Specifications

I/O Port 6-65
6.6.5 Hose Errors
Four types of errors affect the hoses:
• Parity errors on the transmitted data/control information
• Illegal packet errors
• FIFO overflow errors
• I/O port internal errors
Parity errors are detected on all Up Hoses and have corresponding CSR er-
ror bits to indicate the failure to the system. Parity errors cause the I/O
port to generate an error interrupt to the appropriate CPU(s) if interrupts
are enabled.
Illegal packet errors indicate that the UPCTL<3:0> field or some other
field in the packet did not contain a valid code for that field even though
UPDATAVAL was asserted and there were no parity errors. An illegal
packet error occurs under the following conditions:
• UPCTL<3:0> contains an illegal packet type code
• Incorrect number of hose cycles occurs for the packet type received.
This is a sequence error.
• Length code for DMA read packets or DMA write packets is illegal.
Overflow errors occur if the I/O port receives a packet across the Up Hose
and the I/O port’s HDR buffers are already full.
I/O port internal errors occur if the I/O port receives a valid packet across
the Up Hose, but the I/O port detects a failure when trying to process the
packet. Internal errors include illegal I/O port controller states and
underflow/overflow of packet counters.