| Message ID | 20240325131624.26023-1-brgl@bgdev.pl (mailing list archive) |
|---|---|
| Headers | show |
| Series | power: sequencing: implement the subsystem and add first users | expand |
On 2024/3/25 21:16, Bartosz Golaszewski wrote: > From: Bartosz Golaszewski<bartosz.golaszewski@linaro.org> > > Note: I dropped most of the the review and test tags on purpose, the code > changed significantly and warrants a new round of reviews and tests. > > === > > Problem statement #1: Dynamic bus chicken-and-egg problem. > > Certain on-board PCI devices need to be powered up before they are can be > detected but their PCI drivers won't get bound until the device is > powered-up so enabling the relevant resources in the PCI device driver > itself is impossible. > > Problem statement #2: Sharing inter-dependent resources between devices. > > Certain devices that use separate drivers (often on different busses) > share resources (regulators, clocks, etc.). Typically these resources > are reference-counted but in some cases there are additional interactions > between them to consider, for example specific power-up sequence timings. > > === > > The reason for tackling both of these problems in a single series is the > fact the the platform I'm working on - Qualcomm RB5 - deals with both and > both need to be addressed in order to enable WLAN and Bluetooth support > upstream. > > The on-board WLAN/BT package - QCA6391 - has a Power Management Unit that > takes inputs from the host and exposes LDO outputs consumed by the BT and > WLAN modules which can be powered-up and down independently. However > a delay of 100ms must be respected between enabling the BT- and > WLAN-enable GPIOs. > > A similar design with a discreet PMU is also employed in other models of > the WCN family of chips although we can often do without the delays. With > this series we add support for the WCN7850 as well. > > === > > We introduce a new subsystem here - the power sequencing framework. The > qcom-wcn driver that we add is its first user. It implements the power-up > sequences for QCA6390 and WCN7850 chips. However - we only use it to > power-up the bluetooth module in the former. We use it to driver the WLAN > modules in both. The reason for this is that for WCN7850 we have > comprehensive bindings already upstream together with existing DT users. > Porting them to using the pwrseq subsystem can be done separately and in > an incremental manner once the subsystem itself is upstream. We will also > have to ensure backward DT compatibility. To avoid overcomplicating this > series, let's leave it out for now. > > === > > This series is logically split into several sections. I'll go > patch-by-patch and explain each step. > > Patches 1/16-5/16: > > These contain all relevant DT bindings changes. We add new documents for > the QCA6390 & WCN7850 PMUs and ATH12K devices as well as extend the bindings > for the Qualcomm Bluetooth and ATH11K modules with regulators used by them > in QCA6390. > > Patches 6/16-8/16: > > These contain changes to device-tree sources for the three platforms we > work with in this series. We model the PMUs of the WLAN/BT chips as > top-level platform devices on the device tree. In order to limit the scope > of this series and not introduce an excessive amount of confusion with > deprecating DT bindings, we leave the Bluetooth nodes on sm8650 and sm8550 > as is (meaning: they continue to consumer the GPIOs and power inputs from > the host). As the WCN7850 module doesn't require any specific timings, we can > incrementally change that later. > > In both cases we add WLAN nodes that consume the power outputs of the PMU. > For QCA6390 we also make the Bluetooth node of the RB5 consume the outputs > of the PMU - we can do it as the bindings for this chip did not define any > supply handles prior to this series meaning we are able to get this correct > right away. > > Patches 9/16-12/16: > > These contain the bulk of the PCI changes for this series. We introduce > a simple framework for powering up PCI devices before detecting them on > the bus. > > The general approach is as follows: PCI devices that need special > treatment before they can be powered up, scanned and bound to their PCI > drivers must be described on the device-tree as child nodes of the PCI > port node. These devices will be instantiated on the platform bus. They > will in fact be generic platform devices with the compatible of the