mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
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Md Sadre Alam
dc390138a0
commit867621ba20upstream. BAM version 1.6.0 and later changed the behavior of the mask field in command elements for read operations. In older BAM versions, or prior implementation assumptions, the mask field was effectively ignored for read commands. However, starting from BAM v1.6.0, the mask field for read commands is repurposed to carry the upper 4 bits of the destination address, enabling support for 36-bit addressing. For write commands, the mask field continues to function as a traditional write mask. The current driver sets mask = 0xffffffff for all command elements. While this works for write operations, it breaks read operations on BAM v1.6.0+ hardware. In such cases, the hardware interprets the upper address bits as 0xf, resulting in an invalid destination address (0xf_xxxxxxxx instead of 0x0_xxxxxxxx). This leads to failures such as NAND enumeration issues observed on platforms like IPQ5424. Fix this by assigning the mask field based on command type: - For read commands: set mask = 0 (upper address bits = 0) - For write commands: retain mask = 0xffffffff Also update the bam_cmd_element structure documentation to reflect the dual purpose of the mask field across BAM versions. This ensures correct behavior on BAM v1.6.0+ while maintaining backward compatibility with older hardware. Fixes:dfebb055f7("dmaengine: qcom: bam_dma: wrapper functions for command descriptor") Tested-by: Lakshmi Sowjanya D <lakshmi.d@oss.qualcomm.com> Signed-off-by: Md Sadre Alam <md.alam@oss.qualcomm.com> Reviewed-by: Frank Li <Frank.Li@nxp.com> Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@oss.qualcomm.com> Cc: stable@vger.kernel.org Signed-off-by: Varadarajan Narayanan <varadarajan.narayanan@oss.qualcomm.com> Link: https://patch.msgid.link/20260615060908.1263171-1-varadarajan.narayanan@oss.qualcomm.com Signed-off-by: Vinod Koul <vkoul@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.