Change in osmo-bsc[master]: om2k: Fix the frequency specifier for TX/RX/TS conf requests

[tnt]

Hello pespin, Jenkins Builder, 

I'd like you to reexamine a change. Please visit

    https://gerrit.osmocom.org/c/osmo-bsc/+/18119

to look at the new patch set (#3).

Change subject: om2k: Fix the frequency specifier for TX/RX/TS conf requests
......................................................................

om2k: Fix the frequency specifier for TX/RX/TS conf requests

* OM2K_DEI_FREQ_SPEC_RX:

  (hop << 15) | (rx_addr << 10) | arfcn

  . hop     Hopping marker
  . rx_addr is not really the TRX number, it's just a sequential number
            different for all TRX, doesn't need to be 'in-order' of TRX
  . arfcn   The ARFCN number (0 for hopping and 1023 for 'no frequency')

* OM2K_DEI_FREQ_SPEC_TX:

  (hop << 15) | (tx_id << 10) | arfcn

  tx_id Pretty much same as rx_id except here we know that the order
  doesn't have to match TRX order. It seems to even vary from one
  reboot to another on some real-world capture we got.

  . hop     Hopping marker
  . tx_addr Same as 'rx_addr' above but for TX
  . arfcn   The ARFCN number (0 for hopping and 1023 for 'no frequency')

* OM2K_DEI_FREQ_LIST:

  Groups of 3 bytes (24 bits), 1 per frequency used.

  (tx_addr << 20) | (rx_addr << 16) | (is_c0 << 10) | arfcn

  . tx_addr See above
  . rx_addr See above
  . is_c0   Must be 1 if that ARFCN hosts the C0. (first TRX of a MCTR)
  . arfcn   The ARFCN number

  (Note MAIO must also be set properly on the different TRX/TS sharing
   a frequency ... )

The way we generate theses here is what we gathered from real-world
traces:
 - Each 'TX' of each TRX is set to the ARFCN set in that TRX config
 - Each 'RX' of each TRX is configures as 'hopping'
   (which I assume means it will just pick the appropriate freq ?)
 - For each TS, we use :
   . tx_addr of the TRX that has the ARFCN we want to TX on
   . rx_addr of the TRX where the TS we're configuring is
   . arfcn   The actual ARFCN we want to add to the list

This is incomplete but will work for the 1 MCTR case.

Config for multiple MCTR or multiple virtual-bts still need to be
handled but it's not yet known exactly how those need to be
configured.

Signed-off-by: Sylvain Munaut <tnt at 246tNt.com>
Change-Id: Ie39a857543adaa11d1822346d8563ce3718412c8
---
M src/osmo-bsc/abis_om2000.c
1 file changed, 38 insertions(+), 7 deletions(-)


  git pull ssh://gerrit.osmocom.org:29418/osmo-bsc refs/changes/19/18119/3
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Gerrit-Project: osmo-bsc
Gerrit-Branch: master
Gerrit-Change-Id: Ie39a857543adaa11d1822346d8563ce3718412c8
Gerrit-Change-Number: 18119
Gerrit-PatchSet: 3
Gerrit-Owner: tnt <tnt at 246tNt.com>
Gerrit-Reviewer: Jenkins Builder
Gerrit-Reviewer: pespin <pespin at sysmocom.de>
Gerrit-Reviewer: tnt <tnt at 246tNt.com>
Gerrit-MessageType: newpatchset
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