Subject: Re: [PATCH 1/4] powerpc/eeh: Add restore_bars operation

From: Gavin Shan <[email-masked]>
Date: Wed, 1 Jan 2014 11:29:37 +0800

On Sat, Dec 28, 2013 at 09:20:04AM +1100, Benjamin Herrenschmidt wrote:
>On Wed, 2013-12-25 at 16:58 +0800, Gavin Shan wrote:
>> After reset on the specific PE or PHB, we never configure AER
>> correctly on PowerNV platform. We needn't care it on pSeries
>> platform. The patch introduces additional EEH operation eeh_ops::
>> restore_bars() so that we have chance to configure AER correctly
>> for PowerNV platform.
>
>Why call it "restore_bars" if it restores something else (in this case
>AER) ?
>
>I would call it "restore_config" instead... Also rather than adding
>the knowledge of what AER bit works or not for the device, would it
>make sense to instead have a FW call to re-init the device ?
>
>Otherwise, you introduce duplication between Linux and Firmware with
>the risk of getting out of sync...
>

Thanks for your comments, Ben. It's reasonable to have name "restore_config"
and I'll introduce a FW call in next revision as you suggested :-)

Thanks,
Gavin

>> Signed-off-by: Gavin Shan <[email-masked]>
>> ---
>>  arch/powerpc/include/asm/eeh.h               |    1 +
>>  arch/powerpc/kernel/eeh_pe.c                 |    3 +++
>>  arch/powerpc/platforms/pseries/eeh_pseries.c |    4 +++-
>>  3 files changed, 7 insertions(+), 1 deletion(-)
>> 
>> diff --git a/arch/powerpc/include/asm/eeh.h b/arch/powerpc/include/asm/eeh.h
>> index d3e5e9b..4b709bf 100644
>> --- a/arch/powerpc/include/asm/eeh.h
>> +++ b/arch/powerpc/include/asm/eeh.h
>> @@ -157,6 +157,7 @@ struct eeh_ops {
>>  	int (*read_config)(struct device_node *dn, int where, int size, u32 *val);
>>  	int (*write_config)(struct device_node *dn, int where, int size, u32 val);
>>  	int (*next_error)(struct eeh_pe **pe);
>> +	void (*restore_bars)(struct device_node *dn);
>>  };
>>  
>>  extern struct eeh_ops *eeh_ops;
>> diff --git a/arch/powerpc/kernel/eeh_pe.c b/arch/powerpc/kernel/eeh_pe.c
>> index f945053..19eb95a 100644
>> --- a/arch/powerpc/kernel/eeh_pe.c
>> +++ b/arch/powerpc/kernel/eeh_pe.c
>> @@ -737,6 +737,9 @@ static void *eeh_restore_one_device_bars(void *data, void *flag)
>>  	else
>>  		eeh_restore_device_bars(edev, dn);
>>  
>> +	if (eeh_ops->restore_bars)
>> +		eeh_ops->restore_bars(dn);
>> +
>>  	return NULL;
>>  }
>>  
>> diff --git a/arch/powerpc/platforms/pseries/eeh_pseries.c b/arch/powerpc/platforms/pseries/eeh_pseries.c
>> index ccb633e..623adaf 100644
>> --- a/arch/powerpc/platforms/pseries/eeh_pseries.c
>> +++ b/arch/powerpc/platforms/pseries/eeh_pseries.c
>> @@ -689,7 +689,9 @@ static struct eeh_ops pseries_eeh_ops = {
>>  	.get_log		= pseries_eeh_get_log,
>>  	.configure_bridge       = pseries_eeh_configure_bridge,
>>  	.read_config		= pseries_eeh_read_config,
>> -	.write_config		= pseries_eeh_write_config
>> +	.write_config		= pseries_eeh_write_config,
>> +	.next_error		= NULL,
>> +	.restore_bars		= NULL
>>  };
>>  
>>  /**
>
>