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author | juhosg <juhosg@3c298f89-4303-0410-b956-a3cf2f4a3e73> | 2011-11-13 11:26:52 +0000 |
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committer | juhosg <juhosg@3c298f89-4303-0410-b956-a3cf2f4a3e73> | 2011-11-13 11:26:52 +0000 |
commit | 4cc612872a92f33fe0164f0b7762b9f5b2e5c181 (patch) | |
tree | 02d1026a16ab6c9e288a8a15ecbe9188e0650889 /Makefile | |
parent | 5fb5b4483ba809ce225b4bb50a3d42bdc936a397 (diff) |
ar71xx: fix occasional kernel hangs during boot on AR934x
The patch taken from the linux-mips mailing list.
The Kernel hangs occasionally during boot after
"Calibrating delay loop..". This is caused by the
c0_compare_int_usable() routine in cevt-r4k.c
returning false which causes the system to disable
the timer and hang later. The false return happens
because the routine is using a series of four calls
to irq_disable_hazard() as a delay while it waits
for the timer changes to propagate to the cp0 cause
register. On newer MIPS cores, like the 74K, the
series of irq_disable_hazard() calls turn into ehb
instructions and can take as little as a few clock
ticks for all 4 instructions. This is not enough of
a delay, so the routine thinks the timer is not
working.
This fix uses up to a max number of cycle counter
ticks for the delay and uses back_to_back_c0_hazard()
instead of irq_disable_hazard() to handle the hazard
condition between cp0 writes and cp0 reads.
git-svn-id: svn://svn.openwrt.org/openwrt/trunk@29009 3c298f89-4303-0410-b956-a3cf2f4a3e73
Diffstat (limited to 'Makefile')
0 files changed, 0 insertions, 0 deletions