The recommended workaround is a 5-10ms delay before and after accesses.
Therefore, move the affected bus_space_* operations from bus.h to bus.c
and special-case MACE accesses.
CRIME accesses are not affected, so introduce SGIMIPS_BUS_SPACE_CRIME and
use it as the CRIME tag.
My ip32 seems a little bit happier with this change, and my ip22 didn't
notice the change.
fit inside one memory chunk.
Leave 1 page before kernel untouched as that's where our initial kernel
stack before we switch to proc0 stack is (fixes boot problems on my Indy
with small kernels).
virtual memory reservation and a private pool of memory pages -- by a scheme
based on memory pools.
This allows better utilization of memory because buffers can now be allocated
with a granularity finer than the system's native page size (useful for
filesystems with e.g. 1k or 2k fragment sizes). It also avoids fragmentation
of virtual to physical memory mappings (due to the former fixed virtual
address reservation) resulting in better utilization of MMU resources on some
platforms. Finally, the scheme is more flexible by allowing run-time decisions
on the amount of memory to be used for buffers.
On the other hand, the effectiveness of the LRU queue for buffer recycling
may be somewhat reduced compared to the traditional method since, due to the
nature of the pool based memory allocation, the actual least recently used
buffer may release its memory to a pool different from the one needed by a
newly allocated buffer. However, this effect will kick in only if the
system is under memory pressure.
- hpc1_hdd_{ctl,bufptr} and hpc3_hdd_{ctl,bufptr} are
established in hpcreg.h. All references to these fields
are updated with the exception of if_sq: (haltwo,
hpcdma). This makes reading the code and spotting bugs
easier.
- hpcdma.c was applying EOCHAIN to the wrong descriptor
word for the hpc1 case.
- I added scsi_max_xfer to the abstraction layer, and it
allows some crusty #defines in wdsc.c to be removed.
hpc1 now doesn't waste descriptors as it once did.
- hpcreg.h was updated to reflect the lack of XMITDONE
bit in hpc1. HPC1_REV15 added for a test in hpc.c
- hpc.c now verifies HPC1 revisions (1.0 vs 1.5) and
prints the output a little prettier ;)
- power interrupts shouldn't establish on non-IP22
platforms.
divergence between HPC revision 1.5 and revision 3.
The wdsc driver has been updated to reflect this layer (and may now work on
IP20). The sq driver needs a bit more work before it can be committed.
