ARMv6 and greater introduced a new instruction ("bx") which can be used
to return from function calls. Recent CPUs perform better when the
"bx lr" instruction is used rather than the "mov pc, lr" instruction,
and this sequence is strongly recommended to be used by the ARM
architecture manual (section A.4.1.1).
We provide a new macro "ret" with all its variants for the condition
code which will resolve to the appropriate instruction.
Rather than doing this piecemeal, and miss some instances, change all
the "mov pc" instances to use the new macro, with the exception of
the "movs" instruction and the kprobes code. This allows us to detect
the "mov pc, lr" case and fix it up - and also gives us the possibility
of deploying this for other registers depending on the CPU selection.
Reported-by: Will Deacon <will.deacon@arm.com>
Tested-by: Stephen Warren <swarren@nvidia.com> # Tegra Jetson TK1
Tested-by: Robert Jarzmik <robert.jarzmik@free.fr> # mioa701_bootresume.S
Tested-by: Andrew Lunn <andrew@lunn.ch> # Kirkwood
Tested-by: Shawn Guo <shawn.guo@freescale.com>
Tested-by: Tony Lindgren <tony@atomide.com> # OMAPs
Tested-by: Gregory CLEMENT <gregory.clement@free-electrons.com> # Armada XP, 375, 385
Acked-by: Sekhar Nori <nsekhar@ti.com> # DaVinci
Acked-by: Christoffer Dall <christoffer.dall@linaro.org> # kvm/hyp
Acked-by: Haojian Zhuang <haojian.zhuang@gmail.com> # PXA3xx
Acked-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com> # Xen
Tested-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de> # ARMv7M
Tested-by: Simon Horman <horms+renesas@verge.net.au> # Shmobile
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
The TNET variant of DaVinci compiles some code that it shares
with other DaVinci variants, however it has a V6 CPU rather than
an ARM926T, thus the hardcoded call to arm926_flush_kern_cache_all()
in sleep.S will obviously fail, and we need to build with the
v6_flush_kern_cache_all() call instead. This was triggered by
manually altering the DaVinci config to build the TNET version.
Cc: Dave Martin <dave.martin@linaro.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Sekhar Nori <nsekhar@ti.com>
Cc: stable@kernel.org
This patch adds core power management (suspend-to-RAM)
support for DaVinci SoCs.
The code depends on the the "deepsleep" feature to suspend
the SoC and saves power by gating the input clock.
The wakeup can be based on an external event as supported
by the SoC.
Assembly code (in sleep.S) is added to aid gating DDR2
clocks. Code doing this work should not be accessing DDR2.
The assembly code is relocated to SRAM by the code in pm.c
The support has been validated on DA850/OMAP-L138 only
though the code is (hopefully) generic enough that other
SoCs supporting deepsleep feature simply requires SoC
specific code to start using this driver.
Note that all the device drivers don't support suspend/resume
still and are being worked on.
Signed-off-by: Sekhar Nori <nsekhar@ti.com>
Signed-off-by: Kevin Hilman <khilman@deeprootsystems.com>
Russell King