path: root/drivers/gpu/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);