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* [PATCH] clk: spacemit: mark K1 pll1_d8 as critical
@ 2025-06-09 20:08 Alex Elder
  2025-06-09 20:14 ` Alex Elder
  2025-06-10  2:24 ` Haylen Chu
  0 siblings, 2 replies; 11+ messages in thread
From: Alex Elder @ 2025-06-09 20:08 UTC (permalink / raw)
  To: mturquette, sboyd
  Cc: dlan, heylenay, inochiama, elder, linux-clk, spacemit,
	linux-riscv, linux-kernel, Guodong Xu

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@riscstar.com>
Tested-by: Guodong Xu <guodong@riscstar.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


^ permalink raw reply related	[flat|nested] 11+ messages in thread
* [PATCH] clk: spacemit: mark K1 pll1_d8 as critical
@ 2025-06-07 20:27 Alex Elder
  2025-06-08  0:24 ` Yixun Lan
  2025-06-08 19:30 ` kernel test robot
  0 siblings, 2 replies; 11+ messages in thread
From: Alex Elder @ 2025-06-07 20:27 UTC (permalink / raw)
  To: mturquette, sboyd
  Cc: dlan, heylenay, inochiama, elder, linux-clk, spacemit,
	linux-riscv, linux-kernel, Guodong Xu

The pll1_d8 clock is enabled by the boot loader, and is ultimately a
parent for numerous clocks.  Guodong Xu was recently testing DMA,
adding a reset property, and discovered that the needed reset was
not yet ready during initial probe.  It dropped its clock reference,
which dropped parent references, and along the way it dropped the sole
reference to pll1_d8 (from its prior clk_get()).  Clock pll1_d8 got
disabled, which resulted in a non-functioning system.

Mark that clock critical so it doesn't get turned off in this case.
We might be able to turn this flag off someday, but for now it
resolves the problem Guodong encountered.

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@riscstar.com>
Tested-by: Guodong Xu <guodong@riscstar.com>
---
 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)					\
-- 
2.45.2


^ permalink raw reply related	[flat|nested] 11+ messages in thread

end of thread, other threads:[~2025-06-10  2:25 UTC | newest]

Thread overview: 11+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2025-06-09 20:08 [PATCH] clk: spacemit: mark K1 pll1_d8 as critical Alex Elder
2025-06-09 20:14 ` Alex Elder
2025-06-10  2:24 ` Haylen Chu
  -- strict thread matches above, loose matches on Subject: below --
2025-06-07 20:27 Alex Elder
2025-06-08  0:24 ` Yixun Lan
2025-06-08  2:46   ` Alex Elder
2025-06-08  4:46     ` Haylen Chu
2025-06-08 12:56       ` Yixun Lan
2025-06-08 18:31       ` Alex Elder
2025-06-09  4:21         ` Haylen Chu
2025-06-08 19:30 ` kernel test robot

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