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Atapi: limit block count in DMA request (fix #514)

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The block count in DMA requests is limited to 8 bit. Therefore,
if a client requests more than 255 blocks in a single packet request,
split the request in a loop.
This commit is contained in:
Stefan Kalkowski 2012-11-22 16:35:05 +01:00 committed by Norman Feske
parent c63a6d94f6
commit 5f81705488
1 changed files with 38 additions and 22 deletions
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60
os/src/drivers/atapi/ata_device.cc
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@ -123,40 +123,56 @@ void Ata::Device::read_capacity()
void Ata::Device::read(unsigned long block_nr,
unsigned long count, off_t offset) {
if (dma_enabled()) {
while (count > 0) {
unsigned long c = count > 255 ? 255 : count;
if (verbose)
PDBG("DMA read: block %lu, count %lu, offset: %08lx, base: %08lx",
block_nr, count, offset, _base_addr);
if (dma_enabled()) {
if (dma_pci_lba28(dev_num(), CMD_READ_DMA, 0, count, block_nr,
(unsigned char *)(_base_addr + offset), count))
throw Io_error();
if (verbose)
PDBG("DMA read: block %lu, c %lu, offset: %08lx, base: %08lx",
block_nr, c, offset, _base_addr);
if (dma_pci_lba28(dev_num(), CMD_READ_DMA, 0, c, block_nr,
(unsigned char *)(_base_addr + offset), c))
throw Io_error();
}
else
if (reg_pio_data_in_lba28(dev_num(), CMD_READ_SECTORS, 0, c, block_nr,
(unsigned char *)(_base_addr + offset), c, 0))
throw Io_error();
count -= c;
block_nr += c;
offset += c * block_size();
}
else
if (reg_pio_data_in_lba28(dev_num(), CMD_READ_SECTORS, 0, count, block_nr,
(unsigned char *)(_base_addr + offset), count, 0))
throw Io_error();
}
void Ata::Device::write(unsigned long block_nr,
unsigned long count, off_t offset) {
if (dma_enabled()) {
while (count > 0) {
unsigned long c = count > 255 ? 255 : count;
if (verbose)
PDBG("DMA read: block %lu, count %lu, offset: %08lx, base: %08lx",
block_nr, count, offset, _base_addr);
if (dma_enabled()) {
if (dma_pci_lba28(dev_num(), CMD_WRITE_DMA, 0, count, block_nr,
(unsigned char *)(_base_addr + offset), count))
throw Io_error();
if (verbose)
PDBG("DMA read: block %lu, c %lu, offset: %08lx, base: %08lx",
block_nr, c, offset, _base_addr);
if (dma_pci_lba28(dev_num(), CMD_WRITE_DMA, 0, c, block_nr,
(unsigned char *)(_base_addr + offset), c))
throw Io_error();
}
else
if (reg_pio_data_out_lba28(dev_num(), CMD_WRITE_SECTORS, 0, c, block_nr,
(unsigned char *)(_base_addr + offset), c, 0))
throw Io_error();
count -= c;
block_nr += c;
offset += c * block_size();
}
else
if (reg_pio_data_out_lba28(dev_num(), CMD_WRITE_SECTORS, 0, count, block_nr,
(unsigned char *)(_base_addr + offset), count, 0))
throw Io_error();
}