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Date: Mon, 10 Sep 2012 19:28:22 +0200
From: Richard Cochran <richardcochran@...il.com>
To: Christophe Leroy <christophe.leroy@....fr>
Cc: David S Miller <davem@...emloft.net>, netdev@...r.kernel.org,
linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2] lxt PHY: Support for the buggy LXT973 rev A2
On Mon, Sep 10, 2012 at 05:45:49PM +0200, Christophe Leroy wrote:
> This patch adds proper handling of the buggy revision A2 of LXT973 phy, adding
> precautions linked to ERRATA Item 4:
I have a few nit picking remarks, below...
> Item 4: MDIO Interface and Repeated Polling
> Problem: Repeated polling of odd-numbered registers via the MDIO interface
> randomly returns the contents of the previous even register.
> Implication: Managed applications may not obtain the correct register contents
> when a particular register is monitored for device status.
> Workaround: None.
> Status: This erratum has been previously fixed (in rev A3)
This text looks like it has been copied verbatim from a errata
sheet. If so, that document is probably under someone else's
copyright. If am right, then you should paraphrase the erratum
instead, both here and in the code comment.
>
> Signed-off-by: Christophe Leroy <christophe.leroy@....fr>
>
> diff -u linux-3.5-vanilla/drivers/net/phy/lxt.c linux-3.5/drivers/net/phy/lxt.c
> --- linux-3.5-vanilla/drivers/net/phy/lxt.c 2012-07-21 22:58:29.000000000 +0200
> +++ linux-3.5/drivers/net/phy/lxt.c 2012-09-07 18:08:54.000000000 +0200
> @@ -7,6 +7,10 @@
> *
> * Copyright (c) 2004 Freescale Semiconductor, Inc.
> *
> + * Copyright (c) 2010 CSSI
> + *
> + * Added support for buggy LXT973 rev A2
We don't do change logs in the code. That is what git is for.
Also, I think it is a bit of a stretch to add your copyright here.
> + *
> * This program is free software; you can redistribute it and/or modify it
> * under the terms of the GNU General Public License as published by the
> * Free Software Foundation; either version 2 of the License, or (at your
> @@ -54,8 +58,12 @@
> #define MII_LXT971_ISR 19 /* Interrupt Status Register */
>
> /* register definitions for the 973 */
> -#define MII_LXT973_PCR 16 /* Port Configuration Register */
> +#define MII_LXT973_PCR 16 /* Port Configuration Register */
> #define PCR_FIBER_SELECT 1
> +#define MII_LXT973_SFR 27 /* Special Function Register */
> +
> +#define PHYDEV_PRIV_FIBER 1
> +#define PHYDEV_PRIV_REVA2 2
>
> MODULE_DESCRIPTION("Intel LXT PHY driver");
> MODULE_AUTHOR("Andy Fleming");
> @@ -99,6 +107,9 @@
> return err;
> }
>
> +/* register definitions for the 973 */
> +#define MII_LXT973_PCR 16 /* Port Configuration Register */
> +#define PCR_FIBER_SELECT 1
>
> static int lxt971_ack_interrupt(struct phy_device *phydev)
> {
> @@ -122,9 +133,141 @@
> return err;
> }
>
> +/*
> + * ERRATA on LXT973
> + *
> + * Item 4: MDIO Interface and Repeated Polling
> + * Problem: Repeated polling of odd-numbered registers via the MDIO interface randomly returns the
> + * contents of the previous even register.
> + * Implication: Managed applications may not obtain the correct register contents when a particular
> + * register is monitored for device status.
> + * Workaround: None.
> + * Status: This erratum has been previously fixed (in rev A3)
> + *
> + */
Please make sure that the above text is your own words.
> +static int lxt973a2_update_link(struct phy_device *phydev)
> +{
> + int status;
> + int control;
> + int retry = 8; /* we try 8 times */
> +
> + /* Do a fake read */
> + status = phy_read(phydev, MII_BMSR);
> +
> + if (status < 0)
> + return status;
> +
> + control = phy_read(phydev, MII_BMCR);
> + if (control < 0)
> + return control;
> +
> + do {
> + /* Read link and autonegotiation status */
> + status = phy_read(phydev, MII_BMSR);
> + } while (status>=0 && retry-- && status == control);
spacing: status >= 0
> +
> + if (status < 0)
> + return status;
> +
> + if ((status & BMSR_LSTATUS) == 0)
> + phydev->link = 0;
> + else
> + phydev->link = 1;
> +
> + return 0;
> +}
> +
> +int lxt973a2_read_status(struct phy_device *phydev)
> +{
> + int adv;
> + int err;
> + int lpa;
> + int lpagb = 0;
> +
> + /* Update the link, but return if there was an error */
> + err = lxt973a2_update_link(phydev);
> + if (err)
> + return err;
> +
> + if (AUTONEG_ENABLE == phydev->autoneg) {
> + int retry = 1;
> +
> + adv = phy_read(phydev, MII_ADVERTISE);
> +
> + if (adv < 0)
> + return adv;
> +
> + do {
> + lpa = phy_read(phydev, MII_LPA);
> +
> + if (lpa < 0)
> + return lpa;
> +
> + /* If both registers are equal, it is suspect but not impossible, hence a new try */
Trailing white space. Line is way too long.
