Hi Richard, jbx6244@xxxxxxxxx wrote on Mon, 17 Jul 2023 12:49:43 +0200: > On 7/15/23 17:55, Miquel Raynal wrote: > > Hi Johan, > > > > jbx6244@xxxxxxxxx wrote on Sat, 15 Jul 2023 12:49:18 +0200: > > > >> A NAND chip can contain a different data format then the MTD framework > >> expects in the erase blocks for the Bad Block Table(BBT). > >> Result is a failed probe, while nothing wrong with the hardware. > >> Some MTD flags need to be set to gain access again. > >> > >> Skip the automatic BBT scan with the NAND_SKIP_BBTSCAN option > >> so that the original content is unchanged during the driver probe. > >> The NAND_NO_BBM_QUIRK option allows us to erase bad blocks with > >> the nand_erase_nand() function and the flash_erase command. > >> > >> Add nand-skip-bbtscan and nand-no-bbm-quirk Device Tree options, > >> so the user has the "freedom of choice" by neutral > >> access mode to read and write in whatever format is needed. > > > > > This sounds like a partial solution. How do you handle bad blocks? > > Hi Miquel, > > See below some Rockchip related links: > > The file rk_ftl_arm_v7.S is marked GPL2, so I can freely refer/decode/hack to/in that. > For rk3066 a closed source piece called usbplug is still needed to program initial U-boot. > This usbplug contains similar code as in the S file and formats the NAND for FTL. > U-boot is not small enough yet (WIP if I have the time) to replace that. > Long story short is that on Rockchip NAND's we can expect pages with various ECC and scrambled/randomized all over the place. > > One effect is that when the MTD framework driver is probed a first time the BBT pages don't look what was expected. > For this first probe to be successful I must be able to turn of the MTD internal BBT scan and then erase/format all blocks except boot blocks of course. > During this first run bad blocks are handled by/tested/kept track of/set BBM in user space. > This is not meant as permanent mode.(except maybe if this S file is converted as open source FTL (WIP)) > > Richard doesn't like module parameters, so I can't simply do modprobe for example in a script. > After that the whole kernel/MTD must rebooted without these DT options. Richard, do you think we should support such use case? Any direction would help. > > This patch does make parameters/flags available for all. > If that is too much freedom to handle I can parse them in the Rockchip driver, let me know. > > Linux always gets away with the "it must be generic functionality" excuse. > In U-boot there is the same driver with little or no interaction with the user, so we must deal with that. > Please advise how we can solve this in a simple nice automated way. > > > Johan > > === > > function FlashSetRandomizer() > https://github.com/rockchip-linux/kernel/blob/develop-4.4/drivers/rk_nand/rk_ftl_arm_v7.S#L120 > https://github.com/rockchip-linux/u-boot/blob/next-dev/drivers/rknand/rk_ftl_arm_v7.S#L199 > > Proof of concept for U-boot: > [v2,06/11] rockchip: idb: add randomizer option > http://patchwork.ozlabs.org/project/uboot/patch/0b295d0e-53d6-b35a-3058-861e203b4d83@xxxxxxxxx/ > > > > >> Signed-off-by: Johan Jonker <jbx6244@xxxxxxxxx> > >> --- > >> > >> Previous discussion: > >> [PATCH v3 3/3] mtd: rawnand: rockchip-nand-controller: add skipbbt option > >> https://lore.kernel.org/linux-mtd/1618382560.2326931.1689261435022.JavaMail.zimbra@xxxxxx/ > >> --- > >> drivers/mtd/nand/raw/nand_base.c | 6 ++++++ > >> 1 file changed, 6 insertions(+) > >> > >> diff --git a/drivers/mtd/nand/raw/nand_base.c b/drivers/mtd/nand/raw/nand_base.c > >> index a6af521832aa..f0fa5c3519b1 100644 > >> --- a/drivers/mtd/nand/raw/nand_base.c > >> +++ b/drivers/mtd/nand/raw/nand_base.c > >> @@ -5521,6 +5521,12 @@ static int rawnand_dt_init(struct nand_chip *chip) > >> if (of_property_read_bool(dn, "nand-is-boot-medium")) > >> chip->options |= NAND_IS_BOOT_MEDIUM; > >> > >> + if (of_property_read_bool(dn, "nand-no-bbm-quirk")) > >> + chip->options |= NAND_NO_BBM_QUIRK; > >> + > >> + if (of_property_read_bool(dn, "nand-skip-bbtscan")) > >> + chip->options |= NAND_SKIP_BBTSCAN; > >> + > >> if (of_property_read_bool(dn, "nand-on-flash-bbt")) > >> chip->bbt_options |= NAND_BBT_USE_FLASH; > >> > >> -- > >> 2.30.2 > >> > > > > > > Thanks, > > Miquèl Thanks, Miquèl
