Re: [PATCH] ARM: /proc/atags: Export also for DT

[Rob Herring <robherring2@gmail.com>]

On Tue, Jan 27, 2015 at 7:21 AM, Pavel Machek <pavel@ucw.cz> wrote:
> On Mon 2015-01-26 14:33:21, Rob Herring wrote:
>> On Mon, Jan 26, 2015 at 1:16 PM, Pali Rohár <pali.rohar@gmail.com> wrote:
>> > This patch will cause that decompressor store full ATAG structure into DT tree ("/atags"):
>> >
>
>> > +       /* include the terminating ATAG_NONE */
>> > +       atag_size = (char *)atag - (char *)atag_list + sizeof(struct tag_header);
>> > +       setprop(fdt, "/", "atags", atag_list, atag_size);
>> > +
>> >         if (memcount) {
>> >                 setprop(fdt, "/memory", "reg", mem_reg_property,
>> >                         4 * memcount * memsize);
>> >
>> >
>> >
>> > And this patch will export ATAG structure from DT tree ("/atags") into /proc/atags file:
>>
>> Please properly send your patches.
>
> Actually, when sending patches for discussion, this is format easier
> to read.

Some people might prefer them as attachments too...

>> > Some userspace applications needs access to ATAG structure where can be stored some information passed
>> > from bootloader to kernel. Example is Nokia N900 device and NOLO bootloader which provides information
>> > about bootreason (device was started by power button or by alarm or restarted...) and bootmode (normal
>> > mode or device update mode).
>>
>> This goes in the commit message.
>>
>> These would be non-standard fields which are not upstream. I don't
>> know that we care in that case...
>
> Other devices are going to care about boot reason, too, and we might
> as well be compatible...

What other devices? Where is bootreason in the list of ATAGS:

#define ATAG_MEM        0x54410002
#define ATAG_VIDEOTEXT  0x54410003
#define ATAG_RAMDISK    0x54410004
#define ATAG_INITRD     0x54410005
#define ATAG_INITRD2    0x54420005
#define ATAG_SERIAL     0x54410006
#define ATAG_REVISION   0x54410007
#define ATAG_VIDEOLFB   0x54410008
#define ATAG_CMDLINE    0x54410009
#define ATAG_ACORN      0x41000101
#define ATAG_MEMCLK     0x41000402

Rob