| Message ID | 20220609121838.v22.2.I7c9a1f1d6ced41dd8310e8a03da666a32364e790@changeid (mailing list archive) |
|---|---|
| State | Superseded |
| Headers | show |
| Series | usb: misc: Add onboard_usb_hub driver | expand |
Hi, On Thu, Jun 9, 2022 at 12:20 PM Matthias Kaehlcke <mka@chromium.org> wrote: > > @@ -11,6 +11,7 @@ usbcore-y += phy.o port.o > usbcore-$(CONFIG_OF) += of.o > usbcore-$(CONFIG_USB_PCI) += hcd-pci.o > usbcore-$(CONFIG_ACPI) += usb-acpi.o > +usbcore-$(CONFIG_USB_ONBOARD_HUB) += ../misc/onboard_usb_hub_pdevs.o I'm OK with this solution of just linking the code into the "usbcore" if USB folks are. Thinking about it, I guess another way to solve the circular dependency is to somehow create some type of generic notification scheme where the USB hub driver subscribes to "a hub has appeared" notification. ...but I don't personally have any intuition about whether people would like that better than your solution. > +config USB_ONBOARD_HUB > + bool "Onboard USB hub support" > + depends on OF || COMPILE_TEST > + help > + Say Y here if you want to support discrete onboard USB hubs that > + don't require an additional control bus for initialization, but > + need some non-trivial form of initialization, such as enabling a > + power regulator. An example for such a hub is the Realtek > + RTS5411. > + > + This driver can be used as a module but its state (module vs > + builtin) must match the state of the USB subsystem. Enabling > + this config will enable the driver and it will automatically > + match the state of the USB subsystem. If this driver is a > + module it will be called onboard_usb_hub. > + > +if USB_ONBOARD_HUB > +config USB_ONBOARD_HUB_ACTUAL > + tristate > + default m if USB=m > + default y if USB=y > +endif Do you still need to play the games with "_ACTUAL"? The USB core no longer calls the hub directly. I think that means you can just "depend on USB" and be done with the mess. That allows USB to be builtin and USB_ONBOARD_HUB can be a module, right? > +static int onboard_hub_probe(struct platform_device *pdev) > +{ > + struct device *dev = &pdev->dev; > + struct onboard_hub *hub; > + int err; > + > + hub = devm_kzalloc(dev, sizeof(*hub), GFP_KERNEL); > + if (!hub) > + return -ENOMEM; > + > + hub->vdd = devm_regulator_get(dev, "vdd"); > + if (IS_ERR(hub->vdd)) > + return PTR_ERR(hub->vdd); > + > + hub->dev = dev; > + mutex_init(&hub->lock); > + INIT_LIST_HEAD(&hub->udev_list); > + > + dev_set_drvdata(dev, hub); > + > + err = onboard_hub_power_on(hub); > + if (err) > + return err; > + > + /* > + * The USB driver might have been detached from the USB devices by > + * onboard_hub_remove(), make sure to re-attach it if needed. > + * > + * This needs to be done deferred to avoid self-deadlocks on systems > + * with nested onboard hubs. > + */ > + INIT_WORK(&hub->attach_usb_driver_work, onboard_hub_attach_usb_driver); > + schedule_work(&hub->attach_usb_driver_work); I'm sure that the above is totally necessary but it's been long enough since I looked at this code last that I've totally forgotten why. Any chance you could add comments to say under what situation onboard_hub_remove() would have detached the USB driver? Is this something where you unbind the platform driver and then bind it again? ...and why does that cause the driver to be detached? > +/** > + * onboard_hub_create_pdevs -- create platform devices for onboard USB hubs > + * @parent_hub : parent hub to scan for connected onboard hubs > + * @pdev_list : list of onboard hub platform devices owned by the parent hub > + * > + * Creates a platform device for each supported onboard hub that is connected to > + * the given parent hub. To keep track of the platform devices they are added to > + * a list that is owned by the parent hub. I'm ashamed to admit how long it took me to remember why exactly we needed a platform device to begin with and why the normal USB devices weren't enough (it's because we won't enumerate the USB devices until we're powered and so the platform device is in charge of powering things up). Finally I re-read the commit message and then it made sense, but someone looking at the code later might not think to look at the commit message for a while. Maybe remind people in the comments for this function? Even if it's somewhere else in the code and I missed it, I wouldn't mind a tiny blurb here. > +void onboard_hub_create_pdevs(struct usb_device *parent_hub, struct list_head *pdev_list) > +{ > + int i; > + struct usb_hcd *hcd = bus_to_hcd(parent_hub->bus); > + struct device_node *np, *npc; > + struct platform_device *pdev = NULL; > + struct pdev_list_entry *pdle; > + > + if (!parent_hub->dev.of_node) > + return; > + > + for (i = 1; i <= parent_hub->maxchild; i++) { > + np = usb_of_get_device_node(parent_hub, i); > + if (!np) > + continue; > + > + if (!of_is_onboard_usb_hub(np)) > + goto node_put; > + > + npc = of_parse_phandle(np, "companion-hub", 0); > + if (npc) { > + /* > + * Hubs with companions share the same platform device. > + * Create the plaform device only for the hub that is > + * connected to the primary HCD (directly or through > + * other hubs). > + */ > + if (!usb_hcd_is_primary_hcd(hcd)) { > + of_node_put(npc); > + goto node_put; > + } > + > + pdev = of_find_device_by_node(npc); > + of_node_put(npc); > + } else { > + /* > + * For root hubs this function can be called multiple times > + * for the same root hub node (the HCD node). Make sure only > + * one platform device is created for this hub. > + */ > + if (!parent_hub->parent && !usb_hcd_is_primary_hcd(hcd)) > + goto node_put; I don't understand the "else" case above. What case exactly are we handling again? This is when: * the hub is presumably just a 2.0 hub since there is no companion. * our parent is the root hub and the USB 2.0 hub we're looking at is not the primary ...but that doesn't make a lot of sense to me? I must have missed something... In general though, do we even need to look at the "companion-hub" property? If this node matches an onboard USB hub and it's the primary HCD then we want a platform dev. Otherwise we don't, right? -Doug
Hi Doug, Thanks for the review! On Wed, Jun 15, 2022 at 02:09:43PM -0700, Doug Anderson wrote: > Hi, > > On Thu, Jun 9, 2022 at 12:20 PM Matthias Kaehlcke <mka@chromium.org> wrote: > > > > @@ -11,6 +11,7 @@ usbcore-y += phy.o port.o > > usbcore-$(CONFIG_OF) += of.o > > usbcore-$(CONFIG_USB_PCI) += hcd-pci.o > > usbcore-$(CONFIG_ACPI) += usb-acpi.o > > +usbcore-$(CONFIG_USB_ONBOARD_HUB) += ../misc/onboard_usb_hub_pdevs.o > > I'm OK with this solution of just linking the code into the "usbcore" > if USB folks are. Thinking about it, I guess another way to solve the > circular dependency is to somehow create some type of generic > notification scheme where the USB hub driver subscribes to "a hub has > appeared" notification. ...but I don't personally have any intuition > about whether people would like that better than your solution. Not sure if it would be better (if feasible). In any case it would require the hub to be powered (to be enumerated) which is precisely what the onboard_usb_hub driver intends to do. > > +config USB_ONBOARD_HUB > > + bool "Onboard USB hub support" > > + depends on OF || COMPILE_TEST > > + help > > + Say Y here if you want to support discrete onboard USB hubs that > > + don't require an additional control bus for initialization, but > > + need some non-trivial form of initialization, such as enabling a > > + power regulator. An example for such a hub is the Realtek > > + RTS5411. > > + > > + This driver can be used as a module but its state (module vs > > + builtin) must match the state of the USB subsystem. Enabling > > + this config will enable the driver and it will automatically > > + match the state of the USB subsystem. If this driver is a > > + module it will be called onboard_usb_hub. > > + > > +if USB_ONBOARD_HUB > > +config USB_ONBOARD_HUB_ACTUAL > > + tristate > > + default m if USB=m > > + default y if USB=y > > +endif > > Do you still need to play the games with "_ACTUAL"? The USB core no > longer calls the hub directly. I think that means you can just "depend > on USB" and be done with the mess. That allows USB to be builtin and > USB_ONBOARD_HUB can be a module, right? Good point, with the pdev creation inside the USB core it shouldn't be needed anymore. > > +static int onboard_hub_probe(struct platform_device *pdev) > > +{ > > + struct device *dev = &pdev->dev; > > + struct onboard_hub *hub; > > + int err; > > + > > + hub = devm_kzalloc(dev, sizeof(*hub), GFP_KERNEL); > > + if (!hub) > > + return -ENOMEM; > > + > > + hub->vdd = devm_regulator_get(dev, "vdd"); > > + if (IS_ERR(hub->vdd)) > > + return PTR_ERR(hub->vdd); > > + > > + hub->dev = dev; > > + mutex_init(&hub->lock); > > + INIT_LIST_HEAD(&hub->udev_list); > > + > > + dev_set_drvdata(dev, hub); > > + > > + err = onboard_hub_power_on(hub); > > + if (err) > > + return err; > > + > > + /* > > + * The USB driver might have been detached from the USB devices by > > + * onboard_hub_remove(), make sure to re-attach it if needed. > > + * > > + * This needs to be done deferred to avoid self-deadlocks on systems > > + * with nested onboard hubs. > > + */ > > + INIT_WORK(&hub->attach_usb_driver_work, onboard_hub_attach_usb_driver); > > + schedule_work(&hub->attach_usb_driver_work); > > I'm sure that the above is totally necessary but it's been long enough > since I looked at this code last that I've totally forgotten why. Any > chance you could add comments to say under what situation > onboard_hub_remove() would have detached the USB driver? Is this > something where you unbind the platform driver and then bind it again? Yes, that's the scenario in which I encountered that the hub USB devices wouldn't be bound to the onboard_hub_driver again. > ...and why does that cause the driver to be detached? We call device_release_driver(udev) in onboard_hub_remove() to make sure the USB devices don't keep a reference to the platform device after it is removed. > > +/** > > + * onboard_hub_create_pdevs -- create platform devices for onboard USB hubs > > + * @parent_hub : parent hub to scan for connected onboard hubs > > + * @pdev_list : list of onboard hub platform devices owned by the parent hub > > + * > > + * Creates a platform device for each supported onboard hub that is connected to > > + * the given parent hub. To keep track of the platform devices they are added to > > + * a list that is owned by the parent hub. > > I'm ashamed to admit how long it took me to remember why exactly we > needed a platform device to begin with and why the normal USB devices > weren't enough (it's because we won't enumerate the USB devices until > we're powered and so the platform device is in charge of powering > things up). Finally I re-read the commit message and then it made > sense, but someone looking at the code later might not think to look > at the commit message for a while. Maybe remind people in the comments > for this function? Even if it's somewhere else in the code and I > missed it, I wouldn't mind a tiny blurb here. Ok, I can add a short note. > > +void onboard_hub_create_pdevs(struct usb_device *parent_hub, struct list_head *pdev_list) > > +{ > > + int i; > > + struct usb_hcd *hcd = bus_to_hcd(parent_hub->bus); > > + struct device_node *np, *npc; > > + struct platform_device *pdev = NULL; > > + struct pdev_list_entry *pdle; > > + > > + if (!parent_hub->dev.of_node) > > + return; > > + > > + for (i = 1; i <= parent_hub->maxchild; i++) { > > + np = usb_of_get_device_node(parent_hub, i); > > + if (!np) > > + continue; > > + > > + if (!of_is_onboard_usb_hub(np)) > > + goto node_put; > > + > > + npc = of_parse_phandle(np, "companion-hub", 0); > > + if (npc) { > > + /* > > + * Hubs with companions share the same platform device. > > + * Create the plaform device only for the hub that is > > + * connected to the primary HCD (directly or through > > + * other hubs). > > + */ > > + if (!usb_hcd_is_primary_hcd(hcd)) { > > + of_node_put(npc); > > + goto node_put; > > + } > > + > > + pdev = of_find_device_by_node(npc); > > + of_node_put(npc); > > + } else { > > + /* > > + * For root hubs this function can be called multiple times > > + * for the same root hub node (the HCD node). Make sure only > > + * one platform device is created for this hub. > > + */ > > + if (!parent_hub->parent && !usb_hcd_is_primary_hcd(hcd)) > > + goto node_put; > > I don't understand the "else" case above. What case exactly are we > handling again? This is when: > * the hub is presumably just a 2.0 hub since there is no companion. > * our parent is the root hub and the USB 2.0 hub we're looking at is > not the primary The 'else' case can be entered for hubs connected to a root hub or to another hub further down in the tree, but we bail out only for first level hubs. > ...but that doesn't make a lot of sense to me? I must have missed something... It's not super-obvious, this bit is important: "this function can be called multiple times for the same root hub node". For any first level hub we only create a pdev if this function is called on behalf of the primary HCD. That is also true of a hub connected to the secondary HCD. We only want to create one pdev and there is supposedly always a primary HCD. Maybe it would be slightly clearer if the function returned before the loop if this condition is met. Unfortunately we can't just always ignore the secondary HCD because: > In general though, do we even need to look at the "companion-hub" > property? If this node matches an onboard USB hub and it's the primary > HCD then we want a platform dev. Otherwise we don't, right? This wouldn't work for some topologies like: 3.x root hub <nothing connected> 2.x root hub 2.x-only hub no platform device would be created for the 2.x-only hub since it isn't connected to the primary HCD or 3.x root hub 3.x hub 2.x root hub 2.x hub 2.x-only hub The first level hub would have a platform device for being a companion hub of the 3.x hub, however no pdev would be created for the second level hub since the 2.x root hub isn't primary.
