21c51692fc
Mirror changes done in SOF tree. The changes do not rely on BIT/GENMASK on purpose to keep the structure and flags common with the firmware tree. The DAI_CONFIG IPC is currently used in multiple ways. It is sent to the DSP firmware when enabling static or dynamic pipelines, in hw_params or prepare callbacks for Intel SSP, HDaudio and ALH, on trigger_stop and hw_free. This IPC has been abused a bit in the past, i.e. the values used for some of the DAI-specific fields are used to either allocate or free resources. Two typical examples are Intel HDaudio and SoundWire/ALH DAIs, where using a zero DMA channel number or stream tag signals to the firmware the DMA channels or tags allocated earlier can be freed. Rather than add a new IPC for 'hw_params' and 'hw_free', this patch suggests supporting a 2-bit value conveying the 'stage' information in an existing IPC structure. Only 3 possible values are used. The mapping between HW_PARAMS and HW_FREE flags and ALSA definitions is not strictly 1:1, e.g. in some cases the HW_PARAM flag might be set during the .prepare callback, while the HW_FREE might be sent during the ALSA .trigger for stop/suspend. The semantics of the flags is to reserve and start/stop all needed resources, typically hardware related such as DMAs or clocks, when the HW_PARAMS is set, while the HW_FREE flag allows the firmware to release the resources allocated. The data transfers are still controlled within the firmware through the propagation of the trigger command. The driver can then pass information that the DAI_CONFIG was invoked in e.g. a pipeline/DAI setup, hw_params or hw_free stage without having to use a special DAI-specific encoding. Unfortunately we can't remove old encodings due to backwards-compatibility requirements but for new cases, such as the SSP in follow-up patches, we can make the IPC less cryptic. This change is tagged as ABI 3.19 and is completely backwards compatible. Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com> Reviewed-by: Bard Liao <bard.liao@intel.com> Reviewed-by: Guennadi Liakhovetski <guennadi.liakhovetski@linux.intel.com> Reviewed-by: Brent Lu <brent.lu@intel.com> Link: https://lore.kernel.org/r/20211004171430.103674-3-pierre-louis.bossart@linux.intel.com Signed-off-by: Mark Brown <broonie@kernel.org> |
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| arch | ||
| block | ||
| certs | ||
| crypto | ||
| Documentation | ||
| drivers | ||
| fs | ||
| include | ||
| init | ||
| ipc | ||
| kernel | ||
| lib | ||
| LICENSES | ||
| mm | ||
| net | ||
| samples | ||
| scripts | ||
| security | ||
| sound | ||
| tools | ||
| usr | ||
| virt | ||
| .clang-format | ||
| .cocciconfig | ||
| .get_maintainer.ignore | ||
| .gitattributes | ||
| .gitignore | ||
| .mailmap | ||
| COPYING | ||
| CREDITS | ||
| Kbuild | ||
| Kconfig | ||
| MAINTAINERS | ||
| Makefile | ||
| 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.