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    SubjectRe: [PATCH v3 4/6] mtd: rawnand: add NVIDIA Tegra NAND Flash controller driver
    On Sat, 9 Jun 2018 08:41:57 +0200
    Boris Brezillon <boris.brezillon@bootlin.com> wrote:

    > On Sat, 09 Jun 2018 08:23:51 +0200
    > Stefan Agner <stefan@agner.ch> wrote:
    >
    > > On 09.06.2018 07:52, Boris Brezillon wrote:
    > > > On Fri, 08 Jun 2018 23:51:01 +0200
    > > > Stefan Agner <stefan@agner.ch> wrote:
    > > >
    > > >
    > > >> >
    > > >> > void tegra_nand_controller_reset(struct tegra_nand_controller *ctrl)
    > > >> > {
    > > >> > int err;
    > > >> >
    > > >> > disable_irq(ctrl->irq);
    > > >> >
    > > >> > err = reset_control_reset(ctrl->rst);
    > > >> > if (err) {
    > > >> > dev_err(ctrl->dev, "Failed to reset HW: %d\n", err);
    > > >> > msleep(HW_TIMEOUT);
    > > >> > }
    > > >> >
    > > >> > writel_relaxed(NAND_CMD_STATUS, ctrl->regs + HWSTATUS_CMD);
    > > >> > writel_relaxed(HWSTATUS_MASK, ctrl->regs + HWSTATUS_MASK);
    > > >> > writel_relaxed(INT_MASK, ctrl->regs + ISR);
    > > >>
    > > >> If we do a controller reset, there is much more state than that which
    > > >> needs to be restored. A lot of it is not readily available currently
    > > >> (timing, ECC settings...)
    > > >
    > > > This is actually a good test to detect what is not properly initialized
    > > > by the driver. Timings should be configured correctly through
    > > > ->setup_data_interface(). ECC engine should be disabled by default and
    > > > only enabled when ->{read,write}_page() is called.
    > > >
    > >
    > > Is setup_data_interface guaranteed to be called after a failed
    > > ->exec_op()/{read,write}_page()?
    >
    > No. Maybe I misunderstood when tegra_nand_controller_reset() was
    > supposed to be called. That's something I would call only once, early
    > in the probe function, so that the controller is placed in a well-known
    > state before we start using it. Definitely not something you should
    > call after each error.

    Note that if you really want to reset the controller after an error,
    you should also iterate over all chips and call nand_reset() on them.

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