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From: Andrew Lunn <andrew@lunn.ch>
To: Ansuel Smith <ansuelsmth@gmail.com>
Cc: devicetree@vger.kernel.org, Vignesh Raghavendra <vigneshr@ti.com>,
	Boris Brezillon <bbrezillon@kernel.org>,
	Richard Weinberger <richard@nod.at>,
	Russell King <linux@armlinux.org.uk>,
	linux-kernel@vger.kernel.org, Rob Herring <robh+dt@kernel.org>,
	linux-mtd@lists.infradead.org,
	Miquel Raynal <miquel.raynal@bootlin.com>,
	Jakub Kicinski <kuba@kernel.org>,
	netdev@vger.kernel.org, Frank Rowand <frowand.list@gmail.com>,
	"David S. Miller" <davem@davemloft.net>,
	Heiner Kallweit <hkallweit1@gmail.com>
Subject: Re: [PATCH v2 4/4] dt-bindings: net: Document use of mac-address-increment
Date: Sun, 20 Sep 2020 02:31:28 +0200	[thread overview]
Message-ID: <20200920003128.GC3673389@lunn.ch> (raw)
In-Reply-To: <20200919223026.20803-5-ansuelsmth@gmail.com>

> +  mac-address-increment:
> +    description:
> +      The MAC address can optionally be increased (or decreased using
> +      negative values) from the original value readed (from a nvmem cell

Read is irregular, there is no readed, just read.

> +      for example). This can be used if the mac is readed from a dedicated
> +      partition and must be increased based on the number of device
> +      present in the system.

You should probably add there is no underflow/overflow to other bytes
of the MAC address. 00:01:02:03:04:ff + 1 == 00:01:02:03:04:00.

> +    minimum: -255
> +    maximum: 255
> +
> +  mac-address-increment-byte:
> +    description:
> +      If 'mac-address-increment' is defined, this will tell what byte of
> +      the mac-address will be increased. If 'mac-address-increment' is
> +      not defined, this option will do nothing.
> +    default: 5
> +    minimum: 0
> +    maximum: 5

Is there a real need for this? A value of 0 seems like a bad idea,
since a unicast address could easily become a multicast address, which
is not valid for an interface address. It also does not seem like a
good idea to allow the OUI to be changed. So i think only bytes 3-5
should be allowed, but even then, i don't think this is needed, unless
you do have a clear use case.

    Andrew

______________________________________________________
Linux MTD discussion mailing list
http://lists.infradead.org/mailman/listinfo/linux-mtd/

WARNING: multiple messages have this Message-ID (diff)
From: Andrew Lunn <andrew@lunn.ch>
To: Ansuel Smith <ansuelsmth@gmail.com>
Cc: Miquel Raynal <miquel.raynal@bootlin.com>,
	Richard Weinberger <richard@nod.at>,
	Vignesh Raghavendra <vigneshr@ti.com>,
	Rob Herring <robh+dt@kernel.org>,
	"David S. Miller" <davem@davemloft.net>,
	Jakub Kicinski <kuba@kernel.org>,
	Heiner Kallweit <hkallweit1@gmail.com>,
	Russell King <linux@armlinux.org.uk>,
	Frank Rowand <frowand.list@gmail.com>,
	Boris Brezillon <bbrezillon@kernel.org>,
	linux-mtd@lists.infradead.org, devicetree@vger.kernel.org,
	linux-kernel@vger.kernel.org, netdev@vger.kernel.org
Subject: Re: [PATCH v2 4/4] dt-bindings: net: Document use of mac-address-increment
Date: Sun, 20 Sep 2020 02:31:28 +0200	[thread overview]
Message-ID: <20200920003128.GC3673389@lunn.ch> (raw)
In-Reply-To: <20200919223026.20803-5-ansuelsmth@gmail.com>

> +  mac-address-increment:
> +    description:
> +      The MAC address can optionally be increased (or decreased using
> +      negative values) from the original value readed (from a nvmem cell

Read is irregular, there is no readed, just read.

> +      for example). This can be used if the mac is readed from a dedicated
> +      partition and must be increased based on the number of device
> +      present in the system.

You should probably add there is no underflow/overflow to other bytes
of the MAC address. 00:01:02:03:04:ff + 1 == 00:01:02:03:04:00.

> +    minimum: -255
> +    maximum: 255
> +
> +  mac-address-increment-byte:
> +    description:
> +      If 'mac-address-increment' is defined, this will tell what byte of
> +      the mac-address will be increased. If 'mac-address-increment' is
> +      not defined, this option will do nothing.
> +    default: 5
> +    minimum: 0
> +    maximum: 5

Is there a real need for this? A value of 0 seems like a bad idea,
since a unicast address could easily become a multicast address, which
is not valid for an interface address. It also does not seem like a
good idea to allow the OUI to be changed. So i think only bytes 3-5
should be allowed, but even then, i don't think this is needed, unless
you do have a clear use case.

    Andrew

  reply	other threads:[~2020-09-20  0:33 UTC|newest]

Thread overview: 18+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-09-19 22:30 [PATCH v2 0/4] Actually implement nvmem support for mtd Ansuel Smith
2020-09-19 22:30 ` Ansuel Smith
2020-09-19 22:30 ` [PATCH v2 1/4] mtd: Add nvmem support for mtd nvmem-providers Ansuel Smith
2020-09-19 22:30   ` Ansuel Smith
2020-09-19 22:30 ` [PATCH v2 2/4] dt-bindings: mtd: partition: Document use of nvmem-provider Ansuel Smith
2020-09-19 22:30   ` Ansuel Smith
2020-09-19 22:30 ` [PATCH v2 3/4] of_net: add mac-address-increment support Ansuel Smith
2020-09-19 22:30   ` Ansuel Smith
2020-09-19 22:30 ` [PATCH v2 4/4] dt-bindings: net: Document use of mac-address-increment Ansuel Smith
2020-09-19 22:30   ` Ansuel Smith
2020-09-20  0:31   ` Andrew Lunn [this message]
2020-09-20  0:31     ` Andrew Lunn
2020-09-20  0:39     ` R: " ansuelsmth
2020-09-20  0:39       ` ansuelsmth
2020-09-20  1:22       ` Andrew Lunn
2020-09-20  1:22         ` Andrew Lunn
2020-09-20  9:45         ` ansuelsmth
2020-09-20  9:45           ` ansuelsmth

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