Re: [Intel-wired-lan] [PATCH net-next v4] idpf: add support for IDPF PCI programming interface

["Chittim, Madhu" <madhu.chittim@intel.com>]

On 9/24/2025 7:52 AM, Lobakin, Aleksander wrote:
> From: Pavan Kumar Linga <pavan.kumar.linga@intel.com>
> Date: Tue,  2 Sep 2025 20:58:52 -0700
> 
>> At present IDPF supports only 0x1452 and 0x145C as PF and VF device IDs
>> on our current generation hardware. Future hardware exposes a new set of
>> device IDs for each generation. To avoid adding a new device ID for each
>> generation and to make the driver forward and backward compatible,
>> make use of the IDPF PCI programming interface to load the driver.
>>
>> Write and read the VF_ARQBAL mailbox register to find if the current
>> device is a PF or a VF.
>>
>> PCI SIG allocated a new programming interface for the IDPF compliant
>> ethernet network controller devices. It can be found at:
>> https://members.pcisig.com/wg/PCI-SIG/document/20113
>> with the document titled as 'PCI Code and ID Assignment Revision 1.16'
>> or any latest revisions.
>>
>> Tested this patch by doing a simple driver load/unload on Intel IPU E2000
>> hardware which supports 0x1452 and 0x145C device IDs and new hardware
>> which supports the IDPF PCI programming interface.
>>
>> Reviewed-by: Sridhar Samudrala <sridhar.samudrala@intel.com>
>> Signed-off-by: Madhu Chittim <madhu.chittim@intel.com>
>> Reviewed-by: Simon Horman <horms@kernel.org>
>> Signed-off-by: Pavan Kumar Linga <pavan.kumar.linga@intel.com>
>> ---
>> v4:
>> - add testing info
>> - use resource_size_t instead of long
>> - add error statement for ioremap failure
>>
>> v3:
>> - reworked logic to avoid gotos
>>
>> v2:
>> - replace *u8 with *bool in idpf_is_vf_device function parameter
>> - use ~0 instead of 0xffffff in PCI_DEVICE_CLASS parameter
>>
>> ---
>>   drivers/net/ethernet/intel/idpf/idpf.h        |  1 +
>>   drivers/net/ethernet/intel/idpf/idpf_main.c   | 73 ++++++++++++++-----
>>   drivers/net/ethernet/intel/idpf/idpf_vf_dev.c | 40 ++++++++++
>>   3 files changed, 97 insertions(+), 17 deletions(-)
>>
>> diff --git a/drivers/net/ethernet/intel/idpf/idpf.h b/drivers/net/ethernet/intel/idpf/idpf.h
>> index c56abf8b4c92..4a16e481faf7 100644
>> --- a/drivers/net/ethernet/intel/idpf/idpf.h
>> +++ b/drivers/net/ethernet/intel/idpf/idpf.h
>> @@ -1041,6 +1041,7 @@ void idpf_mbx_task(struct work_struct *work);
>>   void idpf_vc_event_task(struct work_struct *work);
>>   void idpf_dev_ops_init(struct idpf_adapter *adapter);
>>   void idpf_vf_dev_ops_init(struct idpf_adapter *adapter);
>> +int idpf_is_vf_device(struct pci_dev *pdev, bool *is_vf);
>>   int idpf_intr_req(struct idpf_adapter *adapter);
>>   void idpf_intr_rel(struct idpf_adapter *adapter);
>>   u16 idpf_get_max_tx_hdr_size(struct idpf_adapter *adapter);
>> diff --git a/drivers/net/ethernet/intel/idpf/idpf_main.c b/drivers/net/ethernet/intel/idpf/idpf_main.c
>> index 8c46481d2e1f..493604d50143 100644
>> --- a/drivers/net/ethernet/intel/idpf/idpf_main.c
>> +++ b/drivers/net/ethernet/intel/idpf/idpf_main.c
>> @@ -7,11 +7,57 @@
>>   
>>   #define DRV_SUMMARY	"Intel(R) Infrastructure Data Path Function Linux Driver"
>>   
>> +#define IDPF_NETWORK_ETHERNET_PROGIF				0x01
>> +#define IDPF_CLASS_NETWORK_ETHERNET_PROGIF			\
>> +	(PCI_CLASS_NETWORK_ETHERNET << 8 | IDPF_NETWORK_ETHERNET_PROGIF)
>> +
>>   MODULE_DESCRIPTION(DRV_SUMMARY);
>>   MODULE_IMPORT_NS("LIBETH");
>>   MODULE_IMPORT_NS("LIBETH_XDP");
