Hi Stefano,
If the bootcounter address is in a cached memory, a flush of dcache must occur after updateing the bootcounter.
Issue found on i.MX6 where bootcounter is put into the internal (cached) IRAM.
Signed-off-by: Stefano Babic sbabic@denx.de
drivers/bootcount/bootcount.c | 3 +++ 1 file changed, 3 insertions(+)
diff --git a/drivers/bootcount/bootcount.c b/drivers/bootcount/bootcount.c index d5ce450..48594a6 100644 --- a/drivers/bootcount/bootcount.c +++ b/drivers/bootcount/bootcount.c @@ -59,6 +59,9 @@ __weak void bootcount_store(ulong a) raw_bootcount_store(reg, a); raw_bootcount_store(reg + 4, BOOTCOUNT_MAGIC); #endif /* defined(CONFIG_SYS_BOOTCOUNT_SINGLEWORD */
- flush_dcache_range(CONFIG_SYS_BOOTCOUNT_ADDR,
CONFIG_SYS_BOOTCOUNT_ADDR +CONFIG_SYS_CACHELINE_SIZE);
Is it safe to flush the whole cache line?
For iMX6Q I do use SNVS_LPGR register (0x020CC068). It will preserve its content after reset caused by WDT (also reset command in u-boot). I also do use the SINGLEWORD to store "magic" and boot count in a single 32 bit number.
You may also want to consider using SRC_GPRx registers: https://community.nxp.com/message/985790?commentID=985790&et=watches.ema...
As it shall be safe to use them for bootcount scenario. However, I do prefer SNVS_LPGR.
}
__weak ulong bootcount_load(void)
Best regards,
Lukasz Majewski
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