Hi, On Wed, Jun 15, 2022 at 4:22 PM Matthias Kaehlcke <mka@chromium.org> wrote: > > > > +void onboard_hub_create_pdevs(struct usb_device *parent_hub, struct list_head *pdev_list) > > > +{ > > > + int i; > > > + struct usb_hcd *hcd = bus_to_hcd(parent_hub->bus); > > > + struct device_node *np, *npc; > > > + struct platform_device *pdev = NULL; > > > + struct pdev_list_entry *pdle; > > > + > > > + if (!parent_hub->dev.of_node) > > > + return; > > > + > > > + for (i = 1; i <= parent_hub->maxchild; i++) { > > > + np = usb_of_get_device_node(parent_hub, i); > > > + if (!np) > > > + continue; > > > + > > > + if (!of_is_onboard_usb_hub(np)) > > > + goto node_put; > > > + > > > + npc = of_parse_phandle(np, "companion-hub", 0); > > > + if (npc) { > > > + /* > > > + * Hubs with companions share the same platform device. > > > + * Create the plaform device only for the hub that is > > > + * connected to the primary HCD (directly or through > > > + * other hubs). > > > + */ > > > + if (!usb_hcd_is_primary_hcd(hcd)) { > > > + of_node_put(npc); > > > + goto node_put; > > > + } > > > + > > > + pdev = of_find_device_by_node(npc); > > > + of_node_put(npc); > > > + } else { > > > + /* > > > + * For root hubs this function can be called multiple times > > > + * for the same root hub node (the HCD node). Make sure only > > > + * one platform device is created for this hub. > > > + */ > > > + if (!parent_hub->parent && !usb_hcd_is_primary_hcd(hcd)) > > > + goto node_put; > > > > I don't understand the "else" case above. What case exactly are we > > handling again? This is when: > > * the hub is presumably just a 2.0 hub since there is no companion. > > * our parent is the root hub and the USB 2.0 hub we're looking at is > > not the primary > > The 'else' case can be entered for hubs connected to a root hub or to another > hub further down in the tree, but we bail out only for first level hubs. > > > ...but that doesn't make a lot of sense to me? I must have missed something... > > It's not super-obvious, this bit is important: "this function can be called > multiple times for the same root hub node". For any first level hub we only > create a pdev if this function is called on behalf of the primary HCD. That > is also true of a hub connected to the secondary HCD. We only want to create > one pdev and there is supposedly always a primary HCD. > > Maybe it would be slightly clearer if the function returned before the loop > if this condition is met. I guess I'm still pretty confused. You say "For root hubs this function can be called multiple times for the same root hub node". Does that mean that the function will be called multiple times with the same "parent_hub", or something else. Unless it's called with the same "parent_hub" then it seems like if the USB device has a device tree node and that device tree node is for a onboard_usb_hub and there's no companion node then we _always_ want to create the platform device, don't we? If it is called with the same "parent_hub" then I'm confused how your test does something different the first time the function is called vs. the 2nd. -Doug
On Thu, Jun 16, 2022 at 01:12:32PM -0700, Doug Anderson wrote: > Hi, > > On Wed, Jun 15, 2022 at 4:22 PM Matthias Kaehlcke <mka@chromium.org> wrote: > > > > > > +void onboard_hub_create_pdevs(struct usb_device *parent_hub, struct list_head *pdev_list) > > > > +{ > > > > + int i; > > > > + struct usb_hcd *hcd = bus_to_hcd(parent_hub->bus); > > > > + struct device_node *np, *npc; > > > > + struct platform_device *pdev = NULL; > > > > + struct pdev_list_entry *pdle; > > > > + > > > > + if (!parent_hub->dev.of_node) > > > > + return; > > > > + > > > > + for (i = 1; i <= parent_hub->maxchild; i++) { > > > > + np = usb_of_get_device_node(parent_hub, i); > > > > + if (!np) > > > > + continue; > > > > + > > > > + if (!of_is_onboard_usb_hub(np)) > > > > + goto node_put; > > > > + > > > > + npc = of_parse_phandle(np, "companion-hub", 0); > > > > + if (npc) { > > > > + /* > > > > + * Hubs with companions share the same platform device. > > > > + * Create the plaform device only for the hub that is > > > > + * connected to the primary HCD (directly or through > > > > + * other hubs). > > > > + */ > > > > + if (!usb_hcd_is_primary_hcd(hcd)) { > > > > + of_node_put(npc); > > > > + goto node_put; > > > > + } > > > > + > > > > + pdev = of_find_device_by_node(npc); > > > > + of_node_put(npc); > > > > + } else { > > > > + /* > > > > + * For root hubs this function can be called multiple times > > > > + * for the same root hub node (the HCD node). Make sure only > > > > + * one platform device is created for this hub. > > > > + */ > > > > + if (!parent_hub->parent && !usb_hcd_is_primary_hcd(hcd)) > > > > + goto node_put; > > > > > > I don't understand the "else" case above. What case exactly are we > > > handling again? This is when: > > > * the hub is presumably just a 2.0 hub since there is no companion. > > > * our parent is the root hub and the USB 2.0 hub we're looking at is > > > not the primary > > > > The 'else' case can be entered for hubs connected to a root hub or to another > > hub further down in the tree, but we bail out only for first level hubs. > > > > > ...but that doesn't make a lot of sense to me? I must have missed something... > > > > It's not super-obvious, this bit is important: "this function can be called > > multiple times for the same root hub node". For any first level hub we only > > create a pdev if this function is called on behalf of the primary HCD. That > > is also true of a hub connected to the secondary HCD. We only want to create > > one pdev and there is supposedly always a primary HCD. > > > > Maybe it would be slightly clearer if the function returned before the loop > > if this condition is met. > > I guess I'm still pretty confused. You say "For root hubs this > function can be called multiple times for the same root hub node". > Does that mean that the function will be called multiple times with > the same "parent_hub", or something else. It is called with a different "parent_hub", however for root hubs the DT node is the same for both root hubs (it's the DT node of the controller since there are no dedicated nodes for the root hubs). Just to make sure this isn't the source of the confusion: the root hubs are part of the USB controller, not 'external' hubs which are directly connected to the controller. I call the latter 'first level hubs'. > Unless it's called with the same "parent_hub" then it seems like if > the USB device has a device tree node and that device tree node is for > a onboard_usb_hub and there's no companion node then we _always_ want > to create the platform device, don't we? If it is called with the same > "parent_hub" then I'm confused how your test does something different > the first time the function is called vs. the 2nd. Let's use an adapted trogdor DT with only a USB 2.x hub as an example: usb_1_dwc3 { dr_mode = "host"; #address-cells = <1>; #size-cells = <0>; /* 2.x hub on port 1 */ usb_hub_2_x: hub@1 { compatible = "usbbda,5411"; reg = <1>; vdd-supply = <&pp3300_hub>; }; }; 1st call: the 'parent_hub' corresponds to the USB 3.x root hub of usb_1_dwc3, the DT node of the hub is 'usb_1_dwc3'. The function iterates over the ports, finds usb_hub_2_x, enters the else branch (no companion hub), checks that the function was called on behalf of the primary controller and creates the pdev. 2nd call: the 'parent_hub' corresponds to the USB 2.x root hub of usb_1_dwc3, the DT node of the hub is also 'usb_1_dwc3'. The function iterates over the ports, finds usb_hub_2_x, enters the else branch (no companion hub), sees that it is not called on behalf of the primary controller and does not create a second (unnecessary) pdev. Is it clearer now?
