linux-kernel - Re: [PATCH 3/4] memory: jz4780-nemc: Reduce size of const array

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Message-Id: <1547820650.1909.0@crapouillou.net>
Date:   Fri, 18 Jan 2019 11:10:50 -0300
From:   Paul Cercueil <paul@...pouillou.net>
To:     Boris Brezillon <bbrezillon@...nel.org>
Cc:     Rob Herring <robh+dt@...nel.org>,
        Mark Rutland <mark.rutland@....com>,
        Miquel Raynal <miquel.raynal@...tlin.com>,
        devicetree@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH 3/4] memory: jz4780-nemc: Reduce size of const array


Hi,

On Fri, Jan 18, 2019 at 5:15 AM, Boris Brezillon 
<bbrezillon@...nel.org> wrote:
> On Thu, 17 Jan 2019 19:45:49 -0300
> Paul Cercueil <paul@...pouillou.net <mailto:paul@...pouillou.net>> 
> wrote:
> 
>>  The maximum value found in that array is 15, there's no need to 
>> store
>>  these values as uint32_t, a uint8_t is enough.
> 
> Is it really worth the additional cast you add in the code?

They're not needed. I had to verify, because it was not obvious to me.
I'll remove them then.

>> 
>>  Signed-off-by: Paul Cercueil <paul@...pouillou.net 
>> <mailto:paul@...pouillou.net>>
>>  ---
>>   drivers/memory/jz4780-nemc.c | 6 +++---
>>   1 file changed, 3 insertions(+), 3 deletions(-)
>> 
>>  diff --git a/drivers/memory/jz4780-nemc.c 
>> b/drivers/memory/jz4780-nemc.c
>>  index bcf06adefc96..ef3f20e46590 100644
>>  --- a/drivers/memory/jz4780-nemc.c
>>  +++ b/drivers/memory/jz4780-nemc.c
>>  @@ -161,7 +161,7 @@ static bool jz4780_nemc_configure_bank(struct 
>> jz4780_nemc *nemc,
>>   	 * Conversion of tBP and tAW cycle counts to values supported by 
>> the
>>   	 * hardware (round up to the next supported value).
>>   	 */
>>  -	static const uint32_t convert_tBP_tAW[] = {
>>  +	static const u8 convert_tBP_tAW[] = {
>>   		0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10,
>> 
>>   		/* 11 - 12 -> 12 cycles */
>>  @@ -232,7 +232,7 @@ static bool jz4780_nemc_configure_bank(struct 
>> jz4780_nemc *nemc,
>>   			return false;
>>   		}
>> 
>>  -		smcr |= convert_tBP_tAW[cycles] << NEMC_SMCR_TBP_SHIFT;
>>  +		smcr |= (u32)convert_tBP_tAW[cycles] << NEMC_SMCR_TBP_SHIFT;
>>   	}
>> 
>>   	if (of_property_read_u32(node, "ingenic,nemc-tAW", &val) == 0) {
>>  @@ -244,7 +244,7 @@ static bool jz4780_nemc_configure_bank(struct 
>> jz4780_nemc *nemc,
>>   			return false;
>>   		}
>> 
>>  -		smcr |= convert_tBP_tAW[cycles] << NEMC_SMCR_TAW_SHIFT;
>>  +		smcr |= (u32)convert_tBP_tAW[cycles] << NEMC_SMCR_TAW_SHIFT;
>>   	}
>> 
>>   	if (of_property_read_u32(node, "ingenic,nemc-tSTRV", &val) == 0) {
>