Intel 82550 Switch User Manual


 
10/100 Mbps Ethernet Controller Family Open Source Software Developer Manual 151
Wake-up Functionality
The sequence of events after a Dump Wake-up command that the 82559 performs are:
1. Write the byte count field at Dword 1. This field contains the actual number of bytes posted in
the host memory. A value of FFh indicates that the Wake-up packet length exceeded the 120
bytes. In this case only the first 120 bytes are posted.
2. Write the wake-up packet data starting at Dword 2.
3. Write a status word composed of the Complete OK bits equal to A000h at Dword 0.
Prior to the Dump Wake-up packet command, the driver should first initialize the status word to 0.
After the Dump Wake-up packet command, it should pole the Status word for the Complete bit.
Note: The port dump wake-up packet causes an internal selective reset to the 82559.
Note: The interesting packet bit in the PMDR is set together with the PME status bit when an interesting
packet is received.
Note: The 82559 uses the statistic counters resources to store the wake-up packet. The software driver
should assume that the statistic counters are infected at power down state. Therefore, it should
issue a Dump Reset Statistic Counters command before it resumes nominal operation.
Note: Magic Packets are exceptional to all other wake-up packets. The Magic Packets may cause a power
management event and set an indication bit in the PMDR. However, it is not stored by the 82559
for system use when it is awake. The 82559ER does not support Magic Packet wake up.
A.7.4 Power Management Software Flow
The 82559 adheres to the PCI Power Management Specification supporting all three power states
D0 through D3. This section describes the required flow of events for software to set the 82559 into
the power down states.
A.7.4.1 Power Down without Wake-up Capabilities
The 82559 supports a very low power state if wake-up capabilities are not required. The OS should
follow these steps:
1. Clear the PME enable bit in the PMCSR to the PME disable state.
2. Set the 82559 to the D3 power state (by OS).
Note: Step 2 may be executed together with step 1 (same cycle) but not before. If step 2
is executed before step 1, the 82559 might assert PME# if wake on link status
change is enabled. At this state, the 82559 enters the deep power down state, where
the PHY is turned off. At this state, the 82559 consume less than 7 mA if the PCI
Table 68. Dump Data Structure
Offset D31 D0
0 Reserved Status Word (A000h)
1 Reserved Byte Count
2:N Wake-up Packet