form > used for PCI devices already upstream ("pci<vendor ID>,<device ID">). We > add a new directory under drivers/pci/pwrctl/ that contains PCI pwrctl > drivers. These drivers are platform drivers that will now be matched > against the devices instantiated from port children just like any other > platform pairs. > > Both the power control platform device *AND* the associated PCI device > reuse the same OF node and have access to the same properties. The goal > of the platform driver is to request and bring up any required resources > and let the pwrctl framework know that it's now OK to rescan the bus and > detect the devices. When the device is bound, we are notified about it > by the PCI bus notifier event and can establish a device link between the > power control device and the PCI device so that any future extension for > power-management will already be able to work with the correct hierachy. > > The reusing of the OF node is the reason for the small changes to the PCI > OF core: as the bootloader can possibly leave the relevant regulators on > before booting linux, the PCI device can be detected before its platform > abstraction is probed. In this case, we find that device first and mark > its OF node as reused. The pwrctl framework handles the opposite case > (when the PCI device is detected only after the platform driver > successfully enabled it). > > Patch 13/16 - 14/16: > > These add a relatively simple power sequencing subsystem and the first > driver using it: the pwrseq module for the PMUs on the WCN family of chips. > > I'm proposing to add a subsystem that allows different devices to use a shared > power sequence split into consumer-specific as well as common "units". > > A power sequence provider driver registers a set of units with pwrseq > core. Each unit can be enabled and disabled and contains an optional list > of other units which must be enabled before it itself can be. A unit > represents a discreet chunk of the power sequence. > > It also registers a list of targets: a target is an abstraction wrapping > a unit which allows consumers to tell pwrseq which unit they want to > reach. Real-life example is the driver we're adding here: there's a set > of common regulators, two PCIe-specific ones and two enable GPIOs: one > for Bluetooth and one for WLAN. > > The Bluetooth driver requests a descriptor to the power sequencer and > names the target it wants to reach: > > pwrseq = devm_pwrseq_get(dev, "bluetooth"); > > The pwrseq core then knows that when the driver calls: > > pwrseq_power_on(pwrseq); > > It must enable the "bluetooth-enable" unit but it depends on the > "regulators-common" unit so this one is enabled first. The provider > driver is also in charge of assuring an appropriate delay between > enabling the BT and WLAN enable GPIOs. The WLAN-specific resources are > handled by the "wlan-enable" unit and so are not enabled until the WLAN > driver requests the "wlan" target to be powered on. > > Another thing worth discussing is the way we associate the consumer with > the relevant power sequencer. DT maintainers have expressed a discontent > with the existing mmc pwrseq bindings and have NAKed an earlier > initiative to introduce global pwrseq bindings to the kernel[1]. > > In this approach, we model the existing regulators and GPIOs in DT but > the pwrseq subsystem requires each provider to provide a .match() > callback. Whenever a consumer requests a power sequencer handle, we > iterate over the list of pwrseq drivers and call .match() for each. It's > up to the driver to verify in a platform-specific way whether it deals > with its consumer and let the core pwrseq code know. > > The advantage of this over reusing the regulator or reset subsystem is > that it's more generalized and can handle resources of all kinds as well > as deal with any kind of power-on sequences: for instance, Qualcomm has > a PCI switch they want a driver for but this switch requires enabling > some resources first (PCI pwrctl) and then configuring the device over > I2C (which can be handled by the pwrseq provider). > > Patch 15: > > This patch makes the Qualcomm Bluetooth driver get and use the power > sequencer for QCA6390. > > Patch 16: > > While tiny, this patch is possibly the highlight of the entire series. > It uses the two abstraction layers we introduced before to create an > elegant power sequencing PCI power control driver and supports the ath11k > module on