDS_CODE_DATA] = {
		.base = ROGUE_PDSCODEDATA_HEAP_BASE,
		.size = ROGUE_PDSCODEDATA_HEAP_SIZE,
		.flags = 0,
		.page_size_log2 = PVR_DEVICE_PAGE_SHIFT,
	},
	[DRM_PVR_HEAP_USC_CODE] = {
		.base = ROGUE_USCCODE_HEAP_BASE,
		.size = ROGUE_USCCODE_HEAP_SIZE,
		.flags = 0,
		.page_size_log2 = PVR_DEVICE_PAGE_SHIFT,
	},
	[DRM_PVR_HEAP_RGNHDR] = {
		.base = ROGUE_RGNHDR_HEAP_BASE,
		.size = ROGUE_RGNHDR_HEAP_SIZE,
		.flags = 0,
		.page_size_log2 = PVR_DEVICE_PAGE_SHIFT,
	},
	[DRM_PVR_HEAP_VIS_TEST] = {
		.base = ROGUE_VISTEST_HEAP_BASE,
		.size = ROGUE_VISTEST_HEAP_SIZE,
		.flags = 0,
		.page_size_log2 = PVR_DEVICE_PAGE_SHIFT,
	},
	[DRM_PVR_HEAP_TRANSFER_FRAG] = {
		.base = ROGUE_TRANSFER_FRAG_HEAP_BASE,
		.size = ROGUE_TRANSFER_FRAG_HEAP_SIZE,
		.flags = 0,
		.page_size_log2 = PVR_DEVICE_PAGE_SHIFT,
	},
};

int
pvr_static_data_areas_get(const struct pvr_device *pvr_dev,
			  struct drm_pvr_ioctl_dev_query_args *args)
{
	struct drm_pvr_dev_query_static_data_areas query = {0};
	int err;

	if (!args->pointer) {
		args->size = sizeof(struct drm_pvr_dev_query_static_data_areas);
		return 0;
	}

	err = PVR_UOBJ_GET(query, args->size, args->pointer);
	if (err < 0)
		return err;

	if (!query.static_data_areas.array) {
		query.static_data_areas.count = ARRAY_SIZE(static_data_areas);
		query.static_data_areas.stride = sizeof(struct drm_pvr_static_data_area);
		goto copy_out;
	}

	if (query.static_data_areas.count > ARRAY_SIZE(static_data_areas))
		query.static_data_areas.count = ARRAY_SIZE(static_data_areas);

	err = PVR_UOBJ_SET_ARRAY(&query.static_data_areas, static_data_areas);
	if (err < 0)
		return err;

copy_out:
	err = PVR_UOBJ_SET(args->pointer, args->size, query);
	if (err < 0)
		return err;

	args->size = sizeof(query);
	return 0;
}

int
pvr_heap_info_get(const struct pvr_device *pvr_dev,
		  struct drm_pvr_ioctl_dev_query_args *args)
{
	struct drm_pvr_dev_query_heap_info query = {0};
	u64 dest;
	int err;

	if (!args->pointer) {
		args->size = sizeof(struct drm_pvr_dev_query_heap_info);
		return 0;
	}

	err = PVR_UOBJ_GET(query, args->size, args->pointer);
	if (err < 0)
		return err;

	if (!query.heaps.array) {
		query.heaps.count = ARRAY_SIZE(pvr_heaps);
		query.heaps.stride = sizeof(struct drm_pvr_heap);
		goto copy_out;
	}

	if (query.heaps.count > ARRAY_SIZE(pvr_heaps))
		query.heaps.count = ARRAY_SIZE(pvr_heaps);

