(e)MMC status and updates

LCE13, Dublin. 8-12 July 2013Ulf Hansson

Agenda

● Power management● Generic MMC highlights● eMMC 4.5 status● What's is Linaro's future focus?

Power Management :1

● Runtime PM for host devices● Save power in idle by gating clocks, set pinctrls in sleep state

and release references to a power domain.

● Runtime PM for card devices● To be used for idle power management operations.● mmc_get|put_card functions.● Aggressive PM policy, first proof of concept.● Periodic BKOPS may be implemented.● Periodic Cache CTRL may be implemented.● Periodic HS200 re-runting● Some more?

Power Management :2

● Restructure suspend/resume● Separate suspend for cards and hosts.

● Shutdown support for cards● Issue suspend commands.

Generic MMC highlights

● Card removal logics (slow card removal)● Signal voltage switch, UHS SD-cards

● .start_signal_voltage_switch - mandatory.● .card_busy - optional.

● Common MMC DT parser● Common MMC regulator API

● VCC and VCCQ.

eMMC 4.5 status :1● Sanitize – wipe physical unmapped regions

● An mmc ioctl for 3.11.

● MMC_CAP2_SANITIZE.

● Discard – provide garbage collection information

● MMC_CAP_ERASE.

● Power off notification – gracefully cut power

● For 3.11.

● MMC_CAP2_FULL_PWR_CYCLE needed in suspend, otherwise we will fall-back to the SLEEP cmd.

● Data tag – mark file system meta data

● MMC_CAP_CMD23 is needed.

eMMC 4.5 status :2● Cache CTRL – flush the internal eMMC cache

● At REQ_FLUSH and at suspend/shutdown.● MMC_CAP2_CACHE_CTRL.● Do we need a periodic a flush mechanism?

● HS200 – 200MB bandwidth

● .execute_tuning – mandatory.● MMC_CAP2_HS200.● Periodic re-tuning is not supported.● Move protocol code to core layer.● Error handling when running in HS200 mode?

eMMC 4.5 status :3● Packed commands – group requests for increased performance

● MMC_CAP2_PACKED_CMD.

● Large page support

● EXT_CSD_DATA_SECTOR_SIZE bit.

● BKOPS (4.41)

● Initial support for BKOPS, acting on level 2/3.

● Period BKOPS not supported yet.

● eMMC 4.51 makes eMMC 4.5 obsolete

● Security extensions.

● Clarifications to the specification.

What's is Linaro's future focus

● Periodic/Idle based features● eMMC 5.x● Performance optimizations

● Use case profiling database

● F2FS