On Thu, May 12, 2016 at 06:12:44AM +0000, Yoshihiro Shimoda wrote:
> Hi Simon-san,
>
> > From: Behalf Of Simon Horman
> > Sent: Tuesday, May 10, 2016 2:52 PM
> >
> > From: Ai Kyuse <ai.kyuse.uw@xxxxxxxxxxx>
> >
> > Add tuning support for use with SDR104 mode
> >
> > Signed-off-by: Ai Kyuse <ai.kyuse.uw@xxxxxxxxxxx>
> > Signed-off-by: Simon Horman <horms+renesas@xxxxxxxxxxxx>
>
> I have some minor comments :)
>
> < snip >
> > @@ -753,6 +785,157 @@ static int tmio_mmc_start_data(struct tmio_mmc_host *host,
> > return 0;
> > }
> >
> > +#define TMIO_MMC_MAX_TUNING_LOOP 40
> > +
> > +static int tmio_mmc_execute_tuning(struct mmc_host *mmc, u32 opcode)
> > +{
> > + struct tmio_mmc_host *host = mmc_priv(mmc);
> > + struct mmc_ios *ios = &mmc->ios;
> > +
> > + unsigned long timeout, val;
> > + unsigned long *tap;
> > + int tuning_loop_counter = TMIO_MMC_MAX_TUNING_LOOP;
> < snip >
> > + /*
> > + * Issue CMD19 repeatedly till Execute Tuning is set to 0 or the number
> > + * of loops reaches 40 times or a timeout of 150ms occurs.
> > + */
> > + timeout = 150;
>
> The tuning_loop_counter is 40 and timeout is 150.
> However,
>
> > + do {
> > + if (host->prepare_tuning)
> > + host->prepare_tuning(host, val % num);
> > +
> > + if (!tuning_loop_counter && !timeout)
> > + break;
>
> < snip >
>
> > + tuning_loop_counter--;
> > + timeout--;
> > + mdelay(1);
> > + } while ((val < (num * 2)) && (tuning_loop_counter || timeout));
>
> They will be decreased by 1. So, I think we don't need either variable.
Thanks for bringing this to my attention.
As Wolfram pointed out in another sub-thread it looks like this code
is based on sdhci.c. And I believe that the version in that file has
the issue you raise addressed by:
7ce45e950624 ("mmc: sdhci: SD tuning is broken for some controllers").
I'll update this patch accordingly.
>
> > + * The Host Driver has exhausted the maximum number of loops allowed,
> > + * so use fixed sampling frequency.
> > + */
> > + if (tuning_loop_counter || timeout) {
> > + if (host->select_tuning) {
> > + ret = host->select_tuning(host, tap);
> > + if (ret < 0)
> > + goto out;
> > + }
> > + host->done_tuning = true;
> > + } else {
> > + dev_warn(&host->pdev->dev, ": Tuning procedure failed\n");
>
> The first 2 charactors ": " is strange to me.
Yes, thanks for noticing that. I plan to drop ": ".
> > + ret = -EIO;
> > + goto out;
> > + }
> > +
> > +out:
> > + kfree(data_buf);
> > +err_data:
> > + kfree(tap);
> > +err_tap:
> > + if (ret < 0 && host->hw_reset)
> > + host->hw_reset(host);
>
> We can use tmio_mmc_hw_reset() of this patch.
> Then, we can remove the condition of "host->hw_reset".
Thanks, will do.
[...]
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