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Instead of calling dmam_alloc_coherent() once for each 4-bit DMA hardware descriptor, we can have them both in a physical memory page, as long as they are aligned to 16 bytes. This reduces memory consumption, and will make it easier to add more DMA descriptors in the future. Note that the old code would not create the F0 descriptor on SoCs that don't support multiple planes. We don't care, because: - we don't use more memory by allocating two descriptors instead of a single one; - the only SoC that does not support multiple planes (JZ4740) still has two independent DMA channels, for an unknown reason. Signed-off-by: Paul Cercueil <paul@crapouillou.net> Reviewed-by: Sam Ravnborg <sam@ravnborg.org> Link: https://patchwork.freedesktop.org/patch/msgid/20200926170501.1109197-4-paul@crapouillou.net |
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| 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.