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SB16: Map the DMA buffer in kernelspace so we can write to it

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This broke with the >3GB paging overhaul. It's no longer possible to
write directly to physical addresses below the 8MB mark. Physical pages
need to be mapped into kernel VM by using a Region.

Fixes #1099.
This commit is contained in:
Andreas Kling 2020-01-20 13:07:29 +01:00
parent a0b716cfc5
commit b52d0afecf
2 changed files with 9 additions and 5 deletions
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12
Kernel/Devices/SB16.cpp
View file

@ -27,6 +27,7 @@
#include <Kernel/Devices/SB16.h>
#include <Kernel/IO.h>
#include <Kernel/Thread.h>
#include <Kernel/VM/AnonymousVMObject.h>
#include <Kernel/VM/MemoryManager.h>
//#define SB16_DEBUG
@ -123,7 +124,7 @@ ssize_t SB16::read(FileDescription&, u8*, ssize_t)
void SB16::dma_start(uint32_t length)
{
const auto addr = m_dma_buffer_page->paddr().get();
const auto addr = m_dma_region->vmobject().physical_pages()[0]->paddr().get();
const u8 channel = 5; // 16-bit samples use DMA channel 5 (on the master DMA controller)
const u8 mode = 0;
@ -174,8 +175,11 @@ void SB16::wait_for_irq()
ssize_t SB16::write(FileDescription&, const u8* data, ssize_t length)
{
if (!m_dma_buffer_page)
m_dma_buffer_page = MM.allocate_supervisor_physical_page();
if (!m_dma_region) {
auto page = MM.allocate_supervisor_physical_page();
auto vmobject = AnonymousVMObject::create_with_physical_page(*page);
m_dma_region = MM.allocate_kernel_region_with_vmobject(*vmobject, PAGE_SIZE, "SB16 DMA buffer", Region::Access::Write);
}
#ifdef SB16_DEBUG
kprintf("SB16: Writing buffer of %d bytes\n", length);
@ -190,7 +194,7 @@ ssize_t SB16::write(FileDescription&, const u8* data, ssize_t length)
const int sample_rate = 44100;
set_sample_rate(sample_rate);
memcpy(m_dma_buffer_page->paddr().as_ptr(), data, length);
memcpy(m_dma_region->vaddr().as_ptr(), data, length);
dma_start(length);
// 16-bit single-cycle output.

2
Kernel/Devices/SB16.h
View file

@ -63,7 +63,7 @@ private:
void dsp_write(u8 value);
u8 dsp_read();
RefPtr<PhysicalPage> m_dma_buffer_page;
OwnPtr<Region> m_dma_region;
int m_major_version { 0 };
WaitQueue m_irq_queue;