Hi, On Thu, Jun 16, 2022 at 2:08 PM Matthias Kaehlcke <mka@chromium.org> wrote: > > On Thu, Jun 16, 2022 at 01:12:32PM -0700, Doug Anderson wrote: > > Hi, > > > > On Wed, Jun 15, 2022 at 4:22 PM Matthias Kaehlcke <mka@chromium.org> wrote: > > > > > > > > +void onboard_hub_create_pdevs(struct usb_device *parent_hub, struct list_head *pdev_list) > > > > > +{ > > > > > + int i; > > > > > + struct usb_hcd *hcd = bus_to_hcd(parent_hub->bus); > > > > > + struct device_node *np, *npc; > > > > > + struct platform_device *pdev = NULL; > > > > > + struct pdev_list_entry *pdle; > > > > > + > > > > > + if (!parent_hub->dev.of_node) > > > > > + return; > > > > > + > > > > > + for (i = 1; i <= parent_hub->maxchild; i++) { > > > > > + np = usb_of_get_device_node(parent_hub, i); > > > > > + if (!np) > > > > > + continue; > > > > > + > > > > > + if (!of_is_onboard_usb_hub(np)) > > > > > + goto node_put; > > > > > + > > > > > + npc = of_parse_phandle(np, "companion-hub", 0); > > > > > + if (npc) { > > > > > + /* > > > > > + * Hubs with companions share the same platform device. > > > > > + * Create the plaform device only for the hub that is > > > > > + * connected to the primary HCD (directly or through > > > > > + * other hubs). > > > > > + */ > > > > > + if (!usb_hcd_is_primary_hcd(hcd)) { > > > > > + of_node_put(npc); > > > > > + goto node_put; > > > > > + } > > > > > + > > > > > + pdev = of_find_device_by_node(npc); > > > > > + of_node_put(npc); > > > > > + } else { > > > > > + /* > > > > > + * For root hubs this function can be called multiple times > > > > > + * for the same root hub node (the HCD node). Make sure only > > > > > + * one platform device is created for this hub. > > > > > + */ > > > > > + if (!parent_hub->parent && !usb_hcd_is_primary_hcd(hcd)) > > > > > + goto node_put; > > > > > > > > I don't understand the "else" case above. What case exactly are we > > > > handling again? This is when: > > > > * the hub is presumably just a 2.0 hub since there is no companion. > > > > * our parent is the root hub and the USB 2.0 hub we're looking at is > > > > not the primary > > > > > > The 'else' case can be entered for hubs connected to a root hub or to another > > > hub further down in the tree, but we bail out only for first level hubs. > > > > > > > ...but that doesn't make a lot of sense to me? I must have missed something... > > > > > > It's not super-obvious, this bit is important: "this function can be called > > > multiple times for the same root hub node". For any first level hub we only > > > create a pdev if this function is called on behalf of the primary HCD. That > > > is also true of a hub connected to the secondary HCD. We only want to create > > > one pdev and there is supposedly always a primary HCD. > > > > > > Maybe it would be slightly clearer if the function returned before the loop > > > if this condition is met. > > > > I guess I'm still pretty confused. You say "For root hubs this > > function can be called multiple times for the same root hub node". > > Does that mean that the function will be called multiple times with > > the same "parent_hub", or something else. > > It is called with a different "parent_hub", however for root hubs the > DT node is the same for both root hubs (it's the DT node of the > controller since there are no dedicated nodes for the root hubs). > > Just to make sure this isn't the source of the confusion: the root hubs > are part of the USB controller, not 'external' hubs which are directly > connected to the controller. I call the latter 'first level hubs'. > > > Unless it's called with the same "parent_hub" then it seems like if > > the USB device has a device tree node and that device tree node is for > > a onboard_usb_hub and there's no companion node then we _always_ want > > to create the platform device, don't we? If it is called with the same > > "parent_hub" then I'm confused how your test does something different > > the first time the function is called vs. the 2nd. > > Let's use an adapted trogdor DT with only a USB 2.x hub as an example: > > usb_1_dwc3 { > dr_mode = "host"; > #address-cells = <1>; > #size-cells = <0>; > > /* 2.x hub on port 1 */ > usb_hub_2_x: hub@1 { > compatible = "usbbda,5411"; > reg = <1>; > vdd-supply = <&pp3300_hub>; > }; > }; > > 1st call: the 'parent_hub' corresponds to the USB 3.x root hub of > usb_1_dwc3, the DT node of the hub is 'usb_1_dwc3'. The function > iterates over the ports, finds usb_hub_2_x, enters the else branch > (no companion hub), checks that the function was called on behalf > of the primary controller and creates the pdev. > > 2nd call: the 'parent_hub' corresponds to the USB 2.x root hub of > usb_1_dwc3, the DT node of the hub is also 'usb_1_dwc3'. The function > iterates over the ports, finds usb_hub_2_x, enters the else branch > (no companion hub), sees that it is not called on behalf of the > primary controller and does not create a second (unnecessary) pdev. > > Is it clearer now? Ah, I get it now! Sorry for being so dense... So like this: Root hubs (those hubs with no parent) are all created with the same device_node, the one for the controller itself. We don't want to iterate through the same children multiple times, so we bail right away if we're detect that `parent_hub` is a root hub and we're not on the primary HCD. For all other cases the primary and secondary controllers have distinct device_nodes. I guess in theory that test could go before the "companion-hub" test, though I don't see any case where it truly matters... -Doug
On Thu, Jun 16, 2022 at 02:28:38PM -0700, Doug Anderson wrote: > Hi, > > On Thu, Jun 16, 2022 at 2:08 PM Matthias Kaehlcke <mka@chromium.org> wrote: > > > > On Thu, Jun 16, 2022 at 01:12:32PM -0700, Doug Anderson wrote: > > > Hi, > > > > > > On Wed, Jun 15, 2022 at 4:22 PM Matthias Kaehlcke <mka@chromium.org> wrote: > > > > > > > > > > +void onboard_hub_create_pdevs(struct usb_device *parent_hub, struct list_head *pdev_list) > > > > > > +{ > > > > > > + int i; > > > > > > + struct usb_hcd *hcd = bus_to_hcd(parent_hub->bus); > > > > > > + struct device_node *np, *npc; > > > > > > + struct platform_device *pdev = NULL; > > > > > > + struct pdev_list_entry *pdle; > > > > > > + > > > > > > + if (!parent_hub->dev.of_node) > > > > > > + return; > > > > > > + > > > > > > + for (i = 1; i <= parent_hub->maxchild; i++) { > > > > > > + np = usb_of_get_device_node(parent_hub, i); > > > > > > + if (!np) > > > > > > + continue; > > > > > > + > > > > > > + if (!of_is_onboard_usb_hub(np)) > > > > > > + goto node_put; > > > > > > + > > > > > > + npc = of_parse_phandle(np, "companion-hub", 0); > > > > > > + if (npc) { > > > > > > + /* > > > > > > + * Hubs with companions share the same platform device. > > > > > > + * Create the plaform device only for the hub that is > > > > > > + * connected to the primary HCD (directly or through > > > > > > + * other hubs). > > > > > > + */ > > > > > > + if (!usb_hcd_is_primary_hcd(hcd)) { > > > > > > + of_node_put(npc); > > > > > > + goto node_put; > > > > > > + } > > > > > > + > > > > > > + pdev = of_find_device_by_node(npc); > > > > > > + of_node_put(npc); > > > > > > + } else { > > > > > > + /* > > > > > > + * For root hubs this function can be called multiple times > > > > > > + * for the same root hub node (the HCD node). Make sure only > > > > > > + * one platform device is created for this hub. > > > > > > + */ > > > > > > + if (!parent_hub->parent && !usb_hcd_is_primary_hcd(hcd)) > > > > > > + goto node_put; > > > > > > > > > > I don't understand the "else" case above. What case exactly are we > > > > > handling again? This is when: > > > > > * the hub is presumably just a 2.0 hub since there is no companion. > > > > > * our parent is the root hub and the USB 2.0 hub we're looking at is > > > > > not the primary > > > > > > > > The 'else' case can be entered for hubs connected to a root hub or to another > > > > hub further down in the tree, but we bail out only for first level hubs. > > > > > > > > > ...but that doesn't make a lot of sense to me? I must have missed something... > > > > > > > > It's not super-obvious, this bit is important: "this function can be called > > > > multiple times for the same root hub node". For any first level hub we only > > > > create a pdev if this function is called on behalf of the primary HCD. That > > > > is also true of a hub connected to the secondary HCD. We only want to create > > > > one pdev and there is supposedly always a primary HCD. > > > > > > > > Maybe it would be slightly clearer if the function returned before the loop > > > > if this condition is met. > > > > > > I guess I'm still pretty confused. You say "For root hubs this > > > function can be called multiple times for the same root hub node". > > > Does that mean that the function will be called multiple times with > > > the same "parent_hub", or something else. > > > > It is called with a different "parent_hub", however for root hubs the > > DT node is the same for both root hubs (it's the DT node of the > > controller since there are no dedicated nodes for the root hubs). > > > > Just to make sure this isn't the source of the confusion: the root hubs > > are part of the USB controller, not 'external' hubs which are directly > > connected to the controller. I call the latter 'first level hubs'. > > > > > Unless it's called with the same "parent_hub" then it seems like if > > > the USB device has a device tree node and that device tree node is for > > > a onboard_usb_hub and there's no companion node then we _always_ want > > > to create the platform device, don't we? If it is called with the same > > > "parent_hub" then I'm confused how your test does something different > > > the first time the function is called vs. the 2nd. > > > > Let's use an adapted trogdor DT with only a USB 2.x hub as an example: > > > > usb_1_dwc3 { > > dr_mode = "host"; > > #address-cells = <1>; > > #size-cells = <0>; > > > > /* 2.x hub on port 1 */ > > usb_hub_2_x: hub@1 { > > compatible = "usbbda,5411"; > > reg = <1>; > > vdd-supply = <&pp3300_hub>; > > }; > > }; > > > > 1st call: the 'parent_hub' corresponds to the USB 3.x root hub of > > usb_1_dwc3, the DT node of the hub is 'usb_1_dwc3'. The function > > iterates over the ports, finds usb_hub_2_x, enters the else branch > > (no companion hub), checks that the function was called on behalf > > of the primary controller and creates the pdev. > > > > 2nd call: the 'parent_hub' corresponds to the USB 2.x root hub of > > usb_1_dwc3, the DT node of the hub is also 'usb_1_dwc3'. The function > > iterates over the ports, finds usb_hub_2_x, enters the else branch > > (no companion hub), sees that it is not called on behalf of the > > primary controller and does not create a second (unnecessary) pdev. > > > > Is it clearer now? > > Ah, I get it now! Sorry for being so dense... No worries, it's certainly not obvious and probably my commentary could have been clearer. > So like this: > > Root hubs (those hubs with no parent) are all created with the same > device_node, the one for the controller itself. We don't want to > iterate through the same children multiple times, so we bail right > away if we're detect that `parent_hub` is a root hub and we're not on > the primary HCD. yep > For all other cases the primary and secondary controllers have distinct > device_nodes. You probably mean that all non-root hubs have distinct nodes, so for these the function is only called once. > I guess in theory that test could go before the "companion-hub" test, > though I don't see any case where it truly matters... Yeah, I'm still wondering whether it would be slightly less confusing to bail before the loop (besides saving a few cycles), it would eliminate the conflation with the 'companion-hub' check.
