[for-next,1/2] PCI/AER: Helper function for configuring AER registers

From: Kamenee Arumugam <kamenee.arumugam@intel.com>

In some use cases, drivers may need to change the default
AER settings. Introduce a helper function for setting
and clearing the AER configuration registers.

Access to the AER registers is not serialized. If multiple
access is required, correct locking must be done.

Reviewed-by: Mike Marciniszyn <mike.marciniszyn@intel.com>
Reviewed-by: Michael J. Ruhl <michael.j.ruhl@intel.com>
Cc: Andriy Shevchenko <andriy.shevchenko@intel.com>
Signed-off-by: Kamenee Arumugam <kamenee.arumugam@intel.com>
Signed-off-by: Dennis Dalessandro <dennis.dalessandro@intel.com>
---
 drivers/pci/pcie/aer.c |   33 +++++++++++++++++++++++++++++++++
 include/linux/aer.h    |   17 +++++++++++++++++
 2 files changed, 50 insertions(+), 0 deletions(-)

On Wed, Apr 10, 2019 at 05:34:50AM -0700, Dennis Dalessandro wrote:
> From: Kamenee Arumugam <kamenee.arumugam@intel.com>
> 
> In some use cases, drivers may need to change the default
> AER settings. Introduce a helper function for setting
> and clearing the AER configuration registers.
> 
> Access to the AER registers is not serialized. If multiple
> access is required, correct locking must be done.
> 

FWIW,
Reviewed-by: Andriy Shevchenko <andriy.shevchenko@intel.com>

Thanks.

> Reviewed-by: Mike Marciniszyn <mike.marciniszyn@intel.com>
> Reviewed-by: Michael J. Ruhl <michael.j.ruhl@intel.com>
> Cc: Andriy Shevchenko <andriy.shevchenko@intel.com>
> Signed-off-by: Kamenee Arumugam <kamenee.arumugam@intel.com>
> Signed-off-by: Dennis Dalessandro <dennis.dalessandro@intel.com>
> ---
>  drivers/pci/pcie/aer.c |   33 +++++++++++++++++++++++++++++++++
>  include/linux/aer.h    |   17 +++++++++++++++++
>  2 files changed, 50 insertions(+), 0 deletions(-)
> 
> diff --git a/drivers/pci/pcie/aer.c b/drivers/pci/pcie/aer.c
> index f8fc211..b0435f9 100644
> --- a/drivers/pci/pcie/aer.c
> +++ b/drivers/pci/pcie/aer.c
> @@ -353,6 +353,39 @@ int pci_enable_pcie_error_reporting(struct pci_dev *dev)
>  }
>  EXPORT_SYMBOL_GPL(pci_enable_pcie_error_reporting);
>  
> +/**
> + * pcie_aer_clear_and_set_dword - Set or clear AER registers
> + * @dev: pci dev data
> + * @pos: The offset of AER registers
> + * @clear: The bits to clear
> + * @set: The bits to set
> + *
> + * This function must only be used by the driver owning the device.
> + * Return:
> + * * 0 - on success
> + * * Negative error code - on generic failures
> + * * Positive error code - on PCI access errors
> + */
> +int pcie_aer_clear_and_set_dword(struct pci_dev *dev, int pos,
> +				 u32 clear, u32 set)
> +{
> +	u32 data;
> +	int ret;
> +
> +	if (!dev->aer_cap)
> +		return -EIO;
> +
> +	ret = pci_read_config_dword(dev, dev->aer_cap + pos, &data);
> +	if (!ret) {
> +		data &= ~clear;
> +		data |= set;
> +		return pci_write_config_dword(dev, dev->aer_cap + pos, data);
> +	}
> +
> +	return ret;
> +}
> +EXPORT_SYMBOL_GPL(pcie_aer_clear_and_set_dword);
> +
>  int pci_disable_pcie_error_reporting(struct pci_dev *dev)
>  {
>  	if (pcie_aer_get_firmware_first(dev))
> diff --git a/include/linux/aer.h b/include/linux/aer.h
> index 514bffa..e21d65c 100644
> --- a/include/linux/aer.h
> +++ b/include/linux/aer.h
> @@ -46,6 +46,8 @@ struct aer_capability_regs {
>  int pci_disable_pcie_error_reporting(struct pci_dev *dev);
>  int pci_cleanup_aer_uncorrect_error_status(struct pci_dev *dev);
>  int pci_cleanup_aer_error_status_regs(struct pci_dev *dev);
> +int pcie_aer_clear_and_set_dword(struct pci_dev *dev, int pos,
> +				 u32 clear, u32 set);
>  #else
>  static inline int pci_enable_pcie_error_reporting(struct pci_dev *dev)
>  {
> @@ -63,6 +65,12 @@ static inline int pci_cleanup_aer_error_status_regs(struct pci_dev *dev)
>  {
>  	return -EINVAL;
>  }
> +
> +static inline int pcie_aer_clear_and_set_dword(struct pci_dev *dev, int pos,
> +					       u32 clear, u32 set)
> +{
> +	return -EINVAL;
> +}
>  #endif
>  
>  void cper_print_aer(struct pci_dev *dev, int aer_severity,
> @@ -70,5 +78,14 @@ void cper_print_aer(struct pci_dev *dev, int aer_severity,
>  int cper_severity_to_aer(int cper_severity);
>  void aer_recover_queue(int domain, unsigned int bus, unsigned int devfn,
>  		       int severity, struct aer_capability_regs *aer_regs);
> +static inline int pcie_aer_set_dword(struct pci_dev *dev, int pos, u32 set)
> +{
> +	return pcie_aer_clear_and_set_dword(dev, pos, 0, set);
> +}
> +
> +static inline int pcie_aer_clear_dword(struct pci_dev *dev, int pos, u32 clear)
> +{
> +	return pcie_aer_clear_and_set_dword(dev, pos, clear, 0);
> +}
>  #endif //_AER_H_
>  
>