>>   MODULE_LICENSE("GPL");
>>   
>> +/**
>> + * idpf_dev_init - Initialize device specific parameters
>> + * @adapter: adapter to initialize
>> + * @ent: entry in idpf_pci_tbl
>> + *
>> + * Return: %0 on success, -%errno on failure.
>> + */
>> +static int idpf_dev_init(struct idpf_adapter *adapter,
>> +			 const struct pci_device_id *ent)
>> +{
>> +	bool is_vf = false;
>> +	int err;
>> +
>> +	if (ent->class == IDPF_CLASS_NETWORK_ETHERNET_PROGIF) {
>> +		err = idpf_is_vf_device(adapter->pdev, &is_vf);
>> +		if (err)
>> +			return err;
>> +		if (is_vf) {
>> +			idpf_vf_dev_ops_init(adapter);
>> +			adapter->crc_enable = true;
>> +		} else {
>> +			idpf_dev_ops_init(adapter);
>> +		}
>> +
>> +		return 0;
>> +	}
>> +
>> +	switch (ent->device) {
>> +	case IDPF_DEV_ID_PF:
>> +		idpf_dev_ops_init(adapter);
>> +		break;
>> +	case IDPF_DEV_ID_VF:
>> +		idpf_vf_dev_ops_init(adapter);
>> +		adapter->crc_enable = true;
>> +		break;
>> +	default:
>> +		return -ENODEV;
>> +	}
>> +
>> +	return 0;
>> +}
>> +
>>   /**
>>    * idpf_remove - Device removal routine
>>    * @pdev: PCI device information struct
>> @@ -165,21 +211,6 @@ static int idpf_probe(struct pci_dev *pdev, const struct pci_device_id *ent)
>>   	adapter->req_tx_splitq = true;
>>   	adapter->req_rx_splitq = true;
>>   
>> -	switch (ent->device) {
>> -	case IDPF_DEV_ID_PF:
>> -		idpf_dev_ops_init(adapter);
>> -		break;
>> -	case IDPF_DEV_ID_VF:
>> -		idpf_vf_dev_ops_init(adapter);
>> -		adapter->crc_enable = true;
>> -		break;
>> -	default:
>> -		err = -ENODEV;
>> -		dev_err(&pdev->dev, "Unexpected dev ID 0x%x in idpf probe\n",
>> -			ent->device);
>> -		goto err_free;
>> -	}
>> -
>>   	adapter->pdev = pdev;
>>   	err = pcim_enable_device(pdev);
>>   	if (err)
>> @@ -259,11 +290,18 @@ static int idpf_probe(struct pci_dev *pdev, const struct pci_device_id *ent)
>>   	/* setup msglvl */
>>   	adapter->msg_enable = netif_msg_init(-1, IDPF_AVAIL_NETIF_M);
>>   
>> +	err = idpf_dev_init(adapter, ent);
>> +	if (err) {
>> +		dev_err(&pdev->dev, "Unexpected dev ID 0x%x in idpf probe\n",
>> +			ent->device);
>> +		goto destroy_vc_event_wq;
>> +	}
>> +
>>   	err = idpf_cfg_hw(adapter);
>>   	if (err) {
>>   		dev_err(dev, "Failed to configure HW structure for adapter: %d\n",
>>   			err);
>> -		goto err_cfg_hw;
>> +		goto destroy_vc_event_wq;
>>   	}
>>   
>>   	mutex_init(&adapter->vport_ctrl_lock);
>> @@ -284,7 +322,7 @@ static int idpf_probe(struct pci_dev *pdev, const struct pci_device_id *ent)
>>   
>>   	return 0;
>>   
>> -err_cfg_hw:
>> +destroy_vc_event_wq:
>>   	destroy_workqueue(adapter->vc_event_wq);
>>   err_vc_event_wq_alloc:
>>   	destroy_workqueue(adapter->stats_wq);
>> @@ -304,6 +342,7 @@ static int idpf_probe(struct pci_dev *pdev, const struct pci_device_id *ent)
>>   static const struct pci_device_id idpf_pci_tbl[] = {
>>   	{ PCI_VDEVICE(INTEL, IDPF_DEV_ID_PF)},
>>   	{ PCI_VDEVICE(INTEL, IDPF_DEV_ID_VF)},
>> +	{ PCI_DEVICE_CLASS(IDPF_CLASS_NETWORK_ETHERNET_PROGIF, ~0)},
>>   	{ /* Sentinel */ }
>>   };
>>   MODULE_DEVICE_TABLE(pci, idpf_pci_tbl);
>> diff --git a/drivers/net/ethernet/intel/idpf/idpf_vf_dev.c b/drivers/net/ethernet/intel/idpf/idpf_vf_dev.c
>> index 7527b967e2e7..4774b933ae50 100644
>> --- a/drivers/net/ethernet/intel/idpf/idpf_vf_dev.c
>> +++ b/drivers/net/ethernet/intel/idpf/idpf_vf_dev.c
>> @@ -7,6 +7,46 @@
>>   
>>   #define IDPF_VF_ITR_IDX_SPACING		0x40
>>   
>> +#define IDPF_VF_TEST_VAL		0xFEED0000
> 
> 0xfeed0000U

