03ce80a1bb
Qcom SoCs require scaling the interconnect paths for proper working of the peripherals connected through interconnects. Even for accessing the UFS controller, someone should setup the interconnect paths. So far, the bootloaders used to setup the interconnect paths before booting Linux as they need to access the UFS storage for things like fetching boot firmware. But with the advent of multi boot options, bootloader nowadays like in SA8540p SoC do not setup the interconnect paths at all. So trying to configure UFS in the absence of the interconnect path configuration results in a boot crash. To fix this issue, and also to dynamically scale the interconnects (UFS-DDR and CPU-UFS), interconnect API support is added to the Qcom UFS driver. With this support, the interconnect paths are scaled dynamically based on the gear configuration. During the early stage of ufs_qcom_init(), ufs_qcom_icc_init() will setup the paths to max bandwidth to allow configuring the UFS registers. Touching the registers without configuring the icc paths would result in a crash. However, we don't really need to set max vote for the icc paths as any minimal vote would suffice. But the max value would allow initialization to be done faster. After init, the bandwidth will get updated using ufs_qcom_icc_update_bw() based on the gear and lane configuration. The bandwidth values defined in ufs_qcom_bw_table struct are taken from Qcom downstream vendor devicetree source and are calculated as per the UFS3.1 Spec, Section 6.4.1, HS Gear Rates. So it is fixed across platforms. Cc: Brian Masney <bmasney@redhat.com> Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org> Link: https://lore.kernel.org/r/20230731145020.41262-3-manivannan.sadhasivam@linaro.org Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
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.