> + } while (lpa == adv && retry--);
> +
> + lpa &= adv;
> +
> + phydev->speed = SPEED_10;
> + phydev->duplex = DUPLEX_HALF;
> + phydev->pause = phydev->asym_pause = 0;
> +
> + if (lpagb & (LPA_1000FULL | LPA_1000HALF)) {
> + phydev->speed = SPEED_1000;
> +
> + if (lpagb & LPA_1000FULL)
> + phydev->duplex = DUPLEX_FULL;
> + } else if (lpa & (LPA_100FULL | LPA_100HALF)) {
> + phydev->speed = SPEED_100;
> +
> + if (lpa & LPA_100FULL)
> + phydev->duplex = DUPLEX_FULL;
> + } else
I would either put this 'else' with the 'if' on the same line, or add
braces like in the other cases.
> + if (lpa & LPA_10FULL)
> + phydev->duplex = DUPLEX_FULL;
> +
> + if (phydev->duplex == DUPLEX_FULL){
> + phydev->pause = lpa & LPA_PAUSE_CAP ? 1 : 0;
> + phydev->asym_pause = lpa & LPA_PAUSE_ASYM ? 1 : 0;
> + }
> + } else {
> + int bmcr = phy_read(phydev, MII_BMCR);
> +
> + if (bmcr < 0)
> + return bmcr;
> +
> + if (bmcr & BMCR_FULLDPLX)
> + phydev->duplex = DUPLEX_FULL;
> + else
> + phydev->duplex = DUPLEX_HALF;
> +
> + if (bmcr & BMCR_SPEED1000)
> + phydev->speed = SPEED_1000;
> + else if (bmcr & BMCR_SPEED100)
> + phydev->speed = SPEED_100;
> + else
> + phydev->speed = SPEED_10;
> +
> + phydev->pause = phydev->asym_pause = 0;
> + }
> +
> + return 0;
> +}
> +
> +static int lxt973_read_status(struct phy_device *phydev)
> +{
> + return (int)phydev->priv&PHYDEV_PRIV_REVA2 ? lxt973a2_read_status(phydev) : genphy_read_status(phydev);
spacing, and way too long line.
return (int) phydev->priv & PHYDEV_PRIV_REVA2 ?
lxt973a2_read_status(phydev) : genphy_read_status(phydev);
> +}
> +
> static int lxt973_probe(struct phy_device *phydev)
> {
> int val = phy_read(phydev, MII_LXT973_PCR);
> + int priv = 0;
> +
> + phydev->priv = NULL;
> +
> + if (val<0) return val;
spacing
>
> if (val & PCR_FIBER_SELECT) {
> /*
> @@ -136,17 +279,24 @@
> val &= ~BMCR_ANENABLE;
> phy_write(phydev, MII_BMCR, val);
> /* Remember that the port is in fiber mode. */
> - phydev->priv = lxt973_probe;
> - } else {
> - phydev->priv = NULL;
> + priv |= PHYDEV_PRIV_FIBER;
> }
> + val = phy_read(phydev, MII_PHYSID2);
> +
> + if (val<0) return val;
spacing
> +
> + if ((val & 0xf) == 0) { /* rev A2 */
> + dev_info(&phydev->dev, " LXT973 revision A2 has bugs\n");
> + priv |= PHYDEV_PRIV_REVA2;
> + }
> + phydev->priv = (void*)priv;
spacing
> return 0;
> }
>
> static int lxt973_config_aneg(struct phy_device *phydev)
> {
> /* Do nothing if port is in fiber mode. */
> - return phydev->priv ? 0 : genphy_config_aneg(phydev);
> + return (int)phydev->priv&PHYDEV_PRIV_FIBER ? 0 : genphy_config_aneg(phydev);
spacing, and a long line.
You might want to try checkpatch next time.
Thanks,
Richard
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