Re: [PATCH v3] clk: spacemit: mark K1 pll1_d8 as critical

[Alex Elder <elder@riscstar.com>]

On 6/12/25 5:48 PM, Alex Elder wrote:
> 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.

Is there any reason this bug fix cannot be merged?  It was
first posted a month ago, and although there was some initial
discussion that led to revisions, this version has been waiting
for over three weeks.

					-Alex

> 
> 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>
> Reviewed-by: Haylen Chu <heylenay@4d2.org>
> ---
> v3: Define struct with static scope; added Haylen's Reviewed-by
> 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..54d40cd39b275 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)					\
> +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, _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