Hi Martin,
On 13 November 2014 03:28, Martin Dorwig dorwig@tetronik.com wrote:
Am Mittwoch, 12. November 2014, 19:32:21 schrieben Sie:
Hi Martin,
On 30 October 2014 00:45, Martin Dorwig dorwig@tetronik.com wrote:
Am Mittwoch, 29. Oktober 2014, 13:03:41 schrieben Sie:
Hi Martin,
On 28 October 2014 07:23, Martin Dorwig dorwig@tetronik.com wrote:
Hello, after updating u-boot from git v2014.10 i just noticed that my standalone application outputs garbage using putc. after some investigation i found that the gd->jt[XF_putc] is assigned a dev->putc pointer in "common/console.c function console_setfile"
the dev->putc is declared in include/stdio_dev.h as void (*putc)(struct stdio_dev *dev, const char c);
int include/exports.h this function is declared as void putc(const char);
this was introduced with commit id 709ea543b92489e7729d2d7ddd6c9f451e52158c
That's unfortunate. Is the stdio device pointer available in the standalone application?
Perhaps gd->jt should point to a structure of strongly-typed functions? Then we would get a build error in this case.
Regards, Simon
What is the motivation to override the jumptable slots ? Why can't they be untouched like this gd->jt[XF_getc] = getc; gd->jt[XF_tstc] = tstc; gd->jt[XF_putc] = putc; gd->jt[XF_puts] = puts; redirection of the console to another device is honored in the implementation of the functions themselves. for example the putc function: it calls pre_console_putc before a console is present if GD_FLG_DEVINIT is set, it calls fputc(stdout,c) which calls console_putc(stdout,c) which in turn calls stdio_devices[stdout]-
putc(stdio_devices[file], c);
else it calls serial_putc(c)
I have taken a bit of a look at this.
I have not actually touched the jumptable slots. The one you mention was assigned to dev->putc() before and after. The problem is that now dev->putc() has two parameters, the first being 'dev'.
dev->putc() is the device's putc function - typically the serial port or a display.
The putc() function you mention is the console out, that outputs to all stdout devices.
So yes we could change the bahaviour so that it calls putc(). I think this will work, and it probably isn't going to result in a change in behaviour for many boards since they only have a single stdout.
Alternatively we could require the stdio device parameter to be passed in. I'm not sure that will work though - how will the external program get at it?
In any case, teh void *gd->jt[] is not serving our purpose here - it should be changed to proper function pointer types so that the compiler can check that this sort of thing doesn't happen.
Please let me know what you think should be done here.
Regards, Simon
The jumptable is initialized once, and i don't see any reason to overwrite it.
That commit (27b207fd) dates from 2003. Are you wanting to revert an 11-year-old commit or do I misunderstand you?
Adding a parameter to these exported functions will break backward compatibility of existing standalone apps
Yes that's right, but when they move to a newer U-Boot they will need to be updated. Isn't that expected with standalone apps? I can adjust things that are in the mainline tree, but I can't fix up people's third party apps.
I did make a suggestion about how to avoid adding the extra parameter (changing the behaviour to call putc() instead of dev->putc()). What do you think?
Regards, Simon