[U-Boot] [PATCH] [WIP] sandbox: spi/sf emulation

[Mike Frysinger]

On Sat, Oct 29, 2011 at 02:47, Simon Glass wrote:
> On Wed, Oct 26, 2011 at 1:37 PM, Mike Frysinger wrote:
>> On Wed, Oct 26, 2011 at 12:26, Simon Glass wrote:
>>> On Wed, Oct 26, 2011 at 3:30 AM, Mike Frysinger wrote:
>>>> --- a/arch/sandbox/cpu/os.c
>>>> +++ b/arch/sandbox/cpu/os.c
>>>>
>>>> +off_t os_lseek(int fd, off_t offset, int whence)
>>>> +{
>>>> +       return lseek(fd, offset, whence);
>>>> +}
>>>
>>> How are we going to deal with calls to something like this where
>>> 'whence' is defined in an OS-specific header file? I believe we need
>>> to add definitions to os.h to provide this feature, and make them
>>> match Posix. Is there a better way? open has a similar problem.
>>
>> yeah, i noticed this, but was ignoring it for the time being.  the
>> only portable way i think is to have our local os.h provide arbitrary
>> defines which the rest of u-boot will utilize, and then in the os_xxx
>> func, we translate into the host defines.  a bit ugly, but it's the
>> only way to really work since there is no guarantee that something
>> like O_RDONLY will always be defined to 0.
>
> I care less about portability to non-POSIX, others may though. Perhaps
> just defining the types and #defines with a suitable prefix in the
> header file, and then a compile-time assert in the C would be good
> enough.

funny story: POSIX doesn't mandate the values behind the defines, only
that the defines exist and are suitable for CPP usage.  notice i said
"portable" and not "POSIX" ... that was not an accident :).  the
defines may differ across Linux architectures, as well as ABIs (e.g.
x86 vs x86_64 vs x32), as well as C libraries, as well as operating
systems.  in practice, i vaguely recall the few defines we probably
would use (ro/wo/rw/create) are the same across all Linux
arches/ABIs/C libraries, but that's an icky situation to paint
yourself into.

a quick grep would probably clarify if the #if/#error assert logic
would be sufficient to pass compile/run, but not necessarily pass the
wd ;).

>>>> --- a/arch/sandbox/cpu/start.c
>>>> +++ b/arch/sandbox/cpu/start.c
>>>>
>>>> +       if (os_getopt("-h", 0) || os_getopt("--help", 0)) {
>>>> +               serial_puts(usage);
>>>> +               return 0;
>>>> +       }
>>>
>>> I did actually create something to parse args and put them into a
>>> 'state' structure. But it uses getopt_long(). Any reason we can't?
>>
>> on reason i didn't was so i wouldn't have to worry about translating
>> defines/structs used in u-boot and defines/structs used by the host
>> system.  i.e. the same issue we face with bits for os_{open,lseek}.
>
> Well I don't think we should be passing any getopt structures outside
> os.c or parse.c. That is the intent of my state.c - a place where the
> test state / arguments is stored and can be accessed when needed
> without reference to os-dependent code / structures.

hrm, i'm not seeing what you mean, but i'll take a closer look at the code.
-mike