Haibo Chen
16e40e5b1e
mmc: sdhci-esdhc-imx: disable the CMD CRC check for standard tuning
In current code, we add 1ms dealy after each tuning command for standard tuning method. Adding this 1ms dealy is because USDHC default check the CMD CRC and DATA line. If detect the CMD CRC, USDHC standard tuning IC logic do not wait for the tuning data sending out by the card, trigger the buffer read ready interrupt immediately, and step to next cycle. So when next time the new tuning command send out by USDHC, card may still not send out the tuning data of the upper command,then some eMMC cards may stuck, can't response to any command, block the whole tuning procedure. If do not check the CMD CRC for tuning, then do not has this issue. USDHC will wait for the tuning data of each tuning command and check them. If the tuning data pass the check, it also means the CMD line also okay for tuning. So this patch disable the CMD CRC check for tuning, save some time for the whole tuning procedure. Signed-off-by: Haibo Chen <haibo.chen@nxp.com> Link: https://lore.kernel.org/r/1590488522-9292-2-git-send-email-haibo.chen@nxp.com Signed-off-by: Ulf Hansson <ulf.hansson@linaro.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.
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