Subject: Re: [PATCH v3 04/20] cxl: move pci generic code

From: Alejandro Lucero Palau <[email-masked]>
Date: Mon, 16 Sep 2024 10:46:15 +0100

On 9/12/24 00:55, Dave Jiang wrote:
>
> On 9/7/24 1:18 AM, [email-masked] wrote:
>> From: Alejandro Lucero <[email-masked]>
>>
>> Inside cxl/core/pci.c there are helpers for CXL PCIe initialization
>> meanwhile cxl/pci.c implements the functionality for a Type3 device
>> initialization.
>>
>> Move those functions required also for Type2 initialization to
>> cxl/core/pci.c with a specific function using that moved code added in
>> a following patch.
> Please consider rephrasing as:
>
> Move helper functions from cxl/pci.c to cxl/core/pci.c in order to be
> exported and shared with CXL Type2 device initialization.

It makes sense.

I'll do.

>> Signed-off-by: Alejandro Lucero <[email-masked]>
>> ---
>>   drivers/cxl/core/pci.c | 63 ++++++++++++++++++++++++++++++++++++++++++
>>   drivers/cxl/cxlpci.h   |  3 ++
>>   drivers/cxl/pci.c      | 60 ----------------------------------------
>>   3 files changed, 66 insertions(+), 60 deletions(-)
>>
>> diff --git a/drivers/cxl/core/pci.c b/drivers/cxl/core/pci.c
>> index 57370d9beb32..bf57f081ef8f 100644
>> --- a/drivers/cxl/core/pci.c
>> +++ b/drivers/cxl/core/pci.c
>> @@ -1079,6 +1079,69 @@ bool cxl_endpoint_decoder_reset_detected(struct cxl_port *port)
>>   }
>>   EXPORT_SYMBOL_NS_GPL(cxl_endpoint_decoder_reset_detected, CXL);
>>   
>> +/*
>> + * Assume that any RCIEP that emits the CXL memory expander class code
>> + * is an RCD
>> + */
>> +bool is_cxl_restricted(struct pci_dev *pdev)
>> +{
>> +	return pci_pcie_type(pdev) == PCI_EXP_TYPE_RC_END;
>> +}
>> +EXPORT_SYMBOL_NS_GPL(is_cxl_restricted, CXL);
>> +
>> +static int cxl_rcrb_get_comp_regs(struct pci_dev *pdev,
>> +				  struct cxl_register_map *map)
>> +{
>> +	struct cxl_port *port;
>> +	struct cxl_dport *dport;
>> +	resource_size_t component_reg_phys;
>> +
>> +	*map = (struct cxl_register_map) {
>> +		.host = &pdev->dev,
>> +		.resource = CXL_RESOURCE_NONE,
>> +	};
>> +
>> +	port = cxl_pci_find_port(pdev, &dport);
>> +	if (!port)
>> +		return -EPROBE_DEFER;
>> +
>> +	component_reg_phys = cxl_rcd_component_reg_phys(&pdev->dev, dport);
>> +
>> +	put_device(&port->dev);
>> +
>> +	if (component_reg_phys == CXL_RESOURCE_NONE)
>> +		return -ENXIO;
>> +
>> +	map->resource = component_reg_phys;
>> +	map->reg_type = CXL_REGLOC_RBI_COMPONENT;
>> +	map->max_size = CXL_COMPONENT_REG_BLOCK_SIZE;
>> +
>> +	return 0;
>> +}
>> +
>> +int cxl_pci_setup_regs(struct pci_dev *pdev, enum cxl_regloc_type type,
>> +		       struct cxl_register_map *map,
>> +		       u32 *caps)
>> +{
>> +	int rc;
>> +
>> +	rc = cxl_find_regblock(pdev, type, map);
>> +
>> +	/*
>> +	 * If the Register Locator DVSEC does not exist, check if it
>> +	 * is an RCH and try to extract the Component Registers from
>> +	 * an RCRB.
>> +	 */
>> +	if (rc && type == CXL_REGLOC_RBI_COMPONENT && is_cxl_restricted(pdev))
>> +		rc = cxl_rcrb_get_comp_regs(pdev, map);
>> +
>> +	if (rc)
>> +		return rc;
>> +
>> +	return cxl_setup_regs(map, caps);
>> +}
>> +EXPORT_SYMBOL_NS_GPL(cxl_pci_setup_regs, CXL);
>> +
>>   bool cxl_pci_check_caps(struct cxl_dev_state *cxlds, u32 expected_caps,
>>   			u32 *current_caps)
>>   {
>> diff --git a/drivers/cxl/cxlpci.h b/drivers/cxl/cxlpci.h
>> index eb59019fe5f3..786b811effba 100644
>> --- a/drivers/cxl/cxlpci.h
>> +++ b/drivers/cxl/cxlpci.h
>> @@ -113,4 +113,7 @@ void read_cdat_data(struct cxl_port *port);
>>   void cxl_cor_error_detected(struct pci_dev *pdev);
>>   pci_ers_result_t cxl_error_detected(struct pci_dev *pdev,
>>   				    pci_channel_state_t state);
>> +bool is_cxl_restricted(struct pci_dev *pdev);
>> +int cxl_pci_setup_regs(struct pci_dev *pdev, enum cxl_regloc_type type,
>> +		       struct cxl_register_map *map, u32 *caps);
> Does this need to go to a different header like include/cxl/pci.h or something for type2 consumption?
>
> DJ

