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To slightly reduce confusion between "pwrctl" (the power controller and
power sequencing framework) and "bwctrl" (the bandwidth controller),
rename "pwrctl" to "pwrctrl" so they use the same "ctrl" suffix.
Rename drivers/pci/pwrctl/ to drivers/pci/pwrctrl/, including the related
MAINTAINERS, include file (include/linux/pci-pwrctl.h), Makefile, and
Kconfig changes.
This is the minimal rename of files only. A subsequent commit will rename
functions and data structures.
Link: https://lore.kernel.org/r/20241115214428.2061153-2-helgaas@kernel.org
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Signed-off-by: Krzysztof Wilczyński <kwilczynski@kernel.org>
Acked-by: Krzysztof Wilczyński <kw@linux.com>
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As per the kernel device driver model, a pwrctl device is the supplier for
the PCI device, but the device link that enforces the supplier-consumer
relationship was previously created by the pwrctl driver. Therefore, the
driver model didn't prevent probing PCI client drivers before probing the
corresponding pwrctl drivers. This may lead to a race condition if the PCI
device was already powered on by the bootloader (before the pwrctl driver).
If the bootloader did not power on the PCI device, this wouldn't create any
problem as the pwrctl driver will be the one powering on the device, so the
PCI client driver always gets probed afterward. But if the device was
already powered on, then the device will be seen by the PCI core and the
PCI client driver may get probed before its pwrctl driver. This creates a
race condition as the pwrctl driver may change the device power state while
the device is being accessed by the client driver.
One such issue was already reported on the Qcom X13s platform with the WLAN
device and fixed with a hack in the WCN pwrseq driver by a9aaf1ff88a8
("power: sequencing: request the WLAN enable GPIO as-is").
A cleaner way to fix the above mentioned race condition is to ensure that
the pwrctl drivers are always probed before the client drivers.
If the PCI device is associated with a pwrctl platform device with a power
supply, add a device link between the PCI device and the pwrctl device
before device_attach() in pci_bus_add_device().
Note that there is no need to explicitly remove the device link as that
will be taken care of by the driver core when the PCI device gets removed.
Fixes: 4565d2652a37 ("PCI/pwrctl: Add PCI power control core code")
Fixes: 8fb18619d910 ("PCI/pwrctl: Create platform devices for child OF nodes of the port node")
Link: https://lore.kernel.org/r/20241025-pci-pwrctl-rework-v2-3-568756156cbe@linaro.org
Tested-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
Tested-by: Krishna chaitanya chundru <quic_krichai@quicinc.com>
Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
[bhelgaas: squash fix from
https://lore.kernel.org/r/20241120062459.6371-1-manivannan.sadhasivam@linaro.org
for SPARCv9 issue reported by Jonathan Currier <dullfire@yahoo.com>]
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
[kwilczynski: wrap code to 80 columns]
Signed-off-by: Krzysztof Wilczyński <kwilczynski@kernel.org>
Reviewed-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
Cc: stable+noautosel@kernel.org # Depends on power supply check
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If we trigger the bus rescan from sysfs, we'll try to lock the PCI rescan
mutex recursively and deadlock - the platform device will be populated and
probed on the same thread that handles the sysfs write.
Add a workqueue to the pwrctl code on which we schedule the rescan for
controlled PCI devices. While at it: add a new interface for initializing
the pwrctl context where we'd now assign the parent device address and
initialize the workqueue.
Link: https://lore.kernel.org/r/20240823093323.33450-3-brgl@bgdev.pl
Fixes: 4565d2652a37 ("PCI/pwrctl: Add PCI power control core code")
Reported-by: Konrad Dybcio <konradybcio@kernel.org>
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
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Some PCI devices must be powered-on before they can be detected on the
bus. Introduce a simple framework reusing the existing PCI OF
infrastructure.
The way this works is: a DT node representing a PCI device connected to
the port can be matched against its power control platform driver. If
the match succeeds, the driver is responsible for powering-up the device
and calling pci_pwrctl_device_set_ready() which will trigger a PCI bus
rescan as well as subscribe to PCI bus notifications.
When the device is detected and created, we'll make it consume the same
DT node that the platform device did. When the device is bound, we'll
create a device link between it and the parent power control device.
Tested-by: Amit Pundir <amit.pundir@linaro.org>
Tested-by: Neil Armstrong <neil.armstrong@linaro.org> # on SM8550-QRD, SM8650-QRD & SM8650-HDK
Tested-by: Caleb Connolly <caleb.connolly@linaro.org> # OnePlus 8T
Acked-by: Bjorn Helgaas <bhelgaas@google.com>
Link: https://lore.kernel.org/r/20240612082019.19161-5-brgl@bgdev.pl
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
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