[ath9k-devel] Enabling MSI interrupts in ath9k driver

[Felix Radensky <felix@embedded-sol.com>]

Hi, Luis
Luis R. Rodriguez wrote:
> On Wed, Dec 16, 2009 at 3:47 AM, Felix Radensky <felix@embedded-sol.com> wrote:
>   
>> Hi,
>>
>> I'm trying to use Sparklan WPEA-110N mini-PCI-E module (based on Atheros
>> AR9280 chipset)
>> on Freescale P2020RDB board running 2.6.32 kernel. Due to a problem with
>> interrupt routing
>> on this board legacy PCI-E interrupts cannot be used with mini-PCI-E
>> slot. Freescale developers
>> suggested switching ath9k driver to use MSI interrupts. Ralink 2860 card
>> is known to work fine
>> in this slot (it uses MSI).
>>
>> I've modified ath9k driver to call pci_enable_msi() before request_irq()
>> and pci_disable_msi()
>> after free_irq(). The MSI interrupt seems to be allocated successfully,
>> but no interrupts are
>> actually arriving to the card. Below are relevant lines from dmesg.
>>
>> ath: EEPROM regdomain: 0x37
>> ath: EEPROM indicates we should expect a direct regpair map
>> ath: Country alpha2 being used: AT
>> ath: Regpair used: 0x37
>> phy0: Selected rate control algorithm 'ath9k_rate_control'
>> cfg80211: Calling CRDA for country: AT
>> Registered led device: ath9k-phy0::radio
>> Registered led device: ath9k-phy0::assoc
>> Registered led device: ath9k-phy0::tx
>> Registered led device: ath9k-phy0::rx
>> irq: irq 0 on host /soc at ffe00000/msi at 41600 mapped to virtual irq 18
>> phy0: Atheros AR9280 MAC/BB Rev:2 AR5133 RF Rev:d0: mem=0xf2160000, irq=18
>>
>> My hostapd.conf looks like this:
>>
>> interface=wlan0
>> driver=nl80211
>> ssid=FSL_AP1
>> channel=1
>> hw_mode=g
>> ieee80211n=1
>>
>> On startup hostapd prints
>>
>> Configuration file: /etc/hostapd-wlan0.conf
>> Opening raw packet socket for ifindex 1
>> BSS count 1, BSSID mask ff:ff:ff:ff:ff:ff (0 bits)
>> SIOCGIWRANGE: WE(compiled)=22 WE(source)=21 enc_capa=0xf
>> nl80211: Added 802.11b mode based on 802.11g information
>> RATE[0] rate=10 flags=0x2
>> RATE[1] rate=20 flags=0x6
>> RATE[2] rate=55 flags=0x6
>> RATE[3] rate=110 flags=0x6
>> RATE[4] rate=60 flags=0x0
>> RATE[5] rate=90 flags=0x0
>> RATE[6] rate=120 flags=0x0
>> RATE[7] rate=180 flags=0x0
>> RATE[8] rate=240 flags=0x0
>> RATE[9] rate=360 flags=0x0
>> RATE[10] rate=480 flags=0x0
>> RATE[11] rate=540 flags=0x0
>> Passive scanning not supported
>> Flushing old station entries
>> Deauthenticate all stations
>> Mode: IEEE 802.11g  Channel: 1  Frequency: 2412 MHz
>> Using interface wlan0 with hwaddr 00:0e:8e:1f:42:3b and ssid 'FSL_AP1'
>> wlan0: Setup of interface done.
>>
>> What am I missing ?
>>     
>
> Long ago in a galaxy far far away I tried enabling this since it
> seemed from our systems team that although this was never tested it
> *may* work. I enabled it, did some poking but it didn't so gave up. So
> no -- its not supported but if you get it going feel free to send a
> patch :) 
>   

There are definitions of AR_PCIE_MSI and AR_PCIE_MSI_ENABLE in reg.h
Since I don't have chip data sheet, can you explain when this bit should 
be set up,
and whether there are other bits in AR_PCIE_MSI that may be relevant.

Thanks.

Felix.
>   Luis
>