Hi Ulf, On Thu, Jan 30, 2014 at 6:37 AM, Ulf Hansson <ulf.hans...@linaro.org> wrote: > This patchset improves the handling around busy detection in the mmc core > layer > while operating on host supporting MMC_CAP_WAIT_WHILE_BUSY. > > A R1B response is for an mmc command, specified as and R1 but with an optional > busy assertion on the DAT0 line. Hosts supporting MMC_CAP_WAIT_WHILE_BUSY, > normally has a busy detection mechanism build in it's controller HW. > > Using such a feature decreases the need for polling of the card's status using > CMD13, which is the fallback method used by the mmc core for hosts that don't > support MMC_CAP_WAIT_WHILE_BUSY. > > Typcial commands that expects R1B responses are CMD6 (SWITCH), CMD12 (STOP), > CMD38 (ERASE) and CMD5 (SLEEP). This patchset adresses CMD6, CMD5 and improves > some parts where CMD12 are used. If the implemented approach becomes accepted, > a future patchset for CMD38 can be based on top if this patchset. > > Do note, the final two patches implements support for busy detection for the > mmci host driver, since some of it's HW variants do supports busy detection. > > Future suggested improvements related to this patchset: (Please, feel free to > implement any of them :-) ). > > a) For CMD38, select a fixed number maximum blocks to accept for > erase/discard/trim operations. Compute the needed timeout depending on each > card's erase information provided through it's CSD/EXT_CSD registers. Then > follow the same principle as for sending a CMD6. > > b) At least for CMD38, but likely for other commands as well, we could benefit > from doing a _periodic_ CMD13 polling to handle the busy completion. This will > also be useful for hosts supporting MMC_CAP_WAIT_WHILE_BUSY, in particular for > cases where the host are unable to support the needed busy timeout. >
Do you have the plan to implement above two items? Since currently the max_discard_sectors is still calculated based on max_busy_timeout of host, it is possible that for some eMMC chips, the max_discard_sectors is 1, which then cause the erase operation terribly slow. Regards Dong Aisheng > c) Handle timeouts while polling for card's status with CMD13 in cases where > a CMD12 has been used to finalize a data DATA_WRITE transfer. > > > Ulf Hansson (13): > mmc: core: Rename max_discard_to to max_busy_timeout > mmc: core: Rename cmd_timeout_ms to busy_timeout > mmc: core: Add ignore_crc flag to __mmc_switch > mmc: core: Minor simplifications to __mmc_switch > mmc: core: Fixup busy detection for mmc switch operations > mmc: core: Use generic CMD6 time while switching to eMMC HS200 mode > mmc: core: Respect host's max_busy_timeout when sending sleep cmd > mmc: block: Use R1 responses for stop cmds for read requests > mmc: block: Implement card_busy_detect() for busy detection > mmc: block: Respect hw busy detection in card_busy_detect() > mmc: block: Fixup busy detection while invoking stop cmd at recovery > mmc: mmci: Handle CMD irq before DATA irq > mmc: mmci: Enable support for busy detection for ux500 variant > > drivers/mmc/card/block.c | 178 > ++++++++++++++++++++++++++++---------------- > drivers/mmc/core/core.c | 11 +-- > drivers/mmc/core/mmc.c | 34 ++++++--- > drivers/mmc/core/mmc_ops.c | 64 ++++++++++------ > drivers/mmc/host/mmci.c | 54 +++++++++++--- > drivers/mmc/host/mmci.h | 2 + > drivers/mmc/host/sdhci.c | 10 +-- > include/linux/mmc/core.h | 4 +- > include/linux/mmc/host.h | 2 +- > 9 files changed, 241 insertions(+), 118 deletions(-) > > -- > 1.7.9.5 > > -- > To unsubscribe from this list: send the line "unsubscribe linux-mmc" in > the body of a message to majord...@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html -- To unsubscribe from this list: send the line "unsubscribe linux-mmc" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
