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Code |
Description |
IOC$K_DIRECT_DMA_BASE
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This is the base address
on the PCI side, or bus address. There is a synonym for this function
code called IOC$K_DDMA_BASE_BA. A 32-bit result will be returned.
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IOC$DIRECT_DMA_SIZE
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On non-Galaxy machines,
this returns the size of the direct-mapped DMA window (in megabytes).
On a system where the direct-mapped DMA window does not start at zero,
the data returned is zero, implying that no direct-mapped DMA windows
exist. A 32-bit result will be returned.
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IOC$K_DDMA_WIN_SIZE
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On all systems, this will
always return the size of the direct-mapped DMA window (in megabytes).
A 32-bit result will be returned.
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IOC$K_DIRECT_DMA_BASE_PA
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This is the base physical address in
memory of the direct-mapped DMA window. A 32-bit result will be returned.
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The address returned with the IOC$K_DIRECT_DMA_BASE_PA code
is necessary to compute the offset. (This usually used to be the
1 GB difference between the memory PA and the bus address.) The
offset is defined as the signed difference between the base bus
address and the base memory address. This is now not necessarily
1 gigabyte.