linux-kernel - Re: [PATCH v4 8/9] mips: ralink: get cpu rate from new driver code

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <c1a69db7-96c2-f3ad-3ef2-9a655b10bfb5@linaro.org>
Date:   Sat, 17 Jun 2023 16:48:18 +0200
From:   Krzysztof Kozlowski <krzysztof.kozlowski@...aro.org>
To:     Sergio Paracuellos <sergio.paracuellos@...il.com>,
        linux-clk@...r.kernel.org
Cc:     linux-mips@...r.kernel.org, tsbogend@...ha.franken.de,
        john@...ozen.org, linux-kernel@...r.kernel.org,
        p.zabel@...gutronix.de, mturquette@...libre.com, sboyd@...nel.org,
        robh+dt@...nel.org, krzysztof.kozlowski+dt@...aro.org,
        matthias.bgg@...il.com, devicetree@...r.kernel.org,
        arinc.unal@...nc9.com
Subject: Re: [PATCH v4 8/9] mips: ralink: get cpu rate from new driver code

On 17/06/2023 07:24, Sergio Paracuellos wrote:
> At very early stage on boot, there is a need to set 'mips_hpt_frequency'.
> This timer frequency is a half of the CPU frequency. To get clocks properly
> set we need to call to 'of_clk_init()' and properly get cpu clock frequency
> afterwards. Depending on the SoC, CPU clock index in the clock provider is
> different being two for MT7620 SoC and one for the rest. Hence, adapt code
> to be aligned with new clock driver.


>  void __init plat_time_init(void)
>  {
> +	struct of_phandle_args clkspec;
>  	struct clk *clk;
> +	int cpu_clk_idx;
>  
>  	ralink_of_remap();
>  
> -	ralink_clk_init();
> -	clk = clk_get_sys("cpu", NULL);
> +	cpu_clk_idx = clk_cpu_index();
> +	if (cpu_clk_idx == -1)
> +		panic("unable to get CPU clock index");
> +
> +	of_clk_init(NULL);
> +	clkspec.np = of_find_node_by_name(NULL, "sysc");
> +	clkspec.args_count = 1;
> +	clkspec.args[0] = cpu_clk_idx;
> +	clk = of_clk_get_from_provider(&clkspec);

This is very obfuscated way of getting clock. Why can't you get it from
"clocks" property of "cpu", like every other recent platform?

Anyway, NAK for of_find_node_by_name(), because you now create ABI for
node name. It's broken approach.

Best regards,
Krzysztof