linux.git/drivers/mmc/core/host.c, branch v5.16

mmc: core: Disable card detect during shutdown

2021-12-20T10:09:15+00:00

It's seems prone to problems by allowing card detect and its corresponding
mmc_rescan() work to run, during platform shutdown. For example, we may end
up turning off the power while initializing a card, which potentially could
damage it.

To avoid this scenario, let's add ->shutdown_pre() callback for the mmc host
class device and then turn of the card detect from there.

Reported-by: Al Cooper 
Suggested-by: Adrian Hunter 
Signed-off-by: Ulf Hansson 
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20211203141555.105351-1-ulf.hansson@linaro.org

mmc: host: factor out clearing the retune state

2021-08-24T08:15:28+00:00

We have this in two places, so let's have a dedicated function. It is
also more readable.

Signed-off-by: Wolfram Sang 
Acked-by: Adrian Hunter 
Reviewed-by: Yoshihiro Shimoda 
Tested-by: Yoshihiro Shimoda 
Link: https://lore.kernel.org/r/20210624151616.38770-4-wsa+renesas@sang-engineering.com
Signed-off-by: Ulf Hansson

mmc: host: add kdoc for mmc_retune_{en|dis}able

2021-08-24T08:15:28+00:00

I wanted to use it in a wrong way, so document the intended way.

Signed-off-by: Wolfram Sang 
Acked-by: Adrian Hunter 
Reviewed-by: Yoshihiro Shimoda 
Tested-by: Yoshihiro Shimoda 
Link: https://lore.kernel.org/r/20210624151616.38770-3-wsa+renesas@sang-engineering.com
Signed-off-by: Ulf Hansson

mmc: core: Don't allocate IDA for OF aliases

2021-07-14T16:55:28+00:00

There's a chance that the IDA allocated in mmc_alloc_host() is not freed
for some time because it's freed as part of a class' release function
(see mmc_host_classdev_release() where the IDA is freed). If another
thread is holding a reference to the class, then only once all balancing
device_put() calls (in turn calling kobject_put()) have been made will
the IDA be released and usable again.

Normally this isn't a problem because the kobject is released before
anything else that may want to use the same number tries to again, but
with CONFIG_DEBUG_KOBJECT_RELEASE=y and OF aliases it becomes pretty
easy to try to allocate an alias from the IDA twice while the first time
it was allocated is still pending a call to ida_simple_remove(). It's
also possible to trigger it by using CONFIG_DEBUG_KOBJECT_RELEASE and
probe defering a driver at boot that calls mmc_alloc_host() before
trying to get resources that may defer likes clks or regulators.

Instead of allocating from the IDA in this scenario, let's just skip it
if we know this is an OF alias. The number is already "claimed" and
devices that aren't using OF aliases won't try to use the claimed
numbers anyway (see mmc_first_nonreserved_index()). This should avoid
any issues with mmc_alloc_host() returning failures from the
ida_simple_get() in the case that we're using an OF alias.

Cc: Matthias Schiffer 
Cc: Sujit Kautkar 
Reported-by: Zubin Mithra 
Fixes: fa2d0aa96941 ("mmc: core: Allow setting slot index via device tree alias")
Signed-off-by: Stephen Boyd 
Link: https://lore.kernel.org/r/20210623075002.1746924-3-swboyd@chromium.org
Cc: stable@vger.kernel.org
Signed-off-by: Ulf Hansson

mmc: core: add support for disabling HS400 mode via DT

2021-06-14T11:57:39+00:00

On some boards the data strobe line isn't wired up, rendering HS400
support broken, even if both the controller and the eMMC claim to
support it. Allow to disable HS400 mode via DT.

Signed-off-by: Lucas Stach 
Link: https://lore.kernel.org/r/20210510190400.105162-3-l.stach@pengutronix.de
Signed-off-by: Ulf Hansson

mmc: core: Convert mmc_of_parse_voltage() to use device property API

2021-04-23T07:29:49+00:00

mmc_of_parse() for a few years has been using device property API.
Convert mmc_of_parse_voltage() as well.

At the same time switch users to new API.

Signed-off-by: Andy Shevchenko 
Link: https://lore.kernel.org/r/20210419112459.25241-2-andriy.shevchenko@linux.intel.com
Signed-off-by: Ulf Hansson

mmc: core: Correct descriptions in mmc_of_parse()

2021-04-23T07:29:48+00:00

Since it has been converted to use device property API, the function
and field descriptions become outdated. Correct them.

