From mboxrd@z Thu Jan 1 00:00:00 1970 From: LW@KARO-electronics.de (Lothar =?UTF-8?B?V2HDn21hbm4=?=) Date: Tue, 29 Jul 2014 08:31:45 +0200 Subject: [PATCHv4 5/5] mtd: gpmi: prevent creating a new BBT when blockmark swapping is disabled In-Reply-To: <20140728052906.GA3095@norris-Latitude-E6410> References: <1402579245-13377-1-git-send-email-LW@KARO-electronics.de> <1402579245-13377-2-git-send-email-LW@KARO-electronics.de> <1402579245-13377-3-git-send-email-LW@KARO-electronics.de> <1402579245-13377-4-git-send-email-LW@KARO-electronics.de> <1402579245-13377-5-git-send-email-LW@KARO-electronics.de> <1402579245-13377-6-git-send-email-LW@KARO-electronics.de> <20140728052906.GA3095@norris-Latitude-E6410> Message-ID: <20140729083145.647b77fc@ipc1.ka-ro> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org Hi, Brian Norris wrote: > Hi Lothar, > > On Thu, Jun 12, 2014 at 03:20:45PM +0200, Lothar Wa?mann wrote: > > Without blockmark swapping, there is no use in creating a BBT from > > scratch, so use a BBT descriptor with NAND_BBT_CREATE unset in this > > case. > > I'm curious: what is your plan if there is no BBT available on your > device, or if it ever gets corrupted? IIUC, nand_bbt will just assume > you have no bad blocks, and it will never write a bad block table to > flash. This also means no subsequent discoverable bad blocks can be > recorded across power cycles, I believe. > That won't happen (unless it's not possible to create a BBT because all the possible blocks for the BBT are bad), because the bootloader will have created one before Linux is started. > Maybe you don't want to specify your own nand_bbt_descr's at all, but > you just need to set: > > chip->bbt_options |= NAND_BBT_CREATE_EMPTY | NAND_BBT_NO_OOB; > > (Note: there's a little bit of fuzziness about NAND_BBT_* flags, where > some are targeted for the nand_chip::bbt_options field, and others > belong in struct nand_bbt_descr::options.) > > But if for some reason we need to keep this patch, a comment below: > > > Signed-off-by: Lothar Wa?mann > > --- > > drivers/mtd/nand/gpmi-nand/gpmi-nand.c | 28 +++++++++++++++++++++++++++- > > 1 file changed, 27 insertions(+), 1 deletion(-) > > > > diff --git a/drivers/mtd/nand/gpmi-nand/gpmi-nand.c b/drivers/mtd/nand/gpmi-nand/gpmi-nand.c > > index 37537b4..fc710d7 100644 > > --- a/drivers/mtd/nand/gpmi-nand/gpmi-nand.c > > +++ b/drivers/mtd/nand/gpmi-nand/gpmi-nand.c > > @@ -43,6 +43,29 @@ static struct nand_bbt_descr gpmi_bbt_descr = { > > .pattern = scan_ff_pattern > > }; > > > > +static uint8_t bbt_pattern[] = {'B', 'b', 't', '0' }; > > +static uint8_t mirror_pattern[] = {'1', 't', 'b', 'B' }; > > + > > +static struct nand_bbt_descr bbt_main_no_oob_descr = { > > + .options = NAND_BBT_LASTBLOCK | NAND_BBT_WRITE | > > + NAND_BBT_2BIT | NAND_BBT_VERSION | NAND_BBT_PERCHIP | > > + NAND_BBT_NO_OOB, > > Please indent the above two lines a bit, preferably matching the > indentation of NAND_BBT_LASTBLOCK. It should be clear that this is a > continuation of the '.options' initialization. > OK. > > + .len = 4, > > + .veroffs = 4, > > + .maxblocks = NAND_BBT_SCAN_MAXBLOCKS, > > + .pattern = bbt_pattern, > > +}; > > + > > +static struct nand_bbt_descr bbt_mirror_no_oob_descr = { > > + .options = NAND_BBT_LASTBLOCK | NAND_BBT_WRITE | > > + NAND_BBT_2BIT | NAND_BBT_VERSION | NAND_BBT_PERCHIP | > > + NAND_BBT_NO_OOB, > > Same here. > > > + .len = 4, > > + .veroffs = 4, > > + .maxblocks = NAND_BBT_SCAN_MAXBLOCKS, > > + .pattern = mirror_pattern, > > +}; > > + > > /* > > * We may change the layout if we can get the ECC info from the datasheet, > > * else we will use all the (page + OOB). > > @@ -1728,8 +1751,11 @@ static int gpmi_nand_init(struct gpmi_nand_data *this) > > chip->bbt_options |= NAND_BBT_NO_OOB_BBM; > > > > if (of_property_read_bool(this->dev->of_node, > > - "fsl,no-blockmark-swap")) > > + "fsl,no-blockmark-swap")) { > > this->swap_block_mark = false; > > + chip->bbt_td = &bbt_main_no_oob_descr; > > + chip->bbt_md = &bbt_mirror_no_oob_descr; > > My initial recommendation for this patch and the previous patch means > that you could just drop both patches and replace them with the > following: > > /* Comment here to explain why... */ > chip->bbt_options |= NAND_BBT_CREATE_EMPTY | > NAND_BBT_NO_OOB | > NAND_BBT_NO_OOB_BBM; OK. Lothar Wa?mann -- ___________________________________________________________ Ka-Ro electronics GmbH | Pascalstra?e 22 | D - 52076 Aachen Phone: +49 2408 1402-0 | Fax: +49 2408 1402-10 Gesch?ftsf?hrer: Matthias Kaussen Handelsregistereintrag: Amtsgericht Aachen, HRB 4996 www.karo-electronics.de | info at karo-electronics.de ___________________________________________________________