powerpc/powernv: Add platform support for stop instruction
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>
diff --git a/arch/powerpc/include/asm/ppc-opcode.h b/arch/powerpc/include/asm/ppc-opcode.h
index 9de9df1..81657a1 100644
--- a/arch/powerpc/include/asm/ppc-opcode.h
+++ b/arch/powerpc/include/asm/ppc-opcode.h
@@ -205,6 +205,8 @@
#define PPC_INST_SLEEP 0x4c0003a4
#define PPC_INST_WINKLE 0x4c0003e4
+#define PPC_INST_STOP 0x4c0002e4
+
/* A2 specific instructions */
#define PPC_INST_ERATWE 0x7c0001a6
#define PPC_INST_ERATRE 0x7c000166
@@ -394,6 +396,8 @@
#define PPC_SLEEP stringify_in_c(.long PPC_INST_SLEEP)
#define PPC_WINKLE stringify_in_c(.long PPC_INST_WINKLE)
+#define PPC_STOP stringify_in_c(.long PPC_INST_STOP)
+
/* BHRB instructions */
#define PPC_CLRBHRB stringify_in_c(.long PPC_INST_CLRBHRB)
#define PPC_MFBHRBE(r, n) stringify_in_c(.long PPC_INST_BHRBE | \