Tegra support several low-power (LPx) states, which are:
- LP0: CPU + Core voltage off and DRAM in self-refresh
- LP1: CPU voltage off and DRAM in self-refresh
- LP2: CPU voltage off
When entering any of the above states the tegra_disable_clean_inv_dcache()
function is called to flush the dcache. The function
tegra_disable_clean_inv_dcache() will either flush the entire data cache or
up to the Level of Unification Inner Shareable (LoUIS) depending on the
value in r0. When tegra_disable_clean_inv_dcache() is called by
tegra20_sleep_core_finish() or tegra30_sleep_core_finish(), to enter LP0
and LP1 power state, the r0 register contains a physical memory address
which will not be equal to TEGRA_FLUSH_CACHE_ALL (1) and so the data cache
will be only flushed to the LoUIS. However, when
tegra_disable_clean_inv_dcache() called by tegra_sleep_cpu_finish() to
enter to LP2 power state, r0 is set to TEGRA_FLUSH_CACHE_ALL to flush the
entire dcache.
Please note that tegra20_sleep_core_finish(), tegra30_sleep_core_finish()
and tegra_sleep_cpu_finish() are called by the boot CPU once all other CPUs
have been disabled and so it seems appropriate to flush the entire cache at
this stage.
Therefore, ensure that r0 is set to TEGRA_FLUSH_CACHE_ALL when calling
tegra_disable_clean_inv_dcache() from tegra20_sleep_core_finish() and
tegra30_sleep_core_finish().
Signed-off-by: Jon Hunter <jonathanh@nvidia.com>
Reviewed-by: Joseph Lo <josephl@nvidia.com>
Signed-off-by: Thierry Reding <treding@nvidia.com>
Commit 7232398abc ("ARM: tegra: Convert PMC to a driver") changed tegra_resume()
location storing from late to early and, as a result, broke suspend on Tegra20.
PMC scratch register 41 is used by tegra LP1 resume code for retrieving stored
physical memory address of common resume function and in the same time used by
tegra20_cpu_shutdown() (shared by Tegra20 cpuidle driver and platform SMP code),
which is storing CPU1 "resettable" status. It implies strict order of scratch
register usage, otherwise resume function address is lost on Tegra20 after
disabling non-boot CPU's on suspend. Fix it by storing "resettable" status in
IRAM instead of PMC scratch register.
Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
Fixes: 7232398abc (ARM: tegra: Convert PMC to a driver)
Cc: <stable@vger.kernel.org> # v3.17+
Signed-off-by: Thierry Reding <treding@nvidia.com>
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>
irammap.h's purpose is to define the layout/usage of IRAM. As such,
TEGRA_IRAM_CODE_AREA should have been added there rather than iomap.h.
Move the define, and rename it something more descriptive.
Cc: Joseph Lo <josephl@nvidia.com>
Signed-off-by: Stephen Warren <swarren@nvidia.com>
The LP1 suspend mode will power off the CPU, clock gated the PLLs and put
SDRAM to self-refresh mode. Any interrupt can wake up device from LP1. The
sequence when LP1 suspending:
* tunning off L1 data cache and the MMU
* putting SDRAM into self-refresh
* storing some EMC registers and SCLK burst policy
* switching CPU to CLK_M (12MHz OSC)
* switching SCLK to CLK_S (32KHz OSC)
* tunning off PLLM, PLLP and PLLC
* shutting off the CPU rail
The sequence of LP1 resuming:
* re-enabling PLLM, PLLP, and PLLC
* restoring some EMC registers and SCLK burst policy
* setting up CCLK burst policy to PLLP
* resuming SDRAM to normal mode
* jumping to the "tegra_resume" from PMC_SCRATCH41
Due to the SDRAM will be put into self-refresh mode, the low level
procedures of LP1 suspending and resuming should be copied to
TEGRA_IRAM_CODE_AREA (TEGRA_IRAM_BASE + SZ_4K) when suspending. Before
restoring the CPU context when resuming, the SDRAM needs to be switched
back to normal mode. And the PLLs need to be re-enabled, SCLK burst policy
be restored, CCLK burst policy be set in PLLP. Then jumping to
"tegra_resume" that was expected to be stored in PMC_SCRATCH41 to restore
CPU context and back to kernel.
