linux-kernel - [PATCH AUTOSEL 4.18 37/59] clk: meson: axg: mark fdiv2 and fdiv3 as critical

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Date:   Wed, 14 Nov 2018 17:23:09 -0500
From:   Sasha Levin <sashal@...nel.org>
To:     stable@...r.kernel.org, linux-kernel@...r.kernel.org
Cc:     Jerome Brunet <jbrunet@...libre.com>,
        Stephen Boyd <sboyd@...nel.org>,
        Sasha Levin <sashal@...nel.org>,
        linux-amlogic@...ts.infradead.org, linux-clk@...r.kernel.org
Subject: [PATCH AUTOSEL 4.18 37/59] clk: meson: axg: mark fdiv2 and fdiv3 as critical

From: Jerome Brunet <jbrunet@...libre.com>

[ Upstream commit d6ee1e7e9004d3d246cdfa14196989e0a9466c16 ]

Similar to gxbb and gxl platforms, axg SCPI Cortex-M co-processor
uses the fdiv2 and fdiv3 to, among other things, provide the cpu
clock.

Until clock hand-off mechanism makes its way to CCF and the generic
SCPI claims platform specific clocks, these clocks must be marked as
critical to make sure they are never disabled when needed by the
co-processor.

Fixes: 05f814402d61 ("clk: meson: add fdiv clock gates")
Signed-off-by: Jerome Brunet <jbrunet@...libre.com>
Acked-by: Neil Armstrong <narmstrong@...libre.com>
Signed-off-by: Stephen Boyd <sboyd@...nel.org>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
 drivers/clk/meson/axg.c | 13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/drivers/clk/meson/axg.c b/drivers/clk/meson/axg.c
index bd4dbc696b88..cfd26fd7e404 100644
--- a/drivers/clk/meson/axg.c
+++ b/drivers/clk/meson/axg.c
@@ -320,6 +320,7 @@ static struct clk_regmap axg_fclk_div2 = {
 		.ops = &clk_regmap_gate_ops,
 		.parent_names = (const char *[]){ "fclk_div2_div" },
 		.num_parents = 1,
+		.flags = CLK_IS_CRITICAL,
 	},
 };
 
@@ -344,6 +345,18 @@ static struct clk_regmap axg_fclk_div3 = {
 		.ops = &clk_regmap_gate_ops,
 		.parent_names = (const char *[]){ "fclk_div3_div" },
 		.num_parents = 1,
+		/*
+		 * FIXME:
+		 * This clock, as fdiv2, is used by the SCPI FW and is required
+		 * by the platform to operate correctly.
+		 * Until the following condition are met, we need this clock to
+		 * be marked as critical:
+		 * a) The SCPI generic driver claims and enable all the clocks
+		 *    it needs
+		 * b) CCF has a clock hand-off mechanism to make the sure the
+		 *    clock stays on until the proper driver comes along
+		 */
+		.flags = CLK_IS_CRITICAL,
 	},
 };
 
-- 
2.17.1