Messages in this thread | | | Date | Sun, 21 Nov 2010 08:32:05 +0800 | Subject | Re: Challenges with doing hardware bring up with Linux first | From | Adrian Chadd <> |
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On 19 November 2010 00:53, Luis R. Rodriguez <lrodriguez@atheros.com> wrote:
>> Also, please review the past multi-os driver initiatives that have >> sprung up over the years (about 1 every 10 years it seems). Please >> learn from the past as to why those have failed every single time, and >> why we don't want to even try to do that again. > > :-) thanks, just testing waters to see what's possible and what > direction to focus more on.
Being involved atm in the "re-multi-OS'ing" of ath code (ie, merging some ath9k bits and pieces back into FreeBSD's HAL), I really appreciate how the bulk of the hardware-fiddling bits are OS agnostic. There's some messiness surrounding the 802.11 stack flags (which the FreeBSD HAL "indirects" via HAL flags, hiding away some of the net80211 internals) but a lot of the net80211 stuff is still tightly integrated with the HAL. There's some platform specific stuff in hardware twiddling functions (eg "am I a 40mhz channel? Am i a 2ghz channel") but so far it's been straightforward to translate the macros.
Now that I've just begun testing (what seems like!) functioning 11n TX/RX in my HAL, I plan on starting to merge in more ath9k related driver code in. I'll provide some more feedback to the ath9k-devel list as I do this. I'm hoping that large chunks of the hardware related code (eg AR9002 calibration) can be thrown in with very minor changes.
But so far, I have this to say:
* decoupling the hardware twiddling stuff from OS/802.11 stack specific stuff is helpful; * some of the base types are different (eg integer type layout, bool, etc), but that's relatively straightforward to merge over; * keeping the bits that need locking in "higher level" files (ie, separate from hardware twiddling as much as possible) is also helpful. * trying to make the actual interface related code (eg "if_ath.c" in FreeBSD; it's been broken out in ath9k) platform agnostic is likely very difficult and a path to the parent posters "fail."
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