linux-kernel - Re: [PATCH 2/2] [NOT_FOR_UPSTREAM] cpufreq: scmi: Add quirk to disable checks in scmi_dev_used_by

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Message-ID: <20250818062044.zawqkalphvxjwt2w@lcpd911>
Date: Mon, 18 Aug 2025 11:50:44 +0530
From: Dhruva Gole <d-gole@...com>
To: Cristian Marussi <cristian.marussi@....com>
CC: <linux-kernel@...r.kernel.org>, <linux-arm-kernel@...ts.infradead.org>,
        <arm-scmi@...r.kernel.org>, <linux-pm@...r.kernel.org>,
        <sudeep.holla@....com>, <james.quinlan@...adcom.com>,
        <f.fainelli@...il.com>, <vincent.guittot@...aro.org>,
        <quic_sibis@...cinc.com>, <dan.carpenter@...aro.org>,
        <johan+linaro@...nel.org>, <rafael@...nel.org>,
        <viresh.kumar@...aro.org>, <quic_mdtipton@...cinc.com>,
        Florian Fainelli
	<florian.fainelli@...adcom.com>
Subject: Re: [PATCH 2/2] [NOT_FOR_UPSTREAM] cpufreq: scmi: Add quirk to
 disable checks in scmi_dev_used_by_cpus()

On Aug 15, 2025 at 11:27:36 +0100, Cristian Marussi wrote:
> From: Florian Fainelli <florian.fainelli@...adcom.com>
> 
> Broadcom STB platforms were early adopters of the SCMI framework and as
> a result, not all deployed systems have a Device Tree entry where SCMI
> protocol 0x13 (PERFORMANCE) is declared as a clock provider, nor are the
> CPU Device Tree node(s) referencing protocol 0x13 as their clock
> provider.
> 
> Leverage the quirks framework recently introduce to match on the
> Broadcom SCMI vendor and in that case, disable the Device Tree
> properties checks being done by scmi_dev_used_by_cpus().
> 
> Suggested-by: Cristian Marussi <cristian.marussi@....com>
> Fixes: 6c9bb8692272 ("cpufreq: scmi: Skip SCMI devices that aren't used by the CPUs")
> Signed-off-by: Florian Fainelli <florian.fainelli@...adcom.com>
> [Cristian: Moved quirk directly into scmi_dev_used_by_cpus]
> Signed-off-by: Cristian Marussi <cristian.marussi@....com>
> 
> ----
> @Florian: I reworked this minimally to avoid the global as I was mentioning.
> No change around the version match either...so the NOT_FOR_UPSTREAM tag.
> (also the if (true) i smaybe a bit idiotic...)
> Please check if it is fine and modify as you see fit.
> ---
>  drivers/cpufreq/scmi-cpufreq.c     | 9 +++++++++
>  drivers/firmware/arm_scmi/quirks.c | 2 ++
>  include/linux/scmi_quirks.h        | 1 +
>  3 files changed, 12 insertions(+)
> 
> diff --git a/drivers/cpufreq/scmi-cpufreq.c b/drivers/cpufreq/scmi-cpufreq.c
> index ef078426bfd5..9b7cbc4e87d9 100644
> --- a/drivers/cpufreq/scmi-cpufreq.c
> +++ b/drivers/cpufreq/scmi-cpufreq.c
> @@ -19,6 +19,7 @@
>  #include <linux/pm_qos.h>
>  #include <linux/slab.h>
>  #include <linux/scmi_protocol.h>
> +#include <linux/scmi_quirks.h>
>  #include <linux/types.h>
>  #include <linux/units.h>
>  
> @@ -393,6 +394,12 @@ static struct cpufreq_driver scmi_cpufreq_driver = {
>  	.set_boost	= cpufreq_boost_set_sw,
>  };
>  
> +#define QUIRK_SCMI_CPUFREQ_CHECK_DT_PROPS			\
> +	({							\
> +		if (true)					\
> +			return true;				\
> +	})
> +

Probably another checkpatch warning to fix:
8<--------------------------------------------------------------------
WARNING: Macros with flow control statements should be avoided                                                                                                                                                     
#50: FILE: drivers/cpufreq/scmi-cpufreq.c:397:                                                                                                                                                                     
+#define QUIRK_SCMI_CPUFREQ_CHECK_DT_PROPS                      \                                        
+       ({                                                      \                                                                                                                                                  
+               if (true)                                       \                                        
+                       return true;                            \        
+       })                                                                                               
                                                                                                         
total: 0 errors, 1 warnings, 0 checks, 47 lines checked                                                  
-------------------------------------------------------------------->8


-- 
Best regards,
Dhruva Gole
Texas Instruments Incorporated