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Kernel: Restore ATA PIO functionality

Browse source 
First, before this change, specifying 'force_pio' in the kernel
commandline was meaningless because we nevertheless set the DMA flag to
be enabled.

Also, we had a problem in which we used IO::repeated_out16() in PIO
write method. This might work on buggy emulators, but I suspect that on
real hardware this code will fail.

The most difficult problem was to restore the PIO read operation.
Apparently, it seems that we can't use IO::repeated_in16() here because
it will read zeroed data. Currently we rely on a simple loop that
invokes IO::in16() to a buffer. Also, the interrupt handling stage in
the PIO read method is moved to be handled inside the loop of reading
the requested sectors.
This commit is contained in:
Liav A 2020-04-14 22:48:02 +03:00 committed by Andreas Kling
parent 3f698db85d
commit f5090ab810
1 changed files with 47 additions and 35 deletions
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82
Kernel/Devices/PATAChannel.cpp
View file

@ -136,10 +136,9 @@ PATAChannel::PATAChannel(PCI::Address address, ChannelType type, bool force_pio)
{
disable_irq();
m_dma_enabled.resource() = true;
m_dma_enabled.resource() = !force_pio;
ProcFS::add_sys_bool("ide_dma", m_dma_enabled);
m_prdt_page = MM.allocate_supervisor_physical_page();
initialize(force_pio);
detect_disks();
disable_irq();
@ -157,14 +156,15 @@ void PATAChannel::prepare_for_irq()
void PATAChannel::initialize(bool force_pio)
{
PCI::enable_interrupt_line(pci_address());
if (force_pio) {
klog() << "PATAChannel: Requested to force PIO mode; not setting up DMA";
return;
}
// Let's try to set up DMA transfers.
PCI::enable_bus_mastering(pci_address());
PCI::enable_interrupt_line(pci_address());
m_prdt_page = MM.allocate_supervisor_physical_page();
prdt().end_of_table = 0x8000;
m_dma_buffer_page = MM.allocate_supervisor_physical_page();
klog() << "PATAChannel: Bus master IDE: " << m_bus_master_base;
@ -402,57 +402,66 @@ bool PATAChannel::ata_write_sectors_with_dma(u32 lba, u16 count, const u8* inbuf
return true;
}
bool PATAChannel::ata_read_sectors(u32 start_sector, u16 count, u8* outbuf, bool slave_request)
bool PATAChannel::ata_read_sectors(u32 lba, u16 count, u8* outbuf, bool slave_request)
{
ASSERT(count <= 256);
LOCKER(s_lock());
#ifdef PATA_DEBUG
dbg() << "PATAChannel::ata_read_sectors request (" << count << " sector(s) @ " << start_sector << " into " << outbuf << ")";
dbg() << "PATAChannel::ata_read_sectors request (" << count << " sector(s) @ " << lba << " into " << outbuf << ")";
#endif
while (m_io_base.offset(ATA_REG_STATUS).in<u8>() & ATA_SR_BSY)
;
#ifdef PATA_DEBUG
klog() << "PATAChannel: Reading " << count << " sector(s) @ LBA " << start_sector;
klog() << "PATAChannel: Reading " << count << " sector(s) @ LBA " << lba;
#endif
u8 devsel = 0xe0;
if (slave_request)
devsel |= 0x10;
m_io_base.offset(ATA_REG_SECCOUNT0).out<u8>(count == 256 ? 0 : LSB(count));
m_io_base.offset(ATA_REG_LBA0).out<u8>(start_sector & 0xff);
m_io_base.offset(ATA_REG_LBA1).out<u8>((start_sector >> 8) & 0xff);
