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

[Conor Dooley]

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)
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