[PATCH dev-4.7 1/2] net/faraday: Avoid PHYSTS_CHG interrupt

[Gavin Shan]

On Mon, Aug 01, 2016 at 05:57:02PM +0930, Joel Stanley wrote:
>On Thu, 2016-07-28 at 11:04 +1000, Gavin Shan wrote:
>> Bit#11 in MACCR (0x50) designates the signal level for PHY link
>> status change. It's cleared, meaning high level enabled, by default.
>> However, we can see continuous interrupt (bit#6) in ISR (0x0) for it
>> and it's obviously a false alarm. The side effect is CPU cycles
>> wasted
>> to process the false alarm.
>> 
>> This sets bit#11 in MACCR (0x50) to avoid the bogus interrupt.
>
>Thanks.
>
>I assume you're seeing this with the hardware in NCSI mode?
>
>Is the patch okay for other use cases?
>

Yeah, the only available testing environment is NCSI. I didn't
test it on PHY based AST2500. Joel, please give it a shoot on
your AST2500 board before merging it. By the way, the interrupt
(PHYSTS_CHG) shouldn't be used even we have a PHY connected as
polling mechanism is specified to retrieve the link status in
ftgmac100.c

Thanks,
Gavin

>Cheers,
>
>Joel
>
>> 
>> Signed-off-by: Gavin Shan <gwshan at linux.vnet.ibm.com>
>> ---
>>  drivers/net/ethernet/faraday/ftgmac100.c | 1 +
>>  drivers/net/ethernet/faraday/ftgmac100.h | 1 +
>>  2 files changed, 2 insertions(+)
>> 
>> diff --git a/drivers/net/ethernet/faraday/ftgmac100.c
>> b/drivers/net/ethernet/faraday/ftgmac100.c
>> index e805c4d..f00911a 100644
>> --- a/drivers/net/ethernet/faraday/ftgmac100.c
>> +++ b/drivers/net/ethernet/faraday/ftgmac100.c
>> @@ -224,6 +224,7 @@ static void ftgmac100_init_hw(struct ftgmac100
>> *priv)
>>  				 FTGMAC100_MACCR_RXMAC_EN	| \
>>  				 FTGMAC100_MACCR_FULLDUP	| \
>>  				 FTGMAC100_MACCR_CRC_APD	| \
>> +				 FTGMAC100_MACCR_PHY_LINK_LEVEL | \
>>  				 FTGMAC100_MACCR_RX_RUNT	| \
>>  				 FTGMAC100_MACCR_RX_BROADPKT)
>>  
>> diff --git a/drivers/net/ethernet/faraday/ftgmac100.h
>> b/drivers/net/ethernet/faraday/ftgmac100.h
>> index c258586..d07b6ea 100644
>> --- a/drivers/net/ethernet/faraday/ftgmac100.h
>> +++ b/drivers/net/ethernet/faraday/ftgmac100.h
>> @@ -152,6 +152,7 @@
>>  #define FTGMAC100_MACCR_FULLDUP		(1 << 8)
>>  #define FTGMAC100_MACCR_GIGA_MODE	(1 << 9)
>>  #define FTGMAC100_MACCR_CRC_APD		(1 << 10)
>> +#define FTGMAC100_MACCR_PHY_LINK_LEVEL	(1 << 11)
>>  #define FTGMAC100_MACCR_RX_RUNT		(1 << 12)
>>  #define FTGMAC100_MACCR_JUMBO_LF	(1 << 13)
>>  #define FTGMAC100_MACCR_RX_ALL		(1 << 14)
>