[U-Boot] ctrl-c detection (on 4xx platforms)

[U-Boot] ctrl-c detection (on 4xx platforms)

[Matthias Fuchs]

Hi,

I noticed some strange CTRL-C behavior in a BSP command. 
When I run my bsp command interactively everything is fine.
The command waits for a condition and displays a rotating cursor
(see board/esd/common/cmd_loadpci.c):

...
int do_loadpci(cmd_tbl_t *cmdtp, int flag, int argc, char *argv[])
{
	...
	char str[] = "\\|/-";
	...

	while(1) {
		...
		*ptr = 0xffffffff;
		puts("\nWaiting for action from pci host -");

		/*
		 * Wait for host to write the start address
		 */
		while (*ptr == 0xffffffff) {
			count++;
			if (!(count % 100)) {
				count2++;
				putc(0x08); /* backspace */
				putc(str[count2 % 4]);
			}

			/* Abort if ctrl-c was pressed */
			if (ctrlc()) {
				puts("\nAbort\n");
				return 0;
			}

			udelay(1000);
		}
	}
	...
}

But when I call this bsp command as bootcmd CTRL-C does not stop the while loop. So CTRL-C 
is not detected. Any idea?

Matthias

[U-Boot] ctrl-c detection (on 4xx platforms)

[Wolfgang Denk]

Dear Matthias Fuchs,

In message <200809111723.54133.matthias.fuchs@esd-electronics.com> you wrote:
> 
> I noticed some strange CTRL-C behavior in a BSP command. 
> When I run my bsp command interactively everything is fine.
...
> But when I call this bsp command as bootcmd CTRL-C does not stop the while loop. So CTRL-C 
> is not detected. Any idea?

Do you happen to have CONFIG_AUTOBOOT_KEYED set in your board
configuration?

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 at denx.de
Program maintenance is an entropy-increasing process,  and  even  its
most skilfull execution only delays the subsidence of the system into
unfixable obsolescence.       - Fred Brooks, "The Mythical Man Month"

[U-Boot] ctrl-c detection (on 4xx platforms)

[Matthias Fuchs]

Hi Wolfgang,

yes I do have CONFIG_AUTOBOOT_KEYED enabled. It's the PMC440 board:

include/configs/PMC440.h:
...
#define CONFIG_AUTOBOOT_KEYED	1
#define CONFIG_AUTOBOOT_PROMPT	\
	"Press SPACE to abort autoboot in %d seconds\n", bootdelay
#undef CONFIG_AUTOBOOT_DELAY_STR
#define CONFIG_AUTOBOOT_STOP_STR " "
...

Matthias


On Thursday 11 September 2008 22:55, Wolfgang Denk wrote:
> Dear Matthias Fuchs,
> 
> In message <200809111723.54133.matthias.fuchs@esd-electronics.com> you wrote:
> > 
> > I noticed some strange CTRL-C behavior in a BSP command. 
> > When I run my bsp command interactively everything is fine.
> ...
> > But when I call this bsp command as bootcmd CTRL-C does not stop the while loop. So CTRL-C 
> > is not detected. Any idea?
> 
> Do you happen to have CONFIG_AUTOBOOT_KEYED set in your board
> configuration?
> 
> Best regards,
> 
> Wolfgang Denk
> 

[U-Boot] ctrl-c detection (on 4xx platforms)

[Matthias Fuchs]

Hi,

when I disable CONFIG_AUTOBOOT_KEYED ctrl-c checking is not disabled.
We are using CONFIG_AUTOBOOT_KEYED to have a special key (SPACE) to
abort autoboot and not the 'any' key.

Is there any special reason why ctrl-c checking is disabled for CONFIG_AUTOBOOT_KEYED?

