Re: [PATCH] clk: sophgo: fix warning emitted by objtool

[Inochi Amaoto]

On Fri, Jul 19, 2024 at 07:57:27PM GMT, limiao wrote:
> From: limiao <limiao@xxxxxxxxxx>
> 
> for ARCH=x86, the combination of CONFIG_OBJTOOL=y enables
> a host tool named 'objtool' which runs at compile time,
> when CONFIG_CLK_SOPHGO_CV1800=y or m, objtool will produces
> the following warning:
> 
> drivers/clk/sophgo/clk-cv18xx-ip.o: warning: objtool:
> mmux_round_rate() falls through to next function aclk_set_rate()
> 
> we can find the reason from objtool help document(tools/objtool/
> Documentation/objtool.txt):
> 

I think it is duplicate of
https://lore.kernel.org/linux-clk/c8e66d51f880127549e2a3e623be6787f62b310d.1720506143.git.liqiang01@xxxxxxxxxx/

> Objtool warnings
> ----------------
> ...
> 8. file.o: warning: objtool: funcA() falls through to next function funcB()
> ...
>    2) funcA() uses the unreachable() annotation in a section of code
>      that is actually reachable.
> 
> so we replace unreachable() with returning an errno to avoid this warning.
> 
> Signed-off-by: limiao<limiao@xxxxxxxxxx>
> ---
>  drivers/clk/sophgo/clk-cv18xx-ip.c | 6 ++++--
>  1 file changed, 4 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/clk/sophgo/clk-cv18xx-ip.c b/drivers/clk/sophgo/clk-cv18xx-ip.c
> index 805f561725ae..0fe9a9bd3f49 100644
> --- a/drivers/clk/sophgo/clk-cv18xx-ip.c
> +++ b/drivers/clk/sophgo/clk-cv18xx-ip.c
> @@ -602,7 +602,7 @@ static inline struct cv1800_clk_mmux *hw_to_cv1800_clk_mmux(struct clk_hw *hw)
>  	return container_of(common, struct cv1800_clk_mmux, common);
>  }
>  
> -static u8 mmux_get_parent_id(struct cv1800_clk_mmux *mmux)
> +static int mmux_get_parent_id(struct cv1800_clk_mmux *mmux)
>  {
>  	struct clk_hw *hw = &mmux->common.hw;
>  	struct clk_hw *parent = clk_hw_get_parent(hw);
> @@ -613,7 +613,7 @@ static u8 mmux_get_parent_id(struct cv1800_clk_mmux *mmux)
>  			return i;
>  	}
>  
> -	unreachable();
> +	return -EINVAL;
>  }
>  
>  static int mmux_enable(struct clk_hw *hw)
> @@ -648,6 +648,8 @@ static long mmux_round_rate(struct clk_hw *parent, unsigned long *parent_rate,
>  			return *parent_rate;
>  
>  		id = mmux_get_parent_id(mmux);
> +		if (id < 0)
> +			return *parent_rate;
>  	}
>  
>  	div_id = mmux->parent2sel[id];
> -- 
> 2.25.1
>