netdev - Re: [PATCH v3 1/3] phylib: Convert MDIO and PHY Lib drivers to support 10G

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Message-ID: <48DF651F-324E-415E-A1E1-49E6F7237D42@freescale.com>
Date:	Thu, 13 Oct 2011 10:59:09 -0500
From:	Andy Fleming <afleming@...escale.com>
To:	Ben Hutchings <bhutchings@...arflare.com>
CC:	<davem@...emloft.net>, <netdev@...r.kernel.org>
Subject: Re: [PATCH v3 1/3] phylib: Convert MDIO and PHY Lib drivers to support 10G


On Oct 13, 2011, at 10:46 AM, Ben Hutchings wrote:

> On Thu, 2011-10-13 at 09:37 -0500, Andy Fleming wrote:
>> 10G MDIO is a totally different protocol (clause 45 of 802.3).
>> Supporting this new protocol requires a couple of changes:
>> 
>> * Add a new parameter to the mdiobus_read functions to specify the
>>  "device address" inside the PHY.
>> * Add a phy45_read/write function which takes advantage of that
>>  new parameter
>> * Convert all of the existing drivers to use the new format
>> 
>> I created a new clause-45-specific read/write functions because:
>> 1) phy_read and phy_write are highly overloaded functions, and
>>   finding every instance which is actually the PHY Lib version
>>   was quite difficult
>> 2) Most code which invokes phy_read/phy_write inside PHY Lib is
>>   Clause-22-specific. None of the phy_read/phy_write invocations
>>   were useable on 10G PHYs
> [...]
>> diff --git a/drivers/net/phy/phy.c b/drivers/net/phy/phy.c
>> index 3cbda08..00f5cfe 100644
>> --- a/drivers/net/phy/phy.c
>> +++ b/drivers/net/phy/phy.c
>> @@ -322,7 +322,8 @@ int phy_mii_ioctl(struct phy_device *phydev,
>> 
>> 	case SIOCGMIIREG:
>> 		mii_data->val_out = mdiobus_read(phydev->bus, mii_data->phy_id,
>> -						 mii_data->reg_num);
>> +						MDIO_DEVAD_NONE,
>> +						mii_data->reg_num);
>> 		break;
>> 
>> 	case SIOCSMIIREG:
>> @@ -354,7 +355,7 @@ int phy_mii_ioctl(struct phy_device *phydev,
>> 		}
>> 
>> 		mdiobus_write(phydev->bus, mii_data->phy_id,
>> -			      mii_data->reg_num, val);
>> +				MDIO_DEVAD_NONE, mii_data->reg_num, val);
>> 
>> 		if (mii_data->reg_num == MII_BMCR &&
>> 		    val & BMCR_RESET &&
> 
> What about c45 support here?  It's not terribly difficult to do…

Ok, I'll take a look at that.

> 
>> diff --git a/drivers/net/phy/phy_device.c b/drivers/net/phy/phy_device.c
>> index 83a5a5a..22281d4 100644
>> --- a/drivers/net/phy/phy_device.c
>> +++ b/drivers/net/phy/phy_device.c
>> @@ -4,9 +4,11 @@
>>  * Framework for finding and configuring PHYs.
>>  * Also contains generic PHY driver
>>  *
>> + * 10G PHY Driver support mostly appropriated from drivers/net/mdio.c
>> + *
> 
> If you're saying you copied a significant amount of code, shouldn't you
> add the copyright notice too?

Ah, yeah, I'll fix that.


> 
> [...]
>> @@ -640,7 +660,6 @@ static int genphy_setup_forced(struct phy_device *phydev)
>> 	return err;
>> }
>> 
>> -
>> /**
>>  * genphy_restart_aneg - Enable and Restart Autonegotiation
>>  * @phydev: target phy_device struct
>> @@ -665,7 +684,6 @@ int genphy_restart_aneg(struct phy_device *phydev)
>> }
>> EXPORT_SYMBOL(genphy_restart_aneg);
>> 
>> -
>> /**
>>  * genphy_config_aneg - restart auto-negotiation or write BMCR
>>  * @phydev: target phy_device struct
>> @@ -882,6 +900,7 @@ static int genphy_config_init(struct phy_device *phydev)
>> 
>> 	return 0;
>> }
>> +
>> int genphy_suspend(struct phy_device *phydev)
>> {
>> 	int value;
>> @@ -1022,7 +1041,7 @@ static struct phy_driver genphy_driver = {
>> 	.read_status	= genphy_read_status,
>> 	.suspend	= genphy_suspend,
>> 	.resume		= genphy_resume,
>> -	.driver		= {.owner= THIS_MODULE, },
>> +	.driver		= {.owner = THIS_MODULE, },
>> };
>> 
>> static int __init phy_init(void)
>> @@ -1035,7 +1054,12 @@ static int __init phy_init(void)
>> 
>> 	rc = phy_driver_register(&genphy_driver);
>> 	if (rc)
>> -		mdio_bus_exit();
>> +		goto genphy_register_failed;
>> +
>> +	return rc;
>> +
>> +genphy_register_failed:
>> +	mdio_bus_exit();
>> 
>> 	return rc;
>> }
> 
> These changes are unrelated to c45.


Ah, yeah, these are residual from the 10G generic code.  I'll go ahead and forward those changes into the gen10g patch


> 
>> diff --git a/include/linux/phy.h b/include/linux/phy.h
>> index 54fc413..ae1fdd8 100644
>> --- a/include/linux/phy.h
>> +++ b/include/linux/phy.h
> [...]
>> @@ -65,6 +66,7 @@ typedef enum {
>> 	PHY_INTERFACE_MODE_RGMII_TXID,
>> 	PHY_INTERFACE_MODE_RTBI,
>> 	PHY_INTERFACE_MODE_SMII,
>> +	PHY_INTERFACE_MODE_XGMII
>> } phy_interface_t;
> [...]
> 
> XAUI, XFI?
> 
> (Maybe the distinction doesn't matter in this context.)


Yeah, I'm not quite sure. The term "interface" is meant to convey interface information needed by the PHY driver (and possibly the ethernet controller). My setup is:

MAC->XGMII->XAUI->XGMII->PHY

Right now it's being used somewhat sketchily to distinguish 10G from non-10G. I'd be fine with adding XAUI and XFI, I just don't know yet whether it's relevant. I'm currently working with a sample size of 1 for what I've done, plus information gleaned from the spec.

Andy
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