Re: [PATCH V4 13/23] RISC-V: cpufeature: Add ACPI support in riscv_fill_hwcap()

From: Conor Dooley <conor@kernel.org>
To: Sunil V L <sunilvl@ventanamicro.com>
Cc: linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org,
	linux-riscv@lists.infradead.org, linux-acpi@vger.kernel.org,
	linux-crypto@vger.kernel.org,
	platform-driver-x86@vger.kernel.org, llvm@lists.linux.dev,
	Jonathan Corbet <corbet@lwn.net>,
	Paul Walmsley <paul.walmsley@sifive.com>,
	Palmer Dabbelt <palmer@dabbelt.com>,
	Albert Ou <aou@eecs.berkeley.edu>, Len Brown <lenb@kernel.org>,
	Daniel Lezcano <daniel.lezcano@linaro.org>,
	Thomas Gleixner <tglx@linutronix.de>,
	Weili Qian <qianweili@huawei.com>,
	Zhou Wang <wangzhou1@hisilicon.com>,
	Herbert Xu <herbert@gondor.apana.org.au>,
	Marc Zyngier <maz@kernel.org>,
	Maximilian Luz <luzmaximilian@gmail.com>,
	Hans de Goede <hdegoede@redhat.com>,
	Mark Gross <markgross@kernel.org>,
	Nathan Chancellor <nathan@kernel.org>,
	Nick Desaulniers <ndesaulniers@google.com>,
	Tom Rix <trix@redhat.com>,
	"Rafael J . Wysocki" <rafael@kernel.org>,
	"David S . Miller" <davem@davemloft.net>,
	"Rafael J . Wysocki" <rafael.j.wysocki@intel.com>,
	Andrew Jones <ajones@ventanamicro.com>
Subject: Re: [PATCH V4 13/23] RISC-V: cpufeature: Add ACPI support in riscv_fill_hwcap()
Date: Sat, 29 Apr 2023 11:31:20 +0100	[thread overview]
Message-ID: <20230429-voucher-tutor-715fd4f6c24e@spud> (raw)
In-Reply-To: <20230404182037.863533-14-sunilvl@ventanamicro.com>

[-- Attachment #1.1: Type: text/plain, Size: 1686 bytes --]

Hey Sunil,

On Tue, Apr 04, 2023 at 11:50:27PM +0530, Sunil V L wrote:

> @@ -103,14 +109,36 @@ void __init riscv_fill_hwcap(void)
>  
>  	bitmap_zero(riscv_isa, RISCV_ISA_EXT_MAX);
>  
> -	for_each_of_cpu_node(node) {
> +	if (!acpi_disabled) {
> +		status = acpi_get_table(ACPI_SIG_RHCT, 0, &rhct);
> +		if (ACPI_FAILURE(status))
> +			return;
> +	}
> +
> +	for_each_possible_cpu(cpu) {
>  		unsigned long this_hwcap = 0;
>  		DECLARE_BITMAP(this_isa, RISCV_ISA_EXT_MAX);
>  		const char *temp;
>  
> -		if (of_property_read_string(node, "riscv,isa", &isa)) {
> -			pr_warn("Unable to find \"riscv,isa\" devicetree entry\n");
> -			continue;
> +		if (acpi_disabled) {
> +			node = of_cpu_device_node_get(cpu);
> +			if (node) {
> +				rc = of_property_read_string(node, "riscv,isa", &isa);
> +				of_node_put(node);
> +				if (rc) {
> +					pr_warn("Unable to find \"riscv,isa\" devicetree entry\n");
> +					continue;
> +				}
> +			} else {
> +				pr_warn("Unable to find cpu node\n");
> +				continue;

I was poking at this the last few days and went back to look at the ACPI
code again. Is there a reason we don't do early-return here? IOW:

	node = of_cpu_device_node_get(cpu);
	if (!node) {
		pr_warn()
		continue;
	}

	rc = of_property_read_string(node, "riscv,isa", &isa);
	of_node_put(node);
	if (rc) {
		pr_warn();
		continue;
	}

Cheers,
Conor.

> +			}
> +		} else {
> +			rc = acpi_get_riscv_isa(rhct, cpu, &isa);
> +			if (rc < 0) {
> +				pr_warn("Unable to get ISA for the hart - %d\n", cpu);
> +				continue;
> +			}
>  		}
>  
>  		temp = isa;
> @@ -243,6 +271,9 @@ void __init riscv_fill_hwcap(void)

[-- Attachment #1.2: signature.asc --]
[-- Type: application/pgp-signature, Size: 228 bytes --]

[-- Attachment #2: Type: text/plain, Size: 161 bytes --]

_______________________________________________
linux-riscv mailing list
linux-riscv@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-riscv