[eepro100] 82559 Rx DMA burst limiting.
Robin Kletke
robink@atvideo.com
Wed, 24 Oct 2001 08:08:41 -0700
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Could someone please give me the correct settings for limiting the 82559 =
as PCI Master when doing DMA burst writes into processor memory? I am =
attempting to run on an ARM7 variant (custom ASIC), that is giving a PCI =
target-disconnect during the 82559 burst write (CBE =3D 0111). In these =
cases, the 82559 attempts to burst a large number of 32 bit words to the =
ARM, but the ARM asserts TRDY and STOP (target-disconnect). The 82559 =
eventually does disconnect, but the final 32 bit word of the burst is =
lost and not written to local ARM memory. I suspect that there is a =
problem with the ARM ASIC PCI/local bus bridge, but need to fix this in =
another way.
My hope was to limit the burst size of the 82559 to 4 or 5 32 bit words. =
However, after setting rxdmacount and txdmacount to various values, =
(4,4) (4,0x84), I don't see any change in the 82559 cycles.
What is required to set and enable the dma counters? Does byte 5, bit 7 =
=3D=3D 1 enable or disable? Various versions of the various drivers =
seem to contradict themselves.
Thanks for the help
Robin Kletke
Superior Software, Inc.
robink@ssinw.com
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Could someone please give me the correct settings =
for limiting=20
the 82559 as PCI Master when doing DMA burst writes into processor =
memory? =20
I am attempting to run on an ARM7 variant (custom ASIC), that is giving =
a PCI=20
target-disconnect during the 82559 burst write (CBE =3D 0111). In =
these=20
cases, the 82559 attempts to burst a large number of 32 bit words to the =
ARM,=20
but the ARM asserts TRDY and STOP (target-disconnect). The 82559=20
eventually does disconnect, but the final 32 bit word of the burst is =
lost and=20
not written to local ARM memory. I suspect that there is a problem =
with=20
the ARM ASIC PCI/local bus bridge, but need to fix this in another=20
way.
My hope was to limit the burst size of the 82559 to =
4 or 5 32=20
bit words. However, after setting rxdmacount and txdmacount to various =
values,=20
(4,4) (4,0x84), I don't see any change in the 82559 cycles.
What is required to set and enable the dma =
counters? =20
Does byte 5, bit 7 =3D=3D 1 enable or disable? Various versions of =
the various=20
drivers seem to contradict themselves.
Thanks for the help
Robin Kletke
Superior Software, Inc.