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When a Slave device becomes synchronized with the bus, it may report its presence in PING frames, as well as optionally asserting an in-band PREQ signal. The bus driver will detect a new Device0, start the enumeration process and assign it a non-zero device number. The SoundWire enumeration provides an arbitration to deal with multiple Slaves reporting ATTACHED at the same time. The bus driver will also invoke the driver .probe() callback associated with this device. The probe() depends on the Linux device core, which handles the match operations and may result in modules being loaded. Once the non-zero device number is programmed, the Slave will report its new status in PING frames and the Master hardware will typically report this status change with an interrupt. At this point, the .update_status() callback of the codec driver will be invoked (usually from an interrupt thread or workqueue scheduled from the interrupt thread). The first race condition which can happen is between the .probe(), which allocates the resources, and .update_status() where initializations are typically handled. The .probe() is only called once during the initial boot, while .update_status() will be called for every bus hardware reset and if the Slave device loses synchronization (an unlikely event but with non-zero probability). The time difference between the end of the enumeration process and a change of status reported by the hardware may be as small as one SoundWire PING frame. The scheduling of the interrupt thread, which invokes .update_status() is not deterministic, but can be small enough to create a race condition. With a 48 kHz frame rate and ideal scheduling cases, the .probe() may be pre-empted within double-digit microseconds. Since there is no guarantee that the .probe() completes by the time .update_status() is invoked as a result of an interrupt, it's not unusual for the .update_status() to rely on data structures that have not been allocated yet, leading to kernel oopses. This patch adds a probe_complete utility, which is used in the sdw_update_slave_status() routine. The codec driver does not need to do anything and can safely assume all resources are allocated in its update_status() callback. Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
When the Master starts the bus (be it during the initial boot or system resume), it usually performs a HardReset to make sure electrical levels are correct, then enables the control channel. While the PM framework guarantees that the Slave devices will only become 'active' once the Master completes the bus initialization, there is still a risk of a race condition: the Slave enumeration is handled in a separate interrupt thread triggered by hardware status changes, so the Slave device may not be ready to accept commands when the Slave driver tries to access the registers and restore settings in its resume or pm_runtime_resume callbacks. In those cases, any read/write commands from/to the Slave device will result in a timeout. This patch adds an enumeration_complete structure. When the bus is goes through a HardReset sequence and restarted, the Slave will be marked as UNATTACHED, which will result in a call to init_completion(). When the Slave reports its presence during PING frames as a non-zero Device, the Master hardware will issue an interrupt and the bus driver will invoke complete(). The order between init_completion()/complete() is predictable since this is a Master-initiated transition. The Slave driver may use wait_for_completion() in its resume callback. When regmap is used, the Slave driver will typically set its regmap in cache-only mode on suspend, then on resume block on wait_for_completion(&enumeration_complete) to guarantee it is safe to start read/write transactions. It may then exit the cache-only mode and use a regmap_sync to restore settings. All these steps are optional, their use completely depends on the Slave device capabilities and how the Slave driver is implemented. Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Slave drivers may have different ways of handling their settings, with or without regmap. During the integration of codec drivers, done in partnership between Intel and Realtek, it became desirable to implement a predictable order between low-level initializations performed in .update_status() (invoked by an interrupt thread) and the settings restored in the resume steps (invoked by the PM core). This patch builds on the previous solution to wait for the Slave device to be fully enumerated. The complete() in this case is signaled not before the .update_status() is called, but after .update_status() returns. Without this patch, the settings were not properly restored, leading to timing-dependent 'no sound after resume' or 'no headset detected after resume' bug reports. Depending on how initialization is handled, a Slave device driver may wait for enumeration_complete, or for initialization_complete, both are valid synchronization points. They are initialized at the same time, they only differ on when complete() is invoked. Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
…nces The Slave device initialization can be split in 4 different cases: 1. Master-initiated hardware reset, system suspend-resume and pm_runtime based on clock-stop mode1. To avoid timeouts and a bad audio experience, the Slave device resume operations need to wait for the Slave device to be re-enumerated and its settings restored. 2. Exit from clock-stop mode0. In this case, the Slave device is required to remain enumerated and its context preserved while the clock is stopped, so no re-initialization or wait_for_completion() is necessary. 3. Slave-initiated pm_runtime D3 transition. With the parent child relationship, it is possible that a Slave device becomes 'suspended' while its parent is still 'active' with the bus clock still toggling. In this case, during the pm_runtime resume operation, there is no need to wait for any settings to be restored. 4. Slave reset (sync loss or implementation-defined). In that case the bus remains operational and the Slave device will be re-initialized when it becomes ATTACHED again. In previous patches, we suggested the use of wait_for_completion() to deal with the case #1, but case #2 and #3 do not need any wait. To account for those differences, this patch adds an unattach_request field. The field is explicitly set by the Master for the case #1, and if non-zero the Slave device shall wait on resume. In all other cases, the Slave resume operations can proceed without wait. The only request tracked so far is Master HardReset, but the request is declared as a bit mask for future extensions (if needed). The definition for this value is added in bus.h and does not need to be exposed in sdw.h Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
