Messages in this thread |  | | Date | Wed, 6 May 2026 15:53:11 -0500 | | Subject | Re: [PATCH v2 1/2] usb: xhci-pci: add generic auxiliary device interface | | From | Mario Limonciello <> |
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On 5/6/26 15:40, Jihong Min wrote: > [You don't often get email from hurryman2212@gmail.com. Learn why this is important at https://aka.ms/LearnAboutSenderIdentification ] > > Some xHCI PCI controllers expose controller-specific functionality that is > not part of generic xHCI operation and is better handled by optional child > drivers in other subsystems. Add a small auxiliary device registration path > for selected xHCI PCI controllers. > > The initial table creates an xhci_pci.hwmon auxiliary device for AMD > 1022:43fd controllers. Store the created auxiliary device in devres so the > xhci-pci remove path destroys it before HCD teardown. Use a > PCI-domain-qualified id so auxiliary device names remain unique across PCI > domains. > > This keeps xhci-pci responsible only for publishing selected controller > functions while allowing subsystem-specific drivers to bind through the > auxiliary bus. > > Assisted-by: Codex:gpt-5.5 > Signed-off-by: Jihong Min <hurryman2212@gmail.com> > --- > drivers/usb/host/Kconfig | 10 ++++ > drivers/usb/host/xhci-pci.c | 114 ++++++++++++++++++++++++++++++++++++ > 2 files changed, 124 insertions(+) > > diff --git a/drivers/usb/host/Kconfig b/drivers/usb/host/Kconfig > index 0a277a07cf70..e0c2c7ac5c97 100644 > --- a/drivers/usb/host/Kconfig > +++ b/drivers/usb/host/Kconfig > @@ -42,6 +42,16 @@ config USB_XHCI_PCI > depends on USB_PCI > default y > > +config USB_XHCI_PCI_AUXDEV > + bool "xHCI PCI auxiliary device support" > + depends on USB_XHCI_PCI > + select AUXILIARY_BUS > + help > + This enables xHCI PCI support for registering auxiliary devices > + for selected controllers. It is used by optional child drivers > + that bind to xHCI PCI controller-specific functionality through > + the auxiliary bus. > + > config USB_XHCI_PCI_RENESAS > tristate "Support for additional Renesas xHCI controller with firmware" > depends on USB_XHCI_PCI > diff --git a/drivers/usb/host/xhci-pci.c b/drivers/usb/host/xhci-pci.c > index 585b2f3117b0..1ab27d2182eb 100644 > --- a/drivers/usb/host/xhci-pci.c > +++ b/drivers/usb/host/xhci-pci.c > @@ -8,6 +8,8 @@ > * Some code borrowed from the Linux EHCI driver. > */ > > +#include <linux/auxiliary_bus.h> > +#include <linux/device/devres.h> > #include <linux/pci.h> > #include <linux/slab.h> > #include <linux/module.h> > @@ -103,6 +105,114 @@ static int xhci_pci_run(struct usb_hcd *hcd); > static int xhci_pci_update_hub_device(struct usb_hcd *hcd, struct usb_device *hdev, > struct usb_tt *tt, gfp_t mem_flags); > > +#if IS_ENABLED(CONFIG_USB_XHCI_PCI_AUXDEV) > +static const struct { > + struct pci_device_id id; > + const char *aux_dev_name; > +} pci_ids_have_aux[] = { > + { > + .id = { PCI_DEVICE(PCI_VENDOR_ID_AMD, 0x43fd) }, /* PROM21 xHCI */ > + .aux_dev_name = "hwmon", > + }, > + { /* end: all zeroes */ } > +}; > + > +struct xhci_pci_aux_devres { > + struct auxiliary_device *auxdev; > +}; > + > +static bool xhci_pci_aux_match_id(const struct pci_device_id *id, > + const struct pci_dev *pdev) > +{ > + if (id->vendor != PCI_ANY_ID && id->vendor != pdev->vendor) > + return false; > + if (id->device != PCI_ANY_ID && id->device != pdev->device) > + return false; > + if (id->subvendor != PCI_ANY_ID && > + id->subvendor != pdev->subsystem_vendor) > + return false; > + if (id->subdevice != PCI_ANY_ID && > + id->subdevice != pdev->subsystem_device) > + return false; > + > + return !((id->class ^ pdev->class) & id->class_mask);
What's wrong with pci_match_id()?