Hi, On Thu, Jun 16, 2022 at 3:01 PM Matthias Kaehlcke <mka@chromium.org> wrote: > > On Thu, Jun 16, 2022 at 02:28:38PM -0700, Doug Anderson wrote: > > Hi, > > > > On Thu, Jun 16, 2022 at 2:08 PM Matthias Kaehlcke <mka@chromium.org> wrote: > > > > > > On Thu, Jun 16, 2022 at 01:12:32PM -0700, Doug Anderson wrote: > > > > Hi, > > > > > > > > On Wed, Jun 15, 2022 at 4:22 PM Matthias Kaehlcke <mka@chromium.org> wrote: > > > > > > > > > > > > +void onboard_hub_create_pdevs(struct usb_device *parent_hub, struct list_head *pdev_list) > > > > > > > +{ > > > > > > > + int i; > > > > > > > + struct usb_hcd *hcd = bus_to_hcd(parent_hub->bus); > > > > > > > + struct device_node *np, *npc; > > > > > > > + struct platform_device *pdev = NULL; > > > > > > > + struct pdev_list_entry *pdle; > > > > > > > + > > > > > > > + if (!parent_hub->dev.of_node) > > > > > > > + return; > > > > > > > + > > > > > > > + for (i = 1; i <= parent_hub->maxchild; i++) { > > > > > > > + np = usb_of_get_device_node(parent_hub, i); > > > > > > > + if (!np) > > > > > > > + continue; > > > > > > > + > > > > > > > + if (!of_is_onboard_usb_hub(np)) > > > > > > > + goto node_put; > > > > > > > + > > > > > > > + npc = of_parse_phandle(np, "companion-hub", 0); > > > > > > > + if (npc) { > > > > > > > + /* > > > > > > > + * Hubs with companions share the same platform device. > > > > > > > + * Create the plaform device only for the hub that is > > > > > > > + * connected to the primary HCD (directly or through > > > > > > > + * other hubs). > > > > > > > + */ > > > > > > > + if (!usb_hcd_is_primary_hcd(hcd)) { > > > > > > > + of_node_put(npc); > > > > > > > + goto node_put; > > > > > > > + } > > > > > > > + > > > > > > > + pdev = of_find_device_by_node(npc); > > > > > > > + of_node_put(npc); > > > > > > > + } else { > > > > > > > + /* > > > > > > > + * For root hubs this function can be called multiple times > > > > > > > + * for the same root hub node (the HCD node). Make sure only > > > > > > > + * one platform device is created for this hub. > > > > > > > + */ > > > > > > > + if (!parent_hub->parent && !usb_hcd_is_primary_hcd(hcd)) > > > > > > > + goto node_put; > > > > > > > > > > > > I don't understand the "else" case above. What case exactly are we > > > > > > handling again? This is when: > > > > > > * the hub is presumably just a 2.0 hub since there is no companion. > > > > > > * our parent is the root hub and the USB 2.0 hub we're looking at is > > > > > > not the primary > > > > > > > > > > The 'else' case can be entered for hubs connected to a root hub or to another > > > > > hub further down in the tree, but we bail out only for first level hubs. > > > > > > > > > > > ...but that doesn't make a lot of sense to me? I must have missed something... > > > > > > > > > > It's not super-obvious, this bit is important: "this function can be called > > > > > multiple times for the same root hub node". For any first level hub we only > > > > > create a pdev if this function is called on behalf of the primary HCD. That > > > > > is also true of a hub connected to the secondary HCD. We only want to create > > > > > one pdev and there is supposedly always a primary HCD. > > > > > > > > > > Maybe it would be slightly clearer if the function returned before the loop > > > > > if this condition is met. > > > > > > > > I guess I'm still pretty confused. You say "For root hubs this > > > > function can be called multiple times for the same root hub node". > > > > Does that mean that the function will be called multiple times with > > > > the same "parent_hub", or something else. > > > > > > It is called with a different "parent_hub", however for root hubs the > > > DT node is the same for both root hubs (it's the DT node of the > > > controller since there are no dedicated nodes for the root hubs). > > > > > > Just to make sure this isn't the source of the confusion: the root hubs > > > are part of the USB controller, not 'external' hubs which are directly > > > connected to the controller. I call the latter 'first level hubs'. > > > > > > > Unless it's called with the same "parent_hub" then it seems like if > > > > the USB device has a device tree node and that device tree node is for > > > > a onboard_usb_hub and there's no companion node then we _always_ want > > > > to create the platform device, don't we? If it is called with the same > > > > "parent_hub" then I'm confused how your test does something different > > > > the first time the function is called vs. the 2nd. > > > > > > Let's use an adapted trogdor DT with only a USB 2.x hub as an example: > > > > > > usb_1_dwc3 { > > > dr_mode = "host"; > > > #address-cells = <1>; > > > #size-cells = <0>; > > > > > > /* 2.x hub on port 1 */ > > > usb_hub_2_x: hub@1 { > > > compatible = "usbbda,5411"; > > > reg = <1>; > > > vdd-supply = <&pp3300_hub>; > > > }; > > > }; > > > > > > 1st call: the 'parent_hub' corresponds to the USB 3.x root hub of > > > usb_1_dwc3, the DT node of the hub is 'usb_1_dwc3'. The function > > > iterates over the ports, finds usb_hub_2_x, enters the else branch > > > (no companion hub), checks that the function was called on behalf > > > of the primary controller and creates the pdev. > > > > > > 2nd call: the 'parent_hub' corresponds to the USB 2.x root hub of > > > usb_1_dwc3, the DT node of the hub is also 'usb_1_dwc3'. The function > > > iterates over the ports, finds usb_hub_2_x, enters the else branch > > > (no companion hub), sees that it is not called on behalf of the > > > primary controller and does not create a second (unnecessary) pdev. > > > > > > Is it clearer now? > > > > Ah, I get it now! Sorry for being so dense... > > No worries, it's certainly not obvious and probably my commentary could > have been clearer. > > > So like this: > > > > Root hubs (those hubs with no parent) are all created with the same > > device_node, the one for the controller itself. We don't want to > > iterate through the same children multiple times, so we bail right > > away if we're detect that `parent_hub` is a root hub and we're not on > > the primary HCD. > > yep > > > For all other cases the primary and secondary controllers have distinct > > device_nodes. > > You probably mean that all non-root hubs have distinct nodes, so for these > the function is only called once. > > > I guess in theory that test could go before the "companion-hub" test, > > though I don't see any case where it truly matters... > > Yeah, I'm still wondering whether it would be slightly less confusing to > bail before the loop (besides saving a few cycles), it would eliminate > the conflation with the 'companion-hub' check. I'm not sure how that would work, though? You'd essentially need two loops then? -Doug
On Thu, Jun 16, 2022 at 03:46:15PM -0700, Doug Anderson wrote: > Hi, > > On Thu, Jun 16, 2022 at 3:01 PM Matthias Kaehlcke <mka@chromium.org> wrote: > > > > On Thu, Jun 16, 2022 at 02:28:38PM -0700, Doug Anderson wrote: > > > Hi, > > > > > > On Thu, Jun 16, 2022 at 2:08 PM Matthias Kaehlcke <mka@chromium.org> wrote: > > > > > > > > On Thu, Jun 16, 2022 at 01:12:32PM -0700, Doug Anderson wrote: > > > > > Hi, > > > > > > > > > > On Wed, Jun 15, 2022 at 4:22 PM Matthias Kaehlcke <mka@chromium.org> wrote: > > > > > > > > > > > > > > +void onboard_hub_create_pdevs(struct usb_device *parent_hub, struct list_head *pdev_list) > > > > > > > > +{ > > > > > > > > + int i; > > > > > > > > + struct usb_hcd *hcd = bus_to_hcd(parent_hub->bus); > > > > > > > > + struct device_node *np, *npc; > > > > > > > > + struct platform_device *pdev = NULL; > > > > > > > > + struct pdev_list_entry *pdle; > > > > > > > > + > > > > > > > > + if (!parent_hub->dev.of_node) > > > > > > > > + return; > > > > > > > > + > > > > > > > > + for (i = 1; i <= parent_hub->maxchild; i++) { > > > > > > > > + np = usb_of_get_device_node(parent_hub, i); > > > > > > > > + if (!np) > > > > > > > > + continue; > > > > > > > > + > > > > > > > > + if (!of_is_onboard_usb_hub(np)) > > > > > > > > + goto node_put; > > > > > > > > + > > > > > > > > + npc = of_parse_phandle(np, "companion-hub", 0); > > > > > > > > + if (npc) { > > > > > > > > + /* > > > > > > > > + * Hubs with companions share the same platform device. > > > > > > > > + * Create the plaform device only for the hub that is > > > > > > > > + * connected to the primary HCD (directly or through > > > > > > > > + * other hubs). > > > > > > > > + */ > > > > > > > > + if (!usb_hcd_is_primary_hcd(hcd)) { > > > > > > > > + of_node_put(npc); > > > > > > > > + goto node_put; > > > > > > > > + } > > > > > > > > + > > > > > > > > + pdev = of_find_device_by_node(npc); > > > > > > > > + of_node_put(npc); > > > > > > > > + } else { > > > > > > > > + /* > > > > > > > > + * For root hubs this function can be called multiple times > > > > > > > > + * for the same root hub node (the HCD node). Make sure only > > > > > > > > + * one platform device is created for this hub. > > > > > > > > + */ > > > > > > > > + if (!parent_hub->parent && !usb_hcd_is_primary_hcd(hcd)) > > > > > > > > + goto node_put; > > > > > > > > > > > > > > I don't understand the "else" case above. What case exactly are we > > > > > > > handling again? This is when: > > > > > > > * the hub is presumably just a 2.0 hub since there is no companion. > > > > > > > * our parent is the root hub and the USB 2.0 hub we're looking at is > > > > > > > not the primary > > > > > > > > > > > > The 'else' case can be entered for hubs connected to a root hub or to another > > > > > > hub further down in the tree, but we bail out only for first level hubs. > > > > > > > > > > > > > ...but that doesn't make a lot of sense to me? I must have missed something... > > > > > > > > > > > > It's not super-obvious, this bit is important: "this function can be called > > > > > > multiple times for the same root hub node". For any first level hub we only > > > > > > create a pdev if this function is called on behalf of the primary HCD. That > > > > > > is also true of a hub connected to the secondary HCD. We only want to create > > > > > > one pdev and there is supposedly always a primary HCD. > > > > > > > > > > > > Maybe it would be slightly clearer if the function returned before the loop > > > > > > if this condition is met. > > > > > > > > > > I guess I'm still pretty confused. You say "For root hubs this > > > > > function can be called multiple times for the same root hub node". > > > > > Does that mean that the function will be called multiple times with > > > > > the same "parent_hub", or something else. > > > > > > > > It is called with a different "parent_hub", however for root hubs the > > > > DT node is the same for both root hubs (it's the DT node of the > > > > controller since there are no dedicated nodes for the root hubs). > > > > > > > > Just to make sure this isn't the source of the confusion: the root hubs > > > > are part of the USB controller, not 'external' hubs which are directly > > > > connected to the controller. I call the latter 'first level hubs'. > > > > > > > > > Unless it's called with the same "parent_hub" then it seems like if > > > > > the USB device has a device tree node and that device tree node is for > > > > > a onboard_usb_hub and there's no companion node then we _always_ want > > > > > to create the platform device, don't we? If it is called with the same > > > > > "parent_hub" then I'm confused how your test does something different > > > > > the first time the function is called vs. the 2nd. > > > > > > > > Let's use an adapted trogdor DT with only a USB 2.x hub as an example: > > > > > > > > usb_1_dwc3 { > > > > dr_mode = "host"; > > > > #address-cells = <1>; > > > > #size-cells = <0>; > > > > > > > > /* 2.x hub on port 1 */ > > > > usb_hub_2_x: hub@1 { > > > > compatible = "usbbda,5411"; > > > > reg = <1>; > > > > vdd-supply = <&pp3300_hub>; > > > > }; > > > > }; > > > > > > > > 1st call: the 'parent_hub' corresponds to the USB 3.x root hub of > > > > usb_1_dwc3, the DT node of the hub is 'usb_1_dwc3'. The function > > > > iterates over the ports, finds usb_hub_2_x, enters the else branch > > > > (no companion hub), checks that the function was called on behalf > > > > of the primary controller and creates the pdev. > > > > > > > > 2nd call: the 'parent_hub' corresponds to the USB 2.x root hub of > > > > usb_1_dwc3, the DT node of the hub is also 'usb_1_dwc3'. The function > > > > iterates over the ports, finds usb_hub_2_x, enters the else branch > > > > (no companion hub), sees that it is not called on behalf of the > > > > primary controller and does not create a second (unnecessary) pdev. > > > > > > > > Is it clearer now? > > > > > > Ah, I get it now! Sorry for being so dense... > > > > No worries, it's certainly not obvious and probably my commentary could > > have been clearer. > > > > > So like this: > > > > > > Root hubs (those hubs with no parent) are all created with the same > > > device_node, the one for the controller itself. We don't want to > > > iterate through the same children multiple times, so we bail right > > > away if we're detect that `parent_hub` is a root hub and we're not on > > > the primary HCD. > > > > yep > > > > > For all other cases the primary and secondary controllers have distinct > > > device_nodes. > > > > You probably mean that all non-root hubs have distinct nodes, so for these > > the function is only called once. > > > > > I guess in theory that test could go before the "companion-hub" test, > > > though I don't see any case where it truly matters... > > > > Yeah, I'm still wondering whether it would be slightly less confusing to > > bail before the loop (besides saving a few cycles), it would eliminate > > the conflation with the 'companion-hub' check. > > I'm not sure how that would work, though? You'd essentially need two loops then? Maybe I got myself confused, but I think the behavior would be the same as now, without a second loop: We never create a pdev if the parent is a root hub and the controller is the secondary. Even for a hub with companion the pdev is only created when the call comes from the primary controller. Does that make sense?
