On Tue, Nov 17, 2015 at 07:41:21AM +0000, Simon Arlott wrote: > On 17/11/15 00:40, Brian Norris wrote: > > + bcm-kernel-feedback-list > > > > On Mon, Nov 16, 2015 at 10:05:39PM +0000, Simon Arlott wrote: > >> If an error occurs in flash above 4GB in PIO mode then the EXT_ADDR > >> registers will be set to the location of the error and never cleared. > >> > >> Reset them to 0 before reading. > >> > >> Signed-off-by: Simon Arlott <[email protected]> > > > > Patch looks OK. Did you see this problem in practice, or is this just > > theoretical? I thought the documentation seemed to suggest these > > registers were cleared together with their non-_EXT counterparts. But > > implementation definitely trumps documentation for HW. > > It's theoretical (I don't have 4GB+ flash), but the Broadcom version of > the NAND driver does this.
That's a funny thing to say :) There never really was a single "Broadcom version" until we settled on upstreaming this one. It's a direct descendant of this [1], which also does not do these writes, and was tested on >4GB flash, though not extensively. Which product line did you get your driver from, then? Anyway, unless someone still at Broadcom can confirm or deny, I suppose this patch is mostly harmless and I can take it. Brian > > Brian > > > >> --- > >> drivers/mtd/nand/brcmnand/brcmnand.c | 2 ++ > >> 1 file changed, 2 insertions(+) > >> > >> diff --git a/drivers/mtd/nand/brcmnand/brcmnand.c > >> b/drivers/mtd/nand/brcmnand/brcmnand.c > >> index 12c6190..2c8f67f 100644 > >> --- a/drivers/mtd/nand/brcmnand/brcmnand.c > >> +++ b/drivers/mtd/nand/brcmnand/brcmnand.c > >> @@ -1400,6 +1400,8 @@ static int brcmnand_read_by_pio(struct mtd_info > >> *mtd, struct nand_chip *chip, > >> /* Clear error addresses */ > >> brcmnand_write_reg(ctrl, BRCMNAND_UNCORR_ADDR, 0); > >> brcmnand_write_reg(ctrl, BRCMNAND_CORR_ADDR, 0); > >> + brcmnand_write_reg(ctrl, BRCMNAND_UNCORR_EXT_ADDR, 0); > >> + brcmnand_write_reg(ctrl, BRCMNAND_CORR_EXT_ADDR, 0); > >> > >> brcmnand_write_reg(ctrl, BRCMNAND_CMD_EXT_ADDRESS, > >> (host->cs << 16) | ((addr >> 32) & 0xffff)); > >> -- > >> 2.1.4 > >> > >> -- > >> Simon Arlott > > > > > -- > Simon Arlott [1] https://github.com/Broadcom/stblinux-3.8/blob/master/linux/drivers/mtd/nand/brcmstb_nand.c Disclaimer: I used to work at Broadcom. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
