Seems like the BROKEN_DTO also affects EVENT_DATA_COMPLETE, sometimes we don't see that (but we do see EVENT_XFER_COMPLETE), leave the state machine and never come back to it to timeout. I have this happening on emmc specifically, haven't seen it on sdmmc yet. The fix is to also start the timer when we don't see a EVENT_DATA_COMPLETE. More details for how I debugged this can be found at: https://chromium-review.googlesource.com/#/c/233691/ In ~100 reboot tests I haven't seen any hangs, whereas before it was hanging about 20% of the time. diff --git a/drivers/mmc/host/dw_mmc.c b/drivers/mmc/host/dw_mmc.c index 50865e7..c678206 100644 --- a/drivers/mmc/host/dw_mmc.c +++ b/drivers/mmc/host/dw_mmc.c @@ -1685,8 +1685,17 @@ static void dw_mci_tasklet_func(unsigned long priv) case STATE_DATA_BUSY: if (!test_and_clear_bit(EVENT_DATA_COMPLETE, - &host->pending_events)) + &host->pending_events)) { + if (host->quirks & DW_MCI_QUIRK_BROKEN_DTO) { + drto_clks = mci_readl(host, TMOUT) >> 8; + drto_ms = DIV_ROUND_UP(drto_clks * 1000, + host->bus_hz); + + mod_timer(&host->dto_timer, jiffies + + msecs_to_jiffies(drto_ms)); + } break; + } host->data = NULL; set_bit(EVENT_DATA_COMPLETE, &host->completed_events); Alexandru Stan (amstan) On Tue, Dec 2, 2014 at 9:08 PM, Doug Anderson <dianders@xxxxxxxxxxxx> wrote: > Addy, > > On Tue, Dec 2, 2014 at 7:16 PM, Addy Ke <addy.ke@xxxxxxxxxxxxxx> wrote: >> This patch add a new quirk to add a s/w timer to notify the driver >> to terminate current transfer and report a data timeout to the core, >> if DTO interrupt does NOT come within the given time. >> >> dw_mmc call mmc_request_done func to finish transfer depends on >> DTO interrupt. If DTO interrupt does not come in sending data state, >> the current transfer will be blocked. >> >> But this case really exists, when driver reads tuning data from >> card on RK3288-pink2 board. I measured waveforms by oscilloscope >> and found that card clock was always on and data lines were always >> holded high level in sending data state. >> >> We got the reply from synopsys: >> There are two counters but both use the same value of [31:8] bits. >> Data timeout counter doesn't wait for stop clock and you should get >> DRTO even when the clock is not stopped. >> Host Starvation timeout counter is triggered with stop clock condition. >> >> This means that host should get DRTO and DTO interrupt. >> >> But we really don't get any data-related interrupt in RK3X SoCs. >> And driver can't get data transfer state, it can do nothing but wait for. >> >> We don't know why we have this problem, but we need it to fix this problem now. >> And I will post a follow up change when we find the root cause. >> >> Signed-off-by: Addy Ke <addy.ke@xxxxxxxxxxxxxx> >> --- >> Changes in v2: >> - fix some typo. >> - remove extra timeout value (250ms). >> - remove dw_mci_dto_start_monitor func. >> - use "broken-dto" for new quirk and change Subject for it. >> >> Changes in v3: >> - Remove dts for broken-dto, just add this quirk in dw_mci_rockchip_init >> >> drivers/mmc/host/dw_mmc-rockchip.c | 3 +++ >> drivers/mmc/host/dw_mmc.c | 41 +++++++++++++++++++++++++++++++++++++- >> include/linux/mmc/dw_mmc.h | 5 +++++ >> 3 files changed, 48 insertions(+), 1 deletion(-) > > This seems reasonable to me. I do hope that you can get to a root > cause, but I don't think this is a terrible bit of code to carry. > Obviously it's up to the folks who maintain dw_mmc and the mmc > subsystem, but: > > Reviewed-by: Doug Anderson <dianders@xxxxxxxxxxxx> -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
