On 07/25/2011 04:54 PM, Rafał Miłecki wrote:
Hey, I've finally came back to my 14e4:4329 with not working DMA. I
hoped disabling parity will make my DMA work, but this didn't do the
trick.
The card is PCI one with following params:
SSB 2.4
BCM4321
SPROM: 4
PMU: ─
Core rev: 11
PHY: N / 1
Radio: 0x2055 / 4
I've dumped wl and b43 ops and compare them. Noticed something
interesting in DMA setup.
wl:
read32 0xc0200200 -> 0x00000000
write32 0xc0200200<- 0x00000801
write32 0xc0200208<- 0x5f310000
write32 0xc020020c<- 0x00000000
b43:
write32 0xc0200200<- 0x00000801
write32 0xc0200208<- 0x198b2000
write32 0xc020020c<- 0x80000000
Can you see the difference? wl does not put routing (translation) bits
in 0x20c at all. 0x208 on the other hand is suspicious.
It looks that wl is:
1) Using 0x40000000 routing instead of 0x80000000 routing
2) wl puts routing bits in addrlo instead of addrhi
Does the card report 32- or 64-bit addressing?
According to the specs, routing goes always to the addrhi:
The address 2 field is as follows (address 1 contains all address bits):
Mask Function
0x3FFFFFFF Address
0xC0000000 Routing
So I've hacked b43 to use 0x40000000 as translation and to put routing
in addrlo. Wohoo, this helped! For the first time I saw packets using
DMA engine.
What wl is doing is exactly what you would expect for 32-bit DMA. Do a few test
prints in b43_dma_init() to see what dmamask is on input and what value is returned.
Now, the question: when for real we should use such a solution?
If we detect the number of DMA bits correctly, all else should be OK. It may be
that we need a quirk for this card.
Larry, could you check your driver? Can you see anything about this?
Is this maybe PCI (not PCIe!) specific?
It could be. I don't recall anything as new as a Rev 11 802.11 core in PCI. I
looked at it a bit, but I didn't see anything. There is no code that says do
"this" if the card has a 4329 ID. There are some special 4329 routines, but none
seem to have anything to do with DMA.
Larry
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