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alistair23-linux/arch/mips/include/asm/pm-cps.h

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MIPS: pm-cps: add PM state entry code for CPS systems 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: Paul Burton <paul.burton@imgtec.com>
2014-04-14 04:00:56 -06:00
/*
* Copyright (C) 2014 Imagination Technologies
Update MIPS email addresses MIPS will soon not be a part of Imagination Technologies, and as such many @imgtec.com email addresses will no longer be valid. This patch updates the addresses for those who: - Have 10 or more patches in mainline authored using an @imgtec.com email address, or any patches dated within the past year. - Are still with Imagination but leaving as part of the MIPS business unit, as determined from an internal email address list. - Haven't already updated their email address (ie. JamesH) or expressed a desire to be excluded (ie. Maciej). - Acked v2 or earlier of this patch, which leaves Deng-Cheng, Matt & myself. New addresses are of the form firstname.lastname@mips.com, and all verified against an internal email address list. An entry is added to .mailmap for each person such that get_maintainer.pl will report the new addresses rather than @imgtec.com addresses which will soon be dead. Instances of the affected addresses throughout the tree are then mechanically replaced with the new @mips.com address. Signed-off-by: Paul Burton <paul.burton@mips.com> Cc: Deng-Cheng Zhu <dengcheng.zhu@imgtec.com> Cc: Deng-Cheng Zhu <dengcheng.zhu@mips.com> Acked-by: Dengcheng Zhu <dengcheng.zhu@mips.com> Cc: Matt Redfearn <matt.redfearn@imgtec.com> Cc: Matt Redfearn <matt.redfearn@mips.com> Acked-by: Matt Redfearn <matt.redfearn@mips.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: linux-kernel@vger.kernel.org Cc: linux-mips@linux-mips.org Cc: trivial@kernel.org Patchwork: https://patchwork.linux-mips.org/patch/17540/ Signed-off-by: James Hogan <jhogan@kernel.org>
2017-10-25 18:04:33 -06:00
* Author: Paul Burton <paul.burton@mips.com>
MIPS: pm-cps: add PM state entry code for CPS systems 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: Paul Burton <paul.burton@imgtec.com>
2014-04-14 04:00:56 -06:00
*
* This program is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License as published by the
* Free Software Foundation; either version 2 of the License, or (at your
* option) any later version.
*/
#ifndef __MIPS_ASM_PM_CPS_H__
#define __MIPS_ASM_PM_CPS_H__
/*
* The CM & CPC can only handle coherence & power control on a per-core basis,
MIPS: pm-cps: Add MIPSr6 CPU support This patch adds support for CPUs implementing the MIPSr6 ISA to the CPS power management code. Three changes are necessary: 1. In MIPSr6, coupled coherence is necessary when CPUS implement multiple Virtual Processors (VPs). 2. MIPSr6 virtual processors are more like real cores and cannot yield to other VPs on the same core, so drop the MT ASE yield instruction. 3. To halt a MIPSr6 VP, the CPC VP_STOP register is used rather than the MT ASE TCHalt CP0 register. Signed-off-by: Matt Redfearn <matt.redfearn@imgtec.com> Reviewed-by: Paul Burton <paul.burton@imgtec.com> Cc: Adam Buchbinder <adam.buchbinder@gmail.com> Cc: Masahiro Yamada <yamada.masahiro@socionext.com> Cc: Kees Cook <keescook@chromium.org> Cc: linux-mips@linux-mips.org Cc: linux-kernel@vger.kernel.org Patchwork: https://patchwork.linux-mips.org/patch/14225/ Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2016-09-07 03:45:17 -06:00
* thus in an MT system the VP(E)s within each core are coupled and can only
MIPS: pm-cps: add PM state entry code for CPS systems 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: Paul Burton <paul.burton@imgtec.com>
2014-04-14 04:00:56 -06:00
* enter or exit states requiring CM or CPC assistance in unison.
*/
MIPS: pm-cps: Add MIPSr6 CPU support This patch adds support for CPUs implementing the MIPSr6 ISA to the CPS power management code. Three changes are necessary: 1. In MIPSr6, coupled coherence is necessary when CPUS implement multiple Virtual Processors (VPs). 2. MIPSr6 virtual processors are more like real cores and cannot yield to other VPs on the same core, so drop the MT ASE yield instruction. 3. To halt a MIPSr6 VP, the CPC VP_STOP register is used rather than the MT ASE TCHalt CP0 register. Signed-off-by: Matt Redfearn <matt.redfearn@imgtec.com> Reviewed-by: Paul Burton <paul.burton@imgtec.com> Cc: Adam Buchbinder <adam.buchbinder@gmail.com> Cc: Masahiro Yamada <yamada.masahiro@socionext.com> Cc: Kees Cook <keescook@chromium.org> Cc: linux-mips@linux-mips.org Cc: linux-kernel@vger.kernel.org Patchwork: https://patchwork.linux-mips.org/patch/14225/ Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2016-09-07 03:45:17 -06:00
#if defined(CONFIG_CPU_MIPSR6)
# define coupled_coherence cpu_has_vp
#elif defined(CONFIG_MIPS_MT)
MIPS: pm-cps: add PM state entry code for CPS systems 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: Paul Burton <paul.burton@imgtec.com>
2014-04-14 04:00:56 -06:00
# define coupled_coherence cpu_has_mipsmt
#else
# define coupled_coherence 0
#endif
/* Enumeration of possible PM states */
enum cps_pm_state {
CPS_PM_NC_WAIT, /* MIPS wait instruction, non-coherent */
CPS_PM_CLOCK_GATED, /* Core clock gated */
CPS_PM_POWER_GATED, /* Core power gated */
CPS_PM_STATE_COUNT,
};
/**
* cps_pm_support_state - determine whether the system supports a PM state
* @state: the state to test for support
*
* Returns true if the system supports the given state, otherwise false.
*/
extern bool cps_pm_support_state(enum cps_pm_state state);
/**
* cps_pm_enter_state - enter a PM state
* @state: the state to enter
*
* Enter the given PM state. If coupled_coherence is non-zero then it is
* expected that this function be called at approximately the same time on
* each coupled CPU. Returns 0 on successful entry & exit, otherwise -errno.
*/
extern int cps_pm_enter_state(enum cps_pm_state state);
#endif /* __MIPS_ASM_PM_CPS_H__ */