[U-Boot] [PATCH 5/5] Warn when the machine ID isn't passed to an ARM kernel and u-boot is compiled in debug mode. The kernel cannot boot without it.

[Igor Grinberg]

On 07/05/11 00:24, Jason wrote:

> On Mon, Jul 04, 2011 at 04:32:35PM -0400, Christopher Harvey wrote:
>> On Mon, Jul 04, 2011 at 04:13:49PM -0400, Jason wrote:
>>> On Mon, Jul 04, 2011 at 02:55:54PM -0400, Christopher Harvey wrote:
>>>> On Mon, Jul 04, 2011 at 02:08:44PM -0400, Jason wrote:
>>>>> On Mon, Jul 04, 2011 at 01:45:41PM -0400, Christopher Harvey wrote:
>>>>>> +	   Hopefully there will never be this many machines. 
>>>>>> +	   Can't use 0 since 0 is already used as a mach-type. */
>>>>>> +	gd->bd->bi_arch_number = 0xffffffff; 
>>>>>>  
>>>>>>  	gd->bd->bi_baudrate = gd->baudrate;
>>>>>>  	/* Ram ist board specific, so move it to board code ... */
>>>>>> diff --git a/arch/arm/lib/bootm.c b/arch/arm/lib/bootm.c
>>>>>> index 802e833..70b3b76 100644
>>>>>> --- a/arch/arm/lib/bootm.c
>>>>>> +++ b/arch/arm/lib/bootm.c
>>>>>> @@ -113,6 +113,12 @@ int do_bootm_linux(int flag, int argc, char *argv[], bootm_headers_t *images)
>>>>>>  		printf ("Using machid 0x%x from environment\n", machid);
>>>>>>  	}
>>>>>>  
>>>>>> +#ifdef DEBUG
>>>>>> +	if(machid==0xffffffff) {
>>>>>> +	        debug("\nWarning: machid not set! Linux will not finish booting.\n\n");
>>>>> s/finish/start/ ;-)
>>>>>
>>>> I'll have to disagree here.  Linux will decompress and some functions
>>>> will run but it will eventually stop, hence will not finish.
>>> On further investigation, you're right, it doesn't finish
>>> starting/booting.  Sorry for the noise.
>>>
>>>>> Also, shouldn't the compile fail in this case (#error)?  Or, at least #warn?
>>>>>
>>>> The compiler can't know what machid will be at runtime. Maybe a "would
>>>> you like to continue?" prompt could work.
>>> Since the kernel throws a nice fat error message when the MACH_TYPE
>>> doesn't match what it was compiled for, I don't see the point to adding
>>> another message at the same point in the development process.
>> I didn't see that message. Do you know what lines of code in the
>> kernel print it? Or maybe just the message itself? 
> In init/main.c
> 	start_kernel() calls
> 		setup_arch()
>
> In arch/arm/kernel/setup.c
> 	setup_arch() calls
> 		setup_machine_tags() which calls
> 			dump_machine_table()
>
> when the value in r1 doesn't match any of the mach-types the kernel was
> compiled for.

If you don't have the earlyprintk enabled, will this still be seen?
I don't think so...

So, I think there is a point to add a warning message.

-- 
Regards,
Igor.