> +} > + > +static const char *xhci_pci_aux_dev_name(struct pci_dev *pdev) > +{ > + int i; > + > + for (i = 0; pci_ids_have_aux[i].aux_dev_name; i++) { > + if (xhci_pci_aux_match_id(&pci_ids_have_aux[i].id, pdev)) > + return pci_ids_have_aux[i].aux_dev_name; > + } > + > + return NULL; > +} > + > +static void xhci_pci_aux_devres_release(struct device *dev, void *res) > +{ > + struct xhci_pci_aux_devres *devres = res; > + > + if (devres->auxdev) > + auxiliary_device_destroy(devres->auxdev); > +} > + > +static void xhci_pci_try_add_aux_device(struct pci_dev *pdev) > +{ > + struct xhci_pci_aux_devres *devres; > + struct auxiliary_device *auxdev; > + const char *aux_dev_name; > + > + aux_dev_name = xhci_pci_aux_dev_name(pdev); > + if (!aux_dev_name) > + return; > + > + devres = devres_alloc(xhci_pci_aux_devres_release, sizeof(*devres), > + GFP_KERNEL); > + if (!devres) { > + dev_warn(&pdev->dev, > + "failed to allocate auxiliary device state\n"); > + return; > + } > + > + auxdev = auxiliary_device_create(&pdev->dev, KBUILD_MODNAME, > + aux_dev_name, NULL, > + (pci_domain_nr(pdev->bus) << 16) | > + pci_dev_id(pdev)); > + if (!auxdev) { > + devres_free(devres); > + dev_warn(&pdev->dev, "failed to add %s auxiliary device\n", > + aux_dev_name); > + return; > + } > + > + devres->auxdev = auxdev; > + devres_add(&pdev->dev, devres); > +} > + > +static void xhci_pci_try_remove_aux_device(struct pci_dev *pdev) > +{ > + struct xhci_pci_aux_devres *devres; > + > + devres = devres_find(&pdev->dev, xhci_pci_aux_devres_release, NULL, > + NULL); > + if (!devres || !devres->auxdev) > + return; > + > + auxiliary_device_destroy(devres->auxdev); > + devres->auxdev = NULL; > +} > +#else > +static inline void xhci_pci_try_add_aux_device(struct pci_dev *pdev) > +{ > +} > + > +static inline void xhci_pci_try_remove_aux_device(struct pci_dev *pdev) > +{ > +} > +#endif > + > static const struct xhci_driver_overrides xhci_pci_overrides __initconst = { > .reset = xhci_pci_setup, > .start = xhci_pci_run, > @@ -677,6 +787,8 @@ int xhci_pci_common_probe(struct pci_dev *dev, const struct pci_device_id *id) > if (device_property_read_bool(&dev->dev, "ti,pwron-active-high")) > pci_clear_and_set_config_dword(dev, 0xE0, 0, 1 << 22); > > + xhci_pci_try_add_aux_device(dev); > + > return 0; > > put_usb3_hcd: > @@ -713,6 +825,8 @@ void xhci_pci_remove(struct pci_dev *dev) > xhci = hcd_to_xhci(pci_get_drvdata(dev)); > set_power_d3 = xhci->quirks & XHCI_SPURIOUS_WAKEUP; > > + xhci_pci_try_remove_aux_device(dev); > + > xhci->xhc_state |= XHCI_STATE_REMOVING; > > if (pci_choose_state(dev, PMSG_SUSPEND) == PCI_D0) > -- > 2.53.0 >
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