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powerpc/powernv: Add platform support for stop instruction

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POWER ISA v3 defines a new idle processor core mechanism. In summary,
 a) new instruction named stop is added. This instruction replaces
	instructions like nap, sleep, rvwinkle.
 b) new per thread SPR named Processor Stop Status and Control Register
	(PSSCR) is added which controls the behavior of stop instruction.

PSSCR layout:
----------------------------------------------------------
| PLS | /// | SD | ESL | EC | PSLL | /// | TR | MTL | RL |
----------------------------------------------------------
0      4     41   42    43   44     48    54   56    60

PSSCR key fields:
	Bits 0:3  - Power-Saving Level Status. This field indicates the lowest
	power-saving state the thread entered since stop instruction was last
	executed.

	Bit 42 - Enable State Loss
	0 - No state is lost irrespective of other fields
	1 - Allows state loss

	Bits 44:47 - Power-Saving Level Limit
	This limits the power-saving level that can be entered into.

	Bits 60:63 - Requested Level
	Used to specify which power-saving level must be entered on executing
	stop instruction

This patch adds support for stop instruction and PSSCR handling.

Reviewed-by: Gautham R. Shenoy <ego@linux.vnet.ibm.com>
Signed-off-by: Shreyas B. Prabhu <shreyas@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
This commit is contained in:
Shreyas B. Prabhu
2016-07-08 11:50:49 +05:30
committed by Michael Ellerman
parent 0dfffb48ce
commit bcef83a00d
8 changed files with 334 additions and 68 deletions
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10
arch/powerpc/include/asm/reg.h
View File

@@ -145,6 +145,15 @@
#define MSR_64BIT 0
#endif
/* Power Management - Processor Stop Status and Control Register Fields */
#define PSSCR_RL_MASK 0x0000000F /* Requested Level */
#define PSSCR_MTL_MASK 0x000000F0 /* Maximum Transition Level */
#define PSSCR_TR_MASK 0x00000300 /* Transition State */
#define PSSCR_PSLL_MASK 0x000F0000 /* Power-Saving Level Limit */
#define PSSCR_EC 0x00100000 /* Exit Criterion */
#define PSSCR_ESL 0x00200000 /* Enable State Loss */
#define PSSCR_SD 0x00400000 /* Status Disable */
/* Floating Point Status and Control Register (FPSCR) Fields */
#define FPSCR_FX 0x80000000 /* FPU exception summary */
#define FPSCR_FEX 0x40000000 /* FPU enabled exception summary */
@@ -291,6 +300,7 @@
#define SPRN_PMICR 0x354 /* Power Management Idle Control Reg */
#define SPRN_PMSR 0x355 /* Power Management Status Reg */
#define SPRN_PMMAR 0x356 /* Power Management Memory Activity Register */
#define SPRN_PSSCR 0x357 /* Processor Stop Status and Control Register (ISA 3.0) */
#define SPRN_PMCR 0x374 /* Power Management Control Register */
/* HFSCR and FSCR bit numbers are the same */