linux-kernel - Re: [PATCH v4 2/3] riscv: cacheinfo: initialize cacheinfo's level and type from ACPI PPTT

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Date: Thu, 18 Apr 2024 09:41:44 +0100
From: Sudeep Holla <sudeep.holla@....com>
To: Yunhui Cui <cuiyunhui@...edance.com>
Cc: rafael@...nel.org, lenb@...nel.org, linux-acpi@...r.kernel.org,
	Sudeep Holla <sudeep.holla@....com>, linux-kernel@...r.kernel.org,
	paul.walmsley@...ive.com, palmer@...belt.com, aou@...s.berkeley.edu,
	linux-riscv@...ts.infradead.org, bhelgaas@...gle.com,
	james.morse@....com, jhugo@...eaurora.org, jeremy.linton@....com,
	john.garry@...wei.com, Jonathan.Cameron@...wei.com,
	pierre.gondois@....com, tiantao6@...wei.com
Subject: Re: [PATCH v4 2/3] riscv: cacheinfo: initialize cacheinfo's level
 and type from ACPI PPTT

On Thu, Apr 18, 2024 at 11:43:29AM +0800, Yunhui Cui wrote:
> Before cacheinfo can be built correctly, we need to initialize level
> and type. Since RSIC-V currently does not have a register group that
> describes cache-related attributes like ARM64, we cannot obtain them
> directly, so now we obtain cache leaves from the ACPI PPTT table
> (acpi_get_cache_info()) and set the cache type through split_levels.
> 
> Suggested-by: Jeremy Linton <jeremy.linton@....com>
> Suggested-by: Sudeep Holla <sudeep.holla@....com>
> Signed-off-by: Yunhui Cui <cuiyunhui@...edance.com>
> ---
>  arch/riscv/kernel/cacheinfo.c | 22 ++++++++++++++++++++++
>  1 file changed, 22 insertions(+)
> 
> diff --git a/arch/riscv/kernel/cacheinfo.c b/arch/riscv/kernel/cacheinfo.c
> index 30a6878287ad..e47a1e6bd3fe 100644
> --- a/arch/riscv/kernel/cacheinfo.c
> +++ b/arch/riscv/kernel/cacheinfo.c
> @@ -6,6 +6,7 @@
>  #include <linux/cpu.h>
>  #include <linux/of.h>
>  #include <asm/cacheinfo.h>
> +#include <linux/acpi.h>
>  
>  static struct riscv_cacheinfo_ops *rv_cache_ops;
>  
> @@ -78,6 +79,27 @@ int populate_cache_leaves(unsigned int cpu)
>  	struct device_node *prev = NULL;
>  	int levels = 1, level = 1;
>  
> +	if (!acpi_disabled) {
> +		int ret, fw_levels, split_levels;
> +
> +		ret = acpi_get_cache_info(cpu, &fw_levels, &split_levels);
> +		if (ret)
> +			return ret;
> +
> +		BUG_ON((split_levels > fw_levels) ||
> +		       (split_levels + fw_levels > this_cpu_ci->num_leaves));
> +
> +		for (; level <= this_cpu_ci->num_levels; level++) {
> +			if (level <= split_levels) {
> +				ci_leaf_init(this_leaf++, CACHE_TYPE_DATA, level);
> +				ci_leaf_init(this_leaf++, CACHE_TYPE_INST, level);
> +			} else {
> +				ci_leaf_init(this_leaf++, CACHE_TYPE_UNIFIED, level);
> +			}
> +		}
> +		return 0;
> +	}
> +

Much better, so my review still stands 😄

Reviewed-by: Sudeep Holla <sudeep.holla@....com>

>  	if (of_property_read_bool(np, "cache-size"))
>  		ci_leaf_init(this_leaf++, CACHE_TYPE_UNIFIED, level);
>  	if (of_property_read_bool(np, "i-cache-size"))
> -- 
> 2.20.1
> 

-- 
Regards,
Sudeep