netdev - Re: [PATCH] net: mvneta: properly disable HW PHY polling and ensure adjust_link() works

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Message-ID: <7f9b29792af750509fac07cbdfe869dd@cheny.fr>
Date:	Wed, 04 Sep 2013 18:00:30 +0200
From:	yves@...ny.fr
To:	Vincent Donnefort <vdonnefort@...ie.com>
Cc:	Jason Cooper <jason@...edaemon.net>,
	Thomas Petazzoni <thomas.petazzoni@...e-electrons.com>,
	"David S. Miller" <davem@...emloft.net>, netdev@...r.kernel.org,
	Lior Amsalem <alior@...vell.com>,
	Jochen De Smet <jochen.armkernel@...hnim.org>,
	Simon Guinot <simon.guinot@...uanux.org>,
	Ryan Press <ryan@...sslab.us>,
	Ethan Tuttle <ethan@...antuttle.com>, stable@...r.kernel.org,
	Ezequiel Garcia <ezequiel.garcia@...e-electrons.com>,
	Gregory Clement <gregory.clement@...e-electrons.com>,
	Peter Sanford <psanford@...rbuy.io>, Willy Tarreau <w@....eu>,
	linux-arm-kernel@...ts.infradead.org
Subject: Re: [PATCH] net: mvneta: properly disable HW PHY polling and ensure
 adjust_link() works

Le 2013-09-04 17:20, Vincent Donnefort a écrit :
> On Wed, Sep 04, 2013 at 10:50:51AM -0400, Jason Cooper wrote:
>> On Wed, Sep 04, 2013 at 04:21:18PM +0200, Thomas Petazzoni wrote:
>> > This commit fixes a long-standing bug that has been reported by many
>> > users: on some Armada 370 platforms, only the network interface that
>> > has been used in U-Boot to tftp the kernel works properly in
>> > Linux. The other network interfaces can see a 'link up', but are
>> > unable to transmit data. The reports were generally made on the Armada
>> > 370-based Mirabox, but have also been given on the Armada 370-RD
>> > board.
>> >
>> > The network MAC in the Armada 370/XP (supported by the mvneta driver
>> > in Linux) has a functionality that allows it to continuously poll the
>> > PHY and directly update the MAC configuration accordingly (speed,
>> > duplex, etc.). The very first versions of the driver submitted for
>> > review were using this hardware mechanism, but due to this, the driver
>> > was not integrated with the kernel phylib. Following reviews, the
>> > driver was changed to use the phylib, and therefore a software based
>> > polling. In software based polling, Linux regularly talks to the PHY
>> > over the MDIO bus, and sees if the link status has changed. If it's
>> > the case then the adjust_link() callback of the driver is called to
>> > update the MAC configuration accordingly.
>> >
>> > However, it turns out that the adjust_link() callback was not
>> > configuring the hardware in a completely correct way: while it was
>> > setting the speed and duplex bits correctly, it wasn't telling the
>> > hardware to actually take into account those bits rather than what the
>> > hardware-based PHY polling mechanism has concluded. So, in fact the
>> > adjust_link() callback was basically a no-op.
>> >
>> > However, the network happened to be working because on the network
>> > interfaces used by U-Boot for tftp on Armada 370 platforms because the
>> > hardware PHY polling was enabled by the bootloader, and left enabled
>> > by Linux. However, the second network interface not used for tftp (or
>> > both network interfaces if the kernel is loaded from USB, NAND or SD
>> > card) didn't had the hardware PHY polling enabled.
>> >
>> > This patch fixes this situation by:
>> >
>> >  (1) Making sure that the hardware PHY polling is disabled by clearing
>> >      the MVNETA_PHY_POLLING_ENABLE bit in the MVNETA_UNIT_CONTROL
>> >      register in the driver ->probe() function.
>> >
>> >  (2) Making sure that the duplex and speed selections made by the
>> >      adjust_link() callback are taken into account by clearing the
>> >      MVNETA_GMAC_AN_SPEED_EN and MVNETA_GMAC_AN_DUPLEX_EN bits in the
>> >      MVNETA_GMAC_AUTONEG_CONFIG register.
>> >
>> > This patch has been tested on Armada 370 Mirabox, and now both network
>> > interfaces are usable after boot.
>> >
>> > Signed-off-by: Thomas Petazzoni <thomas.petazzoni@...e-electrons.com>
>> > Cc: Willy Tarreau <w@....eu>
>> > Cc: Jochen De Smet <jochen.armkernel@...hnim.org>
>> > Cc: Peter Sanford <psanford@...rbuy.io>
>> > Cc: Ethan Tuttle <ethan@...antuttle.com>
>> > Cc: Chény Yves-Gael <yves@...ny.fr>
>> > Cc: Ryan Press <ryan@...sslab.us>
>> > Cc: Simon Guinot <simon.guinot@...uanux.org>
>> > Cc: vdonnefort@...ie.com
>> > Cc: stable@...r.kernel.org
>> > ---
>> > David, this patch is a fix for a problem that has been here since 3.8
>> > (when the mvneta driver was introduced), so I've Cc'ed stable@ and if
>> > possible I'd like to patch to be included for 3.12.
>> 
>> David,
>> 
>> Offending patch is:
>> 
>>   c5aff18 net: mvneta: driver for Marvell Armada 370/XP network unit
>> 
>> Applies and builds cleanly against v3.8.13, v3.9.11, v3.10.10, and 
>> v3.11
>> 
>> Acked-by: Jason Cooper <jason@...edaemon.net>
>> 
>> thx,
>> 
>> Jason.
> 
> Works with the armada370-rd board.
> 
> Tested-by: Vincent Donnefort <vdonnefort@...il.com>
> 
> Thank you!
> 
> Vincent.
> 

