Re: [PATCH 3/4] Enable ecc-mode selection in the driver

Andrew Lunn
2013-01-16T13:24:22Z

On Wed, Jan 16, 2013 at 12:43:57PM +0100, Stefan Peter wrote:
> Hi Andrew
>
> on 15.01.2013 13:51, Andrew Lunn wrote:
> > On Tue, Jan 15, 2013 at 01:13:12PM +0100, Stefan Peter wrote:
> >> In order to be able to use the ecc-mode, add the bch module to the default
> >> settings for the kirwood boards and enable the activation in orin-nand.c
> >>
> >> Signed-off-by: Stefan Peter <s.peter@mpl.ch>
> >> ---
> >> diff --git a/arch/arm/configs/kirkwood_defconfig b/arch/arm/configs/kirkwood_defconfig
> >> index 93f3794..4a9d3f7 100644
> >> --- a/arch/arm/configs/kirkwood_defconfig
> >> +++ b/arch/arm/configs/kirkwood_defconfig
> >> @@ -84,6 +84,7 @@ CONFIG_MTD_CFI_STAA=y
> >> CONFIG_MTD_PHYSMAP=y
> >> CONFIG_MTD_M25P80=y
> >> CONFIG_MTD_NAND=y
> >> +CONFIG_MTD_NAND_ECC_BCH=y
> >> CONFIG_MTD_NAND_ORION=y
> >> CONFIG_BLK_DEV_LOOP=y
> >> # CONFIG_SCSI_PROC_FS is not set
> >> diff --git a/drivers/mtd/nand/orion_nand.c b/drivers/mtd/nand/orion_nand.c
> >> index cd72b92..1a35257 100644
> >> --- a/drivers/mtd/nand/orion_nand.c
> >> +++ b/drivers/mtd/nand/orion_nand.c
> >> @@ -14,6 +14,7 @@
> >> #include <linux/module.h>
> >> #include <linux/platform_device.h>
> >> #include <linux/of.h>
> >> +#include <linux/of_mtd.h>
> >> #include <linux/mtd/mtd.h>
> >> #include <linux/mtd/nand.h>
> >> #include <linux/mtd/partitions.h>
> >> @@ -130,6 +131,7 @@ static int __init orion_nand_probe(struct platform_device *pdev)
> >> if (!of_property_read_u32(pdev->dev.of_node,
> >> "chip-delay", &val))
> >> board->chip_delay = (u8)val;
> >> + board->ecc_mode = of_get_nand_ecc_mode(pdev->dev.of_node);
> >
> >> } else
> >> board = pdev->dev.platform_data;
> >>
> >> @@ -140,7 +142,8 @@ static int __init orion_nand_probe(struct platform_device *pdev)
> >> nc->IO_ADDR_R = nc->IO_ADDR_W = io_base;
> >> nc->cmd_ctrl = orion_nand_cmd_ctrl;
> >> nc->read_buf = orion_nand_read_buf;
> >> - nc->ecc.mode = NAND_ECC_SOFT;
> >> + nc->ecc.mode = board->ecc_mode == NAND_ECC_SOFT_BCH ?
> >> + NAND_ECC_SOFT_BCH : NAND_ECC_SOFT;
> >
> > Hi Stefan
> >
> > What about a user that wants one of the other valid values?
> > NAND_ECC_OOB_FIRST, NAND_ECC_HW_SYNDROME, etc.
>
> As far as I understand, NAND_ECC_NONE, NAND_ECC_SOFT and
> NAND_ECC_SOFT_BCH are the only ECC modes that do not require
> corresponding hardware support which is missing in the marvell
> 88F6180/88F619x/88F628x. From my point of view, NAND_ECC_NONE does not
> make sense, too, because MLC NAND Flash requires ECC to be usable.
>
> >
> > Would:
> >
> > if (IS_ERR(board->ecc_mode)) {
> > nc->ecc.mode = NAND_ECC_SOFT;
> > dev_info(&pdev->dev, "Defaulting to NAND_ECC_SOFT");
> > } else
> > nc->ecc.mode = board->ecc_mode
> >
> > be better?
>
> I feel safer by limiting the modes to what I could test.

Hi Stefan

O.K, but i still think a warning message would be useful when
board->ecc_mode is an error code.

Andrew