RE: [PATCH 1/3][v2] net: phy: introduce 1000BASE-KX and 10GBASE-KR

-----Original Message-----
From: Andrew Lunn [mailto:andrew@lunn.ch]
Sent: Friday, January 15, 2016 12:44 AM
To: shh.xie@gmail.com
Cc: devicetree@vger.kernel.org; netdev@vger.kernel.org; linuxppc-
dev@lists.ozlabs.org; f.fainelli@gmail.com; davem@davemloft.net; Shaohui =

Xie

Subject: Re: [PATCH 1/3][v2] net: phy: introduce 1000BASE-KX and 10GBASE-=

KR

=20
On Thu, Jan 14, 2016 at 04:23:59PM +0800, shh.xie@gmail.com wrote:

quoted

From: Shaohui Xie <redacted>

This commit adds necessary definitions for the PHY layer to recognize
backplane Ethernet 1000BASE-KX and 10GBASE-KR as valid PHY interfaces,
"1000base-kx" for 1000BASE-KX, "10gbase-kr" for 10GBASE-KR.

Signed-off-by: Shaohui Xie <redacted>
---
changes in v2:
new patch.

 Documentation/devicetree/bindings/net/ethernet.txt | 4 ++--
 include/linux/phy.h                                | 6 ++++++
 2 files changed, 8 insertions(+), 2 deletions(-)

diff --git a/Documentation/devicetree/bindings/net/ethernet.txt

b/Documentation/devicetree/bindings/net/ethernet.txt
index 5d88f37..1166a5c 100644

--- a/Documentation/devicetree/bindings/net/ethernet.txt
+++ b/Documentation/devicetree/bindings/net/ethernet.txt

@@ -11,8 +11,8 @@ The following properties are common to the Ethernet

controllers:

quoted

   the maximum frame size (there's contradiction in ePAPR).
 - phy-mode: string, operation mode of the PHY interface; supported val=

ues are

quoted

   "mii", "gmii", "sgmii", "qsgmii", "tbi", "rev-mii", "rmii",
"rgmii", "rgmii-id",
-  "rgmii-rxid", "rgmii-txid", "rtbi", "smii", "xgmii"; this is now a
de-facto
-  standard property;
+  "rgmii-rxid", "rgmii-txid", "rtbi", "smii", "xgmii", "1000base-kx",
+ "10gbase-kr";  this is now a de-facto standard property;

=20
I know very little about this, so i'm just asking a question. None of the=

 other

interface modes contain a bit rate. So is the bit rate needed for your tw=

o new

modes?
=20
With a bit of googling, K means copper backplane, X means 4B/5B and R mea=

ns

64B/66B. Could there be a 10Gbps KX? a 1GBps KR? Do we actually need the =

speed

here, or is kx and kr sufficient?

Hello Andrew,

1000BASE-KX and 10GBASE-KR are terms in IEEE802.3, so as XGMII and GMII.=20
There are interfaces could be different bit rates but same types,=20
e.g. 100BASE-LX10 and 1000BASE-LX10, or 40GBASE-KR4 and 100GBASE-KR4,=20
having bit rate is clear to represent hardware.

Thank you!

 Shaohui

On 15.01.2016 05:01, Shaohui Xie wrote:

quoted

-----Original Message-----
From: Andrew Lunn [mailto:andrew@lunn.ch]
Sent: Friday, January 15, 2016 12:44 AM
To: shh.xie@gmail.com
Cc: devicetree@vger.kernel.org; netdev@vger.kernel.org; linuxppc-
dev@lists.ozlabs.org; f.fainelli@gmail.com; davem@davemloft.net; Shaohui Xie
Subject: Re: [PATCH 1/3][v2] net: phy: introduce 1000BASE-KX and 10GBASE-KR

On Thu, Jan 14, 2016 at 04:23:59PM +0800, shh.xie@gmail.com wrote:

quoted

From: Shaohui Xie <redacted>

This commit adds necessary definitions for the PHY layer to recognize
backplane Ethernet 1000BASE-KX and 10GBASE-KR as valid PHY interfaces,
"1000base-kx" for 1000BASE-KX, "10gbase-kr" for 10GBASE-KR.

Signed-off-by: Shaohui Xie <redacted>
---
changes in v2:
new patch.

Shaohui,

it would be more useful to describe _what_ is new here compared to v1.

Anyway:

quoted

quoted

 Documentation/devicetree/bindings/net/ethernet.txt | 4 ++--
 include/linux/phy.h                                | 6 ++++++
 2 files changed, 8 insertions(+), 2 deletions(-)

diff --git a/Documentation/devicetree/bindings/net/ethernet.txt

b/Documentation/devicetree/bindings/net/ethernet.txt
index 5d88f37..1166a5c 100644

--- a/Documentation/devicetree/bindings/net/ethernet.txt
+++ b/Documentation/devicetree/bindings/net/ethernet.txt

@@ -11,8 +11,8 @@ The following properties are common to the Ethernet

controllers:

quoted

   the maximum frame size (there's contradiction in ePAPR).
 - phy-mode: string, operation mode of the PHY interface; supported values are
   "mii", "gmii", "sgmii", "qsgmii", "tbi", "rev-mii", "rmii",
"rgmii", "rgmii-id",
-  "rgmii-rxid", "rgmii-txid", "rtbi", "smii", "xgmii"; this is now a
de-facto
-  standard property;
+  "rgmii-rxid", "rgmii-txid", "rtbi", "smii", "xgmii", "1000base-kx",
+ "10gbase-kr";  this is now a de-facto standard property;

I know very little about this, so i'm just asking a question. None of the other
interface modes contain a bit rate. So is the bit rate needed for your two new
modes?

1000BASE-KX and 10GBASE-KR are terms in IEEE802.3, so as XGMII and GMII. 
There are interfaces could be different bit rates but same types, 
e.g. 100BASE-LX10 and 1000BASE-LX10, or 40GBASE-KR4 and 100GBASE-KR4, 
having bit rate is clear to represent hardware.

If you look at the list of possible values for "phy-mode" you'd see that
none of it describes a PHY-to-PHY connection but all are for MAC-to-PHY
connections. Also, names above suggest it already: MII is short for
media _independent_ interface.

I copy Andrew's concerns and think that neither 10000base-kx nor
10gbase-kr belong in the list of phy-mode properties.

Sebastian