NetBSD/sys/arch/arc/TODO

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$NetBSD: TODO,v 1.9 2000/04/15 21:57:37 soda Exp $
To do list (not in any particular order).
o XXX sudden hang up in a few minutes or dozens of minutes.
2000 Mar 17 -current is OK. Mar 29 is NG.
o Move the RO and WIRED attribute from the pte to the pv table.
This saves four instructions in the tlb miss handler.
o Boot. Standalone boot program instead of booting the kernel directly?
o Find out why bitmap load to S3-928 flashes screen. (X server)
Know why (enable linear mode). Need S3 info.
o Can we have 32 double registers?
o 64bit kernel/userland
o repair DeskStation and Algor support
- 64bit device physical address space for Tyne (see OpenBSD pmap.c)
- requires bus_dma
o source code structure is quite obsolete,
general clean up is needed as nisimura-san suggested.
especially:
- introduce struct platform and remove ugly ``switch (cputype)''
in many places.
- redesign interrupt handler framework to be flexible for
possible variations; must be sane and useful for R4030/R4230
'local' devices and any combinations with ISA/EISA/PCI
- implement and use bus_dma, keeping in mind TLB assisted VDMA
that R4030/R4230 chip provides
- clean up bus_space implementation, remove inb/outb
- try to interporate HZ; may be possible for R4030/R4230 system
or 'hardclock() by R4000' system. Clock resolution of 100Hz
without any interporation is substandard
o overblocking on interrupt handler, and related problems
- SR_INT_IE should be enabled before calling hardclock().
Since this is not done currently, spllowersoftclock()
on hardclock() doesn't have effect, and softclock() is
handled with all interrupt disabled in this case.
-> overblocking, possibly causes missing hardclock()
- MIPS3_CLKF_BASEPRI() doesn't work correctly,
when MIPS_INT_MASK_5 (== MIPS_INT_MASK_CLOCK) is disabled.
-> micro optimization on hardclock() doesn't work.
but currently this may make hardclock() latency better
due to above SR_INT_IE problem.
s/MIPS_INT_MASK/MIPS3_INT_MASK/ makes this work, although tricky.
- if (ipending & INT_MASK_REAL_DEV) == 0,
softnet() and softclock() are handled with all interrupt disabled.
-> overblocking, possibly causes missing hardclock()
- softclock() is handled with softnet() disabled.
-> slightly overblocking
- `netisr' handling in netintr() implies potential race condition.
`netisr' access should be protected by splnet().
currently this is not real problem due to above overblocking.
`ssir' handling on many mips ports has same problem.
It should be protected by splnet() or splserial() or splhigh()
(depends on the highest interrupt level which sets `ssir').
Since `ssir' is accessed not only by setsoftnet() but also
by setsoft(), setsoftnet() should protect `ssir' by splserial()
or something. (i.e. priority level which setsoft() will be called)
Probably, it is better to split `ssir' variable for each
priority level.
also, _clearsoftintr() should be called before `ssir' access.
currently this is not real problem due to above overblocking.
o it is better to always disable MIPS_INT_MASK_CLOCK.
those are the points which should be fixed:
mips_idle: li t0, (MIPS_INT_MASK | MIPS_SR_INT_IE)
machdep.c: curpcb->pcb_context[11] = MIPS_INT_MASK | MIPS_SR_INT_IE;
spl0()
splnone()
o fix kernel start address
o merge new wscons
o parse ARC BIOS configuration information and use it
o omit __BROKEN_CONFIG_UNIT_USAGE
o omit __SWAP_BROKEN in <mips/types.h>
o fix implementation of DELAY(), clean up clock implementation
o asc.c scsi clock/NCR53CF94 handling clean up
o if_sn.c ether address handling clean up
o com_lbus.c clock handling clean up
o implement NCR 53c700(?) driver for NEC RISCserver 2200
based on amiga siop driver?
o audio driver
o use MI driver
- use MI ncr53c9x driver instead of home grown asc
- use MI bha driver instead of home grown btl
- make sonic driver MI, and share it with mac68k, newsmips/apbus
- make fd driver MI, and share it with i386
(contact christos about MI fd driver)
- make pccons MI, and share it with i386,
or simply eliminate pccons
- LKM
o ARC boot device name -> NetBSD root device conversion
o and missing MI devices
ses?, lkm, vcoda, ...
o way to specify serial console
o resolve "XXX"
Lots of other things.....