mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
synced 2026-05-13 23:29:10 -04:00
3f450d3eea
Currently the i2c error handling in BAM mode is not working properly in stress condition. 1. After an error, the FIFO are being written with FLUSH and EOT tags which should not be required since already these tags have been written in BAM descriptor itself. 2. QUP state is being moved to RESET in IRQ handler in case of error. When QUP HW encounters an error in BAM mode then it moves the QUP STATE to PAUSE state. In this case, I2C_FLUSH command needs to be executed while moving to RUN_STATE by writing to the QUP_STATE register with the I2C_FLUSH bit set to 1. 3. In Error case, sometimes, QUP generates more than one interrupt which will trigger the complete again. After an error, the flush operation will be scheduled after doing reinit_completion which should be triggered by BAM IRQ callback. If the second QUP IRQ comes during this time then it will call the complete and the transfer function will assume the all the BAM HW descriptors have been completed. 4. The release DMA is being called after each error which will free the DMA tx and rx channels. The error like NACK is very common in I2C transfer and every time this will be overhead. Now, since the error handling is proper so this release channel can be completely avoided. Signed-off-by: Abhishek Sahu <absahu@codeaurora.org> Reviewed-by: Sricharan R <sricharan@codeaurora.org> Reviewed-by: Austin Christ <austinwc@codeaurora.org> Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
Linux kernel ============ This file was moved to Documentation/admin-guide/README.rst Please notice that there are several guides for kernel developers and users. These guides can be rendered in a number of formats, like HTML and PDF. In order to build the documentation, use ``make htmldocs`` or ``make pdfdocs``. There are various text files in the Documentation/ subdirectory, several of them using the Restructured Text markup notation. See Documentation/00-INDEX for a list of what is contained in each file. 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.