[PATCH linux dev-4.7 1/8] mtd: spi-nor: aspeed: fix setting of the register control value for writes

[Joel Stanley]

On Sat, Nov 5, 2016 at 3:30 AM, Cédric Le Goater <clg at kaod.org> wrote:
> The setting of the register control value for writes depends on the
> base value which was defined only if the mask applied to it changed
> the register control value.
>
> Fix that.
>
> Signed-off-by: Cédric Le Goater <clg at kaod.org>
> ---
>  drivers/mtd/spi-nor/aspeed-smc.c | 9 +++++----
>  1 file changed, 5 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/mtd/spi-nor/aspeed-smc.c b/drivers/mtd/spi-nor/aspeed-smc.c
> index f65379bb2287..75ba73ef0660 100644
> --- a/drivers/mtd/spi-nor/aspeed-smc.c
> +++ b/drivers/mtd/spi-nor/aspeed-smc.c
> @@ -756,7 +756,7 @@ static int aspeed_smc_chip_setup_init(struct aspeed_smc_chip *chip,
>  {
>         struct aspeed_smc_controller *controller = chip->controller;
>         const struct aspeed_smc_info *info = controller->info;
> -       u32 reg;
> +       u32 reg, base_reg;
>
>         /*
>          * Always turn on the write enable bit to allow opcodes to be
> @@ -789,12 +789,13 @@ static int aspeed_smc_chip_setup_init(struct aspeed_smc_chip *chip,
>         reg = readl(chip->ctl);
>         dev_dbg(controller->dev, "control register: %08x\n", reg);
>
> -       if ((reg & CONTROL_SPI_KEEP_MASK) != reg) {
> -               chip->ctl_val[smc_base] = reg & CONTROL_SPI_KEEP_MASK;
> +       base_reg = reg & CONTROL_SPI_KEEP_MASK;
> +       if (base_reg != reg) {
>                 dev_info(controller->dev,
>                          "control register changed to: %08x\n",

Is this the kind of message we would see if someone else (the host, or
pflash) was changing the register while the kernel driver was loaded?

If so, we might want to make this a dev_warn or even a WARN in order
make it really clear that a bad thing has happened.

Cheers,

Joel

> -                        chip->ctl_val[smc_base]);
> +                        base_reg);
>         }
> +       chip->ctl_val[smc_base] = base_reg;
>
>         /*
>          * Retain the prior value of the control register as the
> --
> 2.7.4
>