linux-kernel - Re: [PATCH] clk: zynqmp: fix compile testing without ZYNQMP

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Message-ID: <871rb2swd9.fsf@kokedama.swc.toshiba.co.jp>
Date:   Thu, 22 Apr 2021 14:48:18 +0900
From:   Punit Agrawal <punit1.agrawal@...hiba.co.jp>
To:     Arnd Bergmann <arnd@...nel.org>
Cc:     Michael Turquette <mturquette@...libre.com>,
        Stephen Boyd <sboyd@...nel.org>,
        Michal Simek <michal.simek@...inx.com>,
        Arnd Bergmann <arnd@...db.de>,
        Rajan Vaja <rajan.vaja@...inx.com>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Jolly Shah <jolly.shah@...inx.com>,
        Quanyang Wang <quanyang.wang@...driver.com>,
        linux-clk@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH] clk: zynqmp: fix compile testing without ZYNQMP_FIRMWARE

Hi Arnd,

Thanks for the fix.

Arnd Bergmann <arnd@...nel.org> writes:

> From: Arnd Bergmann <arnd@...db.de>
>
> When the firmware code is disabled, the incomplete error handling
> in the clk driver causes compile-time warnings:
>
> drivers/clk/zynqmp/pll.c: In function 'zynqmp_pll_recalc_rate':
> drivers/clk/zynqmp/pll.c:147:29: error: 'fbdiv' is used uninitialized [-Werror=uninitialized]
>   147 |         rate =  parent_rate * fbdiv;
>       |                 ~~~~~~~~~~~~^~~~~~~
> In function 'zynqmp_pll_get_mode',
>     inlined from 'zynqmp_pll_recalc_rate' at drivers/clk/zynqmp/pll.c:148:6:
> drivers/clk/zynqmp/pll.c:61:27: error: 'ret_payload' is used uninitialized [-Werror=uninitialized]
>    61 |         return ret_payload[1];
>       |                ~~~~~~~~~~~^~~
> drivers/clk/zynqmp/pll.c: In function 'zynqmp_pll_recalc_rate':
> drivers/clk/zynqmp/pll.c:53:13: note: 'ret_payload' declared here
>    53 |         u32 ret_payload[PAYLOAD_ARG_CNT];
>       |             ^~~~~~~~~~~
> drivers/clk/zynqmp/clk-mux-zynqmp.c: In function 'zynqmp_clk_mux_get_parent':
> drivers/clk/zynqmp/clk-mux-zynqmp.c:57:16: error: 'val' is used uninitialized [-Werror=uninitialized]
>    57 |         return val;
>       |                ^~~


Not sure what I am missing but I couldn't reproduce these warnings. I
tried a few different ways to toggle CONFIG_ZYNQMP_FIRMWARE.

Regardless...

> As it was apparently intentional to support this for compile testing
> purposes, change the code to have just enough error handling for the
> compiler to not notice the remaining bugs.
>
> Fixes: 21f237534661 ("clk: zynqmp: Drop dependency on ARCH_ZYNQMP")
> Signed-off-by: Arnd Bergmann <arnd@...db.de>
> ---
>  drivers/clk/zynqmp/clk-mux-zynqmp.c | 4 +++-
>  drivers/clk/zynqmp/pll.c            | 8 ++++++--
>  2 files changed, 9 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/clk/zynqmp/clk-mux-zynqmp.c b/drivers/clk/zynqmp/clk-mux-zynqmp.c
> index 06194149be83..2afded3c7c11 100644
> --- a/drivers/clk/zynqmp/clk-mux-zynqmp.c
> +++ b/drivers/clk/zynqmp/clk-mux-zynqmp.c
> @@ -50,9 +50,11 @@ static u8 zynqmp_clk_mux_get_parent(struct clk_hw *hw)
>  
>  	ret = zynqmp_pm_clock_getparent(clk_id, &val);
>  
> -	if (ret)
> +	if (ret) {
>  		pr_warn_once("%s() getparent failed for clock: %s, ret = %d\n",
>  			     __func__, clk_name, ret);
> +		return ret;
> +	}
>  
>  	return val;
>  }
> diff --git a/drivers/clk/zynqmp/pll.c b/drivers/clk/zynqmp/pll.c
> index abe6afbf3407..67d2a2d260c1 100644
> --- a/drivers/clk/zynqmp/pll.c
> +++ b/drivers/clk/zynqmp/pll.c
> @@ -54,9 +54,11 @@ static inline enum pll_mode zynqmp_pll_get_mode(struct clk_hw *hw)
>  	int ret;
>  
>  	ret = zynqmp_pm_get_pll_frac_mode(clk_id, ret_payload);
> -	if (ret)
> +	if (ret) {
>  		pr_warn_once("%s() PLL get frac mode failed for %s, ret = %d\n",
>  			     __func__, clk_name, ret);
> +		return ret;
> +	}
>  
>  	return ret_payload[1];
>  }
> @@ -140,9 +142,11 @@ static unsigned long zynqmp_pll_recalc_rate(struct clk_hw *hw,
>  	int ret;
>  
>  	ret = zynqmp_pm_clock_getdivider(clk_id, &fbdiv);
> -	if (ret)
> +	if (ret) {
>  		pr_warn_once("%s() get divider failed for %s, ret = %d\n",
>  			     __func__, clk_name, ret);
> +		return -1ul;
> +	}
>  
>  	rate =  parent_rate * fbdiv;
>  	if (zynqmp_pll_get_mode(hw) == PLL_MODE_FRAC) {

The changes make sense in that the functions error out sensibly when the
zynqmp firmware driver is not enabled.

Acked-by: Punit Agrawal <punit1.agrawal@...hiba.co.jp>

Punit