Hi, On Thu, Jun 16, 2022 at 5:36 PM Matthias Kaehlcke <mka@chromium.org> wrote: > > On Thu, Jun 16, 2022 at 03:46:15PM -0700, Doug Anderson wrote: > > Hi, > > > > On Thu, Jun 16, 2022 at 3:01 PM Matthias Kaehlcke <mka@chromium.org> wrote: > > > > > > On Thu, Jun 16, 2022 at 02:28:38PM -0700, Doug Anderson wrote: > > > > Hi, > > > > > > > > On Thu, Jun 16, 2022 at 2:08 PM Matthias Kaehlcke <mka@chromium.org> wrote: > > > > > > > > > > On Thu, Jun 16, 2022 at 01:12:32PM -0700, Doug Anderson wrote: > > > > > > Hi, > > > > > > > > > > > > On Wed, Jun 15, 2022 at 4:22 PM Matthias Kaehlcke <mka@chromium.org> wrote: > > > > > > > > > > > > > > > > +void onboard_hub_create_pdevs(struct usb_device *parent_hub, struct list_head *pdev_list) > > > > > > > > > +{ > > > > > > > > > + int i; > > > > > > > > > + struct usb_hcd *hcd = bus_to_hcd(parent_hub->bus); > > > > > > > > > + struct device_node *np, *npc; > > > > > > > > > + struct platform_device *pdev = NULL; > > > > > > > > > + struct pdev_list_entry *pdle; > > > > > > > > > + > > > > > > > > > + if (!parent_hub->dev.of_node) > > > > > > > > > + return; > > > > > > > > > + > > > > > > > > > + for (i = 1; i <= parent_hub->maxchild; i++) { > > > > > > > > > + np = usb_of_get_device_node(parent_hub, i); > > > > > > > > > + if (!np) > > > > > > > > > + continue; > > > > > > > > > + > > > > > > > > > + if (!of_is_onboard_usb_hub(np)) > > > > > > > > > + goto node_put; > > > > > > > > > + > > > > > > > > > + npc = of_parse_phandle(np, "companion-hub", 0); > > > > > > > > > + if (npc) { > > > > > > > > > + /* > > > > > > > > > + * Hubs with companions share the same platform device. > > > > > > > > > + * Create the plaform device only for the hub that is > > > > > > > > > + * connected to the primary HCD (directly or through > > > > > > > > > + * other hubs). > > > > > > > > > + */ > > > > > > > > > + if (!usb_hcd_is_primary_hcd(hcd)) { > > > > > > > > > + of_node_put(npc); > > > > > > > > > + goto node_put; > > > > > > > > > + } > > > > > > > > > + > > > > > > > > > + pdev = of_find_device_by_node(npc); > > > > > > > > > + of_node_put(npc); > > > > > > > > > + } else { > > > > > > > > > + /* > > > > > > > > > + * For root hubs this function can be called multiple times > > > > > > > > > + * for the same root hub node (the HCD node). Make sure only > > > > > > > > > + * one platform device is created for this hub. > > > > > > > > > + */ > > > > > > > > > + if (!parent_hub->parent && !usb_hcd_is_primary_hcd(hcd)) > > > > > > > > > + goto node_put; > > > > > > > > > > > > > > > > I don't understand the "else" case above. What case exactly are we > > > > > > > > handling again? This is when: > > > > > > > > * the hub is presumably just a 2.0 hub since there is no companion. > > > > > > > > * our parent is the root hub and the USB 2.0 hub we're looking at is > > > > > > > > not the primary > > > > > > > > > > > > > > The 'else' case can be entered for hubs connected to a root hub or to another > > > > > > > hub further down in the tree, but we bail out only for first level hubs. > > > > > > > > > > > > > > > ...but that doesn't make a lot of sense to me? I must have missed something... > > > > > > > > > > > > > > It's not super-obvious, this bit is important: "this function can be called > > > > > > > multiple times for the same root hub node". For any first level hub we only > > > > > > > create a pdev if this function is called on behalf of the primary HCD. That > > > > > > > is also true of a hub connected to the secondary HCD. We only want to create > > > > > > > one pdev and there is supposedly always a primary HCD. > > > > > > > > > > > > > > Maybe it would be slightly clearer if the function returned before the loop > > > > > > > if this condition is met. > > > > > > > > > > > > I guess I'm still pretty confused. You say "For root hubs this > > > > > > function can be called multiple times for the same root hub node". > > > > > > Does that mean that the function will be called multiple times with > > > > > > the same "parent_hub", or something else. > > > > > > > > > > It is called with a different "parent_hub", however for root hubs the > > > > > DT node is the same for both root hubs (it's the DT node of the > > > > > controller since there are no dedicated nodes for the root hubs). > > > > > > > > > > Just to make sure this isn't the source of the confusion: the root hubs > > > > > are part of the USB controller, not 'external' hubs which are directly > > > > > connected to the controller. I call the latter 'first level hubs'. > > > > > > > > > > > Unless it's called with the same "parent_hub" then it seems like if > > > > > > the USB device has a device tree node and that device tree node is for > > > > > > a onboard_usb_hub and there's no companion node then we _always_ want > > > > > > to create the platform device, don't we? If it is called with the same > > > > > > "parent_hub" then I'm confused how your test does something different > > > > > > the first time the function is called vs. the 2nd. > > > > > > > > > > Let's use an adapted trogdor DT with only a USB 2.x hub as an example: > > > > > > > > > > usb_1_dwc3 { > > > > > dr_mode = "host"; > > > > > #address-cells = <1>; > > > > > #size-cells = <0>; > > > > > > > > > > /* 2.x hub on port 1 */ > > > > > usb_hub_2_x: hub@1 { > > > > > compatible = "usbbda,5411"; > > > > > reg = <1>; > > > > > vdd-supply = <&pp3300_hub>; > > > > > }; > > > > > }; > > > > > > > > > > 1st call: the 'parent_hub' corresponds to the USB 3.x root hub of > > > > > usb_1_dwc3, the DT node of the hub is 'usb_1_dwc3'. The function > > > > > iterates over the ports, finds usb_hub_2_x, enters the else branch > > > > > (no companion hub), checks that the function was called on behalf > > > > > of the primary controller and creates the pdev. > > > > > > > > > > 2nd call: the 'parent_hub' corresponds to the USB 2.x root hub of > > > > > usb_1_dwc3, the DT node of the hub is also 'usb_1_dwc3'. The function > > > > > iterates over the ports, finds usb_hub_2_x, enters the else branch > > > > > (no companion hub), sees that it is not called on behalf of the > > > > > primary controller and does not create a second (unnecessary) pdev. > > > > > > > > > > Is it clearer now? > > > > > > > > Ah, I get it now! Sorry for being so dense... > > > > > > No worries, it's certainly not obvious and probably my commentary could > > > have been clearer. > > > > > > > So like this: > > > > > > > > Root hubs (those hubs with no parent) are all created with the same > > > > device_node, the one for the controller itself. We don't want to > > > > iterate through the same children multiple times, so we bail right > > > > away if we're detect that `parent_hub` is a root hub and we're not on > > > > the primary HCD. > > > > > > yep > > > > > > > For all other cases the primary and secondary controllers have distinct > > > > device_nodes. > > > > > > You probably mean that all non-root hubs have distinct nodes, so for these > > > the function is only called once. > > > > > > > I guess in theory that test could go before the "companion-hub" test, > > > > though I don't see any case where it truly matters... > > > > > > Yeah, I'm still wondering whether it would be slightly less confusing to > > > bail before the loop (besides saving a few cycles), it would eliminate > > > the conflation with the 'companion-hub' check. > > > > I'm not sure how that would work, though? You'd essentially need two loops then? > > Maybe I got myself confused, but I think the behavior would be the same as > now, without a second loop: > > We never create a pdev if the parent is a root hub and the controller is the > secondary. Even for a hub with companion the pdev is only created when the call > comes from the primary controller. > > Does that make sense? Yes, looking at it with fresh eyes I think you're right. Looking at the "companion-hub" case with fresh eyes, too, I wonder if that can be simpler. If we find a companion hub, do we need both the check for usb_hcd_is_primary_hcd() and the check to see whether the pdev was already created? -Doug
