Add cpu hotplug support for berlin SoCs such as BG2 and BG2Q. These SoC
don't support power off cpu independently, but we also want cpu hotplug
support in these SoCs. We achieve this goal by putting the dying CPU in
WFI state after the coherency is disabled, then asserting the dying CPU
reset bit to put the CPU in reset state.
Signed-off-by: Jisheng Zhang <jszhang@marvell.com>
Signed-off-by: Sebastian Hesselbarth <sebastian.hesselbarth@gmail.com>
In Berlin SoCs, there are two kinds of cpu reset control registers: the
first one's corresponding bits will be self-cleared after some cycles,
while the second one's bits won't. Previously the first kind of reset
control register is used, this patch uses the second kind one to prepare
for the next hotplug commit.
Signed-off-by: Jisheng Zhang <jszhang@marvell.com>
Signed-off-by: Sebastian Hesselbarth <sebastian.hesselbarth@gmail.com>
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>
Adds SMP support for Berlin SoCs. Secondary CPUs are reset, then
execute the instruction we put in the reset exception register, setting
the pc at the address contained in the software reset address register,
which is the physical address of the Berlin secondary startup.
This implementation avoid using the pen lock mechanism.
Signed-off-by: Antoine Ténart <antoine.tenart@free-electrons.com>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: Sebastian Hesselbarth <sebastian.hesselbarth@gmail.com>
Masahiro Yamada
Jisheng Zhang
Russell King
Antoine Ténart