| commit | a2667a032c6207c9d058678d4f5f8422e20603aa | |
| author | Sergei Shtylyov <sergei.shtylyov@cogentembedded.com> | |
| Sat, 8 Sep 2018 20:54:05 +0000 (8 23:54 +0300) | ||
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | |
| Sun, 24 Nov 2019 07:23:03 +0000 (24 08:23 +0100) | ||
| tree | 14b02080d4981b7730ae696f1fa7fd08f405a994 | treesnapshot (tar.gz zip) |
| parent | c0b2af64f99e6f548121aaeac172211968f5b1eb | commitdiff |
clocksource/drivers/sh_cmt: Fixup for 64-bit machines
[ Upstream commit 22627c6f3ed3d9d0df13eec3c831b08f8186c38e ]
When trying to use CMT for clockevents on R-Car gen3 SoCs, I noticed
that 'max_delta_ns' for the broadcast timer (CMT) was shown as 1000 in
/proc/timer_list. It turned out that when calculating it, the driver did
1 << 32 (causing what I think was undefined behavior) resulting in a zero
delta, later clamped to 1000 by cev_delta2ns(). The root cause turned out
to be that the driver abused *unsigned long* for the CMT register values
(which are 16/32-bit), so that the calculation of 'ch->max_match_value'
in sh_cmt_setup_channel() used the wrong branch. Using more proper 'u32'
instead fixed 'max_delta_ns' and even fixed the switching an active
clocksource to CMT (which caused the system to turn non-interactive
before).
Signed-off-by: Sergei Shtylyov <sergei.shtylyov@cogentembedded.com>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 22627c6f3ed3d9d0df13eec3c831b08f8186c38e ]
When trying to use CMT for clockevents on R-Car gen3 SoCs, I noticed
that 'max_delta_ns' for the broadcast timer (CMT) was shown as 1000 in
/proc/timer_list. It turned out that when calculating it, the driver did
1 << 32 (causing what I think was undefined behavior) resulting in a zero
delta, later clamped to 1000 by cev_delta2ns(). The root cause turned out
to be that the driver abused *unsigned long* for the CMT register values
(which are 16/32-bit), so that the calculation of 'ch->max_match_value'
in sh_cmt_setup_channel() used the wrong branch. Using more proper 'u32'
instead fixed 'max_delta_ns' and even fixed the switching an active
clocksource to CMT (which caused the system to turn non-interactive
before).
Signed-off-by: Sergei Shtylyov <sergei.shtylyov@cogentembedded.com>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
| drivers/clocksource/sh_cmt.c | diffblobblamehistory |