On Wed, Mar 22, 2017 at 12:18:00PM +0100, Ulf Hansson wrote: > [...] > > >> >> > >> >> We had other reports for similar problems. The following change fix > >> >> those issues, have you tried this out? > >> >> > >> >> [PATCH] mmc: core: Restore parts of the polling policy when switch to HS/HS DDR > >> >> https://patchwork.kernel.org/patch/9515239/ > >> > > >> > I did the test with next and the behavior is the same. > >> > > >> > mmc0: Invalid UHS-I mode selected > >> > mmc0: switch to bus width 8 ddr failed > >> > mmc0: error -110 whilst initialising MMC card > >> > > >> > It seems the root cause is to perform mmc_set_timing before mmc_switch_status. > >> > >> Okay, I see! This sounds a bit weird. > >> > >> As you know, the CMD6 has been a problematic historically, mostly > >> because of busy detection issues. We have now tried to make the code > >> more robust in __mmc_switch() and its friends. > >> That said, before considering to apply your fix, I would really like > >> us to investigate this a bit more, to make sure we find the correct > >> solution and of course to avoid regressions for other cases. > >> > >> Recently reported issues [1] that was observed for sdhci-esdc-imx, > >> which has been fixed now, can be summarized in these two issues: > >> > >> *) Only 3.3V I/O voltage DDR mode was supported by the SoC. Still the > >> mmc core tried to set 1.8V, which caused errors when switching to HS > >> DDR mode. > >> -> To fix this, we invented MMC_CAP_3_3V_DDR [2] and a corresponding > >> DT binding ("mmc-ddr-3_3v"). Hosts/SoCs, that supports only 3.3V DDR > >> mode, should set this. > >> > >> **). Changing host's timings couldn't be done while the card was busy, > >> because of internal limitations by the sdhci-esdhc-imx controller. The > >> consequence was that the following CMD13 command (to get the switch > >> status), returned the error code -110, perhaps similar to your case. > >> ->To fix this, we decided to move the update of the host's timing, to > >> after we verified the card isn't being busy [3]. > >> > >> > >> From your description to the problem you encounter, I would recommend > >> the following debug steps to try to understand what really goes on. > >> 1. > >> Check if the 3.3V DDR issue is applicable for your case as well, and > >> fix it if it is. > > > > There is a regulator driven by the sdhci controller to manage 3.3V and > > 1.8V I/O voltage. > > > >> > >> 2. > >> Both sdhci-esdhc-imx and sdhci-of-at91, don't have > >> MMC_CAP_WAIT_WHILE_BUSY set. However, both sdhci variants are using > >> the ->card_busy() host ops (assigned to sdhci_card_busy()), which > >> triggers __mmc_switch() to call mmc_poll_for_busy() when it switches > >> to HS DDR mode (CMD6). Could it be that sdhci_card_busy() isn't > >> working properly for sdhci-of-at91? This could lead to that that > >> mmc_poll_for_busy() believes the card isn't busy, while it actually > >> is. > >> > >> To check whether theory 2 stands, I would explore these debug alternatives. > >> *) Remove the assignment of ->card_busy() in sdhci.c, which makes > >> mmc_poll_for_busy() to use CMD13 polling instead. If this works, it > >> would be useful to know how many times a CMD13 is sent to find out > >> when card moves out of busy state. > > > > It doesn't work. > > Okay. So what kind of error do you get when sending the CMD13 to poll? -110? No error when I poll after CMD6. Here is a log with CMD13 to perform the polling: mmc0: clock 52000000Hz busmode 2 powermode 2 cs 0 Vdd 21 width 8 timing 1 mmc0: starting CMD8 arg 00000000 flags 000000b5 mmc0: blksz 512 blocks 1 flags 00000200 tsac 400 ms nsac 1000 mmc0: sdhci: IRQ status 0x00000001 mmc0: sdhci: IRQ status 0x00000002 mmc0: req done (CMD8): 0: 00000900 00000000 00000000 00000000 mmc0: 512 bytes transferred: 0 === mmc_select_hs_ddr: l.1072 === --- __mmc_switch --- __mmc_switch: mmc_wait_for_cmd mmc0: starting CMD6 arg 03b70601 flags 0000049d mmc0: sdhci: IRQ status 0x00000001 mmc0: sdhci: IRQ status 0x00000002 mmc0: req done (CMD6): 0: 00000800 00000000 00000000 00000000 __mmc_switch: mmc_poll_for_busy mmc0: starting CMD13 arg 00010000 flags 00000195 mmc0: sdhci: IRQ status 0x00000001 mmc0: req done (CMD13): 0: 00000900 