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Nícolas F. R. A. Prado f200fff8d0 spmi: mtk-pmif: Serialize PMIF status check and command submission
Before writing the read or write command to the SPMI arbiter through the
PMIF interface, the current status of the channel is checked to ensure
it is idle. However, since the status only changes from idle when the
command is written, it is possible for two concurrent calls to determine
that the channel is idle and simultaneously send their commands. At this
point the PMIF interface hangs, with the status register no longer being
updated, and thus causing all subsequent operations to time out.

This was observed on the mt8195-cherry-tomato-r2 machine, particularly
after commit 46600ab142 ("regulator: Set PROBE_PREFER_ASYNCHRONOUS for
drivers between 5.10 and 5.15") was applied, since then the two MT6315
devices present on the SPMI bus would probe assynchronously and
sometimes (during probe or at a later point) read the bus
simultaneously, breaking the PMIF interface and consequently slowing
down the whole system.

To fix the issue at its root cause, introduce locking around the channel
status check and the command write, so that both become an atomic
operation, preventing race conditions between two (or more) SPMI bus
read/write operations. A spinlock is used since this is a fast bus, as
indicated by the usage of the atomic variant of readl_poll, and
'.fast_io = true' being used in the mt6315 driver, so spinlocks are
already used for the regmap access.

Fixes: b45b3ccef8 ("spmi: mediatek: Add support for MT6873/8192")
Signed-off-by: Nícolas F. R. A. Prado <nfraprado@collabora.com>
Link: https://lore.kernel.org/r/20230724154739.493724-1-nfraprado@collabora.com
Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Reviewed-by: Alexandre Mergnat <amergnat@baylibre.com>
Signed-off-by: Stephen Boyd <sboyd@kernel.org>
Link: https://lore.kernel.org/r/20231206231733.4031901-2-sboyd@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-12-15 17:27:04 +01:00
arch - Add a forgotten CPU vendor check in the AMD microcode post-loading 2023-12-10 10:53:55 -08:00
block block-6.7-2023-12-01 2023-12-02 06:39:30 +09:00
certs This update includes the following changes: 2023-11-02 16:15:30 -10:00
crypto This push fixes a regression in ahash and hides the Kconfig sub-options for the jitter RNG. 2023-11-09 17:04:58 -08:00
Documentation dt-bindings: nvmem: add new stm32mp25 compatible for stm32-romem 2023-12-15 13:30:08 +01:00
drivers spmi: mtk-pmif: Serialize PMIF status check and command submission 2023-12-15 17:27:04 +01:00
fs Char/Misc driver fixes for 6.7-rc5 2023-12-09 12:44:10 -08:00
include misc: rtsx: add to support new card reader rts5264 new definition and function 2023-12-15 17:27:04 +01:00
init rootfs: Fix support for rootfstype= when root= is given 2023-12-07 10:29:21 +09:00
io_uring io_uring/af_unix: disable sending io_uring over sockets 2023-12-07 10:35:19 -07:00
ipc Many singleton patches against the MM code. The patch series which are 2023-11-02 19:38:47 -10:00
kernel - Make sure tasks are thawed exactly and only once to avoid their state 2023-12-10 11:09:16 -08:00
lib 31 hotfixes. 10 of these address pre-6.6 issues and are marked cc:stable. 2023-12-08 08:36:23 -08:00
LICENSES
mm mm/madvise: add cond_resched() in madvise_cold_or_pageout_pte_range() 2023-12-06 16:12:50 -08:00
net io_uring-6.7-2023-12-08 2023-12-08 12:32:38 -08:00
rust Kbuild updates for v6.7 2023-11-04 08:07:19 -10:00
samples Landlock updates for v6.7-rc1 2023-11-03 09:28:53 -10:00
scripts 31 hotfixes. 10 of these address pre-6.6 issues and are marked cc:stable. 2023-12-08 08:36:23 -08:00
security + Features 2023-11-03 09:48:17 -10:00
sound ALSA: hda/realtek: Add quirk for Lenovo Yoga Pro 7 2023-12-07 19:21:08 +01:00
tools tools/testing/nvdimm: Add compile-test coverage for ndtest 2023-12-15 17:07:12 +01:00
usr
virt Revert "KVM: Prevent module exit until all VMs are freed" 2023-12-01 08:12:30 -08:00
.clang-format
.cocciconfig
.get_maintainer.ignore
.gitattributes
.gitignore kbuild: rpm-pkg: generate kernel.spec in rpmbuild/SPECS/ 2023-10-03 20:49:09 +09:00
.mailmap .mailmap: add a new address mapping for Chester Lin 2023-12-06 16:12:45 -08:00
.rustfmt.toml
COPYING
CREDITS MAINTAINERS: drop Antti Palosaari 2023-12-06 16:12:49 -08:00
Kbuild
Kconfig
MAINTAINERS coresight: Updates for Linux v6.8 2023-12-12 14:34:15 +01:00
Makefile Linux 6.7-rc5 2023-12-10 14:33:40 -08:00
README

Linux kernel
============

There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.  The formatted documentation can also be read online at:

    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.