On Fri, Jun 17, 2022 at 08:09:06AM -0700, Doug Anderson wrote: > Hi, > > On Thu, Jun 16, 2022 at 5:36 PM Matthias Kaehlcke <mka@chromium.org> wrote: > > > > On Thu, Jun 16, 2022 at 03:46:15PM -0700, Doug Anderson wrote: > > > Hi, > > > > > > On Thu, Jun 16, 2022 at 3:01 PM Matthias Kaehlcke <mka@chromium.org> wrote: > > > > > > > > On Thu, Jun 16, 2022 at 02:28:38PM -0700, Doug Anderson wrote: > > > > > Hi, > > > > > > > > > > On Thu, Jun 16, 2022 at 2:08 PM Matthias Kaehlcke <mka@chromium.org> wrote: > > > > > > > > > > > > On Thu, Jun 16, 2022 at 01:12:32PM -0700, Doug Anderson wrote: > > > > > > > Hi, > > > > > > > > > > > > > > On Wed, Jun 15, 2022 at 4:22 PM Matthias Kaehlcke <mka@chromium.org> wrote: > > > > > > > > > > > > > > > > > > +void onboard_hub_create_pdevs(struct usb_device *parent_hub, struct list_head *pdev_list) > > > > > > > > > > +{ > > > > > > > > > > + int i; > > > > > > > > > > + struct usb_hcd *hcd = bus_to_hcd(parent_hub->bus); > > > > > > > > > > + struct device_node *np, *npc; > > > > > > > > > > + struct platform_device *pdev = NULL; > > > > > > > > > > + struct pdev_list_entry *pdle; > > > > > > > > > > + > > > > > > > > > > + if (!parent_hub->dev.of_node) > > > > > > > > > > + return; > > > > > > > > > > + > > > > > > > > > > + for (i = 1; i <= parent_hub->maxchild; i++) { > > > > > > > > > > + np = usb_of_get_device_node(parent_hub, i); > > > > > > > > > > + if (!np) > > > > > > > > > > + continue; > > > > > > > > > > + > > > > > > > > > > + if (!of_is_onboard_usb_hub(np)) > > > > > > > > > > + goto node_put; > > > > > > > > > > + > > > > > > > > > > + npc = of_parse_phandle(np, "companion-hub", 0); > > > > > > > > > > + if (npc) { > > > > > > > > > > + /* > > > > > > > > > > + * Hubs with companions share the same platform device. > > > > > > > > > > + * Create the plaform device only for the hub that is > > > > > > > > > > + * connected to the primary HCD (directly or through > > > > > > > > > > + * other hubs). > > > > > > > > > > + */ > > > > > > > > > > + if (!usb_hcd_is_primary_hcd(hcd)) { > > > > > > > > > > + of_node_put(npc); > > > > > > > > > > + goto node_put; > > > > > > > > > > + } > > > > > > > > > > + > > > > > > > > > > + pdev = of_find_device_by_node(npc); > > > > > > > > > > + of_node_put(npc); > > > > > > > > > > + } else { > > > > > > > > > > + /* > > > > > > > > > > + * For root hubs this function can be called multiple times > > > > > > > > > > + * for the same root hub node (the HCD node). Make sure only > > > > > > > > > > + * one platform device is created for this hub. > > > > > > > > > > + */ > > > > > > > > > > + if (!parent_hub->parent && !usb_hcd_is_primary_hcd(hcd)) > > > > > > > > > > + goto node_put; > > > > > > > > > > > > > > > > > > I don't understand the "else" case above. What case exactly are we > > > > > > > > > handling again? This is when: > > > > > > > > > * the hub is presumably just a 2.0 hub since there is no companion. > > > > > > > > > * our parent is the root hub and the USB 2.0 hub we're looking at is > > > > > > > > > not the primary > > > > > > > > > > > > > > > > The 'else' case can be entered for hubs connected to a root hub or to another > > > > > > > > hub further down in the tree, but we bail out only for first level hubs. > > > > > > > > > > > > > > > > > ...but that doesn't make a lot of sense to me? I must have missed something... > > > > > > > > > > > > > > > > It's not super-obvious, this bit is important: "this function can be called > > > > > > > > multiple times for the same root hub node". For any first level hub we only > > > > > > > > create a pdev if this function is called on behalf of the primary HCD. That > > > > > > > > is also true of a hub connected to the secondary HCD. We only want to create > > > > > > > > one pdev and there is supposedly always a primary HCD. > > > > > > > > > > > > > > > > Maybe it would be slightly clearer if the function returned before the loop > > > > > > > > if this condition is met. > > > > > > > > > > > > > > I guess I'm still pretty confused. You say "For root hubs this > > > > > > > function can be called multiple times for the same root hub node". > > > > > > > Does that mean that the function will be called multiple times with > > > > > > > the same "parent_hub", or something else. > > > > > > > > > > > > It is called with a different "parent_hub", however for root hubs the > > > > > > DT node is the same for both root hubs (it's the DT node of the > > > > > > controller since there are no dedicated nodes for the root hubs). > > > > > > > > > > > > Just to make sure this isn't the source of the confusion: the root hubs > > > > > > are part of the USB controller, not 'external' hubs which are directly > > > > > > connected to the controller. I call the latter 'first level hubs'. > > > > > > > > > > > > > Unless it's called with the same "parent_hub" then it seems like if > > > > > > > the USB device has a device tree node and that device tree node is for > > > > > > > a onboard_usb_hub and there's no companion node then we _always_ want > > > > > > > to create the platform device, don't we? If it is called with the same > > > > > > > "parent_hub" then I'm confused how your test does something different > > > > > > > the first time the function is called vs. the 2nd. > > > > > > > > > > > > Let's use an adapted trogdor DT with only a USB 2.x hub as an example: > > > > > > > > > > > > usb_1_dwc3 { > > > > > > dr_mode = "host"; > > > > > > #address-cells = <1>; > > > > > > #size-cells = <0>; > > > > > > > > > > > > /* 2.x hub on port 1 */ > > > > > > usb_hub_2_x: hub@1 { > > > > > > compatible = "usbbda,5411"; > > > > > > reg = <1>; > > > > > > vdd-supply = <&pp3300_hub>; > > > > > > }; > > > > > > }; > > > > > > > > > > > > 1st call: the 'parent_hub' corresponds to the USB 3.x root hub of > > > > > > usb_1_dwc3, the DT node of the hub is 'usb_1_dwc3'. The function > > > > > > iterates over the ports, finds usb_hub_2_x, enters the else branch > > > > > > (no companion hub), checks that the function was called on behalf > > > > > > of the primary controller and creates the pdev. > > > > > > > > > > > > 2nd call: the 'parent_hub' corresponds to the USB 2.x root hub of > > > > > > usb_1_dwc3, the DT node of the hub is also 'usb_1_dwc3'. The function > > > > > > iterates over the ports, finds usb_hub_2_x, enters the else branch > > > > > > (no companion hub), sees that it is not called on behalf of the > > > > > > primary controller and does not create a second (unnecessary) pdev. > > > > > > > > > > > > Is it clearer now? > > > > > > > > > > Ah, I get it now! Sorry for being so dense... > > > > > > > > No worries, it's certainly not obvious and probably my commentary could > > > > have been clearer. > > > > > > > > > So like this: > > > > > > > > > > Root hubs (those hubs with no parent) are all created with the same > > > > > device_node, the one for the controller itself. We don't want to > > > > > iterate through the same children multiple times, so we bail right > > > > > away if we're detect that `parent_hub` is a root hub and we're not on > > > > > the primary HCD. > > > > > > > > yep > > > > > > > > > For all other cases the primary and secondary controllers have distinct > > > > > device_nodes. > > > > > > > > You probably mean that all non-root hubs have distinct nodes, so for these > > > > the function is only called once. > > > > > > > > > I guess in theory that test could go before the "companion-hub" test, > > > > > though I don't see any case where it truly matters... > > > > > > > > Yeah, I'm still wondering whether it would be slightly less confusing to > > > > bail before the loop (besides saving a few cycles), it would eliminate > > > > the conflation with the 'companion-hub' check. > > > > > > I'm not sure how that would work, though? You'd essentially need two loops then? > > > > Maybe I got myself confused, but I think the behavior would be the same as > > now, without a second loop: > > > > We never create a pdev if the parent is a root hub and the controller is the > > secondary. Even for a hub with companion the pdev is only created when the call > > comes from the primary controller. > > > > Does that make sense? > > Yes, looking at it with fresh eyes I think you're right. > > Looking at the "companion-hub" case with fresh eyes, too, I wonder if > that can be simpler. If we find a companion hub, do we need both the > check for usb_hcd_is_primary_hcd() and the check to see whether the > pdev was already created? I was also doubting about this and concluded that it is still needed. Let's use once more the trogdor config as example, which has one physical onboard hub chip with a USB 3.1 hub and a USB 2.1 companion hub, connected to the dwc3 controller: &usb_1_dwc3 { dr_mode = "host"; #address-cells = <1>; #size-cells = <0>; /* 2.x hub on port 1 */ usb_hub_2_x: hub@1 { compatible = "usbbda,5411"; reg = <1>; vdd-supply = <&pp3300_hub>; companion-hub = <&usb_hub_3_x>; }; /* 3.x hub on port 2 */ usb_hub_3_x: hub@2 { compatible = "usbbda,411"; reg = <2>; vdd-supply = <&pp3300_hub>; companion-hub = <&usb_hub_2_x>; }; }; Let's assume we don't check for the pdev. With our change above for root hubs the loop is now only executed for the primary HCD. In the first iteration we encounter the 2.x hub, it has a companion hub, but that alone doesn't tell us much, so we create a pdev. In the next iteration we encouter the 3.x hub, it also has a companion hub, but we don't know/check that the companion already has a pdev, so we create another one for the same physical hub.
