All ARMv5 and older CPUs invalidate their caches in the early assembly
setup function, prior to enabling the MMU. This is because the L1
cache should not contain any data relevant to the execution of the
kernel at this point; all data should have been flushed out to memory.
This requirement should also be true for ARMv6 and ARMv7 CPUs - indeed,
these typically do not search their caches when caching is disabled (as
it needs to be when the MMU is disabled) so this change should be safe.
ARMv7 allows there to be CPUs which search their caches while caching is
disabled, and it's permitted that the cache is uninitialised at boot;
for these, the architecture reference manual requires that an
implementation specific code sequence is used immediately after reset
to ensure that the cache is placed into a sane state. Such
functionality is definitely outside the remit of the Linux kernel, and
must be done by the SoC's firmware before _any_ CPU gets to the Linux
kernel.
Changing the data cache clean+invalidate to a mere invalidate allows us
to get rid of a lot of platform specific hacks around this issue for
their secondary CPU bringup paths - some of which were buggy.
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Tested-by: Florian Fainelli <f.fainelli@gmail.com>
Tested-by: Heiko Stuebner <heiko@sntech.de>
Tested-by: Dinh Nguyen <dinguyen@opensource.altera.com>
Acked-by: Sebastian Hesselbarth <sebastian.hesselbarth@gmail.com>
Tested-by: Sebastian Hesselbarth <sebastian.hesselbarth@gmail.com>
Acked-by: Shawn Guo <shawn.guo@linaro.org>
Tested-by: Thierry Reding <treding@nvidia.com>
Acked-by: Thierry Reding <treding@nvidia.com>
Tested-by: Geert Uytterhoeven <geert+renesas@glider.be>
Tested-by: Michal Simek <michal.simek@xilinx.com>
Tested-by: Wei Xu <xuwei5@hisilicon.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
The automatic CPU power state machine for B15 CPUs does not work
reliably as-is. This patch implements a manual sequence in software to
replace it.
This was tested successfully with over 10,000 hotplug cycles of
something like this:
echo 0 > /sys/devices/system/cpu/cpu1/online
echo 1 > /sys/devices/system/cpu/cpu1/online
whereas the existing sequence often locks up after a few hundred cycles.
Fixes: 62639c2f53 ("ARM: brcmstb: reintroduce SMP support")
Acked-by: Gregory Fong <gregory.0xf0@gmail.com>
Signed-off-by: Brian Norris <computersforpeace@gmail.com>
Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
Support for SMP bringup of the B15 CPUs on Broadcom STB chips was added
in commit 4fbe66d990 but was reverted in
commit fc3e825fa9 to address some late
review comments. This reintroduces SMP support.
Signed-off-by: Marc Carino <marc.ceeeee@gmail.com>
Signed-off-by: Brian Norris <computersforpeace@gmail.com>
Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
There were several issues (of varying degree of importance) pointed out
with this code late in the review cycle, yet the code was still merged.
Let's rip it out for now and look at resubmitting at a later time.
This reverts most of commit 4fbe66d990.
Signed-off-by: Brian Norris <computersforpeace@gmail.com>
Signed-off-by: Olof Johansson <olof@lixom.net>
The BCM7xxx series of Broadcom SoCs are used primarily in set-top boxes.
This patch adds machine support for the ARM-based Broadcom SoCs.
Signed-off-by: Marc Carino <marc.ceeeee@gmail.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Brian Norris <computersforpeace@gmail.com>
Signed-off-by: Matt Porter <mporter@linaro.org>
