linux-stable.git/drivers/spmi, branch v6.7.2

spmi: mtk-pmif: Serialize PMIF status check and command submission

2024-01-25T23:45:23+00:00

[ Upstream commit f200fff8d019f2754f91f5d715652e3e3fdf3604 ]

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point the PMIF interface hangs, with the status register no longer being
updated, and thus causing all subsequent operations to time out.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 46600ab142f8 ("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: b45b3ccef8c0 ("spmi: mediatek: Add support for MT6873/8192")
Signed-off-by: Nícolas F. R. A. Prado 
Link: https://lore.kernel.org/r/20230724154739.493724-1-nfraprado@collabora.com
Reviewed-by: AngeloGioacchino Del Regno 
Reviewed-by: Alexandre Mergnat 
Signed-off-by: Stephen Boyd 
Link: https://lore.kernel.org/r/20231206231733.4031901-2-sboyd@kernel.org
Signed-off-by: Greg Kroah-Hartman 
Signed-off-by: Sasha Levin

spmi: rename spmi device lookup helper

2023-11-01T10:02:18+00:00

Rename the SPMI device helper which is used to lookup a device from its
OF node as spmi_find_device_by_of_node() so that it reflects the
implementation and matches how other helpers like this are named.

This will specifically make it more clear that this is a lookup function
which returns a reference counted structure.

Signed-off-by: Johan Hovold 
Acked-by: Stephen Boyd 
Link: https://lore.kernel.org/r/20231003152927.15000-6-johan+linaro@kernel.org
Signed-off-by: Lee Jones

spmi: document spmi_device_from_of() refcounting

2023-11-01T10:02:18+00:00

Add a comment documenting that the spmi_device_from_of() takes a
reference to the embedded struct device that needs to be dropped after
use.

Signed-off-by: Johan Hovold 
Acked-by: Stephen Boyd 
Link: https://lore.kernel.org/r/20231003152927.15000-5-johan+linaro@kernel.org
Signed-off-by: Lee Jones

spmi: Add a check for remove callback when removing a SPMI driver

2023-04-20T12:16:39+00:00

When removing a SPMI driver, there can be a crash due to NULL pointer
dereference if it does not have a remove callback defined. This is
one such call trace observed when removing the QCOM SPMI PMIC driver:

 dump_backtrace.cfi_jt+0x0/0x8
 dump_stack_lvl+0xd8/0x16c
 panic+0x188/0x498
 __cfi_slowpath+0x0/0x214
 __cfi_slowpath+0x1dc/0x214
 spmi_drv_remove+0x16c/0x1e0
 device_release_driver_internal+0x468/0x79c
 driver_detach+0x11c/0x1a0
 bus_remove_driver+0xc4/0x124
 driver_unregister+0x58/0x84
 cleanup_module+0x1c/0xc24 [qcom_spmi_pmic]
 __do_sys_delete_module+0x3ec/0x53c
 __arm64_sys_delete_module+0x18/0x28
 el0_svc_common+0xdc/0x294
 el0_svc+0x38/0x9c
 el0_sync_handler+0x8c/0xf0
 el0_sync+0x1b4/0x1c0

If a driver has all its resources allocated through devm_() APIs and
does not need any other explicit cleanup, it would not require a
remove callback to be defined. Hence, add a check for remove callback
presence before calling it when removing a SPMI driver.

Link: https://lore.kernel.org/r/1671601032-18397-2-git-send-email-quic_jprakash@quicinc.com
Fixes: 6f00f8c8635f ("mfd: qcom-spmi-pmic: Use devm_of_platform_populate()")
Fixes: 5a86bf343976 ("spmi: Linux driver framework for SPMI")
Signed-off-by: Jishnu Prakash 
Signed-off-by: Stephen Boyd 
Link: https://lore.kernel.org/r/20230413223834.4084793-7-sboyd@kernel.org
Signed-off-by: Greg Kroah-Hartman

spmi: fix W=1 kernel-doc warnings

2023-04-20T12:16:39+00:00

Fix all W=1 kernel-doc warnings in drivers/spmi/:

drivers/spmi/spmi.c:414: warning: expecting prototype for spmi_controller_alloc(). Prototype was for spmi_device_alloc() instead
drivers/spmi/spmi.c:592: warning: expecting prototype for spmi_driver_register(). Prototype was for __spmi_driver_register() instead
drivers/spmi/spmi.c:592: warning: Function parameter or member 'owner' not described in '__spmi_driver_register'
drivers/spmi/spmi-pmic-arb.c:155: warning: cannot understand function prototype: 'struct spmi_pmic_arb '
drivers/spmi/spmi-pmic-arb.c:203: warning: cannot understand function prototype: 'struct pmic_arb_ver_ops '
drivers/spmi/spmi-pmic-arb.c:219: warning: expecting prototype for struct pmic_arb_ver. Prototype was for struct pmic_arb_ver_ops instead

