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When high-speed DMA paths are used to transfer arbitrary data over a Thunderbolt link, DMA rings should be in frame mode instead of raw mode. The latter is used by the control channel (ring 0). In frame mode each data frame can hold up to 4kB payload. This patch modifies the DMA ring code to allow configuring a ring to be in frame mode by passing a new flag (RING_FLAG_FRAME) to the ring when it is allocated. In addition there might be need to enable end-to-end (E2E) workaround for the ring to prevent losing Rx frames in certain situations. We add another flag (RING_FLAG_E2E) that can be used for this purpose. This code is based on the work done by Amir Levy and Michael Jamet. Signed-off-by: Michael Jamet <michael.jamet@intel.com> Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com> Reviewed-by: Yehezkel Bernat <yehezkel.bernat@intel.com> Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Linux kernel ============ This file was moved to Documentation/admin-guide/README.rst Please notice that there are several guides for kernel developers and users. These guides can be rendered in a number of formats, like HTML and PDF. In order to build the documentation, use ``make htmldocs`` or ``make pdfdocs``. There are various text files in the Documentation/ subdirectory, several of them using the Restructured Text markup notation. See Documentation/00-INDEX for a list of what is contained in each file. 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.