Hi Sasha,
On Sun, Apr 12, 2020 at 1:11 AM Sasha Levin sashal@kernel.org wrote:
From: Geert Uytterhoeven geert+renesas@glider.be
[ Upstream commit 408324a3c5383716939eea8096a0f999a0665f7e ]
SH-Mobile AG5 and R-Car H1 SoCs are based on the Cortex-A9 MPCore, which includes a global timer.
Enable the ARM global timer on these SoCs, which will be used for:
- the scheduler clock, improving scheduler accuracy from 10 ms to 3 or 4 ns,
- delay loops, allowing removal of calls to shmobile_init_delay() from the corresponding machine vectors.
Note that when using an old DTB lacking the global timer, the kernel will still work. However, loops-per-jiffies will no longer be preset, and the delay loop will need to be calibrated during boot.
I.e. to avoid this delay, this patch is best backported after backporting 8443ffd1bbd5be74 ("ARM: dts: r8a7779: Add device node for ARM global timer"), df1a0aac0a533e6f ("ARM: dts: sh73a0: Add device node for ARM global timer").
While the former has been backported to v5.[45]-stable, the latter hasn't, probably because it depends on 61b58e3f6e518c51 ("ARM: dts: sh73a0: Rename twd clock to periph clock")
So please backport the last two commits first. Thanks!
Signed-off-by: Geert Uytterhoeven geert+renesas@glider.be Link: https://lore.kernel.org/r/20191211135222.26770-5-geert+renesas@glider.be Signed-off-by: Sasha Levin sashal@kernel.org
Gr{oetje,eeting}s,
Geert