[U-Boot,1/2] Add board_panic_no_console to deal with early critical errors

Tested-by: Simon Glass <sjg@chromium.org>
Signed-off-by: Simon Glass <sjg@chromium.org>
---
 include/common.h |    8 ++++++++
 lib/vsprintf.c   |   26 ++++++++++++++++++++++++--
 2 files changed, 32 insertions(+), 2 deletions(-)

Hi Simon

On Tue, Aug 30, 2011 at 2:05 AM, Simon Glass <sjg@chromium.org> wrote:
> Tested-by: Simon Glass <sjg@chromium.org>
> Signed-off-by: Simon Glass <sjg@chromium.org>
> ---
>  include/common.h |    8 ++++++++
>  lib/vsprintf.c   |   26 ++++++++++++++++++++++++--
>  2 files changed, 32 insertions(+), 2 deletions(-)
>
> diff --git a/include/common.h b/include/common.h
> index 12a1074..856df9a 100644
> --- a/include/common.h
> +++ b/include/common.h
> @@ -250,6 +250,14 @@ int        last_stage_init(void);
>  extern ulong monitor_flash_len;
>  int mac_read_from_eeprom(void);
>

[snip]

> +/* Provide a default function for when no console is available */
> +static void __board_panic_no_console(const char *msg)
> +{
> +       /* Just return since we can't access the console */
> +}
> +
> +void board_panic_no_console(const char *msg) __attribute__((weak,
> +                                       alias("__board_panic_no_console")));
> +
>  void panic(const char *fmt, ...)
>  {
> +       char str[CONFIG_SYS_PBSIZE];
>        va_list args;
> +
>        va_start(args, fmt);
> -       vprintf(fmt, args);
> -       putc('\n');
> +
> +       /* TODO)sjg): Move to vsnprintf() when available */
> +       vsprintf(str, fmt, args);
>        va_end(args);
> +
> +       if (gd->have_console) {
> +               puts(str);
> +               putc('\n');
> +       } else {
> +               board_panic_no_console(str);
> +       }
> +

This patch highlights why console squelching should be done in console.c.
We are ending up with more and more if (gd->have_console) all over the
place. With the console squelching patch I posted earlier, I think it might
be easier to create a weak 'panic_printf()' which aliases to printf() which
the board can override if it has the ability to generate emergency output
before console is initialised. Console output will be squelched if the
board does not define such an override.

Regards,

Graeme

Hi Graeme,

On Mon, Aug 29, 2011 at 4:15 PM, Graeme Russ <graeme.russ@gmail.com> wrote:
> Hi Simon
>
> On Tue, Aug 30, 2011 at 2:05 AM, Simon Glass <sjg@chromium.org> wrote:
>> Tested-by: Simon Glass <sjg@chromium.org>
>> Signed-off-by: Simon Glass <sjg@chromium.org>
>> ---
>>  include/common.h |    8 ++++++++
>>  lib/vsprintf.c   |   26 ++++++++++++++++++++++++--
>>  2 files changed, 32 insertions(+), 2 deletions(-)
>>
>> diff --git a/include/common.h b/include/common.h
>> index 12a1074..856df9a 100644
>> --- a/include/common.h
>> +++ b/include/common.h
>> @@ -250,6 +250,14 @@ int        last_stage_init(void);
>>  extern ulong monitor_flash_len;
>>  int mac_read_from_eeprom(void);
>>
>
> [snip]
>
>> +/* Provide a default function for when no console is available */
>> +static void __board_panic_no_console(const char *msg)
>> +{
>> +       /* Just return since we can't access the console */
>> +}
>> +
>> +void board_panic_no_console(const char *msg) __attribute__((weak,
>> +                                       alias("__board_panic_no_console")));
>> +
>>  void panic(const char *fmt, ...)
>>  {
>> +       char str[CONFIG_SYS_PBSIZE];
>>        va_list args;
>> +
>>        va_start(args, fmt);
>> -       vprintf(fmt, args);
>> -       putc('\n');
>> +
>> +       /* TODO)sjg): Move to vsnprintf() when available */
>> +       vsprintf(str, fmt, args);
>>        va_end(args);
>> +
>> +       if (gd->have_console) {
>> +               puts(str);
>> +               putc('\n');
>> +       } else {
>> +               board_panic_no_console(str);
>> +       }
>> +
>
> This patch highlights why console squelching should be done in console.c.
> We are ending up with more and more if (gd->have_console) all over the
> place. With the console squelching patch I posted earlier, I think it might
> be easier to create a weak 'panic_printf()' which aliases to printf() which
> the board can override if it has the ability to generate emergency output
> before console is initialised. Console output will be squelched if the
> board does not define such an override.

