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  1. 30 May, 2014 24 commits
  3. 29 May, 2014 2 commits
  5. 28 May, 2014 14 commits
    • Paul Burton's avatar
      MIPS: Malta: CPS SMP by default · 32201453
      Paul Burton authored 
      The CONFIG_MIPS_CPS SMP implementation should be able to handle all
cases the CONFIG_MIPS_CMP implementation does, but without requiring
bootloader assistance. It is also required in order to make use of
features such as hotplug & cpuidle core power gating. Enable it by
default for Malta configs that previously enabled the now deprecated
CONFIG_MIPS_CMP, and disable the latter. The local version suffix "cmp"
is removed rather than replaced with "cps" since there are other ways to
tell that the CPS SMP implementation is in use (the "VPE topology" line
in the boot log being one).
Signed-off-by: default avatarPaul Burton <paul.burton@imgtec.com>
      32201453
    • Paul Burton's avatar
      cpuidle: cpuidle-cps: add MIPS CPS cpuidle driver · d0508944
      Paul Burton authored 
      This patch adds a cpuidle driver for systems based around the MIPS
Coherent Processing System (CPS) architecture. It supports four idle
states:

  - The standard MIPS wait instruction.

  - The non-coherent wait, clock gated & power gated states exposed by
    the recently added pm-cps layer.

The pm-cps layer is used to enter all the deep idle states. Since cores
in the clock or power gated states cannot service interrupts, the
gic_send_ipi_single function is modified to send a power up command for
the appropriate core to the CPC in cases where the target CPU has marked
itself potentially incoherent.
Signed-off-by: default avatarPaul Burton <paul.burton@imgtec.com>
      d0508944
    • Paul Burton's avatar
      cpuidle: declare cpuidle_dev in cpuidle.h · f08dbf8a
      Paul Burton authored 
      Declaring this allows drivers which need to initialise each struct
cpuidle_device at initialisation time to make use of the structures
already defined in cpuidle.c, rather than having to wastefully define
their own.
Signed-off-by: default avatarPaul Burton <paul.burton@imgtec.com>
      f08dbf8a
    • Paul Burton's avatar
      MIPS: include cpuidle Kconfig menu · c095ebaf
      Paul Burton authored 
      This patch simply includes the cpuidle Kconfig entries in preparation
for cpuidle drivers used on MIPS systems.
Signed-off-by: default avatarPaul Burton <paul.burton@imgtec.com>
      c095ebaf
    • Paul Burton's avatar
      MIPS: cpuidle wait instruction state · da9f970f
      Paul Burton authored 
      Defines a macro intended to allow trivial use of the regular MIPS wait
instruction from cpuidle drivers, which may simply invoke the macro
within their array of states.
Signed-off-by: default avatarPaul Burton <paul.burton@imgtec.com>
      da9f970f
    • Paul Burton's avatar
      MIPS: smp-cps: duplicate core0 CCA on secondary cores · 0155a065
      Paul Burton authored 
      Rather than hardcoding CCA=0x5 for secondary cores, re-use the CCA from
the boot CPU. This allows overrides of the CCA using the cca= kernel
parameter to take effect on all CPUs for consistency.
Signed-off-by: default avatarPaul Burton <paul.burton@imgtec.com>
      0155a065
    • Paul Burton's avatar
      MIPS: smp-cps: set a coherent default CCA · 33b68665
      Paul Burton authored 
      This patch sets a default CCA suited for use with multi-core SMP on all
current MIPS CPS based systems. It may still be overriden by the cca=
argument on the kernel command line.
Signed-off-by: default avatarPaul Burton <paul.burton@imgtec.com>
      33b68665
    • Paul Burton's avatar
      MIPS: smp-cps: prevent multi-core SMP with unsuitable CCA · 5c399f6e
      Paul Burton authored 
      If the user or bootloader sets the CCA to a value which is not suited
for multi-core SMP (ie. anything non-coherent) then limit the system to
using only a single core and warn the user.
Signed-off-by: default avatarPaul Burton <paul.burton@imgtec.com>
      5c399f6e
    • Paul Burton's avatar
      MIPS: smp-cps: hotplug support · 1d8f1f5a
      Paul Burton authored 
      This patch adds support for offlining CPUs via hotplug when using the
CONFIG_MIPS_CPS SMP implementation. When a CPU is offlined one of 2
things will happen:

  - If the CPU is part of a core which implements the MT ASE and there
    is at least one other VPE online within that core then the VPE will
    be halted by settings its TCHalt bit.

  - Otherwise if supported the core will be powered down via the CPC.

  - Otherwise the CPU will hang by executing an infinite loop.

