0ec058ece2
Refer ARM DDI 0487I.a ID081822, D17.3.8, DBGDTRTX_EL0, "If TXfull is set to 1, set DTRRX and DTRTX to UNKNOWN" Thus one should always check for TXfull condition before hvc can be used as an early console. This is similar to what is being done today in hvc_dcc_console_init() and hvc_dcc_init(). The count 0x4000000 has been obtained from uboot (v2024.01-rc3) drivers/serial/arm_dcc.c "TIMEOUT_COUNT". It reads the dcc status and waits for 0x4000000 times for the TX Fifo to be available before returning an error. Thus, it will prevent DCC to be used as early console. Signed-off-by: Ayan Kumar Halder <ayan.kumar.halder@amd.com> Link: https://lore.kernel.org/r/20231205123534.3376883-1-ayan.kumar.halder@amd.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.