Matthias

On Friday 12 September 2008 09:00, Matthias Fuchs wrote:
> Hi Wolfgang,
> 
> yes I do have CONFIG_AUTOBOOT_KEYED enabled. It's the PMC440 board:
> 
> include/configs/PMC440.h:
> ...
> #define CONFIG_AUTOBOOT_KEYED	1
> #define CONFIG_AUTOBOOT_PROMPT	\
> 	"Press SPACE to abort autoboot in %d seconds\n", bootdelay
> #undef CONFIG_AUTOBOOT_DELAY_STR
> #define CONFIG_AUTOBOOT_STOP_STR " "
> ...
> 
> Matthias
> 
> 
> On Thursday 11 September 2008 22:55, Wolfgang Denk wrote:
> > Dear Matthias Fuchs,
> > 
> > In message <200809111723.54133.matthias.fuchs@esd-electronics.com> you wrote:
> > > 
> > > I noticed some strange CTRL-C behavior in a BSP command. 
> > > When I run my bsp command interactively everything is fine.
> > ...
> > > But when I call this bsp command as bootcmd CTRL-C does not stop the while loop. So CTRL-C 
> > > is not detected. Any idea?
> > 
> > Do you happen to have CONFIG_AUTOBOOT_KEYED set in your board
> > configuration?
> > 
> > Best regards,
> > 
> > Wolfgang Denk
> > 
> _______________________________________________
> U-Boot mailing list
> U-Boot at lists.denx.de
> http://lists.denx.de/mailman/listinfo/u-boot
> 
> 

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[U-Boot] ctrl-c detection (on 4xx platforms)

[Wolfgang Denk]

Dear Matthias Fuchs,

In message <200809120955.10866.matthias.fuchs@esd-electronics.com> you wrote:
> 
> when I disable CONFIG_AUTOBOOT_KEYED ctrl-c checking is not disabled.

I think there is one "dis" ot "not" too many.

> We are using CONFIG_AUTOBOOT_KEYED to have a special key (SPACE) to
> abort autoboot and not the 'any' key.

I thought so.

> Is there any special reason why ctrl-c checking is disabled for CONFIG_AUTOBOOT_KEYED?

Excellent question. Next question, please.


I think the rationale behind this is to prevent users from getting an
interactive  prompt  by  just  pressing  ^C  -   the   intention   of
CONFIG_AUTOBOOT_KEYED  is  similar to a login with password - without
the correct password you are denied access to an  interactive  inter-
face.

But if you could use ^C as soon as the bootcmd  has  started  -  what
should  happen  next?  We cannot simply drop you into the interactive
shell?

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 at denx.de
When the ax entered the forest, the trees said, "The handle is one of
us!"                                               -- Turkish proverb

[U-Boot] ctrl-c detection (on 4xx platforms)

[Matthias Fuchs]

Hi Wolfgang,

On Friday 12 September 2008 11:08:51 Wolfgang Denk wrote:
> Dear Matthias Fuchs,
>
> In message <200809120955.10866.matthias.fuchs@esd-electronics.com> you 
wrote:
> > when I disable CONFIG_AUTOBOOT_KEYED ctrl-c checking is not disabled.
>
> I think there is one "dis" ot "not" too many.
:-)
>
> > We are using CONFIG_AUTOBOOT_KEYED to have a special key (SPACE) to
> > abort autoboot and not the 'any' key.
>
> I thought so.
>
> > Is there any special reason why ctrl-c checking is disabled for
> > CONFIG_AUTOBOOT_KEYED?
>
> Excellent question. Next question, please.
>
>
> I think the rationale behind this is to prevent users from getting an
> interactive  prompt  by  just  pressing  ^C  -   the   intention   of
> CONFIG_AUTOBOOT_KEYED  is  similar to a login with password - without
> the correct password you are denied access to an  interactive  inter-
> face.
I see. This makes sense.
>
> But if you could use ^C as soon as the bootcmd  has  started  -  what
> should  happen  next?  We cannot simply drop you into the interactive
> shell?
Ok, this will cancel the whole mechanism. 

I only want to allow the space key to abort autoboot. With serial console 
cables connected (with no PC on the other side) you sometimes receive some
noise characters because of crosstalk. These chars will stop autoboot -> not 
good! We did never see this when restricting the stopkey to the space key.

Because I only need to abort my special bootcmd during testing I reenabled
ctrl-c checking in my loadpci command. 

Thanks for pointing out the ..KEYED philosophy.

Matthias
>
> Best regards,
>
> Wolfgang Denk