Next patch introduces another function for accel drivers which calls 
this one, hiding things for accel drivers and improving manageability.

Thanks

>>   #endif /* __CXL_PCI_H__ */
>> diff --git a/drivers/cxl/pci.c b/drivers/cxl/pci.c
>> index bec660357eec..2b85f87549c2 100644
>> --- a/drivers/cxl/pci.c
>> +++ b/drivers/cxl/pci.c
>> @@ -463,66 +463,6 @@ static int cxl_pci_setup_mailbox(struct cxl_memdev_state *mds, bool irq_avail)
>>   	return 0;
>>   }
>>   
>> -/*
>> - * Assume that any RCIEP that emits the CXL memory expander class code
>> - * is an RCD
>> - */
>> -static bool is_cxl_restricted(struct pci_dev *pdev)
>> -{
>> -	return pci_pcie_type(pdev) == PCI_EXP_TYPE_RC_END;
>> -}
>> -
>> -static int cxl_rcrb_get_comp_regs(struct pci_dev *pdev,
>> -				  struct cxl_register_map *map)
>> -{
>> -	struct cxl_port *port;
>> -	struct cxl_dport *dport;
>> -	resource_size_t component_reg_phys;
>> -
>> -	*map = (struct cxl_register_map) {
>> -		.host = &pdev->dev,
>> -		.resource = CXL_RESOURCE_NONE,
>> -	};
>> -
>> -	port = cxl_pci_find_port(pdev, &dport);
>> -	if (!port)
>> -		return -EPROBE_DEFER;
>> -
>> -	component_reg_phys = cxl_rcd_component_reg_phys(&pdev->dev, dport);
>> -
>> -	put_device(&port->dev);
>> -
>> -	if (component_reg_phys == CXL_RESOURCE_NONE)
>> -		return -ENXIO;
>> -
>> -	map->resource = component_reg_phys;
>> -	map->reg_type = CXL_REGLOC_RBI_COMPONENT;
>> -	map->max_size = CXL_COMPONENT_REG_BLOCK_SIZE;
>> -
>> -	return 0;
>> -}
>> -
>> -static int cxl_pci_setup_regs(struct pci_dev *pdev, enum cxl_regloc_type type,
>> -			      struct cxl_register_map *map, u32 *caps)
>> -{
>> -	int rc;
>> -
>> -	rc = cxl_find_regblock(pdev, type, map);
>> -
>> -	/*
>> -	 * If the Register Locator DVSEC does not exist, check if it
>> -	 * is an RCH and try to extract the Component Registers from
>> -	 * an RCRB.
>> -	 */
>> -	if (rc && type == CXL_REGLOC_RBI_COMPONENT && is_cxl_restricted(pdev))
>> -		rc = cxl_rcrb_get_comp_regs(pdev, map);
>> -
>> -	if (rc)
>> -		return rc;
>> -
>> -	return cxl_setup_regs(map, caps);
>> -}
>> -
>>   static int cxl_pci_ras_unmask(struct pci_dev *pdev)
>>   {
>>   	struct cxl_dev_state *cxlds = pci_get_drvdata(pdev);