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Serge Semin 993d57bbaa dmaengine: dw-edma: Add CPU to PCI bus address translation
Since 9575632052 ("dmaengine: make slave address physical"), the source
and destination addresses of the DMA slave device have been converted to
physical addresses in the CPU address space. It's the DMA device driver's
responsibility to convert them to the DMA bus address space. In case of the
DW eDMA device, the source or destination peripheral (slave) devices reside
in PCI bus space. Thus we need to perform the PCI Host/Endpoint windows-
based (i.e. DT "ranges" property) address translation; otherwise the eDMA
transactions won't work as expected (or can be even harmful) if the CPU and
PCI address spaces don't match.

Note 1: Even though the DMA interleaved template has both source and
destination addresses declared as dma_addr_t, only the CPU memory range
should be mapped to be seen by the DMA device since it's a subject of the
DMA getting towards the system side. The device part must not be mapped
since the slave device resides in the PCI bus space, which isn't affected
by IOMMUs or iATU translations. DW PCIe eDMA generates corresponding
MWr/MRd TLPs on its own.

Note 2: This functionality is mainly required for the remote eDMA setup
since the CPU address must be manually translated into the PCI bus space
before being written to LLI.{SAR,DAR}. If eDMA is embedded in the locally
accessible DW PCIe Root Port/Endpoint, software-based translation isn't
required since hardware will translate it via the Outbound iATU as long as
the DMA_BYPASS flag is cleared. If DMA_BYPASS is set or there is no
Outbound iATU entry that contains the SAR or DAR (for Read and Write
channel respectively), there won't be any translation performed but DMA
will proceed with the corresponding source/destination address as-is.

Link: https://lore.kernel.org/r/20230113171409.30470-8-Sergey.Semin@baikalelectronics.ru
Tested-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Signed-off-by: Serge Semin <Sergey.Semin@baikalelectronics.ru>
Signed-off-by: Lorenzo Pieralisi <lpieralisi@kernel.org>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Acked-by: Vinod Koul <vkoul@kernel.org>
2023-01-27 17:15:33 +01:00
arch treewide: Convert del_timer*() to timer_shutdown*() 2022-12-25 13:38:09 -08:00
block treewide: Convert del_timer*() to timer_shutdown*() 2022-12-25 13:38:09 -08:00
certs certs: make system keyring depend on built-in x509 parser 2022-09-24 04:31:18 +09:00
crypto This update includes the following changes: 2022-12-14 12:31:09 -08:00
Documentation kernel hardening fixes for v6.2-rc1 2022-12-23 12:00:24 -08:00
drivers dmaengine: dw-edma: Add CPU to PCI bus address translation 2023-01-27 17:15:33 +01:00
fs treewide: Convert del_timer*() to timer_shutdown*() 2022-12-25 13:38:09 -08:00
include dmaengine: dw-edma: Add CPU to PCI bus address translation 2023-01-27 17:15:33 +01:00
init Kbuild updates for v6.2 2022-12-19 12:33:32 -06:00
io_uring io_uring/net: fix cleanup after recycle 2022-12-19 08:28:28 -07:00
ipc Non-MM patches for 6.2-rc1. 2022-12-12 17:28:58 -08:00
kernel kernel hardening fixes for v6.2-rc1 2022-12-23 12:00:24 -08:00
lib test_maple_tree: add test for mas_spanning_rebalance() on insufficient data 2022-12-21 14:31:52 -08:00
LICENSES LICENSES: Add the copyleft-next-0.3.1 license 2022-11-08 15:44:01 +01:00
mm hugetlb: really allocate vma lock for all sharable vmas 2022-12-21 14:31:52 -08:00
net treewide: Convert del_timer*() to timer_shutdown*() 2022-12-25 13:38:09 -08:00
rust rust: types: add Opaque type 2022-12-04 01:59:16 +01:00
samples Char/Misc driver changes for 6.2-rc1 2022-12-16 03:49:24 -08:00
scripts modernize use of grep in coccicheck 2022-12-23 13:56:41 -08:00
security kernel hardening fixes for v6.2-rc1 2022-12-23 12:00:24 -08:00
sound treewide: Convert del_timer*() to timer_shutdown*() 2022-12-25 13:38:09 -08:00
tools perf tools fixes and improvements for v6.2: 2nd batch 2022-12-22 11:07:29 -08:00
usr usr/gen_init_cpio.c: remove unnecessary -1 values from int file 2022-10-03 14:21:44 -07:00
virt ARM64: 2022-12-15 11:12:21 -08:00
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.cocciconfig
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.mailmap Non-MM patches for 6.2-rc1. 2022-12-12 17:28:58 -08:00
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COPYING COPYING: state that all contributions really are covered by this file 2020-02-10 13:32:20 -08:00
CREDITS MAINTAINERS: zram: zsmalloc: Add an additional co-maintainer 2022-12-15 16:37:49 -08:00
Kbuild Kbuild updates for v6.1 2022-10-10 12:00:45 -07:00
Kconfig kbuild: ensure full rebuild when the compiler is updated 2020-05-12 13:28:33 +09:00
MAINTAINERS io_uring-6.2-2022-12-19 2022-12-21 16:28:25 -08:00
Makefile Linux 6.2-rc1 2022-12-25 13:41:39 -08:00
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.