	/* Region header heap is only present if BRN63142 is present. */
	dest = query.heaps.array;
	for (size_t i = 0; i < query.heaps.count; i++) {
		struct drm_pvr_heap heap = pvr_heaps[i];

		if (i == DRM_PVR_HEAP_RGNHDR && !PVR_HAS_QUIRK(pvr_dev, 63142))
			heap.size = 0;

		err = PVR_UOBJ_SET(dest, query.heaps.stride, heap);
		if (err < 0)
			return err;

		dest += query.heaps.stride;
	}

copy_out:
	err = PVR_UOBJ_SET(args->pointer, args->size, query);
	if (err < 0)
		return err;

	args->size = sizeof(query);
	return 0;
}

/**
 * pvr_heap_contains_range() - Determine if a given heap contains the specified
 *                             device-virtual address range.
 * @pvr_heap: Target heap.
 * @start: Inclusive start of the target range.
 * @end: Inclusive end of the target range.
 *
 * It is an error to call this function with values of @start and @end that do
 * not satisfy the condition @start <= @end.
 */
static __always_inline bool
pvr_heap_contains_range(const struct drm_pvr_heap *pvr_heap, u64 start, u64 end)
{
	return pvr_heap->base <= start && end < pvr_heap->base + pvr_heap->size;
}

/**
 * pvr_find_heap_containing() - Find a heap which contains the specified
 *                              device-virtual address range.
 * @pvr_dev: Target PowerVR device.
 * @start: Start of the target range.
 * @size: Size of the target range.
 *
 * Return:
 *  * A pointer to a constant instance of struct drm_pvr_heap representing the
 *    heap containing the entire range specified by @start and @size on
 *    success, or
 *  * %NULL if no such heap exists.
 */
const struct drm_pvr_heap *
pvr_find_heap_containing(struct pvr_device *pvr_dev, u64 start, u64 size)
{
	u64 end;

	if (check_add_overflow(start, size - 1, &end))
		return NULL;

	/*
	 * There are no guarantees about the order of address ranges in
	 * &pvr_heaps, so iterate over the entire array for a heap whose
	 * range completely encompasses the given range.
	 */
	for (u32 heap_id = 0; heap_id < ARRAY_SIZE(pvr_heaps); heap_id++) {
		/* Filter heaps that present only with an associated quirk */
		if (heap_id == DRM_PVR_HEAP_RGNHDR &&
		    !PVR_HAS_QUIRK(pvr_dev, 63142)) {
			continue;
		}

		if (pvr_heap_contains_range(&pvr_heaps[heap_id], start, end))
			return &pvr_heaps[heap_id];
	}

	return NULL;
}

/**
 * pvr_vm_find_gem_object() - Look up a buffer object from a given
 *                            device-virtual address.
 * @vm_ctx: [IN] Target VM context.
 * @device_addr: [IN] Virtual device address at the start of the required
 *               object.
 * @mapped_offset_out: [OUT] Pointer to location to write offset of the start
 *                     of the mapped region within the buffer object. May be
 *                     %NULL if this information is not required.
 * @mapped_size_out: [OUT] Pointer to location to write size of the mapped
 *                   region. May be %NULL if this information is not required.
 *
 * If successful, a reference will be taken on the buffer object. The caller
 * must drop the reference with pvr_gem_object_put().
 *
 * Return:
 *  * The PowerVR buffer object mapped at @device_addr if one exists, or
 *  * %NULL otherwise.
 */
struct pvr_gem_object *
pvr_vm_find_gem_object(struct pvr_vm_context *vm_ctx, u64 device_addr,
		       u64 *mapped_offset_out, u64 *mapped_size_out)
{
	struct pvr_gem_object *pvr_obj;
	struct drm_gpuva *va;

	mutex_lock(&vm_ctx->lock);

	va = drm_gpuva_find_first(&vm_ctx->gpuvm_mgr, device_addr, 1);
	if (!va)
		goto err_unlock;

	pvr_obj = gem_to_pvr_gem(va->gem.obj);
	pvr_gem_object_get(pvr_obj);

	if (mapped_offset_out)
		*mapped_offset_out = va->gem.offset;
	if (mapped_size_out)
		*mapped_size_out = va->va.range;

	mutex_unlock(&vm_ctx->lock);

	return pvr_obj;

err_unlock:
	mutex_unlock(&vm_ctx->lock);

	return NULL;
}

/**
 * pvr_vm_get_fw_mem_context: Get object representing firmware memory context
 * @vm_ctx: Target VM context.
 *
 * Returns:
 *  * FW object representing firmware memory context, or
 *  * %NULL if this VM context does not have a firmware memory context.
 */
struct pvr_fw_object *
pvr_vm_get_fw_mem_context(struct pvr_vm_context *vm_ctx)
{
	return vm_ctx->fw_mem_ctx_obj;
}