QCA6390 and ath12k on WCN7850. > > With this series we can now enable BT and WLAN on several new Qualcomm > boards upstream. > > Tested on RB5, sm8650-qrd and sm8550-qrd. > > Changelog: > > Since v5: > - unify the approach to modelling the WCN WLAN/BT chips by always exposing > the PMU node on the device tree and making the WLAN and BT nodes become > consumers of its power outputs; this includes a major rework of the DT > sources, bindings and driver code; there's no more a separate PCI > pwrctl driver for WCN7850, instead its power-up sequence was moved > into the pwrseq driver common for all WCN chips > - don't set load_uA from new regulator consumers > - fix reported kerneldoc issues > - drop voltage ranges for PMU outputs from DT > - many minor tweaks and reworks > > v1: Original RFC: > > https://lore.kernel.org/lkml/20240104130123.37115-1-brgl@bgdev.pl/T/ > > v2: First real patch series (should have been PATCH v2) adding what I > referred to back then as PCI power sequencing: > > https://lore.kernel.org/linux-arm-kernel/2024021413-grumbling-unlivable-c145@gregkh/T/ > > v3: RFC for the DT representation of the PMU supplying the WLAN and BT > modules inside the QCA6391 package (was largely separate from the > series but probably should have been called PATCH or RFC v3): > > https://lore.kernel.org/all/CAMRc=Mc+GNoi57eTQg71DXkQKjdaoAmCpB=h2ndEpGnmdhVV-Q@mail.gmail.com/T/ > > v4: Second attempt at the full series with changed scope (introduction of > the pwrseq subsystem, should have been RFC v4) > > https://lore.kernel.org/lkml/20240201155532.49707-1-brgl@bgdev.pl/T/ > > v5: Two different ways of handling QCA6390 and WCN7850: > > https://lore.kernel.org/lkml/20240216203215.40870-1-brgl@bgdev.pl/ > > Bartosz Golaszewski (16): > regulator: dt-bindings: describe the PMU module of the QCA6390 package > regulator: dt-bindings: describe the PMU module of the WCN7850 package > dt-bindings: net: bluetooth: qualcomm: describe regulators for QCA6390 > dt-bindings: net: wireless: qcom,ath11k: describe the ath11k on > QCA6390 > dt-bindings: net: wireless: describe the ath12k PCI module > arm64: dts: qcom: sm8550-qrd: add the Wifi node > arm64: dts: qcom: sm8650-qrd: add the Wifi node > arm64: dts: qcom: qrb5165-rb5: add the Wifi node > PCI: hold the rescan mutex when scanning for the first time > PCI/pwrctl: reuse the OF node for power controlled devices > PCI/pwrctl: create platform devices for child OF nodes of the port > node > PCI/pwrctl: add PCI power control core code > power: sequencing: implement the pwrseq core > power: pwrseq: add a driver for the PMU module on the QCom WCN > chipsets > Bluetooth: qca: use the power sequencer for QCA6390 > PCI/pwrctl: add a PCI power control driver for power sequenced devices > > .../net/bluetooth/qualcomm-bluetooth.yaml | 17 + > .../net/wireless/qcom,ath11k-pci.yaml | 46 + > .../bindings/net/wireless/qcom,ath12k.yaml | 100 ++ > .../bindings/regulator/qcom,qca6390-pmu.yaml | 185 +++ > MAINTAINERS | 8 + > arch/arm64/boot/dts/qcom/qrb5165-rb5.dts | 103 +- > arch/arm64/boot/dts/qcom/sm8250.dtsi | 10 + > arch/arm64/boot/dts/qcom/sm8550-qrd.dts | 97 ++ > arch/arm64/boot/dts/qcom/sm8550.dtsi | 10 + > arch/arm64/boot/dts/qcom/sm8650-qrd.dts | 89 ++ > arch/arm64/boot/dts/qcom/sm8650.dtsi | 10 + > drivers/bluetooth/hci_qca.c | 74 +- > drivers/pci/Kconfig | 1 + > drivers/pci/Makefile | 1 + > drivers/pci/bus.c | 9 +- > drivers/pci/of.c | 14 +- > drivers/pci/probe.c | 2 + > drivers/pci/pwrctl/Kconfig | 17 + > drivers/pci/pwrctl/Makefile | 6 + > drivers/pci/pwrctl/core.c | 136 +++ > drivers/pci/pwrctl/pci-pwrctl-pwrseq.c | 89 ++ > drivers/pci/remove.c | 2 + > drivers/power/Kconfig | 1 + > drivers/power/Makefile | 1 + > drivers/power/sequencing/Kconfig | 28 + > drivers/power/sequencing/Makefile | 6 + > drivers/power/sequencing/core.c | 1065 +++++++++++++++++ > drivers/power/sequencing/pwrseq-qcom-wcn.c | 336 ++++++ > include/linux/pci-pwrctl.h | 51 + > include/linux/pwrseq/consumer.h | 56 + > include/linux/pwrseq/provider.h | 75 ++ > 31 files changed, 2614 insertions(+), 31 deletions(-) > create mode 100644 Documentation/devicetree/bindings/net/wireless/qcom,ath12k.yaml > create mode 100644 Documentation/devicetree/bindings/regulator/qcom,qca6390-pmu.yaml > create mode 100644 drivers/pci/pwrctl/Kconfig > create mode 100644 drivers/pci/pwrctl/Makefile > create mode 100644 drivers/pci/pwrctl/core.c > create mode 100644 drivers/pci/pwrctl/pci-pwrctl-pwrseq.c > create mode 100644 drivers/power/sequencing/Kconfig > create mode 100644 drivers/power/sequencing/Makefile > create mode 100644 drivers/power/sequencing/core.c > create mode 100644 drivers/power/sequencing/pwrseq-qcom-wcn.c > create mode 100644 include/linux/pci-pwrctl.h > create mode 100644 include/linux/pwrseq/consumer.h > create mode 100644 include/linux/pwrseq/provider.h I tested the patchset on SM8550 and it does give me working WiFi. However I seethe following warnings during boot. [ 5.973011] mhi mhi0: Requested to power ON [ 6.597591] mhi mhi0: Power on setup success [ 6.597631] sysfs: cannot create duplicate filename '/devices/platform/soc@0/1c00000.pcie/pci0000:00/0000:00:00.0/resource0' [ 6.597634] CPU: 7 PID: 154 Comm: kworker/u32:5 Tainted: G S 6.9.0-rc1-next-20240328-g955237c9980c #1 [ 6.597635] Hardware name: AYN Odin 2 (DT) [ 6.597637] Workqueue: async async_run_entry_fn [ 6.597645] Call trace: [ 6.597646] dump_backtrace+0xa0/0x128 [ 6.597649] show_stack+0x20/0x38 [ 6.597650] dump_stack_lvl+0x74/0x90 [ 6.597653] dump_stack+0x18/0x28 [ 6.597654] sysfs_warn_dup+0x6c/0x90 [ 6.597658] sysfs_add_bin_file_mode_ns+0xdc/0x100 [ 6.597660] sysfs_create_bin_file+0x7c/0xb8 [ 6.597662] pci_create_attr+0xb4/0x1a8 [ 6.597665] pci_create_resource_files+0x64/0xd0 [ 6.597667] pci_create_sysfs_dev_files+0x24/0x40 [ 6.597669] pci_bus_add_device+0x54/0x138 [ 6.597670] pci_bus_add_devices+0x40/0x98 [ 6.597672] pci_host_probe+0x70/0xf0 [ 6.597673] dw_pcie_host_init+0x248/0x658 [ 6.597676] qcom_pcie_probe+0x234/0x330 [ 6.597677] platform_probe+0x70/0xd8 [ 6.597680] really_probe+0xc8/0x3a0 [ 6.597681] __driver_probe_device+0x84/0x170 [ 6.597682] driver_probe_device+0x44/0x120 [ 6.597683] __device_attach_driver+0xc4/0x168 [ 6.597684] bus_for_each_drv+0x8c/0xf0 [ 6.597686] __device_attach_async_helper+0xb4/0x118 [ 6.597687] async_run_entry_fn+0x40/0x178 [ 6.597689] process_one_work+0x16c/0x410 [ 6.597691] worker_thread+0x284/0x3a0 [ 6.597693] kthread+0x118/0x128 [ 6.597693] ret_from_fork+0x10/0x20 [ 6.597698] ------------[ cut here ]------------ [ 6.597698] proc_dir_entry '0000:00/00.0' already registered [ 6.597710] WARNING: CPU: 7 PID: 154 at fs/proc/generic.c:375 proc_register+0x138/0x1d0 [ 6.597713] Modules linked in: [ 6.597714] CPU: 7 PID: 154 Comm: kworker/u32:5 Tainted: G S 6.9.0-rc1-next-20240328-g955237c9980c #1 [ 6.597715] Hardware name: AYN Odin 2 (DT) [ 6.597716] Workqueue: async async_run_entry_fn [ 6.597718] pstate: 61400005 (nZCv daif +PAN -UAO -TCO +DIT -SSBS BTYPE=--) [ 6.597719] pc : proc_register+0x138/0x1d0 [ 6.597721] lr : proc_register+0x138/0x1d0 [ 6.597723] sp : ffff800081e3b9a0 [ 6.597723] x29: ffff800081e3b9a0 x28: 0000000000000000 x27: ffffddb2a28eabe0 [ 6.597725] x26: ffff3425c9ada5c0 x25: ffffddb2a2d4eef0 x24: ffff3425c9ada540 [ 6.597726] x23: 0000000000000004 x22: ffff3425c7b1822c x21: 0000000000000004 [ 6.597727] x20: ffff3425c7b18180 x19: ffff3425c9adaec8 x18: ffffffffffffffff [ 6.597729] x17: 3040636f732f6d72 x16: 6f6674616c702f73 x15: ffff800081e3b910 [ 6.597730] x14: 0000000000000000 x13: 0a64657265747369 x12: 6765722079646165 [ 6.597731] x11: fffffffffff00000 x10: ffffddb2a27c4fb0 x9 : ffffddb29f5d7528 [ 6.597733] x8 : 00000000ffff7fff x7 : ffffddb2a27c4fb0 x6 : 80000000ffff8000 [ 6.597734] x5 : 0000000000000358 x4 : 0000000000000000 x3 : 00000000ffffffff [ 6.597736] x2 : 0000000000000000 x1 : 0000000000000000 x0 : ffff3425c5ce0000 [ 6.597737] Call trace: [ 6.597737] proc_register+0x138/0x1d0 [ 6.597739] proc_create_data+0x48/0x78 [ 6.597741] pci_proc_attach_device+0x84/0x118 [ 6.597743] pci_bus_add_device+0x5c/0x138 [ 6.597744] pci_bus_add_devices+0x40/0x98 [ 6.597745] pci_host_probe+0x70/0xf0 [ 6.597746] dw_pcie_host_init+0x248/0x658 [ 6.597748] qcom_pcie_probe+0x234/0x330 [ 6.597749] platform_probe+0x70/0xd8 [ 6.597750] really_probe+0xc8/0x3a0 [ 6.597751] __driver_probe_device+0x84/0x170 [ 6.597752] driver_probe_device+0x44/0x120 [ 6.597753] __device_attach_driver+0xc4/0x168 [ 6.597754] bus_for_each_drv+0x8c/0xf0 [ 6.597756] __device_attach_async_helper+0xb4/0x118 [ 6.597757] async_run_entry_fn+0x40/0x178 [ 6.597759] process_one_work+0x16c/0x410 [ 6.597760] worker_thread+0x284/0x3a0 [ 6.597761] kthread+0x118/0x128 [ 6.597762] ret_from_fork+0x10/0x20 [ 6.597763] ---[ end trace 0000000000000000 ]--- This probably only occurs when the relevant drivers on compiled as built-in. Similar behavior has been noticed before as well: https://lore.kernel.org/lkml/20240201155532.49707-1-brgl@bgdev.pl/T/#mdeeca9bc8e19458787d53738298abcfff443068a Thanks, Xilin