Hi, On Fri, Jun 17, 2022 at 9:34 AM Matthias Kaehlcke <mka@chromium.org> wrote: > > > Looking at the "companion-hub" case with fresh eyes, too, I wonder if > > that can be simpler. If we find a companion hub, do we need both the > > check for usb_hcd_is_primary_hcd() and the check to see whether the > > pdev was already created? > > I was also doubting about this and concluded that it is still needed. > > Let's use once more the trogdor config as example, which has one physical > onboard hub chip with a USB 3.1 hub and a USB 2.1 companion hub, connected > to the dwc3 controller: > > &usb_1_dwc3 { > dr_mode = "host"; > #address-cells = <1>; > #size-cells = <0>; > > /* 2.x hub on port 1 */ > usb_hub_2_x: hub@1 { > compatible = "usbbda,5411"; > reg = <1>; > vdd-supply = <&pp3300_hub>; > companion-hub = <&usb_hub_3_x>; > }; > > /* 3.x hub on port 2 */ > usb_hub_3_x: hub@2 { > compatible = "usbbda,411"; > reg = <2>; > vdd-supply = <&pp3300_hub>; > companion-hub = <&usb_hub_2_x>; > }; > }; > > Let's assume we don't check for the pdev. With our change above for root hubs > the loop is now only executed for the primary HCD. In the first iteration > we encounter the 2.x hub, it has a companion hub, but that alone doesn't > tell us much, so we create a pdev. In the next iteration we encouter the > 3.x hub, it also has a companion hub, but we don't know/check that the > companion already has a pdev, so we create another one for the same > physical hub. Ah, you are correct. You only run into that case for the root hub, correct? For everything else it's impossible? ...and I guess things would be different if inside the loop you actually set "hcd" to point to the "hcd" of the child device. I guess that's where my confusion keeps stemming from. "hcd" is the parent's host controller which is not always the same as the child's host controller. It would have been keen if we could somehow know the child's host controller and get a pointer to that, but we can't because the child device hasn't been enumerated yet. OK, I'm convinced. I'll mention it in your v23 but maybe I'll have a slightly better chance of figuring this out if/when I look at this again if we rename "hcd" to "parent_hcd". -Doug
On Fri, Jun 24, 2022 at 01:33:19PM -0700, Doug Anderson wrote: > Hi, > > On Fri, Jun 17, 2022 at 9:34 AM Matthias Kaehlcke <mka@chromium.org> wrote: > > > > > Looking at the "companion-hub" case with fresh eyes, too, I wonder if > > > that can be simpler. If we find a companion hub, do we need both the > > > check for usb_hcd_is_primary_hcd() and the check to see whether the > > > pdev was already created? > > > > I was also doubting about this and concluded that it is still needed. > > > > Let's use once more the trogdor config as example, which has one physical > > onboard hub chip with a USB 3.1 hub and a USB 2.1 companion hub, connected > > to the dwc3 controller: > > > > &usb_1_dwc3 { > > dr_mode = "host"; > > #address-cells = <1>; > > #size-cells = <0>; > > > > /* 2.x hub on port 1 */ > > usb_hub_2_x: hub@1 { > > compatible = "usbbda,5411"; > > reg = <1>; > > vdd-supply = <&pp3300_hub>; > > companion-hub = <&usb_hub_3_x>; > > }; > > > > /* 3.x hub on port 2 */ > > usb_hub_3_x: hub@2 { > > compatible = "usbbda,411"; > > reg = <2>; > > vdd-supply = <&pp3300_hub>; > > companion-hub = <&usb_hub_2_x>; > > }; > > }; > > > > Let's assume we don't check for the pdev. With our change above for root hubs > > the loop is now only executed for the primary HCD. In the first iteration > > we encounter the 2.x hub, it has a companion hub, but that alone doesn't > > tell us much, so we create a pdev. In the next iteration we encouter the > > 3.x hub, it also has a companion hub, but we don't know/check that the > > companion already has a pdev, so we create another one for the same > > physical hub. > > Ah, you are correct. You only run into that case for the root hub, > correct? For everything else it's impossible? > > ...and I guess things would be different if inside the loop you > actually set "hcd" to point to the "hcd" of the child device. I guess > that's where my confusion keeps stemming from. "hcd" is the parent's > host controller which is not always the same as the child's host > controller. I'd phrase it differently: for root hubs the 'parent_hub' isn't necessarily the parent of each 'child' node. > It would have been keen if we could somehow know the child's host > controller and get a pointer to that, but we can't because the child > device hasn't been enumerated yet. > > OK, I'm convinced. I'll mention it in your v23 but maybe I'll have a > slightly better chance of figuring this out if/when I look at this > again if we rename "hcd" to "parent_hcd". I'm not convinced that this would generally help to reduce the confusion. To me 'parent_hcd' sounds as if there was a tree of HCDs, which isn't the case. Also one could still read 'parent_hcd' as the HCD of all 'child' nodes. Maybe a bit more verbose documentation like this could help: Some background about the logic in this function, which can be a bit hard to follow: Root hubs don't have dedicated device tree nodes, but use the node of their HCD. The primary and secondary HCD are usually represented by a single DT node. That means the root hubs of the primary and secondary HCD share the same device tree node (the HCD node). As a result this function can be called twice with the same DT node for root hubs. We only want to create a single platform device for each physical onboard hub, hence for root hubs the loop is only executed for the primary hub. Since the function scans through all child nodes it still creates pdevs for onboard hubs connected to the secondary hub if needed. Further there must be only one platform device for onboard hubs with a companion hub (the hub is a single physical device). To achieve this two measures are taken: pdevs for onboard hubs with a companion are only created when the function is called on behalf of the parent hub that is connected to the primary HCD (directly or through other hubs). For onboard hubs connected to root hubs the function processes the nodes of both companions. A platform device is only created if the companion hub doesn't have one already. When writing this I realized that the check for an existing platform device for companions could be put inside an 'if (!parent_hub->parent)' block. It isn't necessary for hubs deeper down in the chain, since their pdev will only be created for the hub (indirectly) connected to the primary HCD.
On Mon, Jun 27, 2022 at 11:14:47AM -0700, Matthias Kaehlcke wrote: > Maybe a bit more verbose documentation like this could help: > > Some background about the logic in this function, which can be a bit hard > to follow: > > Root hubs don't have dedicated device tree nodes, but use the node of their > HCD. The primary and secondary HCD are usually represented by a single DT > node. That means the root hubs of the primary and secondary HCD share the > same device tree node (the HCD node). As a result this function can be > called twice with the same DT node for root hubs. We only want to create a > single platform device for each physical onboard hub, hence for root hubs > the loop is only executed for the primary hub. Since the function scans By "primary hub", you mean "root hub for the primary HCD", right? This should be clarified. > through all child nodes it still creates pdevs for onboard hubs connected > to the secondary hub if needed. And likewise for "secondary hub". > > Further there must be only one platform device for onboard hubs with a > companion hub (the hub is a single physical device). To achieve this two What do you mean by "companion hub"? I think you are using the wrong word here. If you're talking about the relation between the two logical hubs (one attached to the SuperSpeed bus and one attached to the Low/Full/High-speed bus) within a physical USB-3 hub, the correct term for this is "peer". See the existing usages in hub.h, hub.c, and port.c. "Companion" refers to something completely different (i.e., the UHCI or OHCI controllers that handle Low/Full-speed connections on behalf of a High-speed EHCI controller). Alan Stern
On Mon, Jun 27, 2022 at 02:54:03PM -0400, Alan Stern wrote: > On Mon, Jun 27, 2022 at 11:14:47AM -0700, Matthias Kaehlcke wrote: > > Maybe a bit more verbose documentation like this could help: > > > > Some background about the logic in this function, which can be a bit hard > > to follow: > > > > Root hubs don't have dedicated device tree nodes, but use the node of their > > HCD. The primary and secondary HCD are usually represented by a single DT > > node. That means the root hubs of the primary and secondary HCD share the > > same device tree node (the HCD node). As a result this function can be > > called twice with the same DT node for root hubs. We only want to create a > > single platform device for each physical onboard hub, hence for root hubs > > the loop is only executed for the primary hub. Since the function scans > > By "primary hub", you mean "root hub for the primary HCD", right? This > should be clarified. Ok, thanks for the suggestion! > > through all child nodes it still creates pdevs for onboard hubs connected > > to the secondary hub if needed. > > And likewise for "secondary hub". > > > > > Further there must be only one platform device for onboard hubs with a > > companion hub (the hub is a single physical device). To achieve this two > > What do you mean by "companion hub"? I think you are using the wrong > word here. If you're talking about the relation between the two logical > hubs (one attached to the SuperSpeed bus and one attached to the > Low/Full/High-speed bus) within a physical USB-3 hub, the correct term > for this is "peer". See the existing usages in hub.h, hub.c, and > port.c. > > "Companion" refers to something completely different (i.e., the UHCI or > OHCI controllers that handle Low/Full-speed connections on behalf of a > High-speed EHCI controller). Yes it's the relation between the two logical hub. The term 'companion-hub' stems from the binding and has been around since v6 of this series. I guess we should update the binding if the terminology isn't correct.
On Mon, Jun 27, 2022 at 12:06:21PM -0700, Matthias Kaehlcke wrote: > On Mon, Jun 27, 2022 at 02:54:03PM -0400, Alan Stern wrote: > > On Mon, Jun 27, 2022 at 11:14:47AM -0700, Matthias Kaehlcke wrote: > > > > > > Further there must be only one platform device for onboard hubs with a > > > companion hub (the hub is a single physical device). To achieve this two > > > > What do you mean by "companion hub"? I think you are using the wrong > > word here. If you're talking about the relation between the two logical > > hubs (one attached to the SuperSpeed bus and one attached to the > > Low/Full/High-speed bus) within a physical USB-3 hub, the correct term > > for this is "peer". See the existing usages in hub.h, hub.c, and > > port.c. > > > > "Companion" refers to something completely different (i.e., the UHCI or > > OHCI controllers that handle Low/Full-speed connections on behalf of a > > High-speed EHCI controller). > > Yes it's the relation between the two logical hub. The term 'companion-hub' > stems from the binding and has been around since v6 of this series. I guess > we should update the binding if the terminology isn't correct. That sounds like a good idea. Alan Stern
