Re: [PATCH v3 05/20] cxl: add function for type2 cxl regs setup

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

On 9/10/24 07:00, Li, Ming4 wrote:
> On 9/7/2024 4:18 PM, alejandro.lucero-palau@amd.com wrote:
>> From: Alejandro Lucero <alucerop@amd.com>
>>
>> Create a new function for a type2 device initialising
>> cxl_dev_state struct regarding cxl regs setup and mapping.
>>
>> Signed-off-by: Alejandro Lucero <alucerop@amd.com>
>> ---
>>   drivers/cxl/core/pci.c             | 30 ++++++++++++++++++++++++++++++
>>   drivers/net/ethernet/sfc/efx_cxl.c |  6 ++++++
>>   include/linux/cxl/cxl.h            |  2 ++
>>   3 files changed, 38 insertions(+)
>>
>> diff --git a/drivers/cxl/core/pci.c b/drivers/cxl/core/pci.c
>> index bf57f081ef8f..9afcdd643866 100644
>> --- a/drivers/cxl/core/pci.c
>> +++ b/drivers/cxl/core/pci.c
>> @@ -1142,6 +1142,36 @@ int cxl_pci_setup_regs(struct pci_dev *pdev, enum cxl_regloc_type type,
>>   }
>>   EXPORT_SYMBOL_NS_GPL(cxl_pci_setup_regs, CXL);
>>   
>> +int cxl_pci_accel_setup_regs(struct pci_dev *pdev, struct cxl_dev_state *cxlds)
>> +{
>> +	struct cxl_register_map map;
>> +	int rc;
>> +
>> +	rc = cxl_pci_setup_regs(pdev, CXL_REGLOC_RBI_MEMDEV, &map,
>> +				&cxlds->capabilities);
>> +	if (!rc) {
>> +		rc = cxl_map_device_regs(&map, &cxlds->regs.device_regs);
>> +		if (rc)
>> +			return rc;
>> +	}
>> +
>> +	rc = cxl_pci_setup_regs(pdev, CXL_REGLOC_RBI_COMPONENT,
>> +				&cxlds->reg_map, &cxlds->capabilities);
>> +	if (rc)
>> +		dev_warn(&pdev->dev, "No component registers (%d)\n", rc);
>> +
>> +	if (cxlds->capabilities & BIT(CXL_CM_CAP_CAP_ID_RAS)) {
>> +		rc = cxl_map_component_regs(&cxlds->reg_map,
>> +					    &cxlds->regs.component,
>> +					    BIT(CXL_CM_CAP_CAP_ID_RAS));
>> +		if (rc)
>> +			dev_dbg(&pdev->dev, "Failed to map RAS capability.\n");
>> +	}
>> +
>> +	return rc;
>> +}
>> +EXPORT_SYMBOL_NS_GPL(cxl_pci_accel_setup_regs, CXL);
>> +
> I thought this function should be implemented in efx driver, just like what cxl_pci driver does, because I think it is not a generic setup flow for all CXL type-2 devices.
>

The idea here is to have a single function for discovering the 
registers, both Device and Component registers. If an accel has not all 
of them, as in the sfc case, not a problem with the last changes added.

Keeping with the idea of avoiding an accel driver to manipulate 
cxl_dev_state, this accessor is created.


>>   bool cxl_pci_check_caps(struct cxl_dev_state *cxlds, u32 expected_caps,
>>   			u32 *current_caps)
>>   {
>> diff --git a/drivers/net/ethernet/sfc/efx_cxl.c b/drivers/net/ethernet/sfc/efx_cxl.c
>> index bba36cbbab22..fee143e94c1f 100644
>> --- a/drivers/net/ethernet/sfc/efx_cxl.c
>> +++ b/drivers/net/ethernet/sfc/efx_cxl.c
>> @@ -66,6 +66,12 @@ int efx_cxl_init(struct efx_nic *efx)
>>   		goto err;
>>   	}
>>   
>> +	rc = cxl_pci_accel_setup_regs(pci_dev, cxl->cxlds);
>> +	if (rc) {
>> +		pci_err(pci_dev, "CXL accel setup regs failed");
>> +		goto err;
>> +	}
>> +
>>   	return 0;
>>   err:
>>   	kfree(cxl->cxlds);
>> diff --git a/include/linux/cxl/cxl.h b/include/linux/cxl/cxl.h
>> index 4a57bf60403d..f2dcba6cdc22 100644
>> --- a/include/linux/cxl/cxl.h
>> +++ b/include/linux/cxl/cxl.h
>> @@ -5,6 +5,7 @@
>>   #define __CXL_H
>>   
>>   #include <linux/device.h>
>> +#include <linux/pci.h>
>>   
>>   enum cxl_resource {
>>   	CXL_ACCEL_RES_DPA,
>> @@ -50,4 +51,5 @@ int cxl_set_resource(struct cxl_dev_state *cxlds, struct resource res,
>>   		     enum cxl_resource);
>>   bool cxl_pci_check_caps(struct cxl_dev_state *cxlds, u32 expected_caps,
>>   			u32 *current_caps);
>> +int cxl_pci_accel_setup_regs(struct pci_dev *pdev, struct cxl_dev_state *cxlds);
>>   #endif
>