[PATCH kernel v3 16/22] powerpc/powernv: Add purge cache OPAL call

[Alexey Kardashevskiy]

Flushing caches using the dcbf instruction takes quite some time if we
need to flush gigabytes (16GB takes more than 15s); OPAL just added
a big hammer to flush all caches.

This adds opal_purge_cache() which will be used later to flush caches
for coherent GPU memory which might suddenly become unavailable if a GPU
is reset and NVLink is not (re)trained.

Signed-off-by: Alexey Kardashevskiy <aik at ozlabs.ru>
---
 arch/powerpc/include/asm/opal-api.h            | 3 ++-
 arch/powerpc/include/asm/opal.h                | 1 +
 arch/powerpc/platforms/powernv/opal.c          | 1 +
 arch/powerpc/platforms/powernv/opal-wrappers.S | 1 +
 4 files changed, 5 insertions(+), 1 deletion(-)

diff --git a/arch/powerpc/include/asm/opal-api.h b/arch/powerpc/include/asm/opal-api.h
index 870fb7b..55bc640 100644
--- a/arch/powerpc/include/asm/opal-api.h
+++ b/arch/powerpc/include/asm/opal-api.h
@@ -210,7 +210,8 @@
 #define OPAL_PCI_GET_PBCQ_TUNNEL_BAR		164
 #define OPAL_PCI_SET_PBCQ_TUNNEL_BAR		165
 #define	OPAL_NX_COPROC_INIT			167
-#define OPAL_LAST				167
+#define OPAL_CLEAR_CACHE			170
+#define OPAL_LAST				170
 
 #define QUIESCE_HOLD			1 /* Spin all calls at entry */
 #define QUIESCE_REJECT			2 /* Fail all calls with OPAL_BUSY */
diff --git a/arch/powerpc/include/asm/opal.h b/arch/powerpc/include/asm/opal.h
index ff38664..7db576e 100644
--- a/arch/powerpc/include/asm/opal.h
+++ b/arch/powerpc/include/asm/opal.h
@@ -294,6 +294,7 @@ int opal_set_power_shift_ratio(u32 handle, int token, u32 psr);
 int opal_sensor_group_clear(u32 group_hndl, int token);
 int opal_sensor_group_enable(u32 group_hndl, int token, bool enable);
 int opal_nx_coproc_init(uint32_t chip_id, uint32_t ct);
+int opal_purge_cache(void);
 
 s64 opal_signal_system_reset(s32 cpu);
 s64 opal_quiesce(u64 shutdown_type, s32 cpu);
diff --git a/arch/powerpc/platforms/powernv/opal.c b/arch/powerpc/platforms/powernv/opal.c
index beed86f..44ce824 100644
--- a/arch/powerpc/platforms/powernv/opal.c
+++ b/arch/powerpc/platforms/powernv/opal.c
@@ -1113,3 +1113,4 @@ EXPORT_SYMBOL_GPL(opal_int_eoi);
 EXPORT_SYMBOL_GPL(opal_error_code);
 /* Export the below symbol for NX compression */
 EXPORT_SYMBOL(opal_nx_coproc_init);
+EXPORT_SYMBOL(opal_purge_cache);
diff --git a/arch/powerpc/platforms/powernv/opal-wrappers.S b/arch/powerpc/platforms/powernv/opal-wrappers.S
index 2515282..5b886a6 100644
--- a/arch/powerpc/platforms/powernv/opal-wrappers.S
+++ b/arch/powerpc/platforms/powernv/opal-wrappers.S
@@ -331,3 +331,4 @@ OPAL_CALL(opal_pci_set_pbcq_tunnel_bar,		OPAL_PCI_SET_PBCQ_TUNNEL_BAR);
 OPAL_CALL(opal_sensor_read_u64,			OPAL_SENSOR_READ_U64);
 OPAL_CALL(opal_sensor_group_enable,		OPAL_SENSOR_GROUP_ENABLE);
 OPAL_CALL(opal_nx_coproc_init,			OPAL_NX_COPROC_INIT);
+OPAL_CALL(opal_purge_cache,			OPAL_CLEAR_CACHE);
-- 
2.17.1