Guys, and Gals,

Anyone know how to write a function to initiate a DMA transfer from Network interface such as Intel 100/1000 Gig interface straight to memory? I would be using RHEL 5.1/ a 2.6 kernel.

Any ideas would be helpful.

Mike


08:00.0 Ethernet controller: Intel Corporation 82575EB Gigabit Network Connection (rev 02)
Subsystem: Super Micro Computer Inc Unknown device 10a7
Control: I/O+ Mem+ BusMaster+ SpecCycle- MemWINV- VGASnoop- ParErr- Stepping- SERR- FastB2B-
Status: Cap+ 66MHz- UDF- FastB2B- ParErr- DEVSEL=fast >TAbort- <TAbort- <MAbort- >SERR- <PERR-
Latency: 0, Cache Line Size: 32 bytes
Interrupt: pin A routed to IRQ 201
Region 0: Memory at daa20000 (32-bit, non-prefetchable) [size=128K]
Region 1: Memory at daa00000 (32-bit, non-prefetchable) [size=128K]
Region 2: I/O ports at 2000 [size=32]
Region 3: Memory at daa80000 (32-bit, non-prefetchable) [size=16K]
[virtual] Expansion ROM at c2100000 [disabled] [size=128K]
Capabilities: [40] Power Management version 2
Flags: PMEClk- DSI+ D1- D2- AuxCurrent=0mA PME(D0+,D1-,D2-,D3hot+,D3cold+)
Status: D0 PME-Enable- DSel=0 DScale=1 PME-
Capabilities: [50] Message Signalled Interrupts: 64bit+ Queue=0/0 Enable-
Address: 0000000000000000 Data: 0000
Capabilities: [60] MSI-X: Enable+ Mask- TabSize=10
Vector table: BAR=3 offset=00000000
PBA: BAR=3 offset=00002000
Capabilities: [a0] Express Endpoint IRQ 0
Device: Supported: MaxPayload 256 bytes, PhantFunc 0, ExtTag-
Device: Latency L0s <512ns, L1 <64us
Device: AtnBtn- AtnInd- PwrInd-
Device: Errors: Correctable- Non-Fatal- Fatal- Unsupported-
Device: RlxdOrd+ ExtTag- PhantFunc- AuxPwr- NoSnoop+
Device: MaxPayload 128 bytes, MaxReadReq 512 bytes
Link: Supported Speed 2.5Gb/s, Width x4, ASPM L0s L1, Port 12
Link: Latency L0s <4us, L1 <64us
Link: ASPM Disabled RCB 64 bytes CommClk- ExtSynch-
Link: Speed 2.5Gb/s, Width x4
Capabilities: [100] Advanced Error Reporting
Capabilities: [140] Device Serial Number d0-cf-c3-ff-ff-48-30-00

The kernel driver has to support that capability. If the device is to be a bus master, the device must support it in hardware. If the CPU is to be the bus master, the device's memory must be mapped onto the PCI bus.

Beyond that, you might want to read Linux Device Drivers by Alessandro Rubini and Jonathan Corbet. If you google for it, you will find it online.

Give me something useful! Of course the device can support DMA transfer. Its an Intel e1000. Send me some code that I can use.

Hi,

He did provide you useful information. Read the referenced documentation! Write your own code if your able, we are here to assist but not on demand as you seem to present. You will get more help if you show that you are willing to help yourself.