RE: [PATCH v4] Export PBEC Data register into sysfs

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Gentle ping. Could you check this patch?

> Kobayashi, Daisuke wrote:
> > This proposal aims to add a feature that outputs PCIe device power
> > consumption information to sysfs.
> >
> > Add support for PBEC (Power Budgeting Extended Capability) output to
> > the PCIe driver. PBEC is defined in the PCIe specification(PCIe r6.0,
> > sec 7.8.1) and is a standard method for obtaining device power
> > consumption information.
> >
> > PCIe devices can significantly impact the overall power consumption of
> > a system. However, obtaining PCIe device power consumption information
> > has traditionally been difficult.
> >
> > The PBEC Data register changes depending on the value of the PBEC Data
> > Select register. To obtain all PBEC Data register values defined in
> > the device, obtain the value of the PBEC Data register while changing
> > the value of the PBEC Data Select register.
> >
> > Signed-off-by: "Kobayashi,Daisuke" <kobayashi.da-06@xxxxxxxxxxx>
> > ---
> >  Documentation/ABI/testing/sysfs-bus-pci | 17 +++++++++++++++
> >  drivers/pci/pci-sysfs.c                 | 28
> > +++++++++++++++++++++++++
> >  2 files changed, 45 insertions(+)
> >
> > diff --git a/Documentation/ABI/testing/sysfs-bus-pci
> > b/Documentation/ABI/testing/sysfs-bus-pci
> > index ecf47559f495..be1911d948ef 100644
> > --- a/Documentation/ABI/testing/sysfs-bus-pci
> > +++ b/Documentation/ABI/testing/sysfs-bus-pci
> > @@ -500,3 +500,20 @@ Description:
> >  		console drivers from the device.  Raw users of pci-sysfs
> >  		resourceN attributes must be terminated prior to resizing.
> >  		Success of the resizing operation is not guaranteed.
> > +
> > +What:		/sys/bus/pci/devices/.../power_budget
> > +Date:		September 2024
> > +Contact:	Kobayashi Daisuke <kobayashi.da-06@xxxxxxxxxxx>
> > +Description:
> > +		This file provides information about the PCIe power budget
> > +		for the device. It is a read-only file that outputs the values
> > +		of the Power Budgeting Data Register for each power state as
> > a
> > +		series of 32-bit hexadecimal values. Each line represents a
> > +		single Power Budgeting Data register entry, containing the
> > +		power budget for a specific power state.
> > +
> > +		The specific interpretation of these values depends on the
> > +		device and the PCIe specification. Refer to the PCIe
> > +		specification for detailed information about the Power
> > +		Budgeting Data register, including the encoding	of power
> > +		states and the interpretation of Base Power and Data Scale.
> > diff --git a/drivers/pci/pci-sysfs.c b/drivers/pci/pci-sysfs.c index
> > 2321fdfefd7d..c52814a33597 100644
> > --- a/drivers/pci/pci-sysfs.c
> > +++ b/drivers/pci/pci-sysfs.c
> > @@ -182,6 +182,33 @@ static ssize_t resource_show(struct device *dev,
> > struct device_attribute *attr,  }  static DEVICE_ATTR_RO(resource);
> >
> > +static ssize_t power_budget_show(struct device *dev, struct
> > device_attribute *attr,
> > +			 char *buf)
> > +{
> > +	struct pci_dev *pci_dev = to_pci_dev(dev);
> > +	size_t len = 0;
> > +	int i, pos;
> > +	u32 data;
> > +
> > +	pos = pci_find_ext_capability(pci_dev, PCI_EXT_CAP_ID_PWR);
> > +	if (!pos)
> > +		return -EINVAL;
> > +
> > +	for (i = 0; i < 0xff; i++) {
> > +		pci_write_config_byte(pci_dev, pos + PCI_PWR_DSR, (u8)i);
> > +		pci_read_config_dword(pci_dev, pos + PCI_PWR_DATA,
> > &data);
> > +		if (!data) {
> > +			if (len == 0)
> > +				return -EINVAL;
> > +			break;
> > +		}
> > +		len += sysfs_emit_at(buf, len, "%04x\n", data);
> > +	}
> > +
> > +	return len;
> > +}
> > +static DEVICE_ATTR_RO(power_budget);
> > +
> >  static ssize_t max_link_speed_show(struct device *dev,
> >  				   struct device_attribute *attr, char *buf)
> { @@ -629,6 +656,7
> > @@ static struct attribute *pcie_dev_attrs[] = {
> >  	&dev_attr_current_link_width.attr,
> >  	&dev_attr_max_link_width.attr,
> >  	&dev_attr_max_link_speed.attr,
> > +	&dev_attr_power_budget.attr,
> >  	NULL,
> >  };
> >
> > --
> > 2.45.0
> 
> Dear reviews.
> 
> Could you please take a look at the patch when you have time?
> Thank you for your time and consideration.





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