On Sat, Apr 6, 2024 at 5:03 AM Xilin Wu <wuxilin123@gmail.com> wrote: > > I tested the patchset on SM8550 and it does give me working WiFi. However I > seethe following warnings during boot. > > [ 5.973011] mhi mhi0: Requested to power ON > [ 6.597591] mhi mhi0: Power on setup success > [ 6.597631] sysfs: cannot create duplicate filename '/devices/platform/soc@0/1c00000.pcie/pci0000:00/0000:00:00.0/resource0' > [ 6.597634] CPU: 7 PID: 154 Comm: kworker/u32:5 Tainted: G S 6.9.0-rc1-next-20240328-g955237c9980c #1 > [ 6.597635] Hardware name: AYN Odin 2 (DT) > [ 6.597637] Workqueue: async async_run_entry_fn > [ 6.597645] Call trace: > [ 6.597646] dump_backtrace+0xa0/0x128 > [ 6.597649] show_stack+0x20/0x38 > [ 6.597650] dump_stack_lvl+0x74/0x90 > [ 6.597653] dump_stack+0x18/0x28 > [ 6.597654] sysfs_warn_dup+0x6c/0x90 > [ 6.597658] sysfs_add_bin_file_mode_ns+0xdc/0x100 > [ 6.597660] sysfs_create_bin_file+0x7c/0xb8 > [ 6.597662] pci_create_attr+0xb4/0x1a8 > [ 6.597665] pci_create_resource_files+0x64/0xd0 > [ 6.597667] pci_create_sysfs_dev_files+0x24/0x40 > [ 6.597669] pci_bus_add_device+0x54/0x138 > [ 6.597670] pci_bus_add_devices+0x40/0x98 > [ 6.597672] pci_host_probe+0x70/0xf0 > [ 6.597673] dw_pcie_host_init+0x248/0x658 > [ 6.597676] qcom_pcie_probe+0x234/0x330 > [ 6.597677] platform_probe+0x70/0xd8 > [ 6.597680] really_probe+0xc8/0x3a0 > [ 6.597681] __driver_probe_device+0x84/0x170 > [ 6.597682] driver_probe_device+0x44/0x120 > [ 6.597683] __device_attach_driver+0xc4/0x168 > [ 6.597684] bus_for_each_drv+0x8c/0xf0 > [ 6.597686] __device_attach_async_helper+0xb4/0x118 > [ 6.597687] async_run_entry_fn+0x40/0x178 > [ 6.597689] process_one_work+0x16c/0x410 > [ 6.597691] worker_thread+0x284/0x3a0 > [ 6.597693] kthread+0x118/0x128 > [ 6.597693] ret_from_fork+0x10/0x20 > [ 6.597698] ------------[ cut here ]------------ > [ 6.597698] proc_dir_entry '0000:00/00.0' already registered > [ 6.597710] WARNING: CPU: 7 PID: 154 at fs/proc/generic.c:375 proc_register+0x138/0x1d0 > [ 6.597713] Modules linked in: > [ 6.597714] CPU: 7 PID: 154 Comm: kworker/u32:5 Tainted: G S 6.9.0-rc1-next-20240328-g955237c9980c #1 > [ 6.597715] Hardware name: AYN Odin 2 (DT) > [ 6.597716] Workqueue: async async_run_entry_fn > [ 6.597718] pstate: 61400005 (nZCv daif +PAN -UAO -TCO +DIT -SSBS BTYPE=--) > [ 6.597719] pc : proc_register+0x138/0x1d0 > [ 6.597721] lr : proc_register+0x138/0x1d0 > [ 6.597723] sp : ffff800081e3b9a0 > [ 6.597723] x29: ffff800081e3b9a0 x28: 0000000000000000 x27: ffffddb2a28eabe0 > [ 6.597725] x26: ffff3425c9ada5c0 x25: ffffddb2a2d4eef0 x24: ffff3425c9ada540 > [ 6.597726] x23: 0000000000000004 x22: ffff3425c7b1822c x21: 0000000000000004 > [ 6.597727] x20: ffff3425c7b18180 x19: ffff3425c9adaec8 x18: ffffffffffffffff > [ 6.597729] x17: 3040636f732f6d72 x16: 6f6674616c702f73 x15: ffff800081e3b910 > [ 6.597730] x14: 0000000000000000 x13: 0a64657265747369 x12: 6765722079646165 > [ 6.597731] x11: fffffffffff00000 x10: ffffddb2a27c4fb0 x9 : ffffddb29f5d7528 > [ 6.597733] x8 : 00000000ffff7fff x7 : ffffddb2a27c4fb0 x6 : 80000000ffff8000 > [ 6.597734] x5 : 0000000000000358 x4 : 0000000000000000 x3 : 00000000ffffffff > [ 6.597736] x2 : 0000000000000000 x1 : 0000000000000000 x0 : ffff3425c5ce0000 > [ 6.597737] Call trace: > [ 6.597737] proc_register+0x138/0x1d0 > [ 6.597739] proc_create_data+0x48/0x78 > [ 6.597741] pci_proc_attach_device+0x84/0x118 > [ 6.597743] pci_bus_add_device+0x5c/0x138 > [ 6.597744] pci_bus_add_devices+0x40/0x98 > [ 6.597745] pci_host_probe+0x70/0xf0 > [ 6.597746] dw_pcie_host_init+0x248/0x658 > [ 6.597748] qcom_pcie_probe+0x234/0x330 > [ 6.597749] platform_probe+0x70/0xd8 > [ 6.597750] really_probe+0xc8/0x3a0 > [ 6.597751] __driver_probe_device+0x84/0x170 > [ 6.597752] driver_probe_device+0x44/0x120 > [ 6.597753] __device_attach_driver+0xc4/0x168 > [ 6.597754] bus_for_each_drv+0x8c/0xf0 > [ 6.597756] __device_attach_async_helper+0xb4/0x118 > [ 6.597757] async_run_entry_fn+0x40/0x178 > [ 6.597759] process_one_work+0x16c/0x410 > [ 6.597760] worker_thread+0x284/0x3a0 > [ 6.597761] kthread+0x118/0x128 > [ 6.597762] ret_from_fork+0x10/0x20 > [ 6.597763] ---[ end trace 0000000000000000 ]--- > > This probably only occurs when the relevant drivers on compiled as built-in. > Similar behavior has been noticed before as well: > > https://lore.kernel.org/lkml/20240201155532.49707-1-brgl@bgdev.pl/T/#mdeeca9bc8e19458787d53738298abcfff443068a > > Thanks, > Xilin > Thanks for the report. The reason for this was populating the platform devices before the bridge device was fully added. In case of loadable modules this meant the pwrctl probe would be deferred long enough for that to complete so I didn't see it but with pwrctl built-in this would trigger the problem. I fixed it locally and will resend with that addressed. Bart
