bartoszek/zephyr
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

drivers: bbram: npcx: bypass npcx49nf errata rev1.5 No.2.30

Browse Source 
This commit workarounds the BBRAM status register write issue in npcx4:
A write operation to the BKUP_STS register might disable write to all
the Battery-Backed RAM (BBRM). The workaround is to perform a fake read
from the BKUP_STS register after every write to this register.

Signed-off-by: Jun Lin <CHLin56@nuvoton.com>
This commit is contained in:
Jun Lin 2025-03-18 09:26:35 +08:00 committed by Benjamin Cabé
parent dbd1449132
commit a60d88e5cc
2 changed files with 15 additions and 1 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

9
drivers/bbram/Kconfig.npcx
View File

@ -15,3 +15,12 @@ config BBRAM_NPCX_EMUL
depends on EMUL
help
Enable the emulator for the NPCX BBRAM.
config BBRAM_NPCX_STATUS_REG_WRITE_WORKAROUND
bool
default y if SOC_SERIES_NPCX4
help
Workaround the issue documented in NPCX49nF errata rev1_5, No.2.30.
A write operation to the BKUP_STS register might disable write to all
the Battery-Backed RAM. The workaround is to read the BKUP_STS
register after every write to this register.

7
drivers/bbram/bbram_npcx.c
View File

@ -35,6 +35,12 @@ static int get_bit_and_reset(const struct device *dev, int mask)
DRV_STATUS(dev) &= ~mask;
#else
DRV_STATUS(dev) = mask;
if (IS_ENABLED(CONFIG_BBRAM_NPCX_STATUS_REG_WRITE_WORKAROUND)) {
uint8_t __unused read_unused;
read_unused = DRV_STATUS(dev);
}
#endif
return result;
@ -72,7 +78,6 @@ static int bbram_npcx_read(const struct device *dev, size_t offset, size_t size,
return -EINVAL;
}
bytecpy(data, ((uint8_t *)config->base_addr + offset), size);
return 0;
}