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author | Serge Semin <Sergey.Semin@baikalelectronics.ru> | 2020-05-21 17:07:22 +0300 |
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committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2020-06-20 10:23:21 +0200 |
commit | 6180d09d73d792a5b86e66e72acba98c1ac9ac56 (patch) | |
tree | cfb01ba629f6879967509d025205eec17dc1ebaf /arch/m68k/sun3x | |
parent | ea4031568c75cdb5780a83cd336223a436e76671 (diff) |
mips: Add udelay lpj numbers adjustment
[ Upstream commit ed26aacfb5f71eecb20a51c4467da440cb719d66 ]
Loops-per-jiffies is a special number which represents a number of
noop-loop cycles per CPU-scheduler quantum - jiffies. As you
understand aside from CPU-specific implementation it depends on
the CPU frequency. So when a platform has the CPU frequency fixed,
we have no problem and the current udelay interface will work
just fine. But as soon as CPU-freq driver is enabled and the cores
frequency changes, we'll end up with distorted udelay's. In order
to fix this we have to accordinly adjust the per-CPU udelay_val
(the same as the global loops_per_jiffy) number. This can be done
in the CPU-freq transition event handler. We subscribe to that event
in the MIPS arch time-inititalization method.
Co-developed-by: Alexey Malahov <Alexey.Malahov@baikalelectronics.ru>
Signed-off-by: Alexey Malahov <Alexey.Malahov@baikalelectronics.ru>
Signed-off-by: Serge Semin <Sergey.Semin@baikalelectronics.ru>
Reviewed-by: Jiaxun Yang <jiaxun.yang@flygoat.com>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: Paul Burton <paulburton@kernel.org>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Rob Herring <robh+dt@kernel.org>
Cc: devicetree@vger.kernel.org
Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Diffstat (limited to 'arch/m68k/sun3x')
0 files changed, 0 insertions, 0 deletions