From: Bartosz Golaszewski <bartosz.golaszewski@linaro.org> Note: I dropped most of the the review and test tags on purpose, the code changed significantly and warrants a new round of reviews and tests. === Problem statement #1: Dynamic bus chicken-and-egg problem. Certain on-board PCI devices need to be powered up before they are can be detected but their PCI drivers won't get bound until the device is powered-up so enabling the relevant resources in the PCI device driver itself is impossible. Problem statement #2: Sharing inter-dependent resources between devices. Certain devices that use separate drivers (often on different busses) share resources (regulators, clocks, etc.). Typically these resources are reference-counted but in some cases there are additional interactions between them to consider, for example specific power-up sequence timings. === The reason for tackling both of these problems in a single series is the fact the the platform I'm working on - Qualcomm RB5 - deals with both and both need to be addressed in order to enable WLAN and Bluetooth support upstream. The on-board WLAN/BT package - QCA6391 - has a Power Management Unit that takes inputs from the host and exposes LDO outputs consumed by the BT and WLAN modules which can be powered-up and down independently. However a delay of 100ms must be respected between enabling the BT- and WLAN-enable GPIOs. A similar design with a discreet PMU is also employed in other models of the WCN family of chips although we can often do without the delays. With this series we add support for the WCN7850 as well. === We introduce a new subsystem here - the power sequencing framework. The qcom-wcn driver that we add is its first user. It implements the power-up sequences for QCA6390 and WCN7850 chips. However - we only use it to power-up the bluetooth module in the former. We use it to driver the WLAN modules in both. The reason for this is that for WCN7850 we have comprehensive bindings already upstream together with existing DT users. Porting them to using the pwrseq subsystem can be done separately and in an incremental manner once the subsystem itself is upstream. We will also have to ensure backward DT compatibility. To avoid overcomplicating this series, let's leave it out for now. === This series is logically split into several sections. I'll go patch-by-patch and explain each step. Patches 1/16-5/16: These contain all relevant DT bindings changes. We add new documents for the QCA6390 & WCN7850 PMUs and ATH12K devices as well as extend the bindings for the Qualcomm Bluetooth and ATH11K modules with regulators used by them in QCA6390. Patches 6/16-8/16: These contain changes to device-tree sources for the three platforms we work with in this series. We model the PMUs of the WLAN/BT chips as top-level platform devices on the device tree. In order to limit the scope of this series and not introduce an excessive amount of confusion with deprecating DT bindings, we leave the Bluetooth nodes on sm8650 and sm8550 as is (meaning: they continue to consumer the GPIOs and power inputs from the host). As the WCN7850 module doesn't require any specific timings, we can incrementally change that later. In both cases we add WLAN nodes that consume the power outputs of the PMU. For QCA6390 we also make the Bluetooth node of the RB5 consume the outputs of the PMU - we can do it as the bindings for this chip did not define any supply handles prior to this series meaning we are able to get this correct right away. Patches 9/16-12/16: These contain the bulk of the PCI changes for this series. We introduce a simple framework for powering up PCI devices before detecting them on the bus. The general approach is as follows: PCI devices that need special treatment before they can be powered up, scanned and bound to their PCI drivers must be described on the device-tree as child nodes of the PCI port node. These devices will be instantiated on the platform bus. They will in fact be generic platform devices with the