Works with the mirabox armada370 devkit.

Tested-by: Yves-Gael Cheny <yves@...ny.fr>

Many thx,

Yves-Gaël .

>> 
>> > ---
>> >  drivers/net/ethernet/marvell/mvneta.c | 13 ++++++++++++-
>> >  1 file changed, 12 insertions(+), 1 deletion(-)
>> >
>> > diff --git a/drivers/net/ethernet/marvell/mvneta.c b/drivers/net/ethernet/marvell/mvneta.c
>> > index b017818..90ab292 100644
>> > --- a/drivers/net/ethernet/marvell/mvneta.c
>> > +++ b/drivers/net/ethernet/marvell/mvneta.c
>> > @@ -138,7 +138,9 @@
>> >  #define      MVNETA_GMAC_FORCE_LINK_PASS         BIT(1)
>> >  #define      MVNETA_GMAC_CONFIG_MII_SPEED        BIT(5)
>> >  #define      MVNETA_GMAC_CONFIG_GMII_SPEED       BIT(6)
>> > +#define      MVNETA_GMAC_AN_SPEED_EN             BIT(7)
>> >  #define      MVNETA_GMAC_CONFIG_FULL_DUPLEX      BIT(12)
>> > +#define      MVNETA_GMAC_AN_DUPLEX_EN            BIT(13)
>> >  #define MVNETA_MIB_COUNTERS_BASE                 0x3080
>> >  #define      MVNETA_MIB_LATE_COLLISION           0x7c
>> >  #define MVNETA_DA_FILT_SPEC_MCAST                0x3400
>> > @@ -915,6 +917,13 @@ static void mvneta_defaults_set(struct mvneta_port *pp)
>> >  	/* Assign port SDMA configuration */
>> >  	mvreg_write(pp, MVNETA_SDMA_CONFIG, val);
>> >
>> > +	/* Disable PHY polling in hardware, since we're using the
>> > +	 * kernel phylib to do this.
>> > +	 */
>> > +	val = mvreg_read(pp, MVNETA_UNIT_CONTROL);
>> > +	val &= ~MVNETA_PHY_POLLING_ENABLE;
>> > +	mvreg_write(pp, MVNETA_UNIT_CONTROL, val);
>> > +
>> >  	mvneta_set_ucast_table(pp, -1);
>> >  	mvneta_set_special_mcast_table(pp, -1);
>> >  	mvneta_set_other_mcast_table(pp, -1);
>> > @@ -2307,7 +2316,9 @@ static void mvneta_adjust_link(struct net_device *ndev)
>> >  			val = mvreg_read(pp, MVNETA_GMAC_AUTONEG_CONFIG);
>> >  			val &= ~(MVNETA_GMAC_CONFIG_MII_SPEED |
>> >  				 MVNETA_GMAC_CONFIG_GMII_SPEED |
>> > -				 MVNETA_GMAC_CONFIG_FULL_DUPLEX);
>> > +				 MVNETA_GMAC_CONFIG_FULL_DUPLEX |
>> > +				 MVNETA_GMAC_AN_SPEED_EN |
>> > +				 MVNETA_GMAC_AN_DUPLEX_EN);
>> >
>> >  			if (phydev->duplex)
>> >  				val |= MVNETA_GMAC_CONFIG_FULL_DUPLEX;
>> > --
>> > 1.8.1.2
>> >
>> >
>> > _______________________________________________
>> > linux-arm-kernel mailing list
>> > linux-arm-kernel@...ts.infradead.org
>> > http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
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