Re: [dpdk-dev] [dpdk-dev,3/3] nfp: set device dma mask

[Jan Viktorin <viktorin@rehivetech.com>]

On Thu, 12 May 2016 15:34:00 +0100
"Alejandro.Lucero" <alejandro.lucero@netronome.com> wrote:

> - Just hugepages within the supported range will be available.

Again the hyphen is redundant here.

By the way, this text does not describe the change well. If I understood
the whole patch set (I am not quite sure now), the initialization would
fail if there are hugepages out of the given DMA mask. Am I wrong?

I'd expect something like "NFP supports DMA address in range ...".

> 
> Signed-off-by: Alejandro Lucero <alejandro.lucero@netronome.com>
> 
> ---
> drivers/net/nfp/nfp_net.c | 11 +++++++++++
>  1 file changed, 11 insertions(+)
> 
> diff --git a/drivers/net/nfp/nfp_net.c b/drivers/net/nfp/nfp_net.c
> index ea5a2a3..e0e444a 100644
> --- a/drivers/net/nfp/nfp_net.c
> +++ b/drivers/net/nfp/nfp_net.c
> @@ -115,6 +115,14 @@ enum nfp_qcp_ptr {
>  	NFP_QCP_WRITE_PTR
>  };
>  
> +#ifndef DMA_64BIT_MASK
> +#define DMA_64BIT_MASK  0xffffffffffffffffULL
> +#endif
> +
> +#ifndef DMA_BIT_MASK
> +#define DMA_BIT_MASK(n) (((n) == 64) ? DMA_64BIT_MASK : ((1ULL<<(n))-1))
> +#endif

This is quite a generic code, I'd put it into the EAL. Probably, it should
be renamed to something like RTE_DMA_BIT_MASK.

> +
>  /*
>   * nfp_qcp_ptr_add - Add the value to the selected pointer of a queue
>   * @q: Base address for queue structure
> @@ -2441,6 +2449,9 @@ nfp_net_init(struct rte_eth_dev *eth_dev)
>  	/* Recording current stats counters values */
>  	nfp_net_stats_reset(eth_dev);
>  
> +	/* Setting dma_mask */
> +	eth_dev->data->dma_mask = DMA_BIT_MASK(40);

Can we read this from /sys/bus/pci/devices/*/dma_mask_bits? I am not sure
whether is this generic enough but I can see dma_mask_bits for the PCI
devices on my PC.

Regards
Jan

> +
>  	return 0;
>  }
>  




-- 
   Jan Viktorin                  E-mail: Viktorin@RehiveTech.com
   System Architect              Web:    www.RehiveTech.com
   RehiveTech
   Brno, Czech Republic