Re: [PATCH v20 06/22] cxl: Move pci generic code

[Alejandro Lucero Palau <alucerop@amd.com>]

On 11/14/25 00:25, Alison Schofield wrote:
> On Mon, Nov 10, 2025 at 03:36:41PM +0000, alejandro.lucero-palau@amd.com wrote:
>> From: Alejandro Lucero <alucerop@amd.com>
>>
>> Inside cxl/core/pci.c there are helpers for CXL PCIe initialization
>> meanwhile cxl/pci.c implements the functionality for a Type3 device
>> initialization.
> Hi Alejandro,
>
> I'v been looking at Terry's set and the cxl-test build circular
> dependencies. I think this patch may be 'stale', at least in
> the comments, maybe in the wrapped function it removes.


Hi Allison,


I think you are right regarding the comments. I did not update them 
after Terry's changes.


>> Move helper functions from cxl/pci.c to cxl/core/pci.c in order to be
>> exported and shared with CXL Type2 device initialization.
> Terry moves the whole file cxl/pci.c to cxl/core/pci_drv.c.
> That is reflected in what you actually do below, but not in this
> comment.
>
>> Fix cxl mock tests affected by the code move, deleting a function which
>> indeed was not being used since commit 733b57f262b0("cxl/pci: Early
>> setup RCH dport component registers from RCRB").
> This I'm having trouble figuring out. I see __wrap_cxl_rcd_component_reg_phys()
> deleted below. Why is that OK? The func it wraps is still in use below, ie it's
> one you move from core/pci_drv.c to core/pci.c.


I think the comment refers to usage inside the tests. Are you having 
problems or seeing any problem with this removal?


Thank you.