The current interfaces between ASoC and SoundWire are limited by the platform_device infrastructure to an init() and exit() (mapped to the platform driver.probe and .remove) To help with the platform detection, machine driver selection and management of power dependencies between DSP and SoundWire IP, the ASoC side requires: a) an ACPI scan helper, to report if any devices are exposed in the DSDT tables, and if any links are disabled by the BIOS. b) a probe helper that allocates the resources without actually starting the bus. c) a startup helper which does start the bus when all power dependencies are settled. d) an exit helper to free all resources e) an interrupt_enable/disable helper, typically invoked after the startup helper but also used in suspend routines. This patch moves all required interfaces to sdw_intel.h, mainly to allow SoundWire and ASoC parts to be merged separately once the header files are shared between trees. To avoid compilation issues, the conflicts in intel_init.c are blindly removed. This would in theory prevent the code from working, but since there are no users of the Intel Soundwire driver this has no impact. Functionality will be restored when the removal of platform devices is complete. Support for SoundWire + SOF builds will only be provided once all the required pieces are upstream. Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
…erations The SoundWire DAIs for Intel platform are created in drivers/soundwire/intel.c, while the communication with the Intel DSP is all controlled in soc/sof/intel When the DAI status changes, a callback is used to bridge the gap between the two subsystems. The naming of the existing 'config_stream' callback does not map well with any of ALSA/ASoC concepts. This patch renames it as 'params_stream' to be more self-explanatory. A new 'free_stream' callback is added in case any resources allocated in the 'params_stream' stage need to be released. In the SOF implementation, this is used in the hw_free case to release the DMA channels over IPC. These two callbacks now rely on structures which expose the link_id and alh_stream_id (required by the firmware IPC), instead of a list of parameters. The 'void *' definitions are changed to use explicit types, as suggested on alsa-devel during earlier reviews. Signed-off-by: Rander Wang <rander.wang@linux.intel.com> Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Add clearer references to sdw_slave_driver for internal macros No change for sdw_driver and module_sdw_driver to avoid compatibility issues with existing codec devices No functionality change. Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Since we want to introduce master devices, rename macro so that we have consistency between slave and master device access, following the Grey Bus example. Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Align with previous renames and shorten macro No functionality change Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Before we add master driver support, make sure there is no ambiguity and no occurrences of sdw_drv_ functions. No functionality change. Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
There are too many fields called 'res' so add prefix to make it easier to track what the structures are. Pure rename, no functionality change Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Currently the bus does not have any explicit support for master devices. First add explicit support for sdw_slave_type and error checks if this type is not set. In follow-up patches we can add support for the sdw_md_type (md==Master Device), following the Grey Bus example. Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Currently the code deals with uevents at the bus level, but we only care for Slave events Suggested-by: Vinod Koul <vkoul@kernel.org> Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Since we want an explicit support for the SoundWire Master device, add the definitions, following the Grey Bus example. Unlike for the Slave device, we do not set a variable when dealing with the master uevent. Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Use sdw_master_device and driver instead of platform devices To quote GregKH: "Don't mess with a platform device unless you really have no other possible choice. And even then, don't do it and try to do something else. Platform devices are really abused, don't perpetuate it " In addition, rather than a plain-vanilla init/exit, this patch provides 3 steps in the initialization (ACPI scan, probe, startup) which make it easier to verify support and allocate required resources as early as possible, and conversely help make the startup lighter-weight with only hardware register setup. Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Setting an device driver is necessary for ASoC to register DAI components. Signed-off-by: Bard Liao <yung-chuan.liao@linux.intel.com> Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
The existing code does not expose a prepare operation, which is very much needed to deal with underflow and resume operations. Signed-off-by: Rander Wang <rander.wang@linux.intel.com> Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
The existing code does not expose a trigger callback, which is very much required for streaming. The SoundWire stream is enabled and disabled in trigger function. Signed-off-by: Rander Wang <rander.wang@linux.intel.com> Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
The sdw stream is allocated and stored in dai to share the sdw runtime information. Signed-off-by: Rander Wang <rander.wang@linux.intel.com> Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Make sure all calls to the SoundWire stream API are done and involve callback Signed-off-by: Rander Wang <rander.wang@linux.intel.com> Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
This function is required to enable all interrupts across all links. Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
The existing code uses one pair of interrupt handler/thread per link but at the hardware level the interrupt is shared. This works fine for legacy PCI interrupts, but leads to timeouts in MSI (Message-Signaled Interrupt) mode, likely due to edges being lost. This patch unifies interrupt handling for all links with a single threaded IRQ handler. The handler is simplified to the bare minimum of detecting a SoundWire interrupt, and the thread takes care of dealing with interrupt sources. This partition follows the model used for the SOF IPC on HDaudio platforms, where similar timeout issues were noticed and doing all the interrupt handling/clearing in the thread improved reliability/stability. Validation results with 4 links active in parallel show a night-and-day improvement with no timeouts noticed even during stress tests. Latency and quality of service are not affected by the change - mostly because events on a SoundWire link are throttled by the bus frame rate (typically 8..48kHz). Signed-off-by: Bard Liao <yung-chuan.liao@linux.intel.com> Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
