[Cbe-oss-dev] [RFC 3/5] spufs: add purga_dma_queue() capability.

[Benjamin Herrenschmidt]

On Tue, 2007-06-12 at 18:10 +0200, Sebastian Siewior wrote:
> plain text document attachment (spufs-ops_add_purge_dmaqueue.diff)
> After DMA error (misaligned, wrong length, etc) MFC's DMA queue
> has to be purged in order to resume the context. The purge will
> mark all DMA requests as invalid.
> This patch was initially created in order to recover from DMA
> errors. Later on I decided not to recover from DMA bugs but
> stop with BUG() since those errors are an exception and should
> happen under normal circumstances.

This patch is not related to the other ones right ?

Do we need to implement that support in case of userland DMA errors as
well ?

> Signed-off-by: Sebastian Siewior <bigeasy at linux.vnet.ibm.com>
> Index: b/arch/powerpc/platforms/cell/spufs/backing_ops.c
> ===================================================================
> --- a/arch/powerpc/platforms/cell/spufs/backing_ops.c
> +++ b/arch/powerpc/platforms/cell/spufs/backing_ops.c
> @@ -359,6 +359,26 @@ static void spu_backing_restart_dma(stru
>  	/* nothing to do here */
>  }
>  
> +static void spu_backing_purga_dma_queue(struct spu_context *ctx)
> +{
> +	struct spu_priv2_collapsed *p2 = &ctx->csa.priv2;
> +	struct mfc_cq_sr *mfc_ctx_sr;
> +	unsigned int i;
> +
> +	spin_lock(&ctx->csa.register_lock);
> +	/* purge all DMA requests on PPU & SPU side by removing the valid bit */
> +	for (i=0; i< 16; i++) {
> +		mfc_ctx_sr = &p2->spuq[i];
> +		mfc_ctx_sr->u.mfc_cq_ims &= ~MFC_SPU_CQ_ISM_VALID;
> +	}
> +	for (i=0; i< 8; i++) {
> +		mfc_ctx_sr = &p2->puq[i];
> +		mfc_ctx_sr->u.mfc_cq_ims &= ~MFC_PPU_CQ_ISM_VALID;
> +	}
> +
> +	spin_unlock(&ctx->csa.register_lock);
> +}
> +
>  struct spu_context_ops spu_backing_ops = {
>  	.mbox_read = spu_backing_mbox_read,
>  	.mbox_stat_read = spu_backing_mbox_stat_read,
> @@ -387,4 +407,5 @@ struct spu_context_ops spu_backing_ops =
>  	.get_mfc_free_elements = spu_backing_get_mfc_free_elements,
>  	.send_mfc_command = spu_backing_send_mfc_command,
>  	.restart_dma = spu_backing_restart_dma,
> +	.purga_dma_queue = spu_backing_purga_dma_queue,
>  };
> Index: b/arch/powerpc/platforms/cell/spufs/hw_ops.c
> ===================================================================
> --- a/arch/powerpc/platforms/cell/spufs/hw_ops.c
> +++ b/arch/powerpc/platforms/cell/spufs/hw_ops.c
> @@ -312,6 +312,25 @@ static void spu_hw_restart_dma(struct sp
>  		out_be64(&priv2->mfc_control_RW, MFC_CNTL_RESTART_DMA_COMMAND);
>  }
>  
> +static void spu_hw_purga_dma_queue(struct spu_context *ctx)
> +{
> +	struct spu_priv2 __iomem *priv2 = ctx->spu->priv2;
> +	unsigned long long status;
> +	unsigned long long num = 0;
> +
> +	spin_lock_irq(&ctx->spu->register_lock);
> +	out_be64(&priv2->mfc_control_RW, MFC_CNTL_PURGE_DMA_REQUEST);
> +	eieio();
> +
> +	do {
> +		num++;
> +		status = in_be64(&priv2->mfc_control_RW);
> +	} while ((status & MFC_CNTL_PURGE_DMA_STATUS_MASK) !=
> +			MFC_CNTL_PURGE_DMA_COMPLETE);
> +
> +	spin_unlock_irq(&ctx->spu->register_lock);
> +}
> +
>  struct spu_context_ops spu_hw_ops = {
>  	.mbox_read = spu_hw_mbox_read,
>  	.mbox_stat_read = spu_hw_mbox_stat_read,
> @@ -338,4 +357,5 @@ struct spu_context_ops spu_hw_ops = {
>  	.get_mfc_free_elements = spu_hw_get_mfc_free_elements,
>  	.send_mfc_command = spu_hw_send_mfc_command,
>  	.restart_dma = spu_hw_restart_dma,
> +	.purga_dma_queue = spu_hw_purga_dma_queue,
>  };
> Index: b/arch/powerpc/platforms/cell/spufs/spufs.h
> ===================================================================
> --- a/arch/powerpc/platforms/cell/spufs/spufs.h
> +++ b/arch/powerpc/platforms/cell/spufs/spufs.h
> @@ -143,6 +143,7 @@ struct spu_context_ops {
>  	void (*proxydma_info_read) (struct spu_context * ctx,
>  				    struct spu_proxydma_info * info);
>  	void (*restart_dma)(struct spu_context *ctx);
> +	void (*purga_dma_queue)(struct spu_context *ctx);
>  };
>  
>  extern struct spu_context_ops spu_hw_ops;
> Index: b/include/asm-powerpc/spu.h
> ===================================================================
> --- a/include/asm-powerpc/spu.h
> +++ b/include/asm-powerpc/spu.h
> @@ -279,7 +279,15 @@ struct mfc_cq_sr {
>  	u64 mfc_cq_data0_RW;
>  	u64 mfc_cq_data1_RW;
>  	u64 mfc_cq_data2_RW;
> -	u64 mfc_cq_data3_RW;
> +	union {
> +		u64 mfc_cq_data3_RW;
> +		struct {
> +			u32 mfc_cq_ims;
> +#define MFC_SPU_CQ_ISM_VALID (1u << 15)
> +			u32 tag_word;
> +#define MFC_PPU_CQ_ISM_VALID (1u << 15)
> +		} u;
> +	};
>  };
>  
>  struct spu_problem {
> 
> -- 
> 
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