diff options
| author | Shreyas B. Prabhu <shreyas@linux.vnet.ibm.com> | 2014-12-09 21:56:53 +0300 |
|---|---|---|
| committer | Michael Ellerman <mpe@ellerman.id.au> | 2014-12-15 02:46:41 +0300 |
| commit | 77b54e9f213f76a23736940cf94bcd765fc00f40 (patch) | |
| tree | c07273530b9f15c65b48ed147e0b1aabecf55f96 /arch/powerpc/include/asm/ppc-opcode.h | |
| parent | 7cba160ad789a3ad7e68b92bf20eaad6ed171f80 (diff) | |
| download | linux-77b54e9f213f76a23736940cf94bcd765fc00f40.tar.xz | |
powernv/powerpc: Add winkle support for offline cpus
Winkle is a deep idle state supported in power8 chips. A core enters
winkle when all the threads of the core enter winkle. In this state
power supply to the entire chiplet i.e core, private L2 and private L3
is turned off. As a result it gives higher powersavings compared to
sleep.
But entering winkle results in a total hypervisor state loss. Hence the
hypervisor context has to be preserved before entering winkle and
restored upon wake up.
Power-on Reset Engine (PORE) is a dedicated engine which is responsible
for powering on the chiplet during wake up. It can be programmed to
restore the register contests of a few specific registers. This patch
uses PORE to restore register state wherever possible and uses stack to
save and restore rest of the necessary registers.
With hypervisor state restore things fall under three categories-
per-core state, per-subcore state and per-thread state. To manage this,
extend the infrastructure introduced for sleep. Mainly we add a paca
variable subcore_sibling_mask. Using this and the core_idle_state we can
distingush first thread in core and subcore.
Signed-off-by: Shreyas B. Prabhu <shreyas@linux.vnet.ibm.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: linuxppc-dev@lists.ozlabs.org
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Diffstat (limited to 'arch/powerpc/include/asm/ppc-opcode.h')
| -rw-r--r-- | arch/powerpc/include/asm/ppc-opcode.h | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/arch/powerpc/include/asm/ppc-opcode.h b/arch/powerpc/include/asm/ppc-opcode.h index 6f8536208049..5155be7c0d48 100644 --- a/arch/powerpc/include/asm/ppc-opcode.h +++ b/arch/powerpc/include/asm/ppc-opcode.h @@ -194,6 +194,7 @@ #define PPC_INST_NAP 0x4c000364 #define PPC_INST_SLEEP 0x4c0003a4 +#define PPC_INST_WINKLE 0x4c0003e4 /* A2 specific instructions */ #define PPC_INST_ERATWE 0x7c0001a6 @@ -374,6 +375,7 @@ #define PPC_NAP stringify_in_c(.long PPC_INST_NAP) #define PPC_SLEEP stringify_in_c(.long PPC_INST_SLEEP) +#define PPC_WINKLE stringify_in_c(.long PPC_INST_WINKLE) /* BHRB instructions */ #define PPC_CLRBHRB stringify_in_c(.long PPC_INST_CLRBHRB) |