linux/drivers/devfreq/event
Sascha Hauer 9991166494 PM / devfreq: rockchip-dfi: Use free running counter
The DDR_MON counters are free running counters. These are resetted to 0
when starting them over like currently done when reading the current
counter values.

Resetting the counters becomes a problem with perf support we want to
add later, because perf needs counters that are not modified elsewhere.

This patch removes resetting the counters and keeps them running
instead. That means we no longer use the absolute counter values but
instead compare them with the counter values we read last time. Not
stopping the counters also has the impact that they are running while
we are reading them. We cannot read multiple timers atomically, so
the values do not exactly fit together. The effect should be negligible
though as the time between two measurements is some orders of magnitude
bigger than the time we need to read multiple registers.

Link: https://lore.kernel.org/all/20231018061714.3553817-7-s.hauer@pengutronix.de/
Reviewed-by: Sebastian Reichel <sebastian.reichel@collabora.com>
Acked-by: Chanwoo Choi <cw00.choi@samsung.com>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
Signed-off-by: Chanwoo Choi <cw00.choi@samsung.com>
2023-10-18 18:34:09 +09:00
..
exynos-nocp.c PM / devfreq: event: use devm_platform_get_and_ioremap_resource() 2022-12-05 21:57:20 +09:00
exynos-nocp.h PM / devfreq: exynos: Rename Exynos to lowercase 2020-01-06 10:50:09 +09:00
exynos-ppmu.c PM / devfreq: exynos-ppmu: Use device_get_match_data() 2023-10-09 07:29:11 +09:00
exynos-ppmu.h PM / devfreq: exynos: Rename Exynos to lowercase 2020-01-06 10:50:09 +09:00
Kconfig PM / devfreq: exynos: Rename Exynos to lowercase 2020-01-06 10:50:09 +09:00
Makefile treewide: Add SPDX license identifier - Makefile/Kconfig 2019-05-21 10:50:46 +02:00
rockchip-dfi.c PM / devfreq: rockchip-dfi: Use free running counter 2023-10-18 18:34:09 +09:00