Linux-Clk Archive on lore.kernel.org
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From: Samuel Holland <samuel@sholland.org>
To: Maxime Ripard <maxime.ripard@bootlin.com>,
	Chen-Yu Tsai <wens@csie.org>,
	Jassi Brar <jassisinghbrar@gmail.com>,
	Michael Turquette <mturquette@baylibre.com>,
	Stephen Boyd <sboyd@kernel.org>, Rob Herring <robh+dt@kernel.org>,
	Mark Rutland <mark.rutland@arm.com>,
	Corentin Labbe <clabbe.montjoie@gmail.com>,
	Vasily Khoruzhick <anarsoul@gmail.com>
Cc: devicetree@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
	linux-clk@vger.kernel.org, linux-kernel@vger.kernel.org,
	linux-sunxi@googlegroups.com,
	Samuel Holland <samuel@sholland.org>
Subject: [PATCH v4 02/10] clk: sunxi-ng: Mark AR100 clocks as critical
Date: Mon, 19 Aug 2019 22:23:03 -0500
Message-ID: <20190820032311.6506-3-samuel@sholland.org> (raw)
In-Reply-To: <20190820032311.6506-1-samuel@sholland.org>

On sun8i, sun9i, and sun50i SoCs, system suspend/resume support requires
firmware running on the AR100 coprocessor (the "SCP"). Such firmware can
provide additional features, such as thermal monitoring and poweron/off
support for boards without a PMIC.

Since the AR100 may be running critical firmware, even if Linux does not
know about it or directly interact with it (all requests may go through
an intermediary interface such as PSCI), Linux must not turn off its
clock.

At this time, such power management firmware only exists for the A64 and
H5 SoCs.  However, it makes sense to take care of all CCU drivers now
for consistency, and to ease the transition in the future once firmware
is ported to the other SoCs.

Leaving the clock running is safe even if no firmware is present, since
the AR100 stays in reset by default. In most cases, the AR100 clock is
kept enabled by Linux anyway, since it is the parent of all APB0 bus
peripherals. This change only prevents Linux from turning off the AR100
clock in the rare case that no peripherals are in use.

Signed-off-by: Samuel Holland <samuel@sholland.org>
---
 drivers/clk/sunxi-ng/ccu-sun50i-h6-r.c | 2 +-
 drivers/clk/sunxi-ng/ccu-sun8i-r.c     | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/clk/sunxi-ng/ccu-sun50i-h6-r.c b/drivers/clk/sunxi-ng/ccu-sun50i-h6-r.c
index 45a1ed3fe674..adf907020951 100644
--- a/drivers/clk/sunxi-ng/ccu-sun50i-h6-r.c
+++ b/drivers/clk/sunxi-ng/ccu-sun50i-h6-r.c
@@ -45,7 +45,7 @@ static struct ccu_div ar100_clk = {
 		.hw.init	= CLK_HW_INIT_PARENTS("ar100",
 						      ar100_r_apb2_parents,
 						      &ccu_div_ops,
-						      0),
+						      CLK_IS_CRITICAL),
 	},
 };
 
diff --git a/drivers/clk/sunxi-ng/ccu-sun8i-r.c b/drivers/clk/sunxi-ng/ccu-sun8i-r.c
index 4646fdc61053..feef4f750943 100644
--- a/drivers/clk/sunxi-ng/ccu-sun8i-r.c
+++ b/drivers/clk/sunxi-ng/ccu-sun8i-r.c
@@ -45,7 +45,7 @@ static struct ccu_div ar100_clk = {
 		.hw.init	= CLK_HW_INIT_PARENTS_DATA("ar100",
 							   ar100_parents,
 							   &ccu_div_ops,
-							   0),
+							   CLK_IS_CRITICAL),
 	},
 };
 
-- 
2.21.0


  parent reply index

Thread overview: 29+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-08-20  3:23 [PATCH v4 00/10] Allwinner sunxi message box support Samuel Holland
2019-08-20  3:23 ` [PATCH v4 01/10] clk: sunxi-ng: Mark msgbox clocks as critical Samuel Holland
2019-08-20  3:23 ` Samuel Holland [this message]
2019-08-20  7:11   ` [PATCH v4 02/10] clk: sunxi-ng: Mark AR100 " Maxime Ripard
2019-08-20 13:02     ` Samuel Holland
2019-08-21 12:24       ` Maxime Ripard
2019-09-05 18:56         ` Stephen Boyd
2019-08-20  3:23 ` [PATCH v4 03/10] dt-bindings: mailbox: Add a sunxi message box binding Samuel Holland
2019-08-20  7:14   ` Maxime Ripard
2019-08-20 13:04     ` Samuel Holland
2019-08-21 12:07       ` Maxime Ripard
2019-08-20  3:23 ` [PATCH v4 04/10] mailbox: sunxi-msgbox: Add a new mailbox driver Samuel Holland
2019-08-20  8:27   ` Maxime Ripard
2019-08-20 11:18   ` Ondřej Jirman
2019-08-20 13:07     ` Samuel Holland
2019-08-20 13:34       ` Ondřej Jirman
2019-08-21 12:30       ` Maxime Ripard
2019-08-20  3:23 ` [PATCH v4 05/10] ARM: dts: sunxi: a80: Add msgbox node Samuel Holland
2019-08-20  8:15   ` Maxime Ripard
2019-08-20 13:17     ` Samuel Holland
2019-08-23 14:56       ` Maxime Ripard
2019-08-20  3:23 ` [PATCH v4 06/10] ARM: dts: sunxi: a83t: " Samuel Holland
2019-08-20  3:23 ` [PATCH v4 07/10] ARM: dts: sunxi: h3/h5: " Samuel Holland
2019-08-20  3:23 ` [PATCH v4 08/10] arm64: dts: allwinner: a64: " Samuel Holland
2019-08-20  3:23 ` [PATCH v4 09/10] arm64: dts: allwinner: h6: " Samuel Holland
2019-08-20  3:23 ` [PATCH v4 10/10] [DO NOT MERGE] drivers: firmware: msgbox demo Samuel Holland
2019-09-09  3:22 ` [PATCH v4 00/10] Allwinner sunxi message box support Ondřej Jirman
2019-09-09  3:54   ` Samuel Holland
2019-09-09 12:36     ` Ondřej Jirman

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