>
> For my benefit, what is the intended difference between what will be
> in core/pci.c and core/pci_drv.c ?
>
> --Alison
>
>> Signed-off-by: Alejandro Lucero <alucerop@amd.com>
>> Reviewed-by: Dave Jiang <dave.jiang@intel.com>
>> Reviewed-by: Ben Cheatham <benjamin.cheatham@amd.com>
>> Reviewed-by: Fan Ni <fan.ni@samsung.com>
>> Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
>> Reviewed-by: Alison Schofield <alison.schofield@intel.com>
>> Reviewed-by: Dan Williams <dan.j.williams@intel.com>
>> ---
>>   drivers/cxl/core/core.h       |  3 ++
>>   drivers/cxl/core/pci.c        | 62 +++++++++++++++++++++++++++++++
>>   drivers/cxl/core/pci_drv.c    | 70 -----------------------------------
>>   drivers/cxl/core/regs.c       |  1 -
>>   drivers/cxl/cxl.h             |  2 -
>>   drivers/cxl/cxlpci.h          | 13 +++++++
>>   tools/testing/cxl/Kbuild      |  1 -
>>   tools/testing/cxl/test/mock.c | 17 ---------
>>   8 files changed, 78 insertions(+), 91 deletions(-)
>>
>> diff --git a/drivers/cxl/core/core.h b/drivers/cxl/core/core.h
>> index a7a0838c8f23..2b2d3af0b5ec 100644
>> --- a/drivers/cxl/core/core.h
>> +++ b/drivers/cxl/core/core.h
>> @@ -232,4 +232,7 @@ static inline bool cxl_pci_drv_bound(struct pci_dev *pdev) { return false; };
>>   static inline int cxl_pci_driver_init(void) { return 0; }
>>   static inline void cxl_pci_driver_exit(void) { }
>>   #endif
>> +
>> +resource_size_t cxl_rcd_component_reg_phys(struct device *dev,
>> +					   struct cxl_dport *dport);
>>   #endif /* __CXL_CORE_H__ */
>> diff --git a/drivers/cxl/core/pci.c b/drivers/cxl/core/pci.c
>> index a66f7a84b5c8..566d57ba0579 100644
>> --- a/drivers/cxl/core/pci.c
>> +++ b/drivers/cxl/core/pci.c
>> @@ -775,6 +775,68 @@ bool cxl_endpoint_decoder_reset_detected(struct cxl_port *port)
>>   }
>>   EXPORT_SYMBOL_NS_GPL(cxl_endpoint_decoder_reset_detected, "CXL");
>>   
>> +static int cxl_rcrb_get_comp_regs(struct pci_dev *pdev,
>> +				  struct cxl_register_map *map,
>> +				  struct cxl_dport *dport)
>> +{
>> +	resource_size_t component_reg_phys;
>> +
>> +	*map = (struct cxl_register_map) {
>> +		.host = &pdev->dev,
>> +		.resource = CXL_RESOURCE_NONE,
>> +	};
>> +
>> +	struct cxl_port *port __free(put_cxl_port) =
>> +		cxl_pci_find_port(pdev, &dport);
>> +	if (!port)
>> +		return -EPROBE_DEFER;
>> +
>> +	component_reg_phys = cxl_rcd_component_reg_phys(&pdev->dev, dport);
>> +	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)
>> +{
>> +	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)) {
>> +		struct cxl_dport *dport;
>> +		struct cxl_port *port __free(put_cxl_port) =
>> +			cxl_pci_find_port(pdev, &dport);
>> +		if (!port)
>> +			return -EPROBE_DEFER;
>> +
>> +		rc = cxl_rcrb_get_comp_regs(pdev, map, dport);
>> +		if (rc)
>> +			return rc;
>> +
>> +		rc = cxl_dport_map_rcd_linkcap(pdev, dport);
>> +		if (rc)
>> +			return rc;
>> +
>> +	} else if (rc) {
>> +		return rc;
>> +	}
>> +
>> +	return cxl_setup_regs(map);
>> +}
>> +EXPORT_SYMBOL_NS_GPL(cxl_pci_setup_regs, "CXL");
>> +
>>   int cxl_pci_get_bandwidth(struct pci_dev *pdev, struct access_coordinate *c)
>>   {
>>   	int speed, bw;
>> diff --git a/drivers/cxl/core/pci_drv.c b/drivers/cxl/core/pci_drv.c
>> index 18ed819d847d..a35e746e6303 100644
>> --- a/drivers/cxl/core/pci_drv.c
>> +++ b/drivers/cxl/core/pci_drv.c
>> @@ -467,76 +467,6 @@ 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_dport *dport)
>> -{
>> -	resource_size_t component_reg_phys;
>> -
>> -	*map = (struct cxl_register_map) {
>> -		.host = &pdev->dev,
>> -		.resource = CXL_RESOURCE_NONE,
>> -	};
>> -
>> -	struct cxl_port *port __free(put_cxl_port) =
>> -		cxl_pci_find_port(pdev, &dport);
>> -	if (!port)
>> -		return -EPROBE_DEFER;
>> -
>> -	component_reg_phys = cxl_rcd_component_reg_phys(&pdev->dev, dport);
>> -	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)
>> -{
>> -	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)) {
>> -		struct cxl_dport *dport;
>> -		struct cxl_port *port __free(put_cxl_port) =
>> -			cxl_pci_find_port(pdev, &dport);
>> -		if (!port)
>> -			return -EPROBE_DEFER;
>> -
>> -		rc = cxl_rcrb_get_comp_regs(pdev, map, dport);
>> -		if (rc)
