Re: [net PATCH 1/2] octeontx2-af: Set LMT_ENA bit for APR table entries

[Michal Swiatkowski <michal.swiatkowski@linux.intel.com>]

On Wed, May 21, 2025 at 11:38:33AM +0530, Geetha sowjanya wrote:
> From: Subbaraya Sundeep <sbhatta@marvell.com>
> 
> This patch enables the LMT line for a PF/VF by setting the
> LMT_ENA bit in the APR_LMT_MAP_ENTRY_S structure.
> 
> Additionally, it simplifies the logic for calculating the
> LMTST table index by consistently using the maximum
> number of hw supported VFs (i.e., 256).
> 
> Fixes: 873a1e3d207a ("octeontx2-af: cn10k: Setting up lmtst map table").
> Signed-off-by: Subbaraya Sundeep <sbhatta@marvell.com>
> Signed-off-by: Geetha sowjanya <gakula@marvell.com>
> ---
>  .../net/ethernet/marvell/octeontx2/af/rvu_cn10k.c | 15 +++++++++++++--
>  1 file changed, 13 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/net/ethernet/marvell/octeontx2/af/rvu_cn10k.c b/drivers/net/ethernet/marvell/octeontx2/af/rvu_cn10k.c
> index 7fa98aeb3663..3838c04b78c2 100644
> --- a/drivers/net/ethernet/marvell/octeontx2/af/rvu_cn10k.c
> +++ b/drivers/net/ethernet/marvell/octeontx2/af/rvu_cn10k.c
> @@ -15,13 +15,17 @@
>  #define LMT_TBL_OP_WRITE	1
>  #define LMT_MAP_TABLE_SIZE	(128 * 1024)
>  #define LMT_MAPTBL_ENTRY_SIZE	16
> +#define LMT_MAX_VFS		256
> +
> +#define LMT_MAP_ENTRY_ENA      BIT_ULL(20)
> +#define LMT_MAP_ENTRY_LINES    GENMASK_ULL(18, 16)
>  
>  /* Function to perform operations (read/write) on lmtst map table */
>  static int lmtst_map_table_ops(struct rvu *rvu, u32 index, u64 *val,
>  			       int lmt_tbl_op)
>  {
>  	void __iomem *lmt_map_base;
> -	u64 tbl_base;
> +	u64 tbl_base, cfg;
>  
>  	tbl_base = rvu_read64(rvu, BLKADDR_APR, APR_AF_LMT_MAP_BASE);
>  
> @@ -35,6 +39,13 @@ static int lmtst_map_table_ops(struct rvu *rvu, u32 index, u64 *val,
>  		*val = readq(lmt_map_base + index);
>  	} else {
>  		writeq((*val), (lmt_map_base + index));
> +
> +		cfg = FIELD_PREP(LMT_MAP_ENTRY_ENA, 0x1);
> +		/* 2048 LMTLINES */
> +		cfg |= FIELD_PREP(LMT_MAP_ENTRY_LINES, 0x6);
> +
> +		writeq(cfg, (lmt_map_base + (index + 8)));
Is this 8 LMT_MAP_TBL_W1_OFF? It isn't obvious for me why +8, but I
don't know the driver, so maybe it should.

> +
>  		/* Flushing the AP interceptor cache to make APR_LMT_MAP_ENTRY_S
>  		 * changes effective. Write 1 for flush and read is being used as a
>  		 * barrier and sets up a data dependency. Write to 0 after a write
> @@ -52,7 +63,7 @@ static int lmtst_map_table_ops(struct rvu *rvu, u32 index, u64 *val,
>  #define LMT_MAP_TBL_W1_OFF  8
>  static u32 rvu_get_lmtst_tbl_index(struct rvu *rvu, u16 pcifunc)
>  {
> -	return ((rvu_get_pf(pcifunc) * rvu->hw->total_vfs) +
> +	return ((rvu_get_pf(pcifunc) * LMT_MAX_VFS) +
>  		(pcifunc & RVU_PFVF_FUNC_MASK)) * LMT_MAPTBL_ENTRY_SIZE;

Just nit/question, patch looks fine
Reviewed-by: Michal Swiatkowski <michal.swiatkowski@linux.intel.com>

>  }
>  
> -- 
> 2.25.1