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.
