[Skiboot] [PATCH v3 06/13] hiomap: Enable Async IPMI messaging

[Oliver O'Halloran]

On Thu, Nov 7, 2019 at 4:25 AM Deb McLemore <debmc at linux.ibm.com> wrote:
>
> +static int hiomap_wait_for_cc(struct ipmi_hiomap *ctx, int *cc, uint8_t *seq, uint64_t ticks)
> +{
> +       uint64_t now;
> +       uint64_t start_time;
> +       uint64_t wait_time;
> +       uint64_t ipmi_hiomap_ticks;
> +       uint64_t timeout_counter;
> +       int rc;
> +
> +       prlog(PR_TRACE, "Start wait for cc ipmi seq=%i *cc=%i ticks=%llu\n", *seq, *cc, ticks);
> +       rc = 0;
> +       if (this_cpu()->tb_invalid) {
> +               /*
> +                * SYNC paths already have *cc success
> +                * ASYNC will RE-QUEUE and retry
> +                * we just need to skip the tb logic handling
> +                * we need to close the window to have the logic try the move again
> +                */
> +               if (*cc != IPMI_CC_NO_ERROR) {
> +                       lock(&ctx->lock);
> +                       ctx->window_state = closed_window;
> +                       ++ctx->missed_cc_count;
> +                       prlog(PR_NOTICE, "%s tb_invalid, CLOSING WINDOW for cc "
> +                               "ipmi seq=%i ctx->missed_cc_count=%i\n",
> +                               __func__, *seq, ctx->missed_cc_count);
> +                       unlock(&ctx->lock);
> +                       rc = FLASH_ERR_MISSED_CC;
> +               }
> +               prlog(PR_NOTICE, "%s tb_invalid, hopefully this will "
> +                       "retry/recover rc=%i\n",
> +                       __func__, rc);
> +               return rc;
> +       }

Mahesh, what's the correct way to deal with the timebase going invalid
at runtime if we need to do a time_wait()? You added a hack in
1764f2452565 ("opal: Fix hang in time_wait* calls on HMI for TB
errors.") to no-op the timebase if tb_invalid is set so we don't get
stuck in the HMI recovery path, but I guess it breaks anything else
that needs a wait? I would prefer we didn't start open-coding
tb_invalid checks.