Subject: Re: [PATCH 3/5] powerpc/powernv: Cleanup on PNV_EEH_STATE_ENABLED

From: Gavin Shan <[email-masked]>
Date: Sun, 23 Feb 2014 10:12:23 +0800

On Sat, Feb 22, 2014 at 06:56:49AM +1100, Benjamin Herrenschmidt wrote:
>On Fri, 2014-02-21 at 19:53 +0800, Gavin Shan wrote:
>> The flag PNV_EEH_STATE_ENABLED is put into pnv_phb::eeh_state, which
>> is protected by CONFIG_EEH. We needn't that. Instead, we can have
>> pnv_phb::flags and maintain all flags there, which is the purpose
>> of the patch.
>
>Can you explain a bit more why we want to create a new flag set
>that didn't exist before ? This adds confusion so we need a very
>good reason... Do we need to know about the enable state of EEH
>even when CNFIG_EEH is not set ?
>

The commit log was a bit confusing. We didn't create a new flag
here and I just renamed PNV_EEH_STATE_ENABLED to PNV_PHB_FLAG_EEH.
I'll say more in the commit log about it in next revision.

The flag is needed even we have CONFIG_EEH set because we need
switch to EEH, instead of detecting frozen PE and clearing it
in PCI config accessors after EEH is initialized and loaded :-)

Thanks,
Gavin

>> Signed-off-by: Gavin Shan <[email-masked]>
>> ---
>>  arch/powerpc/platforms/powernv/eeh-ioda.c |    2 +-
>>  arch/powerpc/platforms/powernv/pci.c      |    8 ++------
>>  arch/powerpc/platforms/powernv/pci.h      |    7 +++----
>>  3 files changed, 6 insertions(+), 11 deletions(-)
>> 
>> diff --git a/arch/powerpc/platforms/powernv/eeh-ioda.c b/arch/powerpc/platforms/powernv/eeh-ioda.c
>> index 0d1d424..04b4710 100644
>> --- a/arch/powerpc/platforms/powernv/eeh-ioda.c
>> +++ b/arch/powerpc/platforms/powernv/eeh-ioda.c
>> @@ -153,7 +153,7 @@ static int ioda_eeh_post_init(struct pci_controller *hose)
>>  	}
>>  #endif
>>  
>> -	phb->eeh_state |= PNV_EEH_STATE_ENABLED;
>> +	phb->flags |= PNV_PHB_FLAG_EEH;
>>  
>>  	return 0;
>>  }
>> diff --git a/arch/powerpc/platforms/powernv/pci.c b/arch/powerpc/platforms/powernv/pci.c
>> index b555ebc..437c37d 100644
>> --- a/arch/powerpc/platforms/powernv/pci.c
>> +++ b/arch/powerpc/platforms/powernv/pci.c
>> @@ -396,7 +396,7 @@ int pnv_pci_cfg_read(struct device_node *dn,
>>  	if (phb_pe && (phb_pe->state & EEH_PE_ISOLATED))
>>  		return PCIBIOS_SUCCESSFUL;
>>  
>> -	if (phb->eeh_state & PNV_EEH_STATE_ENABLED) {
>> +	if (phb->flags & PNV_PHB_FLAG_EEH) {
>>  		if (*val == EEH_IO_ERROR_VALUE(size) &&
>>  		    eeh_dev_check_failure(of_node_to_eeh_dev(dn)))
>>  			return PCIBIOS_DEVICE_NOT_FOUND;
>> @@ -434,12 +434,8 @@ int pnv_pci_cfg_write(struct device_node *dn,
>>  	}
>>  
>>  	/* Check if the PHB got frozen due to an error (no response) */
>> -#ifdef CONFIG_EEH
>> -	if (!(phb->eeh_state & PNV_EEH_STATE_ENABLED))
>> +	if (!(phb->flags & PNV_PHB_FLAG_EEH))
>>  		pnv_pci_config_check_eeh(phb, dn);
>> -#else
>> -	pnv_pci_config_check_eeh(phb, dn);
>> -#endif
>>  
>>  	return PCIBIOS_SUCCESSFUL;
>>  }
>> diff --git a/arch/powerpc/platforms/powernv/pci.h b/arch/powerpc/platforms/powernv/pci.h
>> index dbeba3d..adeb3c4 100644
>> --- a/arch/powerpc/platforms/powernv/pci.h
>> +++ b/arch/powerpc/platforms/powernv/pci.h
>> @@ -79,24 +79,23 @@ struct pnv_eeh_ops {
>>  	int (*configure_bridge)(struct eeh_pe *pe);
>>  	int (*next_error)(struct eeh_pe **pe);
>>  };
>> -
>> -#define PNV_EEH_STATE_ENABLED	(1 << 0)	/* EEH enabled	*/
>> -
>>  #endif /* CONFIG_EEH */
>>  
>> +#define PNV_PHB_FLAG_EEH	(1 << 0)
>> +
>>  struct pnv_phb {
>>  	struct pci_controller	*hose;
>>  	enum pnv_phb_type	type;
>>  	enum pnv_phb_model	model;
>>  	u64			hub_id;
>>  	u64			opal_id;
>> +	int			flags;
>>  	void __iomem		*regs;
>>  	int			initialized;
>>  	spinlock_t		lock;
>>  
>>  #ifdef CONFIG_EEH
>>  	struct pnv_eeh_ops	*eeh_ops;
>> -	int			eeh_state;
>>  #endif
>>  
>>  #ifdef CONFIG_DEBUG_FS
>
>