compatible of the form used for PCI devices already upstream ("pci<vendor ID>,<device ID">). We add a new directory under drivers/pci/pwrctl/ that contains PCI pwrctl drivers. These drivers are platform drivers that will now be matched against the devices instantiated from port children just like any other platform pairs. Both the power control platform device *AND* the associated PCI device reuse the same OF node and have access to the same properties. The goal of the platform driver is to request and bring up any required resources and let the pwrctl framework know that it's now OK to rescan the bus and detect the devices. When the device is bound, we are notified about it by the PCI bus notifier event and can establish a device link between the power control device and the PCI device so that any future extension for power-management will already be able to work with the correct hierachy. The reusing of the OF node is the reason for the small changes to the PCI OF core: as the bootloader can possibly leave the relevant regulators on before booting linux, the PCI device can be detected before its platform abstraction is probed. In this case, we find that device first and mark its OF node as reused. The pwrctl framework handles the opposite case (when the PCI device is detected only after the platform driver successfully enabled it). Patch 13/16 - 14/16: These add a relatively simple power sequencing subsystem and the first driver using it: the pwrseq module for the PMUs on the WCN family of chips. I'm proposing to add a subsystem that allows different devices to use a shared power sequence split into consumer-specific as well as common "units". A power sequence provider driver registers a set of units with pwrseq core. Each unit can be enabled and disabled and contains an optional list of other units which must be enabled before it itself can be. A unit represents a discreet chunk of the power sequence. It also registers a list of targets: a target is an abstraction wrapping a unit which allows consumers to tell pwrseq which unit they want to reach. Real-life example is the driver we're adding here: there's a set of common regulators, two PCIe-specific ones and two enable GPIOs: one for Bluetooth and one for WLAN. The Bluetooth driver requests a descriptor to the power sequencer and names the target it wants to reach: pwrseq = devm_pwrseq_get(dev, "bluetooth"); The pwrseq core then knows that when the driver calls: pwrseq_power_on(pwrseq); It must enable the "bluetooth-enable" unit but it depends on the "regulators-common" unit so this one is enabled first. The provider driver is also in charge of assuring an appropriate delay between enabling the BT and WLAN enable GPIOs. The WLAN-specific resources are handled by the "wlan-enable" unit and so are not enabled until the WLAN driver requests the "wlan" target to be powered on. Another thing worth discussing is the way we associate the consumer with the relevant power sequencer. DT maintainers have expressed a discontent with the existing mmc pwrseq bindings and have NAKed an earlier initiative to introduce global pwrseq bindings to the kernel[1]. In this approach, we model the existing regulators and GPIOs in DT but the pwrseq subsystem requires each provider to provide a .match() callback. Whenever a consumer requests a power sequencer handle, we iterate over the list of pwrseq drivers and call .match() for each. It's up to the driver to verify in a platform-specific way whether it deals with its consumer and let the core pwrseq code know. The advantage of this over reusing the regulator or reset subsystem is that it's more generalized and can handle resources of all kinds as well as deal with any kind of power-on sequences: for instance, Qualcomm has a PCI switch they want a driver for but this switch requires enabling some resources first (PCI pwrctl) and then configuring the device over I2C (which can be handled by the pwrseq provider). Patch 15: This patch makes the Qualcomm Bluetooth driver get and use the power sequencer for QCA6390. Patch 16: While tiny, this patch is possibly the highlight of the entire series. It uses the two abstraction layers we introduced before to create an elegant power sequencing PCI power control driver and supports the ath11k module on QCA6390 and ath12k on WCN7850. With this series we can now enable BT and WLAN on several new Qualcomm boards upstream. Tested on RB5, sm8650-qrd and