[U-Boot] [PATCH 03/11] st_smi: Return error in case TFF is not set

Stefan Roese
2012-02-27T10:26:18Z

On Friday 24 February 2012 13:23:06 Amit Virdi wrote:
> Curently the code makes wrong assumption that the Transfer finished flag
> shall be set within the stipulated time. However, there may occur a
> scenario in which the TFF flag is not set. Return error in that case.
>
> Signed-off-by: Vipin Kumar <vipin.kumar@st.com>
> Signed-off-by: Amit Virdi <amit.virdi@st.com>
> ---
> drivers/mtd/st_smi.c | 22 ++++++++++++++--------
> 1 files changed, 14 insertions(+), 8 deletions(-)
>
> diff --git a/drivers/mtd/st_smi.c b/drivers/mtd/st_smi.c
> index 82f1fe1..ec19b0d 100644
> --- a/drivers/mtd/st_smi.c
> +++ b/drivers/mtd/st_smi.c
> @@ -58,13 +58,15 @@ static struct flash_dev flash_ids[] = {
> *
> * Wait until TFF is set in status register
> */
> -static void smi_wait_xfer_finish(int timeout)
> +static int smi_wait_xfer_finish(int timeout)
> {
> - while (timeout--) {
> + do {
> if (readl(&smicntl->smi_sr) & TFF)
> - break;
> + return 0;
> udelay(1000);
> - }
> + } while (timeout--);
> +
> + return -1;

Somewhat unrelated to the patch topic, but I don't really like this kind of
timeout loops. Since it always adds at least 1ms delay after initial failing
test. Better use something like this:

static int smi_wait_xfer_finish(int timeout)
{
ulong start = get_timer(0);

while (get_timer(start) < timeout) {
if (readl(&smicntl->smi_sr) & TFF)
return 0;

/* Try again after 100usec */
udelay(100);
}

return -1;
}

You could tune this udelay(100) down more or even remove it completely.

But such a change could be done in a addon cleanup patch, changing all timeout
loops this way. I suggest you take a look at my version, here these loops are
changes. In the designware networking driver as well, iirc.

Thanks,
Stefan

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