devicetree.vger.kernel.org archive mirror
 help / color / mirror / Atom feed
From: Johan Jonker <jbx6244@gmail.com>
To: heiko@sntech.de
Cc: robh+dt@kernel.org, krzysztof.kozlowski+dt@linaro.org,
	devicetree@vger.kernel.org, linux-kernel@vger.kernel.org,
	linux-arm-kernel@lists.infradead.org,
	linux-rockchip@lists.infradead.org
Subject: [PATCH v2] ARM: dts: rockchip: rk3xx: disable arm_global_timer
Date: Sun, 30 Oct 2022 21:56:29 +0100	[thread overview]
Message-ID: <f275ca8d-fd0a-26e5-b978-b7f3df815e0a@gmail.com> (raw)

The clock source and the sched_clock provided by the arm_global_timer
on Rockchip rk3066a/rk3188 are quite unstable because their rates
depend on the CPU frequency.

Recent changes to the arm_global_timer driver makes it impossible to use.

On the other side, the arm_global_timer has a higher rating than the
ROCKCHIP_TIMER, it will be selected by default by the time framework
while we want to use the stable Rockchip clock source.

Keep the arm_global_timer disabled in order to have the
DW_APB_TIMER (rk3066a) or ROCKCHIP_TIMER (rk3188) selected by default.

Signed-off-by: Johan Jonker <jbx6244@gmail.com>
---

ARM: dts: rockchip: disable arm-global-timer for rk3188
https://lore.kernel.org/linux-rockchip/1492374441-23336-26-git-send-email-daniel.lezcano@linaro.org/

clocksource: arm_global_timer: implement rate compensation whenever source clock changes
https://lore.kernel.org/all/20210406130045.15491-2-andrea.merello@gmail.com/
---
 arch/arm/boot/dts/rk3188.dtsi | 1 -
 arch/arm/boot/dts/rk3xxx.dtsi | 7 +++++++
 2 files changed, 7 insertions(+), 1 deletion(-)

diff --git a/arch/arm/boot/dts/rk3188.dtsi b/arch/arm/boot/dts/rk3188.dtsi
index cdd4a0bd5..486a96ce2 100644
--- a/arch/arm/boot/dts/rk3188.dtsi
+++ b/arch/arm/boot/dts/rk3188.dtsi
@@ -607,7 +607,6 @@

 &global_timer {
 	interrupts = <GIC_PPI 11 (GIC_CPU_MASK_SIMPLE(4) | IRQ_TYPE_EDGE_RISING)>;
-	status = "disabled";
 };

 &local_timer {
diff --git a/arch/arm/boot/dts/rk3xxx.dtsi b/arch/arm/boot/dts/rk3xxx.dtsi
index bf285091a..b0ec459ff 100644
--- a/arch/arm/boot/dts/rk3xxx.dtsi
+++ b/arch/arm/boot/dts/rk3xxx.dtsi
@@ -76,6 +76,13 @@
 		reg = <0x1013c200 0x20>;
 		interrupts = <GIC_PPI 11 (GIC_CPU_MASK_SIMPLE(2) | IRQ_TYPE_EDGE_RISING)>;
 		clocks = <&cru CORE_PERI>;
+		status = "disabled";
+		/* The clock source and the sched_clock provided by the arm_global_timer
+		 * on Rockchip rk3066a/rk3188 are quite unstable because their rates
+		 * depend on the CPU frequency.
+		 * Keep the arm_global_timer disabled in order to have the
+		 * DW_APB_TIMER (rk3066a) or ROCKCHIP_TIMER (rk3188) selected by default.
+		 */
 	};

 	local_timer: local-timer@1013c600 {
--
2.20.1


             reply	other threads:[~2022-10-30 20:56 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-10-30 20:56 Johan Jonker [this message]
2022-11-15 11:10 ` [PATCH v2] ARM: dts: rockchip: rk3xx: disable arm_global_timer Heiko Stuebner

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=f275ca8d-fd0a-26e5-b978-b7f3df815e0a@gmail.com \
    --to=jbx6244@gmail.com \
    --cc=devicetree@vger.kernel.org \
    --cc=heiko@sntech.de \
    --cc=krzysztof.kozlowski+dt@linaro.org \
    --cc=linux-arm-kernel@lists.infradead.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-rockchip@lists.infradead.org \
    --cc=robh+dt@kernel.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).