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https://github.com/RGBCube/serenity
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e445ff670d
This allows issuing asynchronous requests for devices and waiting on the completion of the request. The requests can cascade into multiple sub-requests. Since IRQs may complete at any time, if the current process is no longer the same that started the process, we need to swich the paging context before accessing user buffers. Change the PATA driver to use this model.
100 lines
3.5 KiB
C++
100 lines
3.5 KiB
C++
/*
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* Copyright (c) 2018-2020, Andreas Kling <kling@serenityos.org>
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions are met:
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*
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* 1. Redistributions of source code must retain the above copyright notice, this
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* list of conditions and the following disclaimer.
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*
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* 2. Redistributions in binary form must reproduce the above copyright notice,
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* this list of conditions and the following disclaimer in the documentation
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* and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
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* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
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* DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
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* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
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* CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
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* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
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* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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#pragma once
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// Device is the base class of everything that lives in the /dev directory.
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//
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// To expose a Device to the filesystem, simply pass two unique numbers to the constructor,
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// and then mknod a file in /dev with those numbers.
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//
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// There are two main subclasses:
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// - BlockDevice (random access)
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// - CharacterDevice (sequential)
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#include <AK/DoublyLinkedList.h>
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#include <AK/Function.h>
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#include <AK/HashMap.h>
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#include <Kernel/Devices/AsyncDeviceRequest.h>
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#include <Kernel/FileSystem/File.h>
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#include <Kernel/Lock.h>
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#include <Kernel/UnixTypes.h>
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namespace Kernel {
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class Device : public File {
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public:
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virtual ~Device() override;
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unsigned major() const { return m_major; }
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unsigned minor() const { return m_minor; }
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virtual String absolute_path(const FileDescription&) const override;
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virtual String absolute_path() const;
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uid_t uid() const { return m_uid; }
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uid_t gid() const { return m_gid; }
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virtual bool is_device() const override { return true; }
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virtual bool is_disk_device() const { return false; }
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static void for_each(Function<void(Device&)>);
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static Device* get_device(unsigned major, unsigned minor);
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void process_next_queued_request(Badge<AsyncDeviceRequest>, const AsyncDeviceRequest&);
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template<typename AsyncRequestType, typename... Args>
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NonnullRefPtr<AsyncRequestType> make_request(Args&&... args)
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{
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auto request = adopt(*new AsyncRequestType(*this, forward<Args>(args)...));
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bool was_empty;
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{
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ScopedSpinLock lock(m_requests_lock);
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was_empty = m_requests.is_empty();
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m_requests.append(request);
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}
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if (was_empty)
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request->do_start({});
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return request;
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}
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protected:
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Device(unsigned major, unsigned minor);
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void set_uid(uid_t uid) { m_uid = uid; }
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void set_gid(gid_t gid) { m_gid = gid; }
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static HashMap<u32, Device*>& all_devices();
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private:
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unsigned m_major { 0 };
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unsigned m_minor { 0 };
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uid_t m_uid { 0 };
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gid_t m_gid { 0 };
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SpinLock<u8> m_requests_lock;
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DoublyLinkedList<RefPtr<AsyncDeviceRequest>> m_requests;
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};
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}
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