DPDK patches and discussions
 help / color / mirror / Atom feed
From: Chaoyong He <chaoyong.he@corigine.com>
To: Ferruh Yigit <ferruh.yigit@amd.com>, "dev@dpdk.org" <dev@dpdk.org>
Cc: oss-drivers <oss-drivers@corigine.com>,
	Niklas Soderlund <niklas.soderlund@corigine.com>,
	James Hershaw <james.hershaw@corigine.com>
Subject: RE: [PATCH v2 2/2] net/nfp: write link speed to control BAR
Date: Mon, 13 Mar 2023 03:03:18 +0000	[thread overview]
Message-ID: <SJ0PR13MB5545808C27EB5405A6A9E9379EB99@SJ0PR13MB5545.namprd13.prod.outlook.com> (raw)
In-Reply-To: <a9fa6bd3-3813-ab95-34ce-d1772c1d04f0@amd.com>

> On 3/10/2023 6:25 AM, Chaoyong He wrote:
> > +	/**
> > +	 * Shift and mask nn_link_status so that it is effectively the value
> > +	 * at offset NFP_NET_CFG_STS_NSP_LINK_RATE.
> > +	 */
> > +	nn_link_status = (nn_link_status >>
> NFP_NET_CFG_STS_LINK_RATE_SHIFT) &
> > +			 NFP_NET_CFG_STS_LINK_RATE_MASK;
> 
> Thanks for extensive commenting, perhaps this is the source of confusion, I
> can't see how above logic makes effectively the value at offset LINK_RATE.
> 
> NFP_NET_CFG_STS_LINK_RATE_SHIFT = 1
> NFP_NET_CFG_STS_LINK_RATE_MASK  = 0xF
> 
> NFP_NET_CFG_STS               = 0x34
> NFP_NET_CFG_STS_NSP_LINK_RATE = 0x36
> 
> nfp_net_notify_port_speed()
> 	uint16_t speed;
> 	*(0x36) = speed
> 
> nfp_net_link_update()
> 	uint16_t val = *(0x34)
> 	val = (val >> 1) & 0xF;
> 
> 
> How come 'speed' and 'val' are same value?
> 
> Either there is a mistake or FW is making something in the background, I am
> trying to clarify this in past few comments but not able to yet.

Yes, here FW does do something in the background.
----------------------------------------------------------------------------

            16 bit write only                 16 bit read only

| x x x x x x x x x x x x y y y y | x x x x x x x x x x x y y y y x |

                                                 ^                                                ^

                                             0x36                                           0x34
------------------------------------------------------------------------------
The firmware confirm that whatever write into ‘yyyy’ field of 0x36 can be read from ‘yyyy’ field of 0x34.


  reply	other threads:[~2023-03-13  3:03 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-02-21  6:29 [PATCH] " Chaoyong He
2023-02-23 16:39 ` Ferruh Yigit
2023-03-06  7:06   ` Chaoyong He
2023-03-07 13:24     ` Ferruh Yigit
2023-03-10  6:07       ` Chaoyong He
2023-03-10  6:25 ` [PATCH v2 0/2] " Chaoyong He
2023-03-10  6:25   ` [PATCH v2 1/2] net/nfp: add helper functions for read/write 16b values Chaoyong He
2023-03-10  6:25   ` [PATCH v2 2/2] net/nfp: write link speed to control BAR Chaoyong He
2023-03-10 11:15     ` Ferruh Yigit
2023-03-13  3:03       ` Chaoyong He [this message]
2023-03-13  8:39         ` Ferruh Yigit
2023-03-13 10:18   ` [PATCH v2 0/2] " Ferruh Yigit

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=SJ0PR13MB5545808C27EB5405A6A9E9379EB99@SJ0PR13MB5545.namprd13.prod.outlook.com \
    --to=chaoyong.he@corigine.com \
    --cc=dev@dpdk.org \
    --cc=ferruh.yigit@amd.com \
    --cc=james.hershaw@corigine.com \
    --cc=niklas.soderlund@corigine.com \
    --cc=oss-drivers@corigine.com \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).