1. 28 Feb, 2016 1 commit
  2. 12 Apr, 2015 1 commit
  3. 19 Mar, 2015 1 commit
  4. 27 Jan, 2015 1 commit
    • Lorenzo Pieralisi's avatar
      arm64: kernel: remove ARM64_CPU_SUSPEND config option · af3cfdbf
      Lorenzo Pieralisi authored
      
      
      ARM64_CPU_SUSPEND config option was introduced to make code providing
      context save/restore selectable only on platforms requiring power
      management capabilities.
      
      Currently ARM64_CPU_SUSPEND depends on the PM_SLEEP config option which
      in turn is set by the SUSPEND config option.
      
      The introduction of CPU_IDLE for arm64 requires that code configured
      by ARM64_CPU_SUSPEND (context save/restore) should be compiled in
      in order to enable the CPU idle driver to rely on CPU operations
      carrying out context save/restore.
      
      The ARM64_CPUIDLE config option (ARM64 generic idle driver) is therefore
      forced to select ARM64_CPU_SUSPEND, even if there may be (ie PM_SLEEP)
      failed dependencies, which is not a clean way of handling the kernel
      configuration option.
      
      For these reasons, this patch removes the ARM64_CPU_SUSPEND config option
      and makes the context save/restore dependent on CPU_PM, which is selected
      whenever either SUSPEND or CPU_IDLE are configured, cleaning up dependencies
      in the process.
      
      This way, code previously configured through ARM64_CPU_SUSPEND is
      compiled in whenever a power management subsystem requires it to be
      present in the kernel (SUSPEND || CPU_IDLE), which is the behaviour
      expected on ARM64 kernels.
      
      The cpu_suspend and cpu_init_idle CPU operations are added only if
      CPU_IDLE is selected, since they are CPU_IDLE specific methods and
      should be grouped and defined accordingly.
      
      PSCI CPU operations are updated to reflect the introduced changes.
      Signed-off-by: default avatarLorenzo Pieralisi <lorenzo.pieralisi@arm.com>
      Cc: Arnd Bergmann <arnd@arndb.de>
      Cc: Will Deacon <will.deacon@arm.com>
      Cc: Krzysztof Kozlowski <k.kozlowski@samsung.com>
      Cc: Daniel Lezcano <daniel.lezcano@linaro.org>
      Cc: Mark Rutland <mark.rutland@arm.com>
      Signed-off-by: default avatarCatalin Marinas <catalin.marinas@arm.com>
      af3cfdbf
  5. 20 Jan, 2015 1 commit
  6. 11 Jul, 2014 4 commits
  7. 16 Dec, 2013 1 commit
    • Lorenzo Pieralisi's avatar
      arm64: kernel: cpu_{suspend/resume} implementation · 95322526
      Lorenzo Pieralisi authored
      
      
      Kernel subsystems like CPU idle and suspend to RAM require a generic
      mechanism to suspend a processor, save its context and put it into
      a quiescent state. The cpu_{suspend}/{resume} implementation provides
      such a framework through a kernel interface allowing to save/restore
      registers, flush the context to DRAM and suspend/resume to/from
      low-power states where processor context may be lost.
      
      The CPU suspend implementation relies on the suspend protocol registered
      in CPU operations to carry out a suspend request after context is
      saved and flushed to DRAM. The cpu_suspend interface:
      
      int cpu_suspend(unsigned long arg);
      
      allows to pass an opaque parameter that is handed over to the suspend CPU
      operations back-end so that it can take action according to the
      semantics attached to it. The arg parameter allows suspend to RAM and CPU
      idle drivers to communicate to suspend protocol back-ends; it requires
      standardization so that the interface can be reused seamlessly across
      systems, paving the way for generic drivers.
      
      Context memory is allocated on the stack, whose address is stashed in a
      per-cpu variable to keep track of it and passed to core functions that
      save/restore the registers required by the architecture.
      
      Even though, upon successful execution, the cpu_suspend function shuts
      down the suspending processor, the warm boot resume mechanism, based
      on the cpu_resume function, makes the resume path operate as a
      cpu_suspend function return, so that cpu_suspend can be treated as a C
      function by the caller, which simplifies coding the PM drivers that rely
      on the cpu_suspend API.
      
      Upon context save, the minimal amount of memory is flushed to DRAM so
      that it can be retrieved when the MMU is off and caches are not searched.
      
      The suspend CPU operation, depending on the required operations (eg CPU vs
      Cluster shutdown) is in charge of flushing the cache hierarchy either
      implicitly (by calling firmware implementations like PSCI) or explicitly
      by executing the required cache maintainance functions.
      
      Debug exceptions are disabled during cpu_{suspend}/{resume} operations
      so that debug registers can be saved and restored properly preventing
      preemption from debug agents enabled in the kernel.
      Signed-off-by: default avatarLorenzo Pieralisi <lorenzo.pieralisi@arm.com>
      95322526
  8. 04 Jul, 2013 1 commit
  9. 12 Jun, 2013 1 commit
  10. 17 Sep, 2012 1 commit