On Mon, 25 Jul 2016, Heiko Schocher wrote:
... snip ...
Yep ... why do we need "upgrade_available"?
in ./common/autoboot.c on *every* boot bootcount_store() gets called, so on every boot (which can happen very often) the Environment would be written ... not good, for long life of your product (if you have the Env in raw nand flash for example, as for the siemens boards)
If the bootcounter feature is only needed if you really did an update, to most writtes are unnecessary ... so the Userspace App can set also "upgrade_available" to enable the bootcount feature in case we save the bootcounter in the Environment ... and save a lot of writtes to the Env
But if you say "I don;t care how often I write the Environment" you simply can set "upgrade_available" to 1 and have the "original" behaviour of the bootcount feature (incrementing bootcount on each reboot ...)
ok, i am now *totally* confused, so let's start at the beginning. it's my understanding that selecting CONFIG_BOOTCOUNT_LIMIT means you want to use the boot counter, it does *not* select what method you want to use to store the boot counter, correct? but here's the confusing part.
if i look in common/autoboot.c, i see:
const char *bootdelay_process(void) { char *s; int bootdelay; #ifdef CONFIG_BOOTCOUNT_LIMIT unsigned long bootcount = 0; unsigned long bootlimit = 0; #endif /* CONFIG_BOOTCOUNT_LIMIT */
#ifdef CONFIG_BOOTCOUNT_LIMIT bootcount = bootcount_load(); bootcount++; bootcount_store(bootcount); setenv_ulong("bootcount", bootcount); <----- ????? bootlimit = getenv_ulong("bootlimit", 10, 0); #endif /* CONFIG_BOOTCOUNT_LIMIT */
... snip ...
and that's what confuses the heck out of me. i thought that, depending on the technique i wanted to use to store the boot counter (RAM, I2C, whatever), it would use *exclusively* that technique, and while i can see the use of the routines bootcount_load() and bootcount_store(), which are redefined based on the technique you select:
$ grep -rw bootcount_store * bootcount_at91.c:void bootcount_store(ulong a) bootcount_blackfin.c:void bootcount_store(ulong cnt) bootcount.c:__weak void bootcount_store(ulong a) bootcount_davinci.c:void bootcount_store(ulong a) bootcount_env.c:void bootcount_store(ulong a) bootcount_i2c.c:void bootcount_store(ulong a) bootcount_i2c.c: bootcount_store(0); bootcount_ram.c:void bootcount_store(ulong a) $
it appears that, no matter what, the environment *is* updated every single time because of this line in the bootdelay_process() routine:
setenv_ulong("bootcount", bootcount);
why? it seems, from the above, that no matter what boot counter mechanism you use, the environment will be updated because of that line.
i can certainly see in bootcount_env.c where using "upgrade_available" can deselect writing to the environment based on invoking bootcount_store(), but that in no way stops that explicit call to setenv_ulong() in that routine above.
so how am i misunderstanding this? it seems that no matter what boot counter storage mechanism i select, i'll be writing to the environment every time *anyway*.
rday