sm8550-qrd. Changelog: Since v5: - unify the approach to modelling the WCN WLAN/BT chips by always exposing the PMU node on the device tree and making the WLAN and BT nodes become consumers of its power outputs; this includes a major rework of the DT sources, bindings and driver code; there's no more a separate PCI pwrctl driver for WCN7850, instead its power-up sequence was moved into the pwrseq driver common for all WCN chips - don't set load_uA from new regulator consumers - fix reported kerneldoc issues - drop voltage ranges for PMU outputs from DT - many minor tweaks and reworks v1: Original RFC: https://lore.kernel.org/lkml/20240104130123.37115-1-brgl@bgdev.pl/T/ v2: First real patch series (should have been PATCH v2) adding what I referred to back then as PCI power sequencing: https://lore.kernel.org/linux-arm-kernel/2024021413-grumbling-unlivable-c145@gregkh/T/ v3: RFC for the DT representation of the PMU supplying the WLAN and BT modules inside the QCA6391 package (was largely separate from the series but probably should have been called PATCH or RFC v3): https://lore.kernel.org/all/CAMRc=Mc+GNoi57eTQg71DXkQKjdaoAmCpB=h2ndEpGnmdhVV-Q@mail.gmail.com/T/ v4: Second attempt at the full series with changed scope (introduction of the pwrseq subsystem, should have been RFC v4) https://lore.kernel.org/lkml/20240201155532.49707-1-brgl@bgdev.pl/T/ v5: Two different ways of handling QCA6390 and WCN7850: https://lore.kernel.org/lkml/20240216203215.40870-1-brgl@bgdev.pl/ Bartosz Golaszewski (16): regulator: dt-bindings: describe the PMU module of the QCA6390 package regulator: dt-bindings: describe the PMU module of the WCN7850 package dt-bindings: net: bluetooth: qualcomm: describe regulators for QCA6390 dt-bindings: net: wireless: qcom,ath11k: describe the ath11k on QCA6390 dt-bindings: net: wireless: describe the ath12k PCI module arm64: dts: qcom: sm8550-qrd: add the Wifi node arm64: dts: qcom: sm8650-qrd: add the Wifi node arm64: dts: qcom: qrb5165-rb5: add the Wifi node PCI: hold the rescan mutex when scanning for the first time PCI/pwrctl: reuse the OF node for power controlled devices PCI/pwrctl: create platform devices for child OF nodes of the port node PCI/pwrctl: add PCI power control core code power: sequencing: implement the pwrseq core power: pwrseq: add a driver for the PMU module on the QCom WCN chipsets Bluetooth: qca: use the power sequencer for QCA6390 PCI/pwrctl: add a PCI power control driver for power sequenced devices .../net/bluetooth/qualcomm-bluetooth.yaml | 17 + .../net/wireless/qcom,ath11k-pci.yaml | 46 + .../bindings/net/wireless/qcom,ath12k.yaml | 100 ++ .../bindings/regulator/qcom,qca6390-pmu.yaml | 185 +++ MAINTAINERS | 8 + arch/arm64/boot/dts/qcom/qrb5165-rb5.dts | 103 +- arch/arm64/boot/dts/qcom/sm8250.dtsi | 10 + arch/arm64/boot/dts/qcom/sm8550-qrd.dts | 97 ++ arch/arm64/boot/dts/qcom/sm8550.dtsi | 10 + arch/arm64/boot/dts/qcom/sm8650-qrd.dts | 89 ++ arch/arm64/boot/dts/qcom/sm8650.dtsi | 10 + drivers/bluetooth/hci_qca.c | 74 +- drivers/pci/Kconfig | 1 + drivers/pci/Makefile | 1 + drivers/pci/bus.c | 9 +- drivers/pci/of.c | 14 +- drivers/pci/probe.c | 2 + drivers/pci/pwrctl/Kconfig | 17 + drivers/pci/pwrctl/Makefile | 6 + drivers/pci/pwrctl/core.c | 136 +++ drivers/pci/pwrctl/pci-pwrctl-pwrseq.c | 89 ++ drivers/pci/remove.c | 2 + drivers/power/Kconfig | 1 + drivers/power/Makefile | 1 + drivers/power/sequencing/Kconfig | 28 + drivers/power/sequencing/Makefile | 6 + drivers/power/sequencing/core.c | 1065 +++++++++++++++++ drivers/power/sequencing/pwrseq-qcom-wcn.c | 336 ++++++ include/linux/pci-pwrctl.h | 51 + include/linux/pwrseq/consumer.h | 56 + include/linux/pwrseq/provider.h | 75 ++ 31 files changed, 2614 insertions(+), 31 deletions(-) create mode 100644 Documentation/devicetree/bindings/net/wireless/qcom,ath12k.yaml create mode 100644 Documentation/devicetree/bindings/regulator/qcom,qca6390-pmu.yaml create mode 100644 drivers/pci/pwrctl/Kconfig create mode 100644 drivers/pci/pwrctl/Makefile create mode 100644 drivers/pci/pwrctl/core.c create mode 100644 drivers/pci/pwrctl/pci-pwrctl-pwrseq.c create mode 100644 drivers/power/sequencing/Kconfig create mode 100644 drivers/power/sequencing/Makefile create mode 100644 drivers/power/sequencing/core.c create mode 100644 drivers/power/sequencing/pwrseq-qcom-wcn.c create mode 100644 include/linux/pci-pwrctl.h create mode 100644 include/linux/pwrseq/consumer.h create mode 100644 include/linux/pwrseq/provider.h