Re: [PATCH 1/4] cxl/pci: Introduce cxl_gpf_get_dvsec()

[Fan Ni <nifan.cxl@gmail.com>]

On Wed, Feb 19, 2025 at 05:36:01PM -0800, Davidlohr Bueso wrote:
> Add a helper to fetch the port/device GPF dvsecs. This is
> currently only used for ports, but a later patch to export
> dirty count to users will make use of the device one.
> 
> Reviewed-by: Li Ming <ming.li@zohomail.com>
> Signed-off-by: Davidlohr Bueso <dave@stgolabs.net>
> ---

Reviewed-by: Fan Ni <fan.ni@samsung.com>

>  drivers/cxl/core/pci.c | 30 ++++++++++++++++++++----------
>  drivers/cxl/cxl.h      |  2 ++
>  2 files changed, 22 insertions(+), 10 deletions(-)
> 
> diff --git a/drivers/cxl/core/pci.c b/drivers/cxl/core/pci.c
> index a5c65f79db18..96fecb799cbc 100644
> --- a/drivers/cxl/core/pci.c
> +++ b/drivers/cxl/core/pci.c
> @@ -1072,6 +1072,22 @@ int cxl_pci_get_bandwidth(struct pci_dev *pdev, struct access_coordinate *c)
>  #define GPF_TIMEOUT_BASE_MAX 2
>  #define GPF_TIMEOUT_SCALE_MAX 7 /* 10 seconds */
>  
> +u16 cxl_gpf_get_dvsec(struct device *dev, bool is_port)
> +{
> +	u16 dvsec;
> +
> +	if (!dev_is_pci(dev))
> +		return 0;
> +
> +	dvsec = pci_find_dvsec_capability(to_pci_dev(dev), PCI_VENDOR_ID_CXL,
> +			is_port ? CXL_DVSEC_PORT_GPF : CXL_DVSEC_DEVICE_GPF);
> +	if (!dvsec)
> +		dev_warn(dev, "%s GPF DVSEC not present\n",
> +			 is_port ? "Port" : "Device");
> +	return dvsec;
> +}
> +EXPORT_SYMBOL_NS_GPL(cxl_gpf_get_dvsec, "CXL");
> +
>  static int update_gpf_port_dvsec(struct pci_dev *pdev, int dvsec, int phase)
>  {
>  	u64 base, scale;
> @@ -1116,26 +1132,20 @@ int cxl_gpf_port_setup(struct device *dport_dev, struct cxl_port *port)
>  {
>  	struct pci_dev *pdev;
>  
> -	if (!dev_is_pci(dport_dev))
> -		return 0;
> -
> -	pdev = to_pci_dev(dport_dev);
> -	if (!pdev || !port)
> +	if (!port)
>  		return -EINVAL;
>  
>  	if (!port->gpf_dvsec) {
>  		int dvsec;
>  
> -		dvsec = pci_find_dvsec_capability(pdev, PCI_VENDOR_ID_CXL,
> -						  CXL_DVSEC_PORT_GPF);
> -		if (!dvsec) {
> -			pci_warn(pdev, "Port GPF DVSEC not present\n");
> +		dvsec = cxl_gpf_get_dvsec(dport_dev, true);
> +		if (!dvsec)
>  			return -EINVAL;
> -		}
>  
>  		port->gpf_dvsec = dvsec;
>  	}
>  
> +	pdev = to_pci_dev(dport_dev);
>  	update_gpf_port_dvsec(pdev, port->gpf_dvsec, 1);
>  	update_gpf_port_dvsec(pdev, port->gpf_dvsec, 2);
>  
> diff --git a/drivers/cxl/cxl.h b/drivers/cxl/cxl.h
> index 6baec4ba9141..29f2ab0d5bf6 100644
> --- a/drivers/cxl/cxl.h
> +++ b/drivers/cxl/cxl.h
> @@ -901,4 +901,6 @@ bool cxl_endpoint_decoder_reset_detected(struct cxl_port *port);
>  #define __mock static
>  #endif
>  
> +u16 cxl_gpf_get_dvsec(struct device *dev, bool is_port);
> +
>  #endif /* __CXL_H__ */
> -- 
> 2.39.5
>