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| author | Arnd Bergmann <arnd@arndb.de> | 2018-06-18 16:19:24 +0200 |
|---|---|---|
| committer | Stefan Richter <stefanr@s5r6.in-berlin.de> | 2019-11-13 20:59:33 +0100 |
| commit | b98c7518c5345ac5f930fd40ce9d8d2b8dc2ba06 (patch) | |
| tree | aeb59c97efd284684d9b347f3a776d00a11e2363 | |
| parent | 4d856f72c10ecb060868ed10ff1b1453943fc6c8 (diff) | |
| download | linux-b98c7518c5345ac5f930fd40ce9d8d2b8dc2ba06.tar.bz2 | |
firewire: ohci: stop using get_seconds() for BUS_TIME
The ohci driver uses the get_seconds() function to implement the 32-bit
CSR_BUS_TIME register. This was added in 2010 commit a48777e03ad5
("firewire: add CSR BUS_TIME support").
As get_seconds() returns a 32-bit value (on 32-bit architectures), it
seems like a good fit for that register, but it is also deprecated because
of the y2038/y2106 overflow problem, and should be replaced throughout
the kernel with either ktime_get_real_seconds() or ktime_get_seconds().
I'm using the latter here, which uses monotonic time. This has the
advantage of behaving better during concurrent settimeofday() updates
or leap second adjustments and won't overflow a 32-bit integer, but
the downside of using CLOCK_MONOTONIC instead of CLOCK_REALTIME is
that the observed values are not related to external clocks.
If we instead need UTC but can live with clock jumps or overflows,
then we should use ktime_get_real_seconds() instead, retaining the
existing behavior.
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Link: https://lore.kernel.org/lkml/20180711124923.1205200-1-arnd@arndb.de/
Reviewed-by: Clemens Ladisch <clemens@ladisch.de>
Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
| -rw-r--r-- | drivers/firewire/ohci.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/drivers/firewire/ohci.c b/drivers/firewire/ohci.c index 522f3addb5bd..33269316f111 100644 --- a/drivers/firewire/ohci.c +++ b/drivers/firewire/ohci.c @@ -1752,7 +1752,7 @@ static u32 update_bus_time(struct fw_ohci *ohci) if (unlikely(!ohci->bus_time_running)) { reg_write(ohci, OHCI1394_IntMaskSet, OHCI1394_cycle64Seconds); - ohci->bus_time = (lower_32_bits(get_seconds()) & ~0x7f) | + ohci->bus_time = (lower_32_bits(ktime_get_seconds()) & ~0x7f) | (cycle_time_seconds & 0x40); ohci->bus_time_running = true; } |