This patch was triggered by a remark from Russell that
introducing a call to the waituart (needed to fix debug prints
on the Qualcomm platforms) was dangerous because in some cases
this will involve waiting for a modem CTS (clear to send)
signal, and debug messages would maybe not work on platforms
with no modem connected to the UART port: they will just
hang waiting for the modem to assert CTS and this might never
happen.
Looking through all UART debug drivers implementing the waituart
macro I discovered that all users except two actually use this
macro to check if the UART is ready for TX, let's call this
TXRDY.
Only two debug UART drivers actually check for CTS:
- arch/arm/include/debug/8250.S
- arch/arm/include/debug/tegra.S
The former is very significant since the 8250 is possibly
the most common UART on the planet.
We have the following problem: the semantics of waituart are
ambiguous making it dangerous to introduce the macro to debug
code fixing debug prints for Qualcomm. To start to pry this
problem apart, this patch does the following:
- Convert all debug UART drivers to define two macros:
- waituartcts with the clear semantic to wait for CTS
to be asserted
- waituarttxrdy with the clear semantic to wait for the TX
capability of the UART to be ready
- When doing this take care to assign the right function to
each drivers macro, so they now do exactly the above.
- Update the three sites in the kernel invoking the waituart
macro to call waituartcts/waituarttxrdy in sequence, so that
the functional impact on the kernel should be zero.
After this we can start to change the code sites using this
code to do the right thing.
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
Based on 1 normalized pattern(s):
this software is licensed under the terms of the gnu general public
license version 2 as published by the free software foundation and
may be copied distributed and modified under those terms this
program is distributed in the hope that it will be useful but
without any warranty without even the implied warranty of
merchantability or fitness for a particular purpose see the gnu
general public license for more details
extracted by the scancode license scanner the SPDX license identifier
GPL-2.0-only
has been chosen to replace the boilerplate/reference in 285 file(s).
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Alexios Zavras <alexios.zavras@intel.com>
Reviewed-by: Allison Randal <allison@lohutok.net>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190529141900.642774971@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The patch
"ARM: 8432/1: move VMALLOC_END from 0xff000000 to 0xff800000"
(sha1: 6ff0966052)
has moved also start of VMALLOC area because size didn't change.
That's why origin location of vmalloc was
vmalloc : 0xf0000000 - 0xff000000 ( 240 MB)
and now is
vmalloc : 0xf0800000 - 0xff800000 ( 240 MB)
That's why uart virtual addresses need to be changed to reflect this new
memory setup. Starting address should be vmalloc start address.
Signed-off-by: Michal Simek <michal.simek@xilinx.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
earlyprintk messages are not appearing on the terminal
emulator during a big endian kernel boot. In BE mode
sending full words to UART will result in unprintable
characters as they are byte swapped versions of printable
ones. So send only bytes.
Signed-off-by: Arun Chandran <achandran@mvista.com>
Tested-by: Michal Simek <michal.simek@xilinx.com>
Signed-off-by: Michal Simek <michal.simek@xilinx.com>
Enable ARCH_SUPPORTS_BIG_ENDIAN in Kconfig.
zynq_secondary_trampoline is the first function
that is called on secondary CPU.
Reference:
"ARM: mcpm: fix big endian issue in mcpm startup code"
(sha1: 519ceb9fd1)
Fix early printk support. Based on:
"ARM: pl01x debug code endian fix"
(sha1: 76e3faf156)
Signed-off-by: Michal Simek <michal.simek@xilinx.com>
Virtual address have to have the same offset within
a 2MB aligned section of virtual/phycial address space.
Fix uart0 virtual address to be align with physical one.
Also remove UART_SIZE which is completely unused.
Reported-by: Russ Smith <russells@google.com>
Signed-off-by: Michal Simek <michal.simek@xilinx.com>
The majority of changes are necessary to remove dependencies on header
files within arch/arm/mach-zynq/include/mach:
uncompress.h
- Deleted. It is unused for ARCH_MULTIPLATFORM builds.
uart.h:
- Move uart definitions out of uart.h into debug/zynq.S, which is
now the only user
zynq_soc.h:
- Move SCU address definitions into common.c.
- Other #defines, such as PERIPHERAL_CLOCK_RATE, TTC0_BASE, etc, are
unused and can be dropped
Signed-off-by: Josh Cartwright <josh.cartwright@ni.com>
Tested-by: Michal Simek <michal.simek@xilinx.com>
Convert low-level debugging routines to make use of debug_ll_io_init().
This is part of the preparation for ARCH_MULTIPLATFORM support for Zynq.
Signed-off-by: Josh Cartwright <josh.cartwright@ni.com>
Tested-by: Michal Simek <michal.simek@xilinx.com>
2012-11-21 10:52:05 +01:00
Renamed from arch/arm/mach-zynq/include/mach/debug-macro.S (Browse further)
