On 08/28/2012 02:18 PM, Oliver Hartkopp wrote:

[...]

quoted

quoted

I found a very interesting implementation in the Bosch M_CAN specification:

http://www.semiconductors.bosch.de/en/ipmodules/can/canipmodules/m_can/m_can.asp

http://www.semiconductors.bosch.de/media/en/pdf/ipmodules_1/m_can/mcan_users_manual.pdf

Section 2.4.3 Tx Buffer Element (page 45)

---8<---

T1 Bits 31:24 MM[7:0]: Message Marker

Written by CPU during Tx Buffer configuration. Copied into Tx Event FIFO
element for identification of Tx message status.

---8<---

So you can see in the Tx event FIFO, which marked CAN frame has been sent.

This is probably enough to provide just a byte and to create an array of
skb pointers which is referenced by this Message Marker. Maybe 256 markers
are too much ... we could only use 8 markers IMO.

Why not a full u32? Then you're free on the driver side to do what you
want with it.

Yes. You're right. It's a marker - and if i personally only want to handle an
index into an array with 8 elements with my driver it's my choice.

ACK :)

Marc

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