The driver probe takes care of basic initialization and is invoked when a Slave becomes attached, after a match between the Slave DevID registers and ACPI/DT entries. The update_status callback is invoked when a Slave state changes, e.g. when it is assigned a non-zero Device Number and it reports with an ATTACHED/ALERT state. The state change detection is usually hardware-based and based on the SoundWire frame rate (e.g. double-digit microseconds) while the probe is a pure software operation, which may involve a kernel module load. In corner cases, it's possible that the state changes before the probe completes. This patch suggests the use of wait_for_completion to avoid races on startup, so that the update_status callback does not rely on invalid pointers/data structures. Signed-off-by: Rander Wang <rander.wang@intel.com> Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Add support for pm_runtime with the appropriate error checks for sdw_write/read functions, e.g. when pm_runtime is not supported. Also expose internal functions without pm_runtime support, which are required to perform any sort of suspend/resume operation, as well as any enumeration tasks. Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
While handling the Device0, we can safely use sdw_write_no_pm. This move will also helps us track that all other usages of sdw_write() happen when the Slave is already enumerated. Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
These routines are required for power management Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Implement suspend/resume capabilities (not runtime_pm for now) The resume part is essentially a full-blown re-enumeration. When S0ix is supported, we will select clock stop mode when the ACPI target state is S0, and tear down the link for S3. Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Add basic hooks in DAI .startup and .shutdown callbacks. The SoundWire IP should be powered between those two calls. The power dependencies between SoundWire and DSP are handled with the parent/child relationship, before the SoundWire master device becomes active the parent device will become active and power-up the shared rails. For now the strategy is to rely on complete enumeration when the device becomes active, so the code is a copy/paste of the sequence for system suspend/resume. In future patches, the strategy will optionally be to rely on clock stop if the enumeration time is prohibitive or when the devices connected to a link can signal a wake. A module parameter is added to make integration of new Slave devices easier, to e.g. keep the device active or prevent clock-stop. Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
The system resume does the entire bus re-initialization and brings it to full-power. If the device was pm_runtime suspended, there is no need to run the pm_runtime resume sequence after the system runtime. Follow the documentation from runtime_pm.rst, and conditionally disable, set_active and re-enable the device on system resume. Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
When resuming, we need to re-enumerate and restart from UNATTACHED. This will help implement a more robust state machine avoiding race conditions on resume. Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Some Realtek codecs don't support grp_ctrl_valid. Set it to false to prevent DPN_BlockCtrl2 reg write failed. Signed-off-by: Bard Liao <bardliao@gmail.com> Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
If the programming of the dev_number fails due to an IO error, a new device_number will be assigned, resulting in a leak. Make sure we only assign a device_number once per Slave device. Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
The current value for this field is too low and results in some samples getting dropped and playback being faster than normal. Increase the value to a safer value. Signed-off-by: Bard Liao <yung-chuan.liao@linux.intel.com> Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Somehow Intel folks were confused, the property is 2x what the mclk frequency actually is, as checked with the actual bus frequency. Signed-off-by: Bard Liao <yung-chuan.liao@linux.intel.com> Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
useful for debug, but can be verbose so only enable if strictly needed. Signed-off-by: Bard Liao <yung-chuan.liao@linux.intel.com> Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Another Dell laptop uses SOF with CML platform Signed-off-by: Bard Liao <yung-chuan.liao@linux.intel.com>
The existing use of 6 handlers is problematic in MSI mode. Update headers so that all shared interrupts can be handled with a single handler Signed-off-by: Bard Liao <yung-chuan.liao@linux.intel.com> Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
The DSP and SoundWire share the same interrupt, and using multiple handlers is problematic in MSI mode. Refactor the code so that we can use a single handler. Signed-off-by: Bard Liao <yung-chuan.liao@linux.intel.com> Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
…lers We have a single irq handler for SOF interrupts. We can further merge SoundWire ones to completely remove MSI interrupts handling issues leading to timeouts. Signed-off-by: Bard Liao <yung-chuan.liao@linux.intel.com> Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
So we don't need to check it again in irq thread. Signed-off-by: Bard Liao <yung-chuan.liao@linux.intel.com>
bardliao
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| if (hda_dsp_check_ipc_irq(sdev)) | ||
| sdev->irq_event |= SOF_IRQ_IPC; | ||
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| //TODO: disable stream interrupt |
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@bardliao I'm not sure we should disable the stream interrupt. we also use the same INTSTS to check for codec unsolicited responses and we loop 10 times over to do this. If we disable the stream interrupt, that might not be needed anymore and I feel like this could end up causing IPC timeout regressions.
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closing, updated solution will be merged |
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So we don't need to check it again in irq thread.
Signed-off-by: Bard Liao yung-chuan.liao@linux.intel.com