Re: [net-next PATCH v5 01/10] octeontx2-pf: Refactoring RVU driver

[Geethasowjanya Akula]

>-----Original Message-----
>From: Simon Horman <horms@xxxxxxxxxx>
>Sent: Tuesday, June 18, 2024 1:11 PM
>To: Geethasowjanya Akula <gakula@xxxxxxxxxxx>
>Cc: netdev@xxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx; kuba@xxxxxxxxxx;
>davem@xxxxxxxxxxxxx; pabeni@xxxxxxxxxx; edumazet@xxxxxxxxxx; Sunil
>Kovvuri Goutham <sgoutham@xxxxxxxxxxx>; Subbaraya Sundeep Bhatta
><sbhatta@xxxxxxxxxxx>; Hariprasad Kelam <hkelam@xxxxxxxxxxx>
>Subject: [EXTERNAL] Re: [net-next PATCH v5 01/10] octeontx2-pf: Refactoring
>RVU driver
>
>On Tue, Jun 11, 2024 at 09:52:04PM +0530, Geetha sowjanya wrote:
>> Refactoring and export list of shared functions such that they can be
>> used by both RVU NIC and representor driver.
>>
>> Signed-off-by: Geetha sowjanya <gakula@xxxxxxxxxxx>
>
>...
>
>> diff --git a/drivers/net/ethernet/marvell/octeontx2/af/rvu_nix.c
>> b/drivers/net/ethernet/marvell/octeontx2/af/rvu_nix.c
>
>...
>
>> @@ -2949,6 +2952,7 @@ static int nix_tx_vtag_alloc(struct rvu *rvu, int
>blkaddr,
>>  	mutex_unlock(&vlan->rsrc_lock);
>>
>>  	regval = size ? vtag : vtag << 32;
>> +	regval |= (vtag & ~GENMASK_ULL(47, 0)) << 48;
>
>Hi Geetha,
>
>I'm a little confused by the line above.
>
>vtag is a 64 bit value.
>It is masked, leaving the upper 16 bits intact, and the lower 48 bits as zeros.
>It is then left-shifted 48 bits.
>By my reasoning the result is always 0.
>
>e.g.
>  0x123456789abcdef1 & ~GENMASK_ULL(47, 0) => 0x1234000000000000
>  0x1234000000000000 << 48 => 0
>
Will replace as below in next version.
  +     etype =  FIELD_GET(NIX_VLAN_ETYPE_MASK, vtag);
+       regval |= FIELD_PREP(NIX_VLAN_ETYPE_MASK, etype);

>Also, I suspect that FIELD_PREP could be used to good effect here.
>(And, as an aside, elsewhere in this file/driver.)
>
>>  	rvu_write64(rvu, blkaddr,
>>  		    NIX_AF_TX_VTAG_DEFX_DATA(index), regval); @@ -4619,6
>+4623,7 @@
>> static void nix_link_config(struct rvu *rvu, int blkaddr,
>>  	rvu_get_lbk_link_max_frs(rvu, &lbk_max_frs);
>>  	rvu_get_lmac_link_max_frs(rvu, &lmac_max_frs);
>>
>> +	rvu_write64(rvu, blkaddr, NIX_AF_SDP_LINK_CREDIT,
>SDP_LINK_CREDIT);
>>  	/* Set default min/max packet lengths allowed on NIX Rx links.
>>  	 *
>>  	 * With HW reset minlen value of 60byte, HW will treat ARP pkts @@
>> -4630,14 +4635,14 @@ static void nix_link_config(struct rvu *rvu, int
>blkaddr,
>>  				((u64)lmac_max_frs << 16) |
>NIC_HW_MIN_FRS);
>>  	}
>>
>> -	for (link = hw->cgx_links; link < hw->lbk_links; link++) {
>> +	for (link = hw->cgx_links; link < hw->cgx_links + hw->lbk_links;
>> +link++) {
>>  		rvu_write64(rvu, blkaddr, NIX_AF_RX_LINKX_CFG(link),
>>  			    ((u64)lbk_max_frs << 16) | NIC_HW_MIN_FRS);
>>  	}
>>  	if (hw->sdp_links) {
>>  		link = hw->cgx_links + hw->lbk_links;
>>  		rvu_write64(rvu, blkaddr, NIX_AF_RX_LINKX_CFG(link),
>> -			    SDP_HW_MAX_FRS << 16 | NIC_HW_MIN_FRS);
>> +			    SDP_HW_MAX_FRS << 16 | SDP_HW_MIN_FRS);
>>  	}
>>
>>  	/* Get MCS external bypass status for CN10K-B */
>
>...