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Vijaya Krishna Nivarthi
fc673c4eb2
commit90ef2f2961upstream. The maximum size for a DMA data descriptor is 64KB-1 because the size field in HW is 16 bits wide. For this reason, transfers fail at 64KB and beyond. Lower max_dma_len to 60KB so larger transfers are split into multiple DMA blocks and do not hit the failing 64KB boundary. 60KB is chosen as a safe round number below the 64KB-1 hardware limit while satisfying alignment requirements. Tested on x1e80100 (Hamoa) with SPI-NOR flash (/dev/mtd0): Without patch: dd if=/dev/mtd0 of=/tmp/spi_dump.bin bs=32768 count=2 # works dd if=/dev/mtd0 of=/tmp/spi_dump.bin bs=65536 count=1 # fails With patch: dd if=/dev/mtd0 of=/tmp/spi_dump.bin bs=65536 count=1 # works Fixes:b5762d9560("spi: spi-qcom-qspi: Add DMA mode support") Cc: stable@vger.kernel.org Signed-off-by: Vijaya Krishna Nivarthi <vijaya.nivarthi@oss.qualcomm.com> Link: https://patch.msgid.link/20260722092358.459943-1-vnivarth@qti.qualcomm.com Signed-off-by: Mark Brown <broonie@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.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.