Re: hss channellized driver

[Krzysztof Halasa <khc@xxxxxxxxx>]

Hi,

Davide Di Gesualdo <davide.digesualdo@xxxxxxxxxxxxxxxx> writes:

> I'm working on a hss driver for ixdpg425 Intel board; I want to use 
> channellized configuration, and I'd need to know the simplest way to 
> access rx/tx buffer of the device.

I don't know IXDPG HSS hardware. My driver supports channelized mode
for HSS connected directly to the device (no framer, no multiplexing).
It's a bit experimental, though, don't expect stable interface.

Access is through a /dev/hssXchY character device, you'd need to look
at /sys/devices/platform/ixp4xx_hss.*/* files first.

> Moreover, I've seen Krzysztof Halasa's hss driver uses "qmgr_get_entry" 
> in order to get rx_frame and tx_list: what do they exactly are, and how 
> are they used?

HSS signals it's approximate TX and RX position in circular buffers
using the queue. The firmware interface is quite messy and fragile.

> At last, how memory in HSS device is organized? (I mean as for tx/rx 
> buffers).

Circular buffers, every timeslot has 16 or so byte-wide consecutive
buffers. There is also a TX list (also circular) required. For details
see the source.
-- 
Krzysztof Halasa

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