linux-kernel - Re: [PATCH] net: phy: marvell: clear wol event before setting it

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Message-ID: <be2addb5-b3fd-13cb-ad33-f0527931a0d2@nvidia.com>
Date:   Thu, 26 Apr 2018 11:56:33 +0530
From:   Bhadram Varka <vbhadram@...dia.com>
To:     Jisheng Zhang <Jisheng.Zhang@...aptics.com>
CC:     Andrew Lunn <andrew@...n.ch>,
        Florian Fainelli <f.fainelli@...il.com>,
        "David S. Miller" <davem@...emloft.net>, <netdev@...r.kernel.org>,
        <linux-kernel@...r.kernel.org>,
        Jingju Hou <Jingju.Hou@...aptics.com>
Subject: Re: [PATCH] net: phy: marvell: clear wol event before setting it

Hi,
On 4/26/2018 11:45 AM, Jisheng Zhang wrote:
> Hi,
>
> On Thu, 26 Apr 2018 11:10:21 +0530 Bhadram Varka wrote:
>
>> Hi,
>>
>> On 4/19/2018 5:48 PM, Andrew Lunn wrote:
>>> On Thu, Apr 19, 2018 at 04:02:32PM +0800, Jisheng Zhang wrote:
>>>> From: Jingju Hou <Jingju.Hou@...aptics.com>
>>>>
>>>> If WOL event happened once, the LED[2] interrupt pin will not be
>>>> cleared unless reading the CSISR register. So clear the WOL event
>>>> before enabling it.
>>>>
>>>> Signed-off-by: Jingju Hou <Jingju.Hou@...aptics.com>
>>>> Signed-off-by: Jisheng Zhang <Jisheng.Zhang@...aptics.com>
>>>> ---
>>>>    drivers/net/phy/marvell.c | 9 +++++++++
>>>>    1 file changed, 9 insertions(+)
>>>>
>>>> diff --git a/drivers/net/phy/marvell.c b/drivers/net/phy/marvell.c
>>>> index c22e8e383247..b6abe1cbc84b 100644
>>>> --- a/drivers/net/phy/marvell.c
>>>> +++ b/drivers/net/phy/marvell.c
>>>> @@ -115,6 +115,9 @@
>>>>    /* WOL Event Interrupt Enable */
>>>>    #define MII_88E1318S_PHY_CSIER_WOL_EIE			BIT(7)
>>>>    
>>>> +/* Copper Specific Interrupt Status Register */
>>>> +#define MII_88E1318S_PHY_CSISR				0x13
>>>> +
>>>>    /* LED Timer Control Register */
>>>>    #define MII_88E1318S_PHY_LED_TCR			0x12
>>>>    #define MII_88E1318S_PHY_LED_TCR_FORCE_INT		BIT(15)
>>>> @@ -1393,6 +1396,12 @@ static int m88e1318_set_wol(struct phy_device *phydev,
>>>>    		if (err < 0)
>>>>    			goto error;
>>>>    
>>>> +		/* If WOL event happened once, the LED[2] interrupt pin
>>>> +		 * will not be cleared unless reading the CSISR register.
>>>> +		 * So clear the WOL event first before enabling it.
>>>> +		 */
>>>> +		phy_read(phydev, MII_88E1318S_PHY_CSISR);
>>>> +
>>> Hi Jisheng
>>>
>>> The problem with this is, you could be clearing a real interrupt, link
>>> down/up etc. If interrupts are in use, i think the normal interrupt
>>> handling will clear the WOL interrupt? So can you make this read
>>> conditional on !phy_interrupt_is_valid()?
>> So this will clear WoL interrupt bit from Copper Interrupt status register.
>>
>> How about clearing WoL status (Page 17, register 17) for every WOL event ?
>>
> This is already properly done by setting MII_88E1318S_PHY_WOL_CTRL_CLEAR_WOL_STATUS
> in m88e1318_set_wol()
This part of the code executes only when we enable WOL through ethtool 
(ethtool -s eth0 wol g)

Lets say once WOL enabled through magic packet - HW generates WOL 
interrupt once magic packet received.
The problem that I see here is that for the next immediate magic packet 
I don't see WOL interrupt generated by the HW.
I need to explicitly clear WOL status for HW to generate WOL interrupt.