u-boot-brain/drivers/mtd
Masahiro Yamada 1c193c0c6e mtd: rawnand: denali: deassert write protect pin
[ Linux commit 9afbe7c0140f663586edb6e823b616bd7076c00a ]

If the write protect signal from this IP is connected to the NAND
device, this IP can handle the WP# pin via the WRITE_PROTECT
register.

The Denali NAND Flash Memory Controller User's Guide describes
this register like follows:

  When the controller is in reset, the WP# pin is always asserted
  to the device. Once the reset is removed, the WP# is de-asserted.
  The software will then have to come and program this bit to
  assert/de-assert the same.

    1 - Write protect de-assert
    0 - Write protect assert

The default value is 1, so the write protect is de-asserted after
the reset is removed. The driver can write to the device unless
someone has explicitly cleared register before booting the kernel.

The boot ROM of some UniPhier SoCs (LD4, Pro4, sLD8, Pro5) is the
case; the boot ROM clears the WRITE_PROTECT register when the system
is booting from the NAND device, so the NAND device becomes read-only.

Set it to 1 in the driver in order to allow the write access to the
device.

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
2020-05-22 11:21:06 +09:00
..
nand mtd: rawnand: denali: deassert write protect pin 2020-05-22 11:21:06 +09:00
onenand common: Drop linux/bitops.h from common header 2020-05-18 21:19:23 -04:00
spi common: Drop linux/bitops.h from common header 2020-05-18 21:19:23 -04:00
ubi common: Drop linux/bug.h from common header 2020-05-18 21:19:23 -04:00
ubispl common: Drop linux/bitops.h from common header 2020-05-18 21:19:23 -04:00
altera_qspi.c common: Drop linux/bitops.h from common header 2020-05-18 21:19:23 -04:00
cfi_flash.c common: Drop linux/delay.h from common header 2020-05-18 21:19:23 -04:00
cfi_mtd.c SPDX: Convert all of our single license tags to Linux Kernel style 2018-05-07 09:34:12 -04:00
hbmc-am654.c dm: core: Create a new header file for 'compat' features 2020-02-05 19:33:46 -07:00
jedec_flash.c common: Drop log.h from common header 2020-05-18 21:19:18 -04:00
Kconfig configs: migrate CONFIG_SYS_MTDPARTS_RUNTIME to defconfigs 2020-05-08 09:16:26 -04:00
Makefile mtd: Makefile: deep cleanup 2019-12-04 17:10:51 -05:00
mtd_uboot.c common: Drop log.h from common header 2020-05-18 21:19:18 -04:00
mtd-uclass.c mtd: uclass: add probe function 2018-10-02 22:12:31 +05:30
mtdconcat.c common: Drop linux/bug.h from common header 2020-05-18 21:19:23 -04:00
mtdcore.c common: Drop linux/bitops.h from common header 2020-05-18 21:19:23 -04:00
mtdcore.h mtd: move definitions to enlarge their range 2018-09-20 20:10:49 +05:30
mtdpart.c common: Drop linux/bug.h from common header 2020-05-18 21:19:23 -04:00
mw_eeprom.c common: Drop linux/delay.h from common header 2020-05-18 21:19:23 -04:00
pic32_flash.c common: Drop linux/bitops.h from common header 2020-05-18 21:19:23 -04:00
renesas_rpc_hf.c common: Drop linux/bitops.h from common header 2020-05-18 21:19:23 -04:00
st_smi.c common: Drop linux/delay.h from common header 2020-05-18 21:19:23 -04:00
stm32_flash.c common: Drop flash.h from common header 2020-05-18 14:53:28 -04:00
stm32_flash.h stm32: stm32f4: move flash driver to mtd driver location 2016-03-26 18:49:28 -04:00