Fixes: 73a47a9bb3e2 ("mmc: core: Use device_property_read instead of of_property_read")
Signed-off-by: Andy Shevchenko 
Link: https://lore.kernel.org/r/20210419112459.25241-1-andriy.shevchenko@linux.intel.com
Signed-off-by: Ulf Hansson

mmc: core: Fix hanging on I/O during system suspend for removable cards

2021-03-30T09:42:03+00:00

The mmc core uses a PM notifier to temporarily during system suspend, turn
off the card detection mechanism for removal/insertion of (e)MMC/SD/SDIO
cards. Additionally, the notifier may be used to remove an SDIO card
entirely, if a corresponding SDIO functional driver don't have the system
suspend/resume callbacks assigned. This behaviour has been around for a
very long time.

However, a recent bug report tells us there are problems with this
approach. More precisely, when receiving the PM_SUSPEND_PREPARE
notification, we may end up hanging on I/O to be completed, thus also
preventing the system from getting suspended.

In the end what happens, is that the cancel_delayed_work_sync() in
mmc_pm_notify() ends up waiting for mmc_rescan() to complete - and since
mmc_rescan() wants to claim the host, it needs to wait for the I/O to be
completed first.

Typically, this problem is triggered in Android, if there is ongoing I/O
while the user decides to suspend, resume and then suspend the system
again. This due to that after the resume, an mmc_rescan() work gets punted
to the workqueue, which job is to verify that the card remains inserted
after the system has resumed.

To fix this problem, userspace needs to become frozen to suspend the I/O,
prior to turning off the card detection mechanism. Therefore, let's drop
the PM notifiers for mmc subsystem altogether and rely on the card
detection to be turned off/on as a part of the system_freezable_wq, that we
are already using.

Moreover, to allow and SDIO card to be removed during system suspend, let's
manage this from a ->prepare() callback, assigned at the mmc_host_class
level. In this way, we can use the parent device (the mmc_host_class
device), to remove the card device that is the child, in the
device_prepare() phase.

Reported-by: Kiwoong Kim 
Cc: stable@vger.kernel.org # v4.5+
Signed-off-by: Ulf Hansson 
Reviewed-by: Linus Walleij 
Link: https://lore.kernel.org/r/20210310152900.149380-1-ulf.hansson@linaro.org
Reviewed-by: Kiwoong Kim

mmc: core: Add basic support for inline encryption

2021-02-01T11:02:33+00:00

In preparation for adding CQHCI crypto engine (inline encryption)
support, add the code required to make mmc_core and mmc_block aware of
inline encryption.  Specifically:

- Add a capability flag MMC_CAP2_CRYPTO to struct mmc_host.  Drivers
  will set this if the host and driver support inline encryption.

- Embed a blk_keyslot_manager in struct mmc_host.  Drivers will
  initialize this (as a device-managed resource) if the host and driver
  support inline encryption.  mmc_block registers this keyslot manager
  with the request_queue of any MMC card attached to the host.

- Make mmc_block copy the crypto keyslot and crypto data unit number
  from struct request to struct mmc_request, so that drivers will have
  access to them.

- If the MMC host is reset, reprogram all the keyslots to ensure that
  the software state stays in sync with the hardware state.

Co-developed-by: Satya Tangirala 
Signed-off-by: Satya Tangirala 
Acked-by: Adrian Hunter 
Reviewed-by: Satya Tangirala 
Reviewed-and-tested-by: Peng Zhou 
Signed-off-by: Eric Biggers 
Link: https://lore.kernel.org/r/20210126001456.382989-2-ebiggers@kernel.org
Signed-off-by: Ulf Hansson

mmc: core: Add helper for parsing clock phase properties

2021-02-01T10:54:47+00:00

Drivers for MMC hosts that accept phase corrections can take advantage
of the helper by embedding an instance of struct mmc_clk_phase_map in
their private data and invoking mmc_of_parse_clk_phase() to extract
phase parameters. It is the responsibility of the host driver to
translate and apply the extracted values to hardware as required.

Signed-off-by: Andrew Jeffery 
Link: https://lore.kernel.org/r/20210114031433.2388532-2-andrew@aj.id.au
Signed-off-by: Ulf Hansson