00000000 00000000 00000000 mmc_poll_for_busy: l.512 __mmc_switch: mmc_set_timing mmc0: clock 52000000Hz busmode 2 powermode 2 cs 0 Vdd 21 width 8 timing 8 __mmc_switch: mmc_switch_status mmc0: starting CMD13 arg 00010000 flags 00000195 mmc0: sdhci: IRQ status 0x00038000 mmc0: req failed (CMD13): -110, retrying... mmc0: sdhci: IRQ status 0x00038000 mmc0: req failed (CMD13): -110, retrying... mmc0: sdhci: IRQ status 0x00038000 mmc0: req failed (CMD13): -110, retrying... mmc0: sdhci: IRQ status 0x00038000 mmc0: req done (CMD13): -110: 00000000 00000000 00000000 00000000 mmc0: clock 52000000Hz busmode 2 powermode 2 cs 0 Vdd 21 width 8 timing 1 mmc0: Invalid UHS-I mode selected mmc0: switch to bus width 8 ddr failed mmc0: error -110 whilst initialising MMC card mmc0: clock 0Hz busmode 2 powermode 0 cs 0 Vdd 0 width 1 timing 0 > > > > >> **) While using ->card_busy(), I would just add some simple debug > >> prints in mmc_poll_for_busy() to prints its return values. > > > > No error returned. I exit the function after the while loop. > > If I understand correctly, the ->card_busy() callbacks immediately > reports the eMMC card as *not* being busy, right? Yes, with sdhci_card_busy() this time: === mmc_select_hs_ddr: l.1072 === --- __mmc_switch --- __mmc_switch: mmc_wait_for_cmd mmc0: starting CMD6 arg 03b70601 flags 0000049d mmc0: sdhci: IRQ status 0x00000001 mmc0: sdhci: IRQ status 0x00000002 mmc0: req done (CMD6): 0: 00000800 00000000 00000000 00000000 __mmc_switch: mmc_poll_for_busy mmc_poll_for_busy: ops->card_busy mmc_poll_for_busy: l.513 __mmc_switch: mmc_set_timing mmc0: clock 52000000Hz busmode 2 powermode 2 cs 0 Vdd 21 width 8 timing 8 __mmc_switch: mmc_switch_status mmc0: starting CMD13 arg 00010000 flags 00000195 mmc0: sdhci: IRQ status 0x00038000 mmc0: req failed (CMD13): -110, retrying... mmc0: sdhci: IRQ status 0x00038000 mmc0: req failed (CMD13): -110, retrying... mmc0: sdhci: IRQ status 0x00038000 mmc0: req failed (CMD13): -110, retrying... mmc0: sdhci: IRQ status 0x00038000 mmc0: req done (CMD13): -110: 00000000 00000000 00000000 00000000 mmc0: clock 52000000Hz busmode 2 powermode 2 cs 0 Vdd 21 width 8 timing 1 mmc0: Invalid UHS-I mode selected mmc0: switch to bus width 8 ddr failed mmc0: error -110 whilst initialising MMC card > > > > > I continue the investigation to figure out why calling mmc_set_timing before > > mmc_switch_status causes an issue. > > Great! > > Please tell if you need some further help with some more ideas. Ok thanks. To compare, if I put mmc_set_timing after mmc_switch_status: mmc0: clock 52000000Hz busmode 2 powermode 2 cs 0 Vdd 21 width 8 timing 1 mmc0: starting CMD8 arg 00000000 flags 000000b5 mmc0: blksz 512 blocks 1 flags 00000200 tsac 400 ms nsac 1000 mmc0: sdhci: IRQ status 0x00000001 mmc0: sdhci: IRQ status 0x00000002 mmc0: req done (CMD8): 0: 00000900 00000000 00000000 00000000 mmc0: 512 bytes transferred: 0 === mmc_select_hs_ddr: l.1072 === --- __mmc_switch --- __mmc_switch: mmc_wait_for_cmd mmc0: starting CMD6 arg 03b70601 flags 0000049d mmc0: sdhci: IRQ status 0x00000001 mmc0: sdhci: IRQ status 0x00000002 mmc0: req done (CMD6): 0: 00000800 00000000 00000000 00000000 __mmc_switch: mmc_poll_for_busy mmc_poll_for_busy: ops->card_busy mmc_poll_for_busy: l.513 __mmc_switch: mmc_switch_status mmc0: starting CMD13 arg 00010000 flags 00000195 mmc0: sdhci: IRQ status 0x00000001 mmc0: req done (CMD13): 0: 00000900 00000000 00000000 00000000 __mmc_switch: mmc_set_timing mmc0: clock 52000000Hz busmode 2 powermode 2 cs 0 Vdd 21 width 8 timing 8 --- __mmc_switch --- __mmc_switch: mmc_wait_for_cmd mmc0: starting CMD6 arg 03a10101 flags 0000049d mmc0: sdhci: IRQ status 0x00000001 mmc0: sdhci: IRQ status 0x00000002 mmc0: req done (CMD6): 0: 00000800 00000000 00000000 00000000 __mmc_switch: mmc_poll_for_busy mmc_poll_for_busy: ops->card_busy mmc_poll_for_busy: l.513 __mmc_switch: mmc_switch_status mmc0: starting CMD13 arg 00010000 flags 00000195 mmc0: sdhci: IRQ status 0x00000001 mmc0: req done (CMD13): 0: 00000900 00000000 00000000 00000000 mmc0: new DDR MMC card at address 0001 Regards Ludovic -- To unsubscribe from this list: send the line "unsubscribe linux-mmc" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
