Commit Graph

9 Commits

Author SHA1 Message Date
Ulf Hansson 9eadcc0581 mmc: core: Remove MMC_CLKGATE
MMC_CLKGATE was once invented to save power by gating the bus clock at
request inactivity. At that time it served its purpose. The modern way to
deal with power saving for these scenarios, is by using runtime PM.

Nowadays, several host drivers have deployed runtime PM, but for those
that haven't and which still cares power saving at request inactivity,
it's certainly time to deploy runtime PM as it has been around for several
years now.

To simplify code to mmc core and thus decrease maintenance efforts, this
patch removes all code related to MMC_CLKGATE.

Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
2015-10-26 16:00:09 +01:00
Bernie Thompson 51e7e8b632 mmc: core: Add in support to expose PRV for v4 MMCs
The JEDEC MMC v4 spec defines a new PRV value in place of the original
fwrev and hwrev specified in v1. We can expose this in the kernel to enable
user space to more easily determine the product revision of a given MMC.

Signed-off-by: Bernie Thompson <bhthompson@chromium.org>
Reviewed-by: Ulf Hansson <ulf.hansson@linaro.org>
Signed-off-by: Chris Ball <cjb@laptop.org>
2013-03-22 12:10:42 -04:00
Loic Pallardy 188cc0424e mmc: core: Extend sysfs to ext_csd parameters for RPMB support
Extend current sysfs access to ext_csd rpmb parameters (RPMB partition
size) and rel_sector information.

Signed-off-by: Loic Pallardy <loic.pallardy@stericsson.com>
Reviewed-by: Namjae Jeon <linkinjeon@gmail.com>
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Acked-by: Johan Rudholm <johan.rudholm@stericsson.com>
Acked-by: Krishna Konda <kkonda@codeaurora.org>
Signed-off-by: Chris Ball <cjb@laptop.org>
2012-12-06 13:54:48 -05:00
Stephen Boyd 4137e50494 mmc: core: Fixup delayed work clock gating patch
c31b50e (mmc: core: Use delayed work in clock gating framework,
2011-11-14) missed a few things during review:

 o A useless pr_info()

 o milliseconds was written as two words

 o The sysfs file had units in its output

Fix all three problems.

Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
Cc: Sujit Reddy Thumma <sthumma@codeaurora.org>
Signed-off-by: Chris Ball <cjb@laptop.org>
2012-01-11 23:58:43 -05:00
Johan Rudholm add710eaa8 mmc: boot partition ro lock support
Enable boot partitions to be read-only locked until next power on via
a sysfs entry. There will be one sysfs entry for each boot partition:

/sys/block/mmcblkXbootY/ro_lock_until_next_power_on

Each boot partition is locked by writing 1 to its file.

Signed-off-by: Johan Rudholm <johan.rudholm@stericsson.com>
Signed-off-by: John Beckett <john.beckett@stericsson.com>
Signed-off-by: Chris Ball <cjb@laptop.org>
2012-01-11 23:58:43 -05:00
Sujit Reddy Thumma 597dd9d79c mmc: core: Use delayed work in clock gating framework
Current clock gating framework disables the MCI clock as soon as the
request is completed and enables it when a request arrives. This aggressive
clock gating framework, when enabled, cause following issues:

When there are back-to-back requests from the Queue layer, we unnecessarily
end up disabling and enabling the clocks between these requests since 8MCLK
clock cycles is a very short duration compared to the time delay between
back to back requests reaching the MMC layer. This overhead can effect the
overall performance depending on how long the clock enable and disable
calls take which is platform dependent. For example on some platforms we
can have clock control not on the local processor, but on a different
subsystem and the time taken to perform the clock enable/disable can add
significant overhead.

Also if the host controller driver decides to disable the host clock too
when mmc_set_ios function is called with ios.clock=0, it adds additional
delay and it is highly possible that the next request had already arrived
and unnecessarily blocked in enabling the clocks. This is seen frequently
when the processor is executing at high speeds and in multi-core platforms
thus reduces the overall throughput compared to if clock gating is
disabled.

Fix this by delaying turning off the clocks by posting request on
delayed workqueue. Also cancel the unscheduled pending work, if any,
when there is access to card.

sysfs entry is provided to tune the delay as needed, default
value set to 200ms.

Signed-off-by: Sujit Reddy Thumma <sthumma@codeaurora.org>
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Chris Ball <cjb@laptop.org>
2012-01-11 23:58:41 -05:00
Per Forlin 7937e878f9 mmc: documentation of mmc non-blocking request usage and design.
Documentation about the background and the design of mmc non-blocking.
Host driver guidelines to minimize request preparation overhead.

Signed-off-by: Per Forlin <per.forlin@linaro.org>
Acked-by: Randy Dunlap <rdunlap@xenotime.net>
Signed-off-by: Chris Ball <cjb@laptop.org>
2011-07-21 10:34:52 -04:00
Andrei Warkentin 371a689f64 mmc: MMC boot partitions support.
Allows device MMC boot partitions to be accessed. MMC partitions are
treated effectively as separate block devices on the same MMC card.

Signed-off-by: Andrei Warkentin <andreiw@motorola.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Chris Ball <cjb@laptop.org>
2011-05-24 21:01:21 -04:00
Adrian Hunter dfe86cba76 mmc: add erase, secure erase, trim and secure trim operations
SD/MMC cards tend to support an erase operation.  In addition, eMMC v4.4
cards can support secure erase, trim and secure trim operations that are
all variants of the basic erase command.

SD/MMC device attributes "erase_size" and "preferred_erase_size" have been
added.

"erase_size" is the minimum size, in bytes, of an erase operation.  For
MMC, "erase_size" is the erase group size reported by the card.  Note that
"erase_size" does not apply to trim or secure trim operations where the
minimum size is always one 512 byte sector.  For SD, "erase_size" is 512
if the card is block-addressed, 0 otherwise.

SD/MMC cards can erase an arbitrarily large area up to and
including the whole card.  When erasing a large area it may
be desirable to do it in smaller chunks for three reasons:

    1. A single erase command will make all other I/O on the card
       wait.  This is not a problem if the whole card is being erased, but
       erasing one partition will make I/O for another partition on the
       same card wait for the duration of the erase - which could be a
       several minutes.

    2. To be able to inform the user of erase progress.

    3. The erase timeout becomes too large to be very useful.
       Because the erase timeout contains a margin which is multiplied by
       the size of the erase area, the value can end up being several
       minutes for large areas.

"erase_size" is not the most efficient unit to erase (especially for SD
where it is just one sector), hence "preferred_erase_size" provides a good
chunk size for erasing large areas.

For MMC, "preferred_erase_size" is the high-capacity erase size if a card
specifies one, otherwise it is based on the capacity of the card.

For SD, "preferred_erase_size" is the allocation unit size specified by
the card.

"preferred_erase_size" is in bytes.

Signed-off-by: Adrian Hunter <adrian.hunter@nokia.com>
Acked-by: Jens Axboe <axboe@kernel.dk>
Cc: Kyungmin Park <kmpark@infradead.org>
Cc: Madhusudhan Chikkature <madhu.cr@ti.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Ben Gardiner <bengardiner@nanometrics.ca>
Cc: <linux-mmc@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-08-12 08:43:30 -07:00