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

[David Gibson <david@gibson.dropbear.id.au>]

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On Tue, Nov 13, 2018 at 07:28:17PM +1100, Alexey Kardashevskiy wrote:
> 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@ozlabs.ru>

Reviewed-by: David Gibson <david@gibson.dropbear.id.au>

> ---
>  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);

-- 
David Gibson			| I'll have my music baroque, and my code
david AT gibson.dropbear.id.au	| minimalist, thank you.  NOT _the_ _other_
				| _way_ _around_!
http://www.ozlabs.org/~dgibson

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