[U-Boot] [PATCH 62/71] serial: spl: Implement empty functions for SPL

Tom Rini
2012-09-18T18:08:32Z

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On 09/18/12 11:01, Marek Vasut wrote:
> Dear Tom Rini,
>
>> On 09/18/12 10:13, Marek Vasut wrote:
>>> Dear Tom Rini,
>>>
>>>> On Mon, Sep 17, 2012 at 01:21:27AM +0200, Marek Vasut wrote:
>>>>> Implement empty serial_* functions for SPL without serial
>>>>> support enabled. This is imperative to haave once serial
>>>>> multi is enabled unconditionally.
>>>>>
>>>>> Signed-off-by: Marek Vasut <marex@denx.de> Cc: Marek Vasut
>>>>> <marek.vasut@gmail.com> Cc: Tom Rini <trini@ti.com> ---
>>>>>
>>>>> common/serial.c | 12 ++++++++++++ 1 file changed, 12
>>>>> insertions(+)
>>>>>
>>>>> diff --git a/common/serial.c b/common/serial.c index
>>>>> 631af65..cef4ba8 100644 --- a/common/serial.c +++
>>>>> b/common/serial.c @@ -27,6 +27,16 @@
>>>>>
>>>>> #include <post.h> #include <linux/compiler.h>
>>>>>
>>>>> +/* Implement prototypes for SPL without serial support */
>>>>> +#if defined(CONFIG_SPL_BUILD) &&
>>>>> !defined(CONFIG_SPL_SERIAL_SUPPORT) +int serial_init(void)
>>>>> { return 0; } +void serial_setbrg(void) {} +int
>>>>> serial_getc(void) { return 0; } +int serial_tstc(void) {
>>>>> return 0; } +void serial_putc(const char c) {} +void
>>>>> serial_puts(const char *s) {}
>>>>
>>>> This isn't quite right. We need to allow for: - No output
>>>> SPL, strings collected (so #defined to do{} while (0))
>>>
>>> Which is not type-checked and will drag in bugs.
>>
>> Scott has addressed this.
>>
>>>> - puts + printf SPL (CONFIG_SPL_SERIAL_SUPPORT +
>>>> CONFIG_SPL_LIBCOMMON_SUPPORT) - puts only SPL
>>>> (CONFIG_SPL_SERIAL_SUPPORT + #define puts serial_puts/putc).
>>>>
>>>> I'm not asking you to do that, but you will have to adapt to
>>>> it once Jose is done with it. What that means, off the top
>>>> of my head, is we can just drop this patch as in the first
>>>> and last case serial.o will be garbage-collected (or not
>>>> built) and in the middle case, this will be fully used.
>>>
>>> I can't drop this patch as it will break all of SPL when
>>> CONFIG_SERIAL_MULTI is unconditionally enabled.
>>
>> Why is it breaking _all_ of SPL? Have you run-tested this
>> anywhere, especially with SPL? In most cases it should be used
>> and real functions provided or garbage collected away.
>
> Yes, try compiling m28evk without this patch for example, it's
> going to break it. Because CONFIG_SPL_SERIAL_SUPPORT is disabled,
> yet it uses code that contains references to puts() etc.

Progress! Now, why isn't this file being garbage collected? m28evk
is fitting into the first category I said (no output) but now it's not
discarding things that it should be discarding.

- --
Tom
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