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authorArnd Bergmann <arnd@arndb.de>2018-06-18 17:19:24 +0300
committerStefan Richter <stefanr@s5r6.in-berlin.de>2019-11-13 22:59:33 +0300
commitb98c7518c5345ac5f930fd40ce9d8d2b8dc2ba06 (patch)
treeaeb59c97efd284684d9b347f3a776d00a11e2363 /drivers/firewire
parent4d856f72c10ecb060868ed10ff1b1453943fc6c8 (diff)
downloadlinux-b98c7518c5345ac5f930fd40ce9d8d2b8dc2ba06.tar.xz
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>
Diffstat (limited to 'drivers/firewire')
-rw-r--r--drivers/firewire/ohci.c2
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;
}