On Tue, 14 Nov 2023, Mario Limonciello wrote:
> The logic to calculate bandwidth limits may be used at multiple call sites
> so split it up into its own static function instead.
>
> No intended functional changes.
>
> Suggested-by: Ilpo Järvinen <ilpo.jarvinen@xxxxxxxxxxxxxxx>
> Signed-off-by: Mario Limonciello <mario.limonciello@xxxxxxx>
> ---
> v2->v3:
> * Split from previous patch version
> ---
> drivers/pci/pci.c | 60 +++++++++++++++++++++++++++--------------------
> 1 file changed, 34 insertions(+), 26 deletions(-)
>
> diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
> index 55bc3576a985..0ff7883cc774 100644
> --- a/drivers/pci/pci.c
> +++ b/drivers/pci/pci.c
> @@ -6224,6 +6224,38 @@ int pcie_set_mps(struct pci_dev *dev, int mps)
> }
> EXPORT_SYMBOL(pcie_set_mps);
>
> +static u32 pcie_calc_bw_limits(struct pci_dev *dev, u32 bw,
> + struct pci_dev **limiting_dev,
> + enum pci_bus_speed *speed,
> + enum pcie_link_width *width)
> +{
> + enum pcie_link_width next_width;
> + enum pci_bus_speed next_speed;
> + u32 next_bw;
> + u16 lnksta;
> +
> + pcie_capability_read_word(dev, PCI_EXP_LNKSTA, &lnksta);
> +
> + next_speed = pcie_link_speed[FIELD_GET(PCI_EXP_LNKSTA_CLS, lnksta)];
> + next_width = FIELD_GET(PCI_EXP_LNKSTA_NLW, lnksta);
> +
> + next_bw = next_width * PCIE_SPEED2MBS_ENC(next_speed);
> +
> + /* Check if current device limits the total bandwidth */
I'd make this a function comment instead and say:
/* Check if @dev limits the total bandwidth. */
Other than that,
Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@xxxxxxxxxxxxxxx>
--
i.
> + if (!bw || next_bw <= bw) {
> + bw = next_bw;
> +
> + if (limiting_dev)
> + *limiting_dev = dev;
> + if (speed)
> + *speed = next_speed;
> + if (width)
> + *width = next_width;
> + }
> +
> + return bw;
> +}
> +
> /**
> * pcie_bandwidth_available - determine minimum link settings of a PCIe
> * device and its bandwidth limitation
> @@ -6242,39 +6274,15 @@ u32 pcie_bandwidth_available(struct pci_dev *dev, struct pci_dev **limiting_dev,
> enum pci_bus_speed *speed,
> enum pcie_link_width *width)
> {
> - u16 lnksta;
> - enum pci_bus_speed next_speed;
> - enum pcie_link_width next_width;
> - u32 bw, next_bw;
> + u32 bw = 0;
>
> if (speed)
> *speed = PCI_SPEED_UNKNOWN;
> if (width)
> *width = PCIE_LNK_WIDTH_UNKNOWN;
>
> - bw = 0;
> -
> while (dev) {
> - pcie_capability_read_word(dev, PCI_EXP_LNKSTA, &lnksta);
> -
> - next_speed = pcie_link_speed[FIELD_GET(PCI_EXP_LNKSTA_CLS,
> - lnksta)];
> - next_width = FIELD_GET(PCI_EXP_LNKSTA_NLW, lnksta);
> -
> - next_bw = next_width * PCIE_SPEED2MBS_ENC(next_speed);
> -
> - /* Check if current device limits the total bandwidth */
> - if (!bw || next_bw <= bw) {
> - bw = next_bw;
> -
> - if (limiting_dev)
> - *limiting_dev = dev;
> - if (speed)
> - *speed = next_speed;
> - if (width)
> - *width = next_width;
> - }
> -
> + bw = pcie_calc_bw_limits(dev, bw, limiting_dev, speed, width);
> dev = pci_upstream_bridge(dev);
> }
>
>
