6bf754c7e6
IPA v4.5 significantly changes the format of the configuration register used for endpoint aggregation. The AGGR_BYTE_LIMIT field is now larger, and the positions of other fields are shifted. This complicates the way we have to access this register because functions like u32_encode_bits() require their field mask argument to be constant. A further complication is that we want to know the maximum value representable by at least one of these fields, and that too requires a constant field mask. This patch adds support for IPA v4.5 endpoint aggregation registers in a way that continues to support "legacy" IPA hardware. It does so in a way that keeps field masks constant. First, for each variable field mask, we define an inline function whose return value is either the legacy value or the IPA v4.5 value. Second, we define functions for these fields that encode a value to use in each field based on the IPA version (this approach is already used elsewhere). The field mask provided is supplied by the function mentioned above. Finally, for the aggregation byte limit fields where we want to know the maximum representable value, we define a function that returns that maximum, computed from the appropriate field mask. We can no longer verify at build time that our buffer size is in the range that can be represented by the aggregation byte limit field. So remove the test done by a BUILD_BUG_ON() call in ipa_endpoint_validate_build(), and implement a comparable check at the top of ipa_endpoint_data_valid(). Doing that makes ipa_endpoint_validate_build() contain a single line BUILD_BUG_ON() call, so just remove that function and move the remaining line into ipa_endpoint_data_valid(). One final note: the aggregation time limit value for IPA v4.5 needs to be computed differently. That is handled in an upcoming patch. Signed-off-by: Alex Elder <elder@linaro.org> Signed-off-by: Jakub Kicinski <kuba@kernel.org>
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.