kernel.git/drivers/mmc/core/core.h, branch linux-5.12.y

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

2021-05-12T06:39:31Z

commit 17a17bf50612e6048a9975450cf1bd30f93815b5 upstream. 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 Signed-off-by: Greg Kroah-Hartman

mmc: block: Issue a cache flush only when it's enabled

2021-05-12T06:39:31Z

commit 97fce126e279690105ee15be652b465fd96f9997 upstream. In command queueing mode, the cache isn't flushed via the mmc_flush_cache() function, but instead by issuing a CMDQ_TASK_MGMT (CMD48) with a FLUSH_CACHE opcode. In this path, we need to check if cache has been enabled, before deciding to flush the cache, along the lines of what's being done in mmc_flush_cache(). To fix this problem, let's add a new bus ops callback ->cache_enabled() and implement it for the mmc bus type. In this way, the mmc block device driver can call it to know whether cache flushing should be done. Fixes: 1e8e55b67030 (mmc: block: Add CQE support) Cc: stable@vger.kernel.org Reported-by: Brendan Peter Signed-off-by: Avri Altman Tested-by: Brendan Peter Acked-by: Adrian Hunter Link: https://lore.kernel.org/r/20210425060207.2591-2-avri.altman@wdc.com Link: https://lore.kernel.org/r/20210425060207.2591-3-avri.altman@wdc.com [Ulf: Squashed the two patches and made some minor updates] Signed-off-by: Ulf Hansson Signed-off-by: Greg Kroah-Hartman

mmc: core: Re-work HW reset for SDIO cards

2019-11-14T15:28:56Z

It have turned out that it's not a good idea to unconditionally do a power cycle and then to re-initialize the SDIO card, as currently done through mmc_hw_reset() -> mmc_sdio_hw_reset(). This because there may be multiple SDIO func drivers probed, who also shares the same SDIO card. To address these scenarios, one may be tempted to use a notification mechanism, as to allow the core to inform each of the probed func drivers, about an ongoing HW reset. However, supporting such an operation from the func driver point of view, may not be entirely trivial. Therefore, let's use a more simplistic approach to solve the problem, by instead forcing the card to be removed and re-detected, via scheduling a rescan-work. In this way, we can rely on existing infrastructure, as the func driver's ->remove() and ->probe() callbacks, becomes invoked to deal with the cleanup and the re-initialization. This solution may be considered as rather heavy, especially if a func driver doesn't share its card with other func drivers. To address this, let's keep the current immediate HW reset option as well, but run it only when there is one func driver probed for the card. Finally, to allow the caller of mmc_hw_reset(), to understand if the reset is being asynchronously managed from a scheduled work, it returns 1 (propagated from mmc_sdio_hw_reset()). If the HW reset is executed successfully and synchronously it returns 0, which maintains the existing behaviour. Reviewed-by: Douglas Anderson Tested-by: Douglas Anderson Cc: stable@vger.kernel.org # v5.4+ Signed-off-by: Ulf Hansson

treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500

2019-06-19T15:09:55Z

Based on 2 normalized pattern(s): this program is free software you can redistribute it and or modify it under the terms of the gnu general public license version 2 as published by the free software foundation this program is free software you can redistribute it and or modify it under the terms of the gnu general public license version 2 as published by the free software foundation # extracted by the scancode license scanner the SPDX license identifier GPL-2.0-only has been chosen to replace the boilerplate/reference in 4122 file(s). Signed-off-by: Thomas Gleixner Reviewed-by: Enrico Weigelt Reviewed-by: Kate Stewart Reviewed-by: Allison Randal Cc: linux-spdx@vger.kernel.org Link: https://lkml.kernel.org/r/20190604081206.933168790@linutronix.de Signed-off-by: Greg Kroah-Hartman

mmc: core: Move regulator helpers to separate file

2019-02-25T14:20:58Z

The mmc regulator helper functions, are placed in the extensive core.c file. In a step towards trying to create a better structure of files, avoiding too many lines of code per file, let's move these helpers to a new file, regulator.c. Moreover, this within this context it makes sense to also drop the export of mmc_vddrange_to_ocrmask(), but instead let's make it internal to the mmc core. Signed-off-by: Ulf Hansson

mmc: core: remove obsolete mmc_set_blockcount() function

2018-12-17T07:26:24Z

The only user was converted to fill a sbc command which is the proper way to do it because of AutoCMD23 feature of some hosts. Signed-off-by: Wolfram Sang Tested-by: Clément Péron Reviewed-by: Avri Altman Reviewed-by: Niklas Söderlund Signed-off-by: Ulf Hansson

mmc: core: Drop the unused mmc_power_save|restore_host()

2018-07-16T09:21:45Z

The last user of mmc_power_save|restore_host() APIs is gone, hence let's drop them. Drop also the corresponding bus_ops callback, ->power_save|restore() as those becomes redundant. Cc: Tony Lindgren Cc: Eyal Reizer Signed-off-by: Ulf Hansson

mmc: core: Share internal function to set initial signal voltage

2018-05-08T07:33:50Z

Move the corresponding code for setting the initial signal voltage, from mmc_power_up() into a new function, mmc_set_initial_signal_voltage(). Make the function internally available to the mmc core, as to allow the following changes to make use of it. Signed-off-by: Ulf Hansson Tested-by: Quentin Schulz Reviewed-by: Shawn Lin

mmc: core: Export a function mmc_sw_reset() to allow soft reset of cards

2018-05-08T07:33:42Z

It's rather common that a firmware is loaded into an SDIO func device memory, by the corresponding SDIO func driver during ->probe() time. However, to actually start running the new firmware, sometimes a soft reset (no power cycle) and a re-initialization of the card is needed. This is for example the case with the Espressif ESP8089 WiFi chips, when connected to an SDIO interface. To cope with this scenario, let's add a new exported function, mmc_sw_reset(), which may be called when a soft reset and re-initialization of the card are needed. The mmc_sw_reset() is implemented on top of a new bus ops callback, similar to how the mmc_hw_reset() has been implemented. Signed-off-by: Ulf Hansson Tested-by: Quentin Schulz Reviewed-by: Shawn Lin

mmc: core: Rename ->reset() bus ops to ->hw_reset()

2018-05-08T07:33:29Z

The bus ops ->reset() executes a full HW reset of the card, as the calling function mmc_hw_reset() also indicates by its name. Let's convert to follow the similar names, for both the bus ops callback and for the corresponding bus ops functions, as to clarify the purpose of code. Signed-off-by: Ulf Hansson Tested-by: Quentin Schulz Reviewed-by: Shawn Lin