My reasoning for putting this in panic is that the
board_panic_no_console() turns on all UARTS and might fiddle with baud
rates, etc. It should only be called once. Very much an emergency
function and not just a different implementation of puts(). That said,
with your approach above, I suppose panic_printf() would only be
called once.

I would suggest panic_puts() since this would call less external code
and be easier for boards to implement.

Regards,
Simon

>
> Regards,
>
> Graeme
>

Dear Simon Glass,

In message <1314633910-8550-2-git-send-email-sjg@chromium.org> you wrote:
> Tested-by: Simon Glass <sjg@chromium.org>
> Signed-off-by: Simon Glass <sjg@chromium.org>
> ---
>  include/common.h |    8 ++++++++
>  lib/vsprintf.c   |   26 ++++++++++++++++++++++++--
>  2 files changed, 32 insertions(+), 2 deletions(-)

Can we please make this feature conditional, so that boards that are
not going to use it don't have to suffer from the increased code size?

Thanks.

Best regards,

Wolfgang Denk

Hi Wolfgang,

On Mon, Oct 17, 2011 at 1:06 PM, Wolfgang Denk <wd@denx.de> wrote:
> Dear Simon Glass,
>
> In message <1314633910-8550-2-git-send-email-sjg@chromium.org> you wrote:
>> Tested-by: Simon Glass <sjg@chromium.org>
>> Signed-off-by: Simon Glass <sjg@chromium.org>
>> ---
>>  include/common.h |    8 ++++++++
>>  lib/vsprintf.c   |   26 ++++++++++++++++++++++++--
>>  2 files changed, 32 insertions(+), 2 deletions(-)
>
> Can we please make this feature conditional, so that boards that are
> not going to use it don't have to suffer from the increased code size?
>

We can easily make some of it conditional (the exported functions),
but some of it is changes to make the low-level formatter respect an
'end' pointer. I will take a look as there might be something clever
we can do there. We would also need to add, for example, an snprintf()
macro which drops the numeric parameter, so that code which uses
snprintf() continues to work.

Regards,
Simon

> Thanks.
>
> Best regards,
>
> Wolfgang Denk
>
> --
> DENX Software Engineering GmbH,     MD: Wolfgang Denk & Detlev Zundel
> HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany
> Phone: (+49)-8142-66989-10 Fax: (+49)-8142-66989-80 Email: wd@denx.de
> "The combination of a number of things to make existence worthwhile."
> "Yes, the philosophy of 'none,' meaning 'all.'"
>        -- Spock and Lincoln, "The Savage Curtain", stardate 5906.4
>

Hi Wofgang,

On Mon, Oct 17, 2011 at 1:21 PM, Simon Glass <sjg@chromium.org> wrote:
> Hi Wolfgang,
>
> On Mon, Oct 17, 2011 at 1:06 PM, Wolfgang Denk <wd@denx.de> wrote:
>> Dear Simon Glass,
>>
>> In message <1314633910-8550-2-git-send-email-sjg@chromium.org> you wrote:
>>> Tested-by: Simon Glass <sjg@chromium.org>
>>> Signed-off-by: Simon Glass <sjg@chromium.org>
>>> ---
>>>  include/common.h |    8 ++++++++
>>>  lib/vsprintf.c   |   26 ++++++++++++++++++++++++--
>>>  2 files changed, 32 insertions(+), 2 deletions(-)
>>
>> Can we please make this feature conditional, so that boards that are
>> not going to use it don't have to suffer from the increased code size?
>>
>
> We can easily make some of it conditional (the exported functions),
> but some of it is changes to make the low-level formatter respect an
> 'end' pointer. I will take a look as there might be something clever
> we can do there. We would also need to add, for example, an snprintf()
> macro which drops the numeric parameter, so that code which uses
> snprintf() continues to work.
>
> Regards,
> Simon
>
>> Thanks.
>>

I was thinking of your code size comments in snprintf() when I wrote
this - I sent another patch today which deals with that. I am hoping
that that will remove one more barrier to

To address your comment here the code size increase is 42 bytes on
ARMv7 with this option. The patch I have just sent makes it optional.

Regards,
Simon

>> Best regards,
>>
>> Wolfgang Denk
>>
>> --
>> DENX Software Engineering GmbH,     MD: Wolfgang Denk & Detlev Zundel
>> HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany
>> Phone: (+49)-8142-66989-10 Fax: (+49)-8142-66989-80 Email: wd@denx.de
>> "The combination of a number of things to make existence worthwhile."
>> "Yes, the philosophy of 'none,' meaning 'all.'"
>>        -- Spock and Lincoln, "The Savage Curtain", stardate 5906.4
>>
>