Re: [PATCH v4 15/15] PCI/AER: Enable internal errors for CXL Upstream and Downstream Switch Ports

["Bowman, Terry" <terry.bowman@amd.com>]

On 12/24/2024 12:53 PM, Jonathan Cameron wrote:
> On Wed, 11 Dec 2024 17:40:02 -0600
> Terry Bowman <terry.bowman@amd.com> wrote:
>
>> The AER service driver enables PCIe Uncorrectable Internal Errors (UIE) and
>> Correctable Internal errors (CIE) for CXL Root Ports and CXL RCEC's. The
>> UIE and CIE are used in reporting CXL Protocol Errors. The same UIE/CIE
>> enablement is needed for CXL PCIe Upstream and Downstream Ports inorder to
>> notify the associated Root Port and OS.[1]
>>
>> Export the AER service driver's pci_aer_unmask_internal_errors() function
>> to CXL namespace.
>>
>> Remove the function's dependency on the CONFIG_PCIEAER_CXL kernel config
>> because it is now an exported function.
>>
>> Call pci_aer_unmask_internal_errors() during RAS initialization in:
>> cxl_uport_init_ras_reporting() and cxl_dport_init_ras_reporting().
>>
>> [1] PCIe Base Spec r6.2-1.0, 6.2.3.2.2 Masking Individual Errors
>>
>> Signed-off-by: Terry Bowman <terry.bowman@amd.com>
> Whilst I'm in favor of just enabling this across all devices I guess
> I can cope with this more minimal form and it will create fewer bug
> reports :).
> It is a little messy because we are tweaking it from the 'wrong' driver
> but I guess that is fine.
>
> Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
>
> And on that note, happy Christmas / holidays etc all. My backlog
> of review looks much less scary now but I need a beer!
>
> Jonathan
>

I'm not aware of a better way to enable the interrupts in this case. But, I am open
to anyone's ideas for improvement.

Happy holidays everyone!

Regards,
Terry

>
>> ---
>>  drivers/cxl/core/pci.c | 2 ++
>>  drivers/pci/pcie/aer.c | 5 +++--
>>  include/linux/aer.h    | 1 +
>>  3 files changed, 6 insertions(+), 2 deletions(-)
>>
>> diff --git a/drivers/cxl/core/pci.c b/drivers/cxl/core/pci.c
>> index 9734a4c55b29..740ac5d8809f 100644
>> --- a/drivers/cxl/core/pci.c
>> +++ b/drivers/cxl/core/pci.c
>> @@ -886,6 +886,7 @@ void cxl_uport_init_ras_reporting(struct cxl_port *port)
>>  
>>  	cxl_assign_port_error_handlers(pdev);
>>  	devm_add_action_or_reset(port->uport_dev, cxl_clear_port_error_handlers, pdev);
>> +	pci_aer_unmask_internal_errors(pdev);
>>  }
>>  EXPORT_SYMBOL_NS_GPL(cxl_uport_init_ras_reporting, CXL);
>>  
>> @@ -920,6 +921,7 @@ void cxl_dport_init_ras_reporting(struct cxl_dport *dport)
>>  
>>  	cxl_assign_port_error_handlers(pdev);
>>  	devm_add_action_or_reset(dport_dev, cxl_clear_port_error_handlers, pdev);
>> +	pci_aer_unmask_internal_errors(pdev);
>>  }
>>  EXPORT_SYMBOL_NS_GPL(cxl_dport_init_ras_reporting, CXL);
>>  
>> diff --git a/drivers/pci/pcie/aer.c b/drivers/pci/pcie/aer.c
>> index 861521872318..0fa1b1ed48c9 100644
>> --- a/drivers/pci/pcie/aer.c
>> +++ b/drivers/pci/pcie/aer.c
>> @@ -949,7 +949,6 @@ static bool is_internal_error(struct aer_err_info *info)
>>  	return info->status & PCI_ERR_UNC_INTN;
>>  }
>>  
>> -#ifdef CONFIG_PCIEAER_CXL
>>  /**
>>   * pci_aer_unmask_internal_errors - unmask internal errors
>>   * @dev: pointer to the pcie_dev data structure
>> @@ -960,7 +959,7 @@ static bool is_internal_error(struct aer_err_info *info)
>>   * Note: AER must be enabled and supported by the device which must be
>>   * checked in advance, e.g. with pcie_aer_is_native().
>>   */
>> -static void pci_aer_unmask_internal_errors(struct pci_dev *dev)
>> +void pci_aer_unmask_internal_errors(struct pci_dev *dev)
>>  {
>>  	int aer = dev->aer_cap;
>>  	u32 mask;
>> @@ -973,7 +972,9 @@ static void pci_aer_unmask_internal_errors(struct pci_dev *dev)
>>  	mask &= ~PCI_ERR_COR_INTERNAL;
>>  	pci_write_config_dword(dev, aer + PCI_ERR_COR_MASK, mask);
>>  }
>> +EXPORT_SYMBOL_NS_GPL(pci_aer_unmask_internal_errors, CXL);
>>  
>> +#ifdef CONFIG_PCIEAER_CXL
>>  static bool is_cxl_mem_dev(struct pci_dev *dev)
>>  {
>>  	/*
>> diff --git a/include/linux/aer.h b/include/linux/aer.h
>> index 4b97f38f3fcf..093293f9f12b 100644
>> --- a/include/linux/aer.h
>> +++ b/include/linux/aer.h
>> @@ -55,5 +55,6 @@ void pci_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);
>> +void pci_aer_unmask_internal_errors(struct pci_dev *dev);
>>  #endif //_AER_H_
>>