Bringing CPUs back online is then a process of either clearing the
appropriate VPEs TCHalt bit or powering up the appropriate core via the
CPC. Throughout the process the struct core_boot_config vpe_mask field
must be maintained such that mips_cps_boot_vpes will start & stop the
correct VPEs.
Signed-off-by: default avatarPaul Burton <paul.burton@imgtec.com>
      1d8f1f5a
    • Paul Burton's avatar
      MIPS: pm-cps: add PM state entry code for CPS systems · 3179d37e
      Paul Burton authored 
      This patch adds code to generate entry & exit code for various low power
states available on systems based around the MIPS Coherent Processing
System architecture (ie. those with a Coherence Manager, Global
Interrupt Controller & for >=CM2 a Cluster Power Controller). States
supported are:

  - Non-coherent wait. This state first leaves the coherent domain and
    then executes a regular MIPS wait instruction. Power savings are
    found from the elimination of coherency interventions between the
    core and any other coherent requestors in the system.

  - Clock gated. This state leaves the coherent domain and then gates
    the clock input to the core. This removes all dynamic power from the
    core but leaves the core at the mercy of another to restart its
    clock. Register state is preserved, but the core can not service
    interrupts whilst its clock is gated.

  - Power gated. This deepest state removes all power input to the core.
    All register state is lost and the core will restart execution from
    its BEV when another core powers it back up. Because register state
    is lost this state requires cooperation with the CONFIG_MIPS_CPS SMP
    implementation in order for the core to exit the state successfully.

The code will detect which states are available on the current system
during boot & generate the entry/exit code for those states. This will
be used by cpuidle & hotplug implementations.
Signed-off-by: default avatarPaul Burton <paul.burton@imgtec.com>
      3179d37e
    • Paul Burton's avatar
      MIPS: smp-cps: use CPC core-other locking · dd9233d0
      Paul Burton authored 
      The core which the CPC core-other region relates to is based upon the
core-local core-other addressing register. As its name suggests this
register is shared between all VPEs within a core, and if there is a
possibility that multiple VPEs within a core will attempt to access
another core simultaneously then locking is required. This wasn't
previously a problem with the only user being cpu0 during boot, but will
be an issue once hotplug is implemented & may race with other users such
as cpuidle.
Signed-off-by: default avatarPaul Burton <paul.burton@imgtec.com>
      dd9233d0
    • Paul Burton's avatar
      MIPS: smp-cps: flush cache after patching mips_cps_core_entry · 0f4d3d11
      Paul Burton authored 
      The start of mips_cps_core_entry is patched in order to provide the code
with the address of the CM register region at a point where it will be
running non-coherent with the rest of the system. However the cache
wasn't being flushed after that patching which could in principle lead
to secondary cores using an invalid CM base address.

The patching is moved to cps_prepare_cpus since local_flush_icache_range
has not been initialised at the point cps_smp_setup is called.
Signed-off-by: default avatarPaul Burton <paul.burton@imgtec.com>
      0f4d3d11
    • Paul Burton's avatar
      MIPS: smp-cps: function to determine whether CPS SMP is in use · 68c1232f
      Paul Burton authored 
      The core power down state for cpuidle will require that the CPS SMP
implementation is in use. This patch provides a mips_cps_smp_in_use
function which determines whether or not the CPS SMP implementation is
currently in use.
Signed-off-by: default avatarPaul Burton <paul.burton@imgtec.com>
      68c1232f
    • Paul Burton's avatar
      MIPS: smp-cps: rework core/VPE initialisation · 245a7868
      Paul Burton authored 
      When hotplug and/or a powered down idle state are supported cases will
arise where a non-zero VPE must be brought online without VPE 0, and it
where multiple VPEs must be onlined simultaneously. This patch prepares
for that by:

  - Splitting struct boot_config into core & VPE boot config structures,
    allocated one per core or VPE respectively. This allows for multiple
    VPEs to be onlined simultaneously without clobbering each others
    configuration.

  - Indicating which VPEs should be online within a core at any given
    time using a bitmap. This allows multiple VPEs to be brought online
    simultaneously and also indicates to VPE 0 whether it should halt
    after starting any non-zero VPEs that should be online within the
    core. For example if all VPEs within a core are offlined via hotplug
    and the user onlines the second VPE within that core:

      1) The core will be powered up.

      2) VPE 0 will run from the BEV (ie. mips_cps_core_entry) to
         initialise the core.

      3) VPE 0 will start VPE 1 because its bit is set in the cores
         bitmap.

      4) VPE 0 will halt itself because its bit is clear in the cores
         bitmap.

  - Moving the core & VPE initialisation to assembly code which does not
    make any use of the stack. This is because if a non-zero VPE is to
    be brought online in a powered down core then when VPE 0 of that
    core runs it may not have a valid stack, and even if it did then
    it's messy to run through parts of generic kernel code on VPE 0
    before starting the correct VPE.
Signed-off-by: default avatarPaul Burton <paul.burton@imgtec.com>
      245a7868
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