On 04/04/13 14:52, Ulf Hansson wrote: > On 4 April 2013 13:44, Adrian Hunter <adrian.hunter@xxxxxxxxx> wrote: >> On 04/04/13 12:55, Ulf Hansson wrote: >>> On 4 April 2013 10:46, Adrian Hunter <adrian.hunter@xxxxxxxxx> wrote: >>>> On 01/03/13 14:47, Ulf Hansson wrote: >>>>> From: Ulf Hansson <ulf.hansson@xxxxxxxxxx> >>>>> >>>>> The mmc_power_restore|save_host API is only used by SDIO func drivers. SDIO >>>> >>>> NAK - it is also used by eMMC hardware reset i.e. mmc_do_hw_reset() >>> >>> True for eMMC, but for SD card the bus_ops can go away. Thanks for >>> spotting this Adrian! >>> >>> Although, I see some serious problems with the mmc_do_hw_reset >>> function - it could cause eMMC data corruption. >>> >>> Issuing hw reset and doing re-initialization by using the mmc >>> bus_ops->power_restore will mean no consideration is taken to "cache >>> ctrl", "bkops" and "power off notify". I think it must. >>> >>> So the more proper way instead of calling power_restore, should be to >>> use bus_ops->suspend and bus_ops->resume callbacks from the >>> mmc_do_hw_reset function. Additionally if bus_ops->suspend is done >>> successfully, we should be able to skip the actual hw reset and just >>> do bus_ops->resume. >>> >>> Do you have any thoughts on this? >> >> Certainly the bootloader should leave the eMMC is a safe state including: >> flushing the cache or turning it off (why did it turn on?), stopping >> background operations (why did it start them?), disabling power-off >> notification CMD0? (again why it it enable it?) > > Not sure what you mean here. What has a booloader to do with this? When do you think hw reset is used? > >> >> Note that according to spec. CMD0 anyway clears the cache so you have lost >> your data anyway. > > What I am saying that we can try send "cache ctrl" and "power off > notify" before we send CMD0 / do hw reset. The no data shall be lost. With an uninitialized bus? Or an unresponsive card? -- 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
