[RESEND-RFC v2 2/3] powerpc/eeh: Introduce function eeh_pe_reset_freeze_counter()

[Andrew Donnellan]

On 01/03/17 22:24, Vaibhav Jain wrote:
> This patch introduces function eeh_pe_reset_freeze_counter() which can
> be used to reset the PE's freeze count variable outside eeh code. This
> is useful for devices that can acquire a different personality after
> a PERST event (e.g FPGA Adapters). Presently an existing freeze
> count for an adapter with personality N will be taken into account
> when the adapter acquired personality N+1.
>
> By calling eeh_pe_reset_freeze_counter() drivers can reset the freeze
> counter for an adapter once it has acquired a new personality and
> ideally wont be plagued by the failures similar to the one before.
>
> Signed-off-by: Vaibhav Jain <vaibhav at linux.vnet.ibm.com>

LGTM

Reviewed-by: Andrew Donnellan <andrew.donnellan at au1.ibm.com>

> ---
> Change-log:
>
> v1 -> v2
> * Changes as suggested by Russell Currey:
> - Suffixed function names with '()'
> - Rephrased the description comment for functon eeh_pe_reset_freeze_counter()
> - Inserted logging for PHB and PE number inside eeh_pe_reset_freeze_counter()
>
> * Moved definition of eeh_pe_reset_freeze_counter() from eeh.h to eeh_pe.c to
>   avoid adding a header dependency to 'pci-bridge.h'. The function is
>   now marked as an exported gpl symbol.
> ---
>  arch/powerpc/include/asm/eeh.h |  5 +++++
>  arch/powerpc/kernel/eeh_pe.c   | 17 +++++++++++++++++
>  2 files changed, 22 insertions(+)
>
> diff --git a/arch/powerpc/include/asm/eeh.h b/arch/powerpc/include/asm/eeh.h
> index 68806be..8dcfb88 100644
> --- a/arch/powerpc/include/asm/eeh.h
> +++ b/arch/powerpc/include/asm/eeh.h
> @@ -266,6 +266,9 @@ struct eeh_pe *eeh_pe_get(struct eeh_dev *edev);
>  int eeh_add_to_parent_pe(struct eeh_dev *edev);
>  int eeh_rmv_from_parent_pe(struct eeh_dev *edev);
>  int eeh_pe_update_freeze_counter(struct eeh_pe *pe);
> +
> +void eeh_pe_reset_freeze_counter(struct eeh_pe *pe);
> +
>  void *eeh_pe_traverse(struct eeh_pe *root,
>  		eeh_traverse_func fn, void *flag);
>  void *eeh_pe_dev_traverse(struct eeh_pe *root,
> @@ -339,6 +342,8 @@ static inline int eeh_check_failure(const volatile void __iomem *token)
>  	return 0;
>  }
>
> +static inline void eeh_pe_reset_freeze_counter(struct eeh_pe *pe) { }
> +
>  #define eeh_dev_check_failure(x) (0)
>
>  static inline void eeh_addr_cache_build(void) { }
> diff --git a/arch/powerpc/kernel/eeh_pe.c b/arch/powerpc/kernel/eeh_pe.c
> index d367c16..75c781f 100644
> --- a/arch/powerpc/kernel/eeh_pe.c
> +++ b/arch/powerpc/kernel/eeh_pe.c
> @@ -504,6 +504,23 @@ int eeh_rmv_from_parent_pe(struct eeh_dev *edev)
>  }
>
>  /**
> + * eeh_pe_reset_freeze_counter - Resets the PE freeze counter
> + * @pe: EEH PE
> + *
> + * This function is useful while re-configuring an FPGA adapter
> + * as its about to acquire new a personality and you don't want
> + * freeze count to be carry forwarded. As such calling this function
> + * for regular pci devices might be a bad idea.
> + */
> +void eeh_pe_reset_freeze_counter(struct eeh_pe *pe)
> +{
> +	pr_info("Resetting freeze count for PHB#%x-PE#%x\n",
> +		pe->phb->global_number, pe->addr);
> +	pe->freeze_count = 0;
> +}
> +EXPORT_SYMBOL_GPL(eeh_pe_reset_freeze_counter);
> +
> +/**
>   * eeh_pe_update_freeze_counter - Update PE's frozen time stamp
>   * and freeze counter
>   * @pe: EEH PE
>

-- 
Andrew Donnellan              OzLabs, ADL Canberra
andrew.donnellan at au1.ibm.com  IBM Australia Limited