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/*
* Copyright (c) 2020, the SerenityOS developers.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* 1. Redistributions of source code must retain the above copyright notice, this
* list of conditions and the following disclaimer.
*
* 2. Redistributions in binary form must reproduce the above copyright notice,
* this list of conditions and the following disclaimer in the documentation
* and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
* CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include <Kernel/StdLib.h>
#include <Kernel/VirtIO/VirtIOQueue.h>
namespace Kernel {
VirtIOQueue::VirtIOQueue(u16 queue_size, u16 notify_offset)
: m_queue_size(queue_size)
, m_notify_offset(notify_offset)
, m_free_buffers(queue_size)
{
size_t size_of_descriptors = sizeof(VirtIOQueueDescriptor) * queue_size;
size_t size_of_driver = sizeof(VirtIOQueueDriver) + queue_size * sizeof(u16);
size_t size_of_device = sizeof(VirtIOQueueDevice) + queue_size * sizeof(VirtIOQueueDeviceItem);
m_region = MM.allocate_contiguous_kernel_region(page_round_up(size_of_descriptors + size_of_driver + size_of_device), "VirtIO Queue", Region::Access::Read | Region::Access::Write);
if (m_region) {
// TODO: ensure alignment!!!
u8* ptr = m_region->vaddr().as_ptr();
memset(ptr, 0, m_region->size());
m_descriptors = reinterpret_cast<VirtIOQueueDescriptor*>(ptr);
m_driver = reinterpret_cast<VirtIOQueueDriver*>(ptr + size_of_descriptors);
m_device = reinterpret_cast<VirtIOQueueDevice*>(ptr + size_of_descriptors + size_of_driver);
enable_interrupts();
}
}
VirtIOQueue::~VirtIOQueue()
{
}
void VirtIOQueue::enable_interrupts()
{
m_driver->flags = 0;
}
void VirtIOQueue::disable_interrupts()
{
m_driver->flags = 1;
}
bool VirtIOQueue::supply_buffer(const u8* buffer, u32 len, BufferType buffer_type)
{
VERIFY(buffer && len > 0);
VERIFY(m_free_buffers > 0);
auto descriptor_index = m_free_head;
m_descriptors[descriptor_index].flags = static_cast<u16>(buffer_type);
m_descriptors[descriptor_index].address = reinterpret_cast<u64>(buffer);
m_descriptors[descriptor_index].length = len;
m_free_buffers--;
m_free_head = (m_free_head + 1) % m_queue_size;
m_driver->rings[m_driver->index % m_queue_size] = descriptor_index;
full_memory_barrier();
m_driver->index++;
full_memory_barrier();
auto device_flags = m_device->flags;
return !(device_flags & 1); // if bit 1 is enabled the device disabled interrupts
}
bool VirtIOQueue::new_data_available() const
{
return m_device->index != m_used_tail;
}
bool VirtIOQueue::handle_interrupt()
{
if (!new_data_available())
return false;
if (on_data_available)
on_data_available();
return true;
}
}
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