>> -			return rc;
>> -
>> -		rc = cxl_dport_map_rcd_linkcap(pdev, dport);
>> -		if (rc)
>> -			return rc;
>> -
>> -	} else if (rc) {
>> -		return rc;
>> -	}
>> -
>> -	return cxl_setup_regs(map);
>> -}
>> -
>>   static int cxl_pci_ras_unmask(struct pci_dev *pdev)
>>   {
>>   	struct cxl_dev_state *cxlds = pci_get_drvdata(pdev);
>> diff --git a/drivers/cxl/core/regs.c b/drivers/cxl/core/regs.c
>> index fb70ffbba72d..fc7fbd4f39d2 100644
>> --- a/drivers/cxl/core/regs.c
>> +++ b/drivers/cxl/core/regs.c
>> @@ -641,4 +641,3 @@ resource_size_t cxl_rcd_component_reg_phys(struct device *dev,
>>   		return CXL_RESOURCE_NONE;
>>   	return __rcrb_to_component(dev, &dport->rcrb, CXL_RCRB_UPSTREAM);
>>   }
>> -EXPORT_SYMBOL_NS_GPL(cxl_rcd_component_reg_phys, "CXL");
>> diff --git a/drivers/cxl/cxl.h b/drivers/cxl/cxl.h
>> index 1517250b0ec2..536c9d99e0e6 100644
>> --- a/drivers/cxl/cxl.h
>> +++ b/drivers/cxl/cxl.h
>> @@ -222,8 +222,6 @@ int cxl_find_regblock(struct pci_dev *pdev, enum cxl_regloc_type type,
>>   		      struct cxl_register_map *map);
>>   int cxl_setup_regs(struct cxl_register_map *map);
>>   struct cxl_dport;
>> -resource_size_t cxl_rcd_component_reg_phys(struct device *dev,
>> -					   struct cxl_dport *dport);
>>   int cxl_dport_map_rcd_linkcap(struct pci_dev *pdev, struct cxl_dport *dport);
>>   
>>   #define CXL_RESOURCE_NONE ((resource_size_t) -1)
>> diff --git a/drivers/cxl/cxlpci.h b/drivers/cxl/cxlpci.h
>> index 3526e6d75f79..24aba9ff6d2e 100644
>> --- a/drivers/cxl/cxlpci.h
>> +++ b/drivers/cxl/cxlpci.h
>> @@ -74,6 +74,17 @@ static inline bool cxl_pci_flit_256(struct pci_dev *pdev)
>>   	return lnksta2 & PCI_EXP_LNKSTA2_FLIT;
>>   }
>>   
>> +/*
>> + * Assume that the caller has already validated that @pdev has CXL
>> + * capabilities, any RCiEP with CXL capabilities is treated as a
>> + * Restricted CXL Device (RCD) and finds upstream port and endpoint
>> + * registers in a Root Complex Register Block (RCRB).
>> + */
>> +static inline bool is_cxl_restricted(struct pci_dev *pdev)
>> +{
>> +	return pci_pcie_type(pdev) == PCI_EXP_TYPE_RC_END;
>> +}
>> +
>>   int devm_cxl_port_enumerate_dports(struct cxl_port *port);
>>   struct cxl_dev_state;
>>   void read_cdat_data(struct cxl_port *port);
>> @@ -89,4 +100,6 @@ static inline void cxl_uport_init_ras_reporting(struct cxl_port *port,
>>   						struct device *host) { }
>>   #endif
>>   
>> +int cxl_pci_setup_regs(struct pci_dev *pdev, enum cxl_regloc_type type,
>> +		       struct cxl_register_map *map);
>>   #endif /* __CXL_PCI_H__ */
>> diff --git a/tools/testing/cxl/Kbuild b/tools/testing/cxl/Kbuild
>> index d8b8272ef87b..d422c81cefa3 100644
>> --- a/tools/testing/cxl/Kbuild
>> +++ b/tools/testing/cxl/Kbuild
>> @@ -7,7 +7,6 @@ ldflags-y += --wrap=nvdimm_bus_register
>>   ldflags-y += --wrap=devm_cxl_port_enumerate_dports
>>   ldflags-y += --wrap=cxl_await_media_ready
>>   ldflags-y += --wrap=devm_cxl_add_rch_dport
>> -ldflags-y += --wrap=cxl_rcd_component_reg_phys
>>   ldflags-y += --wrap=cxl_endpoint_parse_cdat
>>   ldflags-y += --wrap=cxl_dport_init_ras_reporting
>>   ldflags-y += --wrap=devm_cxl_endpoint_decoders_setup
>> diff --git a/tools/testing/cxl/test/mock.c b/tools/testing/cxl/test/mock.c
>> index 995269a75cbd..92fd5c69bef3 100644
>> --- a/tools/testing/cxl/test/mock.c
>> +++ b/tools/testing/cxl/test/mock.c
>> @@ -226,23 +226,6 @@ struct cxl_dport *__wrap_devm_cxl_add_rch_dport(struct cxl_port *port,
>>   }
>>   EXPORT_SYMBOL_NS_GPL(__wrap_devm_cxl_add_rch_dport, "CXL");
>>   
>> -resource_size_t __wrap_cxl_rcd_component_reg_phys(struct device *dev,
>> -						  struct cxl_dport *dport)
>> -{
>> -	int index;
>> -	resource_size_t component_reg_phys;
>> -	struct cxl_mock_ops *ops = get_cxl_mock_ops(&index);
>> -
>> -	if (ops && ops->is_mock_port(dev))
>> -		component_reg_phys = CXL_RESOURCE_NONE;
>> -	else
>> -		component_reg_phys = cxl_rcd_component_reg_phys(dev, dport);
>> -	put_cxl_mock_ops(index);
>> -
>> -	return component_reg_phys;
>> -}
>> -EXPORT_SYMBOL_NS_GPL(__wrap_cxl_rcd_component_reg_phys, "CXL");
>> -
>>   void __wrap_cxl_endpoint_parse_cdat(struct cxl_port *port)
>>   {
>>   	int index;
>> -- 
>> 2.34.1
>>