Re: [net-next PATCH 1/3] octeontx2-af: Create BPIDs free pool

[Simon Horman <horms@kernel.org>]

On Wed, Jan 24, 2024 at 11:20:12AM +0530, Geetha sowjanya wrote:
> Current code reserves 64 bpids for 64 LBK channels. But in most
> of the cases multiple LBK channels uses same bpid. This leads
> to inefficient use of bpids. Latest HW support configured multiple
> bpids per channel for other interface types (CGX). For better use
> of these bpids, this patch creates pool of free bpids from reserved
> LBK bpids. This free pool is used to allocate bpid on request for
> another interface like sso etc.
> 
> This patch also reduces the number of bpids for cgx interfaces to 8
> and adds proper error code
> 
> Signed-off-by: Geetha sowjanya <gakula@marvell.com>

Hi Geetha,

I have some suggestions for possible follow-up below.
That notwithstanding patch looks good to me.

Reviewed-by: Simon Horman <horms@kernel.org>

> diff --git a/drivers/net/ethernet/marvell/octeontx2/af/rvu_nix.c b/drivers/net/ethernet/marvell/octeontx2/af/rvu_nix.c
> index 66203a90f052..e1eae16b09b3 100644
> --- a/drivers/net/ethernet/marvell/octeontx2/af/rvu_nix.c
> +++ b/drivers/net/ethernet/marvell/octeontx2/af/rvu_nix.c
> @@ -499,14 +499,84 @@ static void nix_interface_deinit(struct rvu *rvu, u16 pcifunc, u8 nixlf)
>  	rvu_cgx_disable_dmac_entries(rvu, pcifunc);
>  }
>  
> +#define NIX_BPIDS_PER_LMAC	8
> +#define NIX_BPIDS_PER_CPT	1
> +static int nix_setup_bpids(struct rvu *rvu, struct nix_hw *hw, int blkaddr)
> +{
> +	struct nix_bp *bp = &hw->bp;
> +	int err, max_bpids;
> +	u64 cfg;
> +
> +	cfg = rvu_read64(rvu, blkaddr, NIX_AF_CONST1);
> +	max_bpids = (cfg >> 12) & 0xFFF;

I don't think this needs to block progress of this patch,
but rather I'm providing this as a suggestion for a follow-up.

I think it would be nice to define a mask, created using GENMASK,
that names the register field (I don't know what it is).
And then uses FIELD_GET here.

Likewise for the 0xFFF below, and possibly elsewhere in this patch.

Further, in patch 2 I see the use of BIT(11) in the following patch.
And existing use of BIT(16) in this file.  I assume are register fields.
If so it would be nice to make #defines to name them too.

> +
> +	/* Reserve the BPIds for CGX and SDP */
> +	bp->cgx_bpid_cnt = rvu->hw->cgx_links * NIX_BPIDS_PER_LMAC;
> +	bp->sdp_bpid_cnt = rvu->hw->sdp_links * (cfg & 0xFFF);
> +	bp->free_pool_base = bp->cgx_bpid_cnt + bp->sdp_bpid_cnt +
> +			     NIX_BPIDS_PER_CPT;
> +	bp->bpids.max = max_bpids - bp->free_pool_base;

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