kernel/dev/iommu/intel/domain_allocator.h

// Copyright 2018 The Fuchsia Authors
//
// Use of this source code is governed by a MIT-style
// license that can be found in the LICENSE file or at
// https://opensource.org/licenses/MIT

#pragma once

#include <err.h>
#include <stdint.h>

#include <fbl/macros.h>

namespace intel_iommu {

// Manages the domain ID space for a given IOMMU.  This is not thread-safe.
class DomainAllocator {
public:
    DomainAllocator();

    // Get an unused domain ID.
    // Returns ZX_ERR_NO_RESOURCES if one cannot be found.
    zx_status_t Allocate(uint32_t* domain_id);

    // Set the number of domain IDs this instance manages.  Panics if this call
    // would reduce the max domain ID to below the current highest allocated one.
    void set_num_domains(uint32_t num);

private:
    DISALLOW_COPY_ASSIGN_AND_MOVE(DomainAllocator);

    uint32_t num_domains_;
    uint32_t next_domain_id_;
};

} // namespace intel_iommu