Link: https://lore.kernel.org/r/20230113064040.26801-1-rdunlap@infradead.org
Cc: Stephen Boyd 
Signed-off-by: Randy Dunlap 
Signed-off-by: Stephen Boyd 
Link: https://lore.kernel.org/r/20230413223834.4084793-6-sboyd@kernel.org
Signed-off-by: Greg Kroah-Hartman

spmi: mtk-pmif: Drop of_match_ptr for ID table

2023-04-20T12:16:39+00:00

The driver can match only via the DT table so the table should be always
used and the of_match_ptr does not have any sense (this also allows ACPI
matching via PRP0001, even though it is not relevant here).

  drivers/spmi/spmi-mtk-pmif.c:517:34: error: ‘mtk_spmi_match_table’ defined but not used [-Werror=unused-const-variable=]

Link: https://lore.kernel.org/r/20230310222857.315629-2-krzysztof.kozlowski@linaro.org
Reviewed-by: AngeloGioacchino Del Regno 
Signed-off-by: Krzysztof Kozlowski 
Signed-off-by: Stephen Boyd 
Link: https://lore.kernel.org/r/20230413223834.4084793-5-sboyd@kernel.org
Signed-off-by: Greg Kroah-Hartman

spmi: pmic-arb: Convert to platform remove callback returning void

2023-04-20T12:16:39+00:00

The .remove() callback for a platform driver returns an int which makes
many driver authors wrongly assume it's possible to do error handling by
returning an error code. However the value returned is (mostly) ignored
and this typically results in resource leaks. To improve here there is a
quest to make the remove callback return void. In the first step of this
quest all drivers are converted to .remove_new() which already returns
void.

Trivially convert this driver from always returning zero in the remove
callback to the void returning variant.

Link: https://lore.kernel.org/r/20230306073446.2194048-4-u.kleine-koenig@pengutronix.de
Signed-off-by: Uwe Kleine-König 
Signed-off-by: Stephen Boyd 
Link: https://lore.kernel.org/r/20230413223834.4084793-4-sboyd@kernel.org
Signed-off-by: Greg Kroah-Hartman

spmi: mtk-pmif: Convert to platform remove callback returning void

2023-04-20T12:16:39+00:00

The .remove() callback for a platform driver returns an int which makes
many driver authors wrongly assume it's possible to do error handling by
returning an error code. However the value returned is (mostly) ignored
and this typically results in resource leaks. To improve here there is a
quest to make the remove callback return void. In the first step of this
quest all drivers are converted to .remove_new() which already returns
void.

Trivially convert this driver from always returning zero in the remove
callback to the void returning variant.

Link: https://lore.kernel.org/r/20230306073446.2194048-3-u.kleine-koenig@pengutronix.de
Reviewed-by: AngeloGioacchino Del Regno 
Signed-off-by: Uwe Kleine-König 
Signed-off-by: Stephen Boyd 
Link: https://lore.kernel.org/r/20230413223834.4084793-3-sboyd@kernel.org
Signed-off-by: Greg Kroah-Hartman

spmi: hisi-spmi-controller: Convert to platform remove callback returning void

2023-04-20T12:16:39+00:00

The .remove() callback for a platform driver returns an int which makes
many driver authors wrongly assume it's possible to do error handling by
returning an error code. However the value returned is (mostly) ignored
and this typically results in resource leaks. To improve here there is a
quest to make the remove callback return void. In the first step of this
quest all drivers are converted to .remove_new() which already returns
void.

Trivially convert this driver from always returning zero in the remove
callback to the void returning variant.

Link: https://lore.kernel.org/r/20230306073446.2194048-2-u.kleine-koenig@pengutronix.de
Signed-off-by: Uwe Kleine-König 
Signed-off-by: Stephen Boyd 
Link: https://lore.kernel.org/r/20230413223834.4084793-2-sboyd@kernel.org
Signed-off-by: Greg Kroah-Hartman

driver core: make struct bus_type.uevent() take a const *

2023-01-27T12:45:52+00:00

The uevent() callback in struct bus_type should not be modifying the
device that is passed into it, so mark it as a const * and propagate the
function signature changes out into all relevant subsystems that use
this callback.

Acked-by: Rafael J. Wysocki 
Acked-by: Hans de Goede 
Link: https://lore.kernel.org/r/20230111113018.459199-16-gregkh@linuxfoundation.org
Signed-off-by: Greg Kroah-Hartman