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commit 67380251e8bbd3302c64fea07f95c31971b91c22 upstream. Requesting a retune before switching to the RPMB partition has been observed to cause CRC errors on the RPMB reads (-EILSEQ). Since RPMB reads can not be retried, the clients would be directly affected by the errors. This commit disables the retune request prior to switching to the RPMB partition: mmc_retune_pause() no longer triggers a retune before the pause period begins. This was verified with the sdhci-of-arasan driver (ZynqMP) configured for HS200 using two separate eMMC cards (DG4064 and 064GB2). In both cases, the error was easy to reproduce triggering every few tenths of reads. With this commit, systems that were utilizing OP-TEE to access RPMB variables will experience an enhanced performance. Specifically, when OP-TEE is configured to employ RPMB as a secure storage solution, it not only writes the data but also the secure filesystem within the partition. As a result, retrieving any variable involves multiple RPMB reads, typically around five. For context, on ZynqMP, each retune request consumed approximately 8ms. Consequently, reading any RPMB variable used to take at the very minimum 40ms. After droping the need to retune before switching to the RPMB partition, this is no longer the case. Signed-off-by: Jorge Ramirez-Ortiz <jorge@foundries.io> Acked-by: Avri Altman <avri.altman@wdc.com> Acked-by: Adrian Hunter <adrian.hunter@intel.com> Link: https://lore.kernel.org/r/20240103112911.2954632-1-jorge@foundries.io Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org> Signed-off-by: Florian Fainelli <florian.fainelli@broadcom.com> 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.