CRIS: GENERIC_TIME fixes

GENERIC_TIME was not functional for CRIS, giving random backward
time jumps.

For CRISv32 implement a new clocksource using the free running counter
and ditch the arch_gettimeoffset.

The random time jumps still existed, but turned out to be the write_seqlock
which was missing around our do_timer() call.

So switch over to GENERIC_TIME using the clocksource for CRISv32.

CRISv10 doesn't have the free running counter needed for the
clocksource trick, but we can still use GENERIC_TIME with
arch_gettimeoffset.

Unfortunately, there were problems in using the prescaler register
to timer0 for the gettimeoffset calculation, so it is now ignored,
making our resolution worse by the tune of 40usec (0.4%) worst case.

At the same time, clean up some formatting and use NSEC_PER_SEC
instead of 1000000000.

Signed-off-by: Jesper Nilsson <jesper.nilsson@axis.com>

1 files changed, 4 insertions, 1 deletions

diff --git a/arch/cris/Kconfig b/arch/cris/Kconfig
index e25bf4440b51..4827c72b9634 100644
--- a/arch/cris/Kconfig
+++ b/arch/cris/Kconfig
@@ -27,7 +27,7 @@ config GENERIC_CMOS_UPDATE
         def_bool y
 
 config ARCH_USES_GETTIMEOFFSET
-        def_bool y
+        def_bool n
 
 config GENERIC_IOMAP
        bool
@@ -131,16 +131,19 @@ choice
 
 config ETRAX100LX
         bool "ETRAX-100LX-v1"
+        select ARCH_USES_GETTIMEOFFSET
         help
           Support version 1 of the ETRAX 100LX.
 
 config ETRAX100LX_V2
         bool "ETRAX-100LX-v2"
+        select ARCH_USES_GETTIMEOFFSET
         help
           Support version 2 of the ETRAX 100LX.
 
 config SVINTO_SIM
         bool "ETRAX-100LX-for-xsim-simulator"
+        select ARCH_USES_GETTIMEOFFSET
         help
           Support the xsim ETRAX Simulator.