linux-kernel - Re: [PATCH] soc: sifive: ccache: reduce printing on init

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Message-ID: <e9132264-bec6-0f39-ff42-d8b6e95b2492@sifive.com>
Date:   Wed, 31 Aug 2022 16:55:10 +0100
From:   Ben Dooks <ben.dooks@...ive.com>
To:     Zong Li <zongbox@...il.com>, Ben Dooks <ben.dooks@...ethink.co.uk>
Cc:     Conor.Dooley@...rochip.com, zong.li@...ive.com, palmer@...belt.com,
        paul.walmsley@...ive.com, aou@...s.berkeley.edu,
        greentime.hu@...ive.com, linux-kernel@...r.kernel.org,
        linux-riscv@...ts.infradead.org
Subject: Re: [PATCH] soc: sifive: ccache: reduce printing on init

On 31/08/2022 06:22, Zong Li wrote:
> Ben Dooks <ben.dooks@...ethink.co.uk> 於 2022年8月31日 週三 凌晨1:04寫道：
>>
>> On 30/08/2022 17:30, Conor.Dooley@...rochip.com wrote:
>>> On 30/08/2022 09:26, Ben Dooks wrote:
>>>> EXTERNAL EMAIL: Do not click links or open attachments unless you know the content is safe
>>>>
>>>> The driver prints out 6 lines on startup, which can easily be redcued
>>>> to two lines without losing any information.
>>>>
>>>> Note, to make the types work better, uint64_t has been replaced with
>>>> ULL to make the unsigned long long match the format in the print
>>>> statement.
>>>>
>>>> Signed-off-by: Ben Dooks <ben.dooks@...ive.com>
>>>> ---
>>>>    drivers/soc/sifive/sifive_ccache.c | 25 +++++++++++--------------
>>>>    1 file changed, 11 insertions(+), 14 deletions(-)
>>>>
>>>> diff --git a/drivers/soc/sifive/sifive_ccache.c b/drivers/soc/sifive/sifive_ccache.c
>>>> index 46ce33db7d30..65a10a6ee211 100644
>>>> --- a/drivers/soc/sifive/sifive_ccache.c
>>>> +++ b/drivers/soc/sifive/sifive_ccache.c
>>>> @@ -76,20 +76,17 @@ static void setup_sifive_debug(void)
>>>>
>>>>    static void ccache_config_read(void)
>>>>    {
>>>> -       u32 regval, val;
>>>> -
>>>> -       regval = readl(ccache_base + SIFIVE_CCACHE_CONFIG);
>>>> -       val = regval & 0xFF;
>>>> -       pr_info("CCACHE: No. of Banks in the cache: %d\n", val);
>>>> -       val = (regval & 0xFF00) >> 8;
>>>> -       pr_info("CCACHE: No. of ways per bank: %d\n", val);
>>>> -       val = (regval & 0xFF0000) >> 16;
>>>> -       pr_info("CCACHE: Sets per bank: %llu\n", (uint64_t)1 << val);
>>>> -       val = (regval & 0xFF000000) >> 24;
>>>> -       pr_info("CCACHE: Bytes per cache block: %llu\n", (uint64_t)1 << val);
>>>> -
>>>> -       regval = readl(ccache_base + SIFIVE_CCACHE_WAYENABLE);
>>>> -       pr_info("CCACHE: Index of the largest way enabled: %d\n", regval);
>>>> +       u32 cfg;
>>>> +
>>>> +       cfg = readl(ccache_base + SIFIVE_CCACHE_CONFIG);
>>>> +
>>>> +       pr_info("CCACHE: %u banks, %u ways, sets/bank=%llu, bytes/block=%llu\n",
>>>> +               (cfg & 0xff), (cfg >> 8) & 0xff,
>>>> +               1ULL << ((cfg >> 16) & 0xff),
>>>
>>> This is just BIT_ULL((cfg >> 16) & 0xff), no?
>>> Would be nice too if these were defined, so you'd have something
>>> like BIT_ULL((cfg >> SETS_PER_BANK_SHIFT) & 0xff)
>>>
>>> I do like the cleanup of the uint64_t & cutting down on the prints
>>> though :) Again, it'd be nice if you and Zong could collaborate on
>>> a combined v2.
>>
>> I think even BIT_UL() would do here, if someone is going to make a
>> cache bigger than 2GiB we'll probably be quite old by then, so v2
>> might have the last two values down as %lu.
>>
> 
> Hi Ben,
> Thanks for your suggestion, If you don't mind, I will take this into
> my V2 patchset.

Thanks.

I may well post v2 of this tomorrow with the BIT_ULL() suggestions
from Conor, or even down to BIT_UL() and use %lu as noted.

> 
>>> Thanks,
>>> Conor.
>>>
>>>> +               1ULL << ((cfg >> 24) & 0xff));
>>>> +
>>>> +       cfg = readl(ccache_base + SIFIVE_CCACHE_WAYENABLE);
>>>> +       pr_info("CCACHE: Index of the largest way enabled: %d\n", cfg);
>>>>    }
>>>>
>>>>    static const struct of_device_id sifive_ccache_ids[] = {
>>>> --
>>>> 2.35.1
>>>>
>>>
>>> _______________________________________________
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>>> linux-riscv@...ts.infradead.org
>>> http://lists.infradead.org/mailman/listinfo/linux-riscv
>>>
>>
>> --
>> Ben Dooks                               http://www.codethink.co.uk/
>> Senior Engineer                         Codethink - Providing Genius
>>
>> https://www.codethink.co.uk/privacy.html
>>
>>
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