Re: [PATCH 2/2] PCI: rcar: Replace unsigned long with u32 in register accessors

[Marek Vasut <marek.vasut@gmail.com>]

On 3/25/19 9:06 AM, Geert Uytterhoeven wrote:
> Hi Marek,
> 
> On Thu, Mar 21, 2019 at 4:20 AM Marek Vasut <marek.vasut@gmail.com> wrote:
>> On 3/18/19 9:19 AM, Geert Uytterhoeven wrote:
>>> On Mon, Mar 18, 2019 at 12:39 AM Marek Vasut <marek.vasut@gmail.com> wrote:
>>>> On 3/17/19 11:22 AM, Geert Uytterhoeven wrote:
>>>>> On Sun, Mar 17, 2019 at 1:06 AM Marek Vasut <marek.vasut@gmail.com> wrote:
>>>>>> On 3/11/19 10:41 AM, Geert Uytterhoeven wrote:
>>>>>>> On Sat, Mar 9, 2019 at 1:56 AM <marek.vasut@gmail.com> wrote:
>>>>>>>> --- a/drivers/pci/controller/pcie-rcar.c
>>>>>>>> +++ b/drivers/pci/controller/pcie-rcar.c
>>>>>>>> @@ -152,14 +152,12 @@ struct rcar_pcie {
>>>>>>>>         struct                  rcar_msi msi;
>>>>>>>>  };
>>>>>>>>
>>>>>>>> -static void rcar_pci_write_reg(struct rcar_pcie *pcie, unsigned long val,
>>>>>>>> -                              unsigned long reg)
>>>>>>>> +static void rcar_pci_write_reg(struct rcar_pcie *pcie, u32 val, u32 reg)
>>>>>>>
>>>>>>> Doesn't unsigned int make more sense for reg?
>>>>>>
>>>>>> Isn't u32 more explicit ?
>>>>>
>>>>> It's just an offset in the register block, with a range much smaller than u32.
>>>>
>>>> We could use u16 ?
>>>
>>> u16 may be more expensive on some processor architectures
>>> (MIPS comes too mind, don't know about ARM).
>>
>> On armv8a, none.
>>
>>>> However, Bjorn's concern was that using unsigned long
>>>> for registers was not recommended ;
>>>
>>> Wasn't that comment meant for the size of the register values?
>>>
>>>> how's unsigned int better ?
>>>
>>> Basic rule "If you don't care about the size, use (unsigned) int"?
>>
>> This only applies to the $shift variable, yes ? The rest are u32 since
>> those contain actual values read/written into the registers.
> 
> There is no "shift" variable. "reg" is a register offset, not an actual register
> value.

Sure

-- 
Best regards,
Marek Vasut