m_io_base.offset(ATA_REG_LBA2).out<u8>((start_sector >> 16) & 0xff);
m_io_base.offset(ATA_REG_HDDEVSEL).out<u8>(devsel | ((start_sector >> 24) & 0xf));
m_control_base.offset(ATA_CTL_CONTROL).out<u8>(0);
m_io_base.offset(ATA_REG_HDDEVSEL).out<u8>(devsel | (static_cast<u8>(slave_request) << 4) | 0x40);
io_delay();
IO::out8(0x3F6, 0x08);
while (!(m_io_base.offset(ATA_REG_STATUS).in<u8>() & ATA_SR_DRDY))
;
m_io_base.offset(ATA_REG_FEATURES).out<u8>(0);
prepare_for_irq();
m_io_base.offset(ATA_REG_COMMAND).out<u8>(ATA_CMD_READ_PIO);
wait_for_irq();
m_io_base.offset(ATA_REG_SECCOUNT0).out<u8>(0);
m_io_base.offset(ATA_REG_LBA0).out<u8>(0);
m_io_base.offset(ATA_REG_LBA1).out<u8>(0);
m_io_base.offset(ATA_REG_LBA2).out<u8>(0);
if (m_device_error)
return false;
m_io_base.offset(ATA_REG_SECCOUNT0).out<u8>(count);
m_io_base.offset(ATA_REG_LBA0).out<u8>((lba & 0x000000ff) >> 0);
m_io_base.offset(ATA_REG_LBA1).out<u8>((lba & 0x0000ff00) >> 8);
m_io_base.offset(ATA_REG_LBA2).out<u8>((lba & 0x00ff0000) >> 16);
for (int i = 0; i < count; i++) {
io_delay();
while (m_io_base.offset(ATA_REG_STATUS).in<u8>() & ATA_SR_BSY)
;
u8 status = m_io_base.offset(ATA_REG_STATUS).in<u8>();
ASSERT(status & ATA_SR_DRQ);
#ifdef PATA_DEBUG
dbg() << "PATAChannel: Retrieving 512 bytes (part " << i << ") (status=" << String::format("%b", status) << "), outbuf=(" << (outbuf + (512 * i)) << ")...";
#endif
IO::repeated_in16(m_io_base.offset(ATA_REG_DATA).get(), outbuf + (512 * i), 256);
for (;;) {
auto status = m_io_base.offset(ATA_REG_STATUS).in<u8>();
if (!(status & ATA_SR_BSY) && (status & ATA_SR_DRDY))
break;
}
m_io_base.offset(ATA_REG_COMMAND).out<u8>(ATA_CMD_READ_PIO);
for (int i = 0; i < count; i++) {
prepare_for_irq();
wait_for_irq();
if (m_device_error)
return false;
u8 status = m_control_base.offset(ATA_CTL_ALTSTATUS).in<u8>();
ASSERT(!(status & ATA_SR_BSY));
auto* buffer = (u16*)(outbuf + i * 512);
#ifdef PATA_DEBUG
dbg() << "PATAChannel: Retrieving 512 bytes (part " << i << ") (status=" << String::format("%b", status) << "), outbuf=(" << buffer << ")...";
#endif
for (int i = 0; i < 256; i++) {
buffer[i] = IO::in16(m_io_base.offset(ATA_REG_DATA).get());
}
}
return true;
}
@ -489,7 +498,7 @@ bool PATAChannel::ata_write_sectors(u32 start_sector, u16 count, const u8* inbuf
for (int i = 0; i < count; i++) {
io_delay();
while (m_io_base.offset(ATA_REG_STATUS).in<u8>() & ATA_SR_BSY)
while ((m_io_base.offset(ATA_REG_STATUS).in<u8>() & ATA_SR_BSY) || !(m_io_base.offset(ATA_REG_STATUS).in<u8>() & ATA_SR_DRQ))
;
u8 status = m_io_base.offset(ATA_REG_STATUS).in<u8>();
@ -499,7 +508,10 @@ bool PATAChannel::ata_write_sectors(u32 start_sector, u16 count, const u8* inbuf
dbg() << "PATAChannel: Writing 512 bytes (part " << i << ") (status=" << String::format("%b", status) << "), inbuf=(" << (inbuf + (512 * i)) << ")...";
#endif
IO::repeated_out16(m_io_base.offset(ATA_REG_DATA).get(), inbuf + (512 * i), 256);
auto* buffer = (u16*)(const_cast<u8*>(inbuf) + i * 512);
for (int i = 0; i < 256; i++) {
IO::out16(m_io_base.offset(ATA_REG_DATA).get(), buffer[i]);
}
prepare_for_irq();
wait_for_irq();
status = m_io_base.offset(ATA_REG_STATUS).in<u8>();