[RFC PATCH 3/3] Add panic_write function to the onenand driver

[Kyungmin Park]

Hi,

> +static void onenand_panic_wait(struct mtd_info *mtd)
> +{
> +	struct onenand_chip *this = mtd->priv;
> +	unsigned int interrupt;
> +	int i;
> +
> +	for (i = 0; i < 20; i++) {
> +		interrupt = this->read_word(this->base + ONENAND_REG_INTERRUPT);
> +		if (interrupt & ONENAND_INT_MASTER)
> +			break;
> +		udelay(1000);
> +	}
> +}

Umm it's waiting with maximum 20msec. how about the increase the index to 20*1000 and use udelay(1).
If we use the busy-waiting, it uses the max 3msec in case of erase.

Anyway I think you don't use the onenand_wait since it has cond_resched(). It's better to use the existing function in case of
panic_write.
Okay try to think what's the better way.

> + */
> +static int onenand_panic_write(struct mtd_info *mtd, loff_t to, size_t len,
> +			 size_t *retlen, const u_char *buf)
> +{
> +	struct onenand_chip *this = mtd->priv;
> +	int column, subpage;
> +	int written = 0;
> +	int ret = 0;
> +
> +	if (this->state == FL_PM_SUSPENDED)
> +		return -EBUSY;
> +
> +	/* Wait for any existing operation to clear */
> +	onenand_panic_wait(mtd);

Reasonable!

> +
> +		this->write_bufferram(mtd, ONENAND_DATARAM, wbuf, 0, mtd->writesize);
> +		this->write_bufferram(mtd, ONENAND_SPARERAM, ffchars, 0, mtd->oobsize);
> +
> +		this->command(mtd, ONENAND_CMD_PROG, to, mtd->writesize);
> +
> +		onenand_panic_wait(mtd);

It has to check the return value and update the bufferram. If not, we can read the wrong data later.

Thank you,
Kyungmin Park