linux-kernel - [PATCH] clk: spacemit: mark K1 pll1

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Message-ID: <20250609200822.468482-1-elder@riscstar.com>
Date: Mon,  9 Jun 2025 15:08:21 -0500
From: Alex Elder <elder@...cstar.com>
To: mturquette@...libre.com,
	sboyd@...nel.org
Cc: dlan@...too.org,
	heylenay@....org,
	inochiama@...look.com,
	elder@...cstar.com,
	linux-clk@...r.kernel.org,
	spacemit@...ts.linux.dev,
	linux-riscv@...ts.infradead.org,
	linux-kernel@...r.kernel.org,
	Guodong Xu <guodong@...cstar.com>
Subject: [PATCH] clk: spacemit: mark K1 pll1_d8 as critical

The pll1_d8 clock is enabled by the boot loader, and is ultimately a
parent for numerous clocks, including those used by APB and AXI buses.
Guodong Xu discovered that this clock got disabled while responding to
getting -EPROBE_DEFER when requesting a reset controller.

The needed clock (CLK_DMA, along with its parents) had already been
enabled.  To respond to the probe deferral return, the CLK_DMA clock
was disabled, and this led to parent clocks also reducing their enable
count.  When the enable count for pll1_d8 was decremented it became 0,
which caused it to be disabled.  This led to a system hang.

Marking that clock critical resolves this by preventing it from being
disabled.

Define a new macro CCU_FACTOR_GATE_DEFINE() to allow clock flags to
be supplied for a CCU_FACTOR_GATE clock.

Fixes: 1b72c59db0add ("clk: spacemit: Add clock support for SpacemiT K1 SoC")
Signed-off-by: Alex Elder <elder@...cstar.com>
Tested-by: Guodong Xu <guodong@...cstar.com>
---
v2: Reworded the description to provide better detail

 drivers/clk/spacemit/ccu-k1.c  |  3 ++-
 drivers/clk/spacemit/ccu_mix.h | 21 +++++++++++++--------
 2 files changed, 15 insertions(+), 9 deletions(-)

diff --git a/drivers/clk/spacemit/ccu-k1.c b/drivers/clk/spacemit/ccu-k1.c
index cdde37a052353..df65009a07bb1 100644
--- a/drivers/clk/spacemit/ccu-k1.c
+++ b/drivers/clk/spacemit/ccu-k1.c
@@ -170,7 +170,8 @@ CCU_FACTOR_GATE_DEFINE(pll1_d4, CCU_PARENT_HW(pll1), APBS_PLL1_SWCR2, BIT(3), 4,
 CCU_FACTOR_GATE_DEFINE(pll1_d5, CCU_PARENT_HW(pll1), APBS_PLL1_SWCR2, BIT(4), 5, 1);
 CCU_FACTOR_GATE_DEFINE(pll1_d6, CCU_PARENT_HW(pll1), APBS_PLL1_SWCR2, BIT(5), 6, 1);
 CCU_FACTOR_GATE_DEFINE(pll1_d7, CCU_PARENT_HW(pll1), APBS_PLL1_SWCR2, BIT(6), 7, 1);
-CCU_FACTOR_GATE_DEFINE(pll1_d8, CCU_PARENT_HW(pll1), APBS_PLL1_SWCR2, BIT(7), 8, 1);
+CCU_FACTOR_GATE_FLAGS_DEFINE(pll1_d8, CCU_PARENT_HW(pll1), APBS_PLL1_SWCR2, BIT(7), 8, 1,
+		CLK_IS_CRITICAL);
 CCU_FACTOR_GATE_DEFINE(pll1_d11_223p4, CCU_PARENT_HW(pll1), APBS_PLL1_SWCR2, BIT(15), 11, 1);
 CCU_FACTOR_GATE_DEFINE(pll1_d13_189, CCU_PARENT_HW(pll1), APBS_PLL1_SWCR2, BIT(16), 13, 1);
 CCU_FACTOR_GATE_DEFINE(pll1_d23_106p8, CCU_PARENT_HW(pll1), APBS_PLL1_SWCR2, BIT(20), 23, 1);
diff --git a/drivers/clk/spacemit/ccu_mix.h b/drivers/clk/spacemit/ccu_mix.h
index 51d19f5d6aacb..668c8139339e1 100644
--- a/drivers/clk/spacemit/ccu_mix.h
+++ b/drivers/clk/spacemit/ccu_mix.h
@@ -101,16 +101,21 @@ static struct ccu_mix _name = {							\
 	}									\
 }
 
+#define CCU_FACTOR_GATE_FLAGS_DEFINE(_name, _parent, _reg_ctrl, _mask_gate, _div,	\
+			       _mul, _flags)					\
+struct ccu_mix _name = {							\
+	.gate	= CCU_GATE_INIT(_mask_gate),					\
+	.factor	= CCU_FACTOR_INIT(_div, _mul),					\
+	.common = {								\
+		.reg_ctrl	= _reg_ctrl,					\
+		CCU_MIX_INITHW(_name, _parent, spacemit_ccu_factor_gate_ops, _flags)	\
+	}									\
+}
+
 #define CCU_FACTOR_GATE_DEFINE(_name, _parent, _reg_ctrl, _mask_gate, _div,	\
 			       _mul)						\
-static struct ccu_mix _name = {							\
-	.gate	= CCU_GATE_INIT(_mask_gate),					\
-	.factor	= CCU_FACTOR_INIT(_div, _mul),					\
-	.common = {								\
-		.reg_ctrl	= _reg_ctrl,					\
-		CCU_MIX_INITHW(_name, _parent, spacemit_ccu_factor_gate_ops, 0)	\
-	}									\
-}
+	CCU_FACTOR_GATE_FLAGS_DEFINE(_name, _parent, _reg_ctrl, _mask_gate, _div,	\
+			       _mul, 0)
 
 #define CCU_MUX_GATE_DEFINE(_name, _parents, _reg_ctrl, _shift, _width,		\
 			    _mask_gate, _flags)					\

base-commit: 19272b37aa4f83ca52bdf9c16d5d81bdd1354494
-- 
2.45.2