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?) Note that according to spec. CMD0 anyway clears the cache so you have lost your data anyway. -- 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
