d3a96c9416
Commit 075167ed71b7 ("drivers: PL011: replace UART_MIS reading with
_RIS & _IMSC") amended this driver's interrupt handler to read the
Raw Interrupt Status (RIS) and Interrupt Mask Set/Clear (IMSC) registers
instead of the Masked Interrupt Status (MIS) register. The change was
made to attain compatibility with SBSA UARTs which lack the MIS register.
However the IMSC register is cached by the driver. Using the cached
copy saves one register read per interrupt.
I've tested this change successfully on a BCM2837 (Raspberry Pi CM3).
Cc: Mathias Duckeck <m.duckeck@kunbus.de>
Cc: Phil Elwell <phil@raspberrypi.org>
Cc: Stefan Wahren <stefan.wahren@i2se.com>
Cc: Andre Przywara <andre.przywara@arm.com>
Cc: Mark Langsdorf <mlangsdo@redhat.com>
Cc: Naresh Bhat <nbhat@cavium.com>
Cc: Russell King <linux@armlinux.org.uk>
Signed-off-by: Lukas Wunner <lukas@wunner.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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.