13f87983fb
All UFS host controllers support DMA clustering. Hence enable DMA
clustering.
Notes:
- The max_segment_size parameter implements the 256 KiB limit for the
PRDT. The dma_boundary parameter represents a boundary that must not be
crossed by DMA scatter/gather lists. I'm not aware of any restrictions
on DMA scatter/gather lists in the UFSHCI specification other than the
256 KiB limit for the PRDT and the 32-bit address restriction for
controllers that only support 32-bits DMA. The latter restriction is
already handled by ufshcd_set_dma_mask().
- Without patch "scsi: ufs: exynos: Fix the maximum segment size", this
patch breaks support for the Exynos controller.
The history of the dma_boundary parameter in the UFS driver is as
follows:
* The initial UFS driver did not set the dma_boundary parameter.
* Commit 4dd4130a722f ("scsi: make sure all drivers set the use_clustering
flag") set the .use_clustering flag.
* Commit 4af14d113bcf ("scsi: remove the use_clustering flag") removed the
use_clustering flag and set the dma_boundary parameter instead.
Cc: Avri Altman <avri.altman@wdc.com>
Cc: Alim Akhtar <alim.akhtar@samsung.com>
Cc: Kiwoong Kim <kwmad.kim@samsung.com>
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Acked-by: Adrian Hunter <adrian.hunter@intel.com>
Reviewed-by: Alim Akhtar <alim.akhtar@samsung.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
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.