[U-Boot] [PATCH v3] arm: socfpga: mailbox: Fix off-by-one error on command length checking

[Marek Vasut]

On 4/22/19 3:20 AM, Ley Foon Tan wrote:
> On Sun, Apr 21, 2019 at 4:30 PM Marek Vasut <marex at denx.de> wrote:
>>
>> On 4/19/19 10:52 PM, Simon Goldschmidt wrote:
>>>
>>>
>>> Marek Vasut <marex at denx.de <mailto:marex at denx.de>> schrieb am Fr., 19.
>>> Apr. 2019, 11:29:
>>>
>>>     On 4/19/19 8:17 AM, Ley Foon Tan wrote:
>>>     > A mailbox command contains 1-DWORD header + arguments. The "len"
>>>     variable
>>>     > only contains the length of the arguments, but not the 1-DWORD header.
>>>     > Include the length of header when checking the ring buffer space to
>>>     > prevent off-by-one error.
>>>
>>>     How long is a DWORD ? Windows API (which we have nothing to do with)
>>>     defines that as 32bit type, "typedef unsigned long DWORD;", see [1].
>>>     But the patch below fixes an off-by-one error , not off by four error ?
>>>
>>>
>>> As all the macros for that mailbox seem to do u32 index access only, I'd
>>> be ok with the commit message if it didn't use the term 'DWORD'...
>>
>> Does that mean MBOX_CMD_BUFFER_SIZE is not in byte units, but in u32 units ?
> Yes, it is in u32 unit. One slot location is u32.
> How about change DWORD to u32 in commit message?

Yes please. It would also make sense to add a comment into the code that
len is not in bytes, but u32 units .

-- 
Best regards,
Marek Vasut