Re: [PATCH v9 3/3] MTD: at91: atmel_nand: Update driver to support Programmable Multibit ECC controller

[Artem Bityutskiy <dedekind1@xxxxxxxxx>]

On Sat, 2012-05-26 at 21:24 +0800, Josh Wu wrote:
> +       while ((pmecc_readl_relaxed(host->ecc, SR) & PMECC_SR_BUSY)) {
> +               if (unlikely(timeout_count++ > PMECC_MAX_TIMEOUT_COUNT)) {
> +                       dev_err(host->dev, "PMECC: Timeout to get ECC value.\n");
> +                       return; /* Time out */

How this error is communicated then up the the user?

> +               }
> +               cpu_relax();
> +       }

I see this pattern all over the place - why people consider it reliable?
Is this code guaranteed to run on the same CPU?

Why not to use loops_per_jiffie * msecs_to_jiffies(TIMOUT) instead to
calculate how many iterations to do? Yes, due to HW register reading and
cpu_relax() the real timeout will be larger, but this is about error
anyway, so it does not hurt to iterate longer?

-- 
Best Regards,
Artem Bityutskiy

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