Will fix
> 
>> +
>> +/**
>> + * idpf_is_vf_device - Helper to find if it is a VF device
>> + * @pdev: PCI device information struct
>> + * @is_vf: used to update VF device status
>> + *
>> + * Return: %0 on success, -%errno on failure.
>> + */
>> +int idpf_is_vf_device(struct pci_dev *pdev, bool *is_vf)
>> +{
>> +	struct resource mbx_region;
>> +	resource_size_t mbx_start;
>> +	void __iomem *mbx_addr;
>> +	resource_size_t len;
>> +
>> +	resource_set_range(&mbx_region,	VF_BASE, IDPF_VF_MBX_REGION_SZ);
> 
> Why use `struct resource` at all here. You  have start and len already.
> Encapsulating them in a resource only complicates the code.
> 
> 	mbx_addr = ioremap(pci_resource_start(pdev, 0) + VF_BASE,
> 			   IDPF_VF_MBX_REGION_SZ);
> 
>> +
>> +	mbx_start = pci_resource_start(pdev, 0) + mbx_region.start;
>> +	len = resource_size(&mbx_region);
>> +
>> +	mbx_addr = ioremap(mbx_start, len);
>> +	if (!mbx_addr) {
>> +		pci_err(pdev, "Failed to allocate BAR0 mbx region\n");
>> +
>> +		return -EIO;
> 
> I'd remove this newline.

Will fix

> 
>> +	}
>> +
>> +	writel(IDPF_VF_TEST_VAL, mbx_addr + VF_ARQBAL - VF_BASE);
>> +
>> +	/* Force memory write to complete before reading it back */
>> +	wmb();
> 
> Make sure you know what you are doing. writel() is not writel_relaxed(),
> it already has a barrier inside.
> 
>> +
>> +	*is_vf = readl(mbx_addr + VF_ARQBAL - VF_BASE) == IDPF_VF_TEST_VAL;
> 
> Maybe put this `mbx_addr + VF_ARQBAL - VF_BASE` in a variable to not
> spell it out two times...
> 
> Also weird logic. You don't map the whole BAR, you map only a piece of
> it. Ok. But going this route, you need to read only one register. Why
> not then
> 
> 	addr = ioremap(pci_resource_start(pdev, 0) + VF_ARQBAL, 4);
> 
> 	writel(IDPF_VF_TEST_VAL, addr);
> 	is_vf = readl(addr) == IDPF_VF_TEST_VAL;
> 
> ?

I like this approach, will fix it

> 
>> +
>> +	iounmap(mbx_addr);
>> +
>> +	return 0;
>> +}
> 
> Instead of returning only either 0 or -EIO and passing the result via a
> pointer to bool, you could instead just return either:
> 
> * IDPF_DEV_ID_PF
> * IDPF_DEV_ID_VF
> * -EIO

Will fix it

> 
>> +
>>   /**
>>    * idpf_vf_ctlq_reg_init - initialize default mailbox registers
>>    * @adapter: adapter structure
> 
> Thanks,
> Olek