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

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Date:   Tue, 30 Aug 2022 18:03:46 +0100
From:   Ben Dooks <ben.dooks@...ethink.co.uk>
To:     Conor.Dooley@...rochip.com, ben.dooks@...ive.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 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.

> 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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> 

-- 
Ben Dooks				http://www.codethink.co.uk/
Senior Engineer				Codethink - Providing Genius

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