Based on the work by:
Colin Cross <ccross@android.com>
Gary King <gking@nvidia.com>
Signed-off-by: Joseph Lo <josephl@nvidia.com>
Signed-off-by: Stephen Warren <swarren@nvidia.com>
Adding a flag for tegra_disable_clean_inv_dcache to flush cache as LoUIS
or ALL. After this patch, the v7_flush_dcache_louis is used for CPU hotplug
and CPU suspend in CPU power down (e.g. CPU idle power-down mode) case. And
the v7_flush_dcache_all is used for CPU cluster power down (e.g. suspend to
LP2 mode).
Signed-off-by: Joseph Lo <josephl@nvidia.com>
Signed-off-by: Stephen Warren <swarren@nvidia.com>
When building a kernel for multiple CPU architecture levels,
cpu_do_idle() is a macro for an indirect function call, which
cannot be called from assembly code as Tegra does.
Adding a trivial C wrapper for this function lets us build
a tegra kernel with ARMv6 support enabled.
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Joseph Lo <josephl@nvidia.com>
Cc: Stephen Warren <swarren@nvidia.com>
The "powered-down" cpuidle mode of Tegra20 needs the CPU0 be the last one
core to go into this mode before other core. The coupled cpuidle framework
can help to sync the MPCore to coupled state then go into "powered-down"
idle mode together. The driver can just assume the MPCore come into
"powered-down" mode at the same time. No need to take care if the CPU_0
goes into this mode along and only can put it into safe idle mode (WFI).
The powered-down state of Tegra20 requires power gating both CPU cores.
When the secondary CPU requests to enter powered-down state, it saves
its own contexts and then enters WFI for waiting CPU0 in the same state.
When the CPU0 requests powered-down state, it attempts to put the secondary
CPU into reset to prevent it from waking up. Then power down both CPUs
together and power off the cpu rail.
Be aware of that, you may see the legacy power state "LP2" in the code
which is exactly the same meaning of "CPU power down".
Based on the work by:
Colin Cross <ccross@android.com>
Gary King <gking@nvidia.com>
Signed-off-by: Joseph Lo <josephl@nvidia.com>
Acked-by: Colin Cross <ccross@android.com>
Signed-off-by: Stephen Warren <swarren@nvidia.com>
The powered-down state of Tegra20 requires power gating both CPU cores.
When the secondary CPU requests to enter powered-down state, it saves
its own contexts and then enters WFI. The Tegra20 had a limition to
power down both CPU cores. The secondary CPU must waits for CPU0 in
powered-down state too. If the secondary CPU be woken up before CPU0
entering powered-down state, then it needs to restore its CPU states
and waits for next chance.
Be aware of that, you may see the legacy power state "LP2" in the code
which is exactly the same meaning of "CPU power down".
Based on the work by:
Colin Cross <ccross@android.com>
Gary King <gking@nvidia.com>
Signed-off-by: Joseph Lo <josephl@nvidia.com>
Signed-off-by: Stephen Warren <swarren@nvidia.com>
Updating the cache maintenance order before CPU shutdown when doing CPU
hotplug.
The old order:
* clean L1 by flush_cache_all
* exit SMP
* CPU shutdown
Adapt to:
* disable L1 data cache by clear C bit
* clean L1 by v7_flush_dcache_louis
* exit SMP
* CPU shutdown
For CPU hotplug case, it's no need to do "flush_cache_all". And we should
disable L1 data cache before clean L1 data cache. Then leaving the SMP
coherency.
Signed-off-by: Joseph Lo <josephl@nvidia.com>
Acked-by: Peter De Schrijver <pdeschrijver@nvidia.com>
Signed-off-by: Stephen Warren <swarren@nvidia.com>
For the naming consistency under the mach-tegra, we re-name the file of
"sleep-tXX" to "sleep-tegraXX" (e.g., sleep-t30 to sleep-tegra30).
Signed-off-by: Joseph Lo <josephl@nvidia.com>
Signed-off-by: Stephen Warren <swarren@nvidia.com>