Hi, On Mon, Jun 27, 2022 at 11:14 AM Matthias Kaehlcke <mka@chromium.org> wrote: > > On Fri, Jun 24, 2022 at 01:33:19PM -0700, Doug Anderson wrote: > > Hi, > > > > On Fri, Jun 17, 2022 at 9:34 AM Matthias Kaehlcke <mka@chromium.org> wrote: > > > > > > > Looking at the "companion-hub" case with fresh eyes, too, I wonder if > > > > that can be simpler. If we find a companion hub, do we need both the > > > > check for usb_hcd_is_primary_hcd() and the check to see whether the > > > > pdev was already created? > > > > > > I was also doubting about this and concluded that it is still needed. > > > > > > Let's use once more the trogdor config as example, which has one physical > > > onboard hub chip with a USB 3.1 hub and a USB 2.1 companion hub, connected > > > to the dwc3 controller: > > > > > > &usb_1_dwc3 { > > > dr_mode = "host"; > > > #address-cells = <1>; > > > #size-cells = <0>; > > > > > > /* 2.x hub on port 1 */ > > > usb_hub_2_x: hub@1 { > > > compatible = "usbbda,5411"; > > > reg = <1>; > > > vdd-supply = <&pp3300_hub>; > > > companion-hub = <&usb_hub_3_x>; > > > }; > > > > > > /* 3.x hub on port 2 */ > > > usb_hub_3_x: hub@2 { > > > compatible = "usbbda,411"; > > > reg = <2>; > > > vdd-supply = <&pp3300_hub>; > > > companion-hub = <&usb_hub_2_x>; > > > }; > > > }; > > > > > > Let's assume we don't check for the pdev. With our change above for root hubs > > > the loop is now only executed for the primary HCD. In the first iteration > > > we encounter the 2.x hub, it has a companion hub, but that alone doesn't > > > tell us much, so we create a pdev. In the next iteration we encouter the > > > 3.x hub, it also has a companion hub, but we don't know/check that the > > > companion already has a pdev, so we create another one for the same > > > physical hub. > > > > Ah, you are correct. You only run into that case for the root hub, > > correct? For everything else it's impossible? > > > > ...and I guess things would be different if inside the loop you > > actually set "hcd" to point to the "hcd" of the child device. I guess > > that's where my confusion keeps stemming from. "hcd" is the parent's > > host controller which is not always the same as the child's host > > controller. > > I'd phrase it differently: for root hubs the 'parent_hub' isn't necessarily > the parent of each 'child' node. > > > It would have been keen if we could somehow know the child's host > > controller and get a pointer to that, but we can't because the child > > device hasn't been enumerated yet. > > > > OK, I'm convinced. I'll mention it in your v23 but maybe I'll have a > > slightly better chance of figuring this out if/when I look at this > > again if we rename "hcd" to "parent_hcd". > > I'm not convinced that this would generally help to reduce the confusion. > To me 'parent_hcd' sounds as if there was a tree of HCDs, which isn't > the case. Also one could still read 'parent_hcd' as the HCD of all > 'child' nodes. > > Maybe a bit more verbose documentation like this could help: > > Some background about the logic in this function, which can be a bit hard > to follow: > > Root hubs don't have dedicated device tree nodes, but use the node of their > HCD. The primary and secondary HCD are usually represented by a single DT > node. That means the root hubs of the primary and secondary HCD share the > same device tree node (the HCD node). As a result this function can be > called twice with the same DT node for root hubs. We only want to create a > single platform device for each physical onboard hub, hence for root hubs > the loop is only executed for the primary hub. Since the function scans > through all child nodes it still creates pdevs for onboard hubs connected > to the secondary hub if needed. > > Further there must be only one platform device for onboard hubs with a > companion hub (the hub is a single physical device). To achieve this two > measures are taken: pdevs for onboard hubs with a companion are only > created when the function is called on behalf of the parent hub that is > connected to the primary HCD (directly or through other hubs). For onboard > hubs connected to root hubs the function processes the nodes of both > companions. A platform device is only created if the companion hub doesn't > have one already. Sounds good. Extra docs explaining this are always good and I'm fine with more docs and leaving it called "hcd" instead of "parent_hcd" > When writing this I realized that the check for an existing platform device > for companions could be put inside an 'if (!parent_hub->parent)' block. It > isn't necessary for hubs deeper down in the chain, since their pdev will only > be created for the hub (indirectly) connected to the primary HCD. Yup. I'm not 100% sure if it's worth adding the extra "if" test or not. Could make the argument either way. -Doug
diff --git a/Documentation/ABI/testing/sysfs-bus-platform-onboard-usb-hub b/Documentation/ABI/testing/sysfs-bus-platform-onboard-usb-hub new file mode 100644 index 000000000000..42deb0552065 --- /dev/null +++ b/Documentation/ABI/testing/sysfs-bus-platform-onboard-usb-hub @@ -0,0 +1,8 @@ +What: /sys/bus/platform/devices/<dev>/always_powered_in_suspend +Date: June 2022 +KernelVersion: 5.20 +Contact: Matthias Kaehlcke <matthias@kaehlcke.net> + linux-usb@vger.kernel.org +Description: + (RW) Controls whether the USB hub remains always powered + during system suspend or not. \ No newline at end of file diff --git a/MAINTAINERS b/MAINTAINERS index a6d3bd9d2a8d..caeef7e111c3 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -14784,6 +14784,13 @@ S: Maintained T: git git://linuxtv.org/media_tree.git F: drivers/media/i2c/ov9734.c +ONBOARD USB HUB DRIVER +M: Matthias Kaehlcke <mka@chromium.org> +L: linux-usb@vger.kernel.org +S: Maintained +F: Documentation/ABI/testing/sysfs-bus-platform-onboard-usb-hub +F: drivers/usb/misc/onboard_usb_hub.c + ONENAND FLASH DRIVER M: Kyungmin Park <kyungmin.park@samsung.com> L: linux-mtd@lists.infradead.org diff --git a/drivers/usb/core/Makefile b/drivers/usb/core/Makefile index 18e874b0441e..0ce219f5a343 100644 --- a/drivers/usb/core/Makefile +++ b/drivers/usb/core/Makefile @@ -11,6 +11,7 @@ usbcore-y += phy.o port.o usbcore-$(CONFIG_OF) += of.o usbcore-$(CONFIG_USB_PCI) += hcd-pci.o usbcore-$(CONFIG_ACPI) += usb-acpi.o +usbcore-$(CONFIG_USB_ONBOARD_HUB) += ../misc/onboard_usb_hub_pdevs.o obj-$(CONFIG_USB) += usbcore.o diff --git a/drivers/usb/misc/Kconfig b/drivers/usb/misc/Kconfig index 4c5ddbd75b7e..993d07d2ffe5 100644 --- a/drivers/usb/misc/Kconfig +++ b/drivers/usb/misc/Kconfig @@ -295,3 +295,26 @@ config BRCM_USB_PINMAP This option enables support for remapping some USB external signals, which are typically on dedicated pins on the chip, to any gpio. + +config USB_ONBOARD_HUB + bool "Onboard USB hub support" + depends on OF || COMPILE_TEST + help + Say Y here if you want to support discrete onboard USB hubs that + don't require an additional control bus for initialization, but + need some non-trivial form of initialization, such as enabling a + power regulator. An example for such a hub is the Realtek + RTS5411. + + This driver can be used as a module but its state (module vs + builtin) must match the state of the USB subsystem. Enabling + this config will enable the driver and it will automatically + match the state of the USB subsystem. If this driver is a + module it will be called onboard_usb_hub. + +if USB_ONBOARD_HUB +config USB_ONBOARD_HUB_ACTUAL + tristate + default m if USB=m + default y if USB=y +endif diff --git a/drivers/usb/misc/Makefile b/drivers/usb/misc/Makefile index 35bdb4b6c3b6..ea65e202a055 100644 --- a/drivers/usb/misc/Makefile +++ b/drivers/usb/misc/Makefile @@ -33,3 +33,4 @@ obj-$(CONFIG_USB_CHAOSKEY) += chaoskey.o obj-$(CONFIG_USB_SISUSBVGA) += sisusbvga/ obj-$(CONFIG_USB_LINK_LAYER_TEST) += lvstest.o obj-$(CONFIG_BRCM_USB_PINMAP) += brcmstb-usb-pinmap.o +obj-$(CONFIG_USB_ONBOARD_HUB_ACTUAL) += onboard_usb_hub.o diff --git a/drivers/usb/misc/onboard_usb_hub.c b/drivers/usb/misc/onboard_usb_hub.c new file mode 100644 index 000000000000..21655b9ff559 --- /dev/null +++ b/drivers/usb/misc/onboard_usb_hub.c @@ -0,0 +1,426 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Driver for onboard USB hubs + * + * Copyright (c) 2022, Google LLC + */ + +#include <linux/device.h> +#include <linux/export.h> +#include <linux/init.h> +#include <linux/kernel.h> +#include <linux/list.h> +#include <linux/module.h> +#include <linux/mutex.h> +#include <linux/of.h> +#include <linux/of_platform.h> +#include <linux/platform_device.h> +#include <linux/regulator/consumer.h> +#include <linux/slab.h> +#include <linux/suspend.h> +#include <linux/sysfs.h> +#include <linux/usb.h> +#include <linux/usb/hcd.h> +#include <linux/usb/onboard_hub.h> +#include <linux/workqueue.h> + +#include "onboard_usb_hub.h" + +static struct usb_device_driver onboard_hub_usbdev_driver; + +/************************** Platform driver **************************/ + +struct usbdev_node { + struct usb_device *udev; + struct list_head list; +}; + +struct onboard_hub { + struct regulator *vdd; + struct device *dev; + bool always_powered_in_suspend; + bool is_powered_on; + bool going_away; + struct list_head udev_list; + struct work_struct attach_usb_driver_work; + struct mutex lock; +}; + +static int onboard_hub_power_on(struct onboard_hub *hub) +{ + int err; + + err = regulator_enable(hub->vdd); + if (err) { + dev_err(hub->dev, "failed to enable regulator: %d\n", err); + return err; + } + + hub->is_powered_on = true; + + return 0; +} + +static int onboard_hub_power_off(struct onboard_hub *hub) +{ + int err; + + err = regulator_disable(hub->vdd); + if (err) { + dev_err(hub->dev, "failed to disable regulator: %d\n", err); + return err; + } + + hub->is_powered_on = false; + + return 0; +} + +static int __maybe_unused onboard_hub_suspend(struct device *dev) +{ + struct onboard_hub *hub = dev_get_drvdata(dev); + struct usbdev_node *node; + bool power_off = true; + + if (hub->always_powered_in_suspend) + return 0; + + mutex_lock(&hub->lock); + + list_for_each_entry(node, &hub->udev_list, list) { + if (!device_may_wakeup(node->udev->bus->controller)) + continue; + + if (usb_wakeup_enabled_descendants(node->udev)) { + power_off = false; + break; + } + } + + mutex_unlock(&hub->lock); + + if (!power_off) + return 0; + + return onboard_hub_power_off(hub); +} + +static int __maybe_unused onboard_hub_resume(struct device *dev) +{ + struct onboard_hub *hub = dev_get_drvdata(dev); + + if (hub->is_powered_on) + return 0; + + return onboard_hub_power_on(hub); +} + +static inline void get_udev_link_name(const struct usb_device *udev, char *buf, size_t size) +{ + snprintf(buf, size, "usb_dev.%s", dev_name(&udev->dev)); +} + +static int onboard_hub_add_usbdev(struct onboard_hub *hub, struct usb_device *udev) +{ + struct usbdev_node *node; + char link_name[64]; + int err; + + mutex_lock(&hub->lock); + + if (hub->going_away) { + err = -EINVAL; + goto error; + } + + node = kzalloc(sizeof(*node), GFP_KERNEL); + if (!node) { + err = -ENOMEM; + goto error; + } + + node->udev = udev; + + list_add(&node->list, &hub->udev_list); + + mutex_unlock(&hub->lock); + + get_udev_link_name(udev, link_name, sizeof(link_name)); + WARN_ON(sysfs_create_link(&hub->dev->kobj, &udev->dev.kobj, link_name)); + + return 0; + +error: + mutex_unlock(&hub->lock); + + return err; +} + +static void onboard_hub_remove_usbdev(struct onboard_hub *hub, const struct usb_device *udev) +{ + struct usbdev_node *node; + char link_name[64]; + + get_udev_link_name(udev, link_name, sizeof(link_name)); + sysfs_remove_link(&hub->dev->kobj, link_name); + + mutex_lock(&hub->lock); + + list_for_each_entry(node, &hub->udev_list, list) { + if (node->udev == udev) { + list_del(&node->list); + kfree(node); + break; + } + } + + mutex_unlock(&hub->lock); +} + +static ssize_t always_powered_in_suspend_show(struct device *dev, struct device_attribute *attr, + char *buf) +{ + const struct onboard_hub *hub = dev_get_drvdata(dev); + + return sysfs_emit(buf, "%d\n", hub->always_powered_in_suspend); +} + +static ssize_t always_powered_in_suspend_store(struct device *dev, struct device_attribute *attr, + const char *buf, size_t count) +{ + struct onboard_hub *hub = dev_get_drvdata(dev); + bool val; + int ret; + + ret = kstrtobool(buf, &val); + if (ret < 0) + return ret; + + hub->always_powered_in_suspend = val; + + return count; +} +static DEVICE_ATTR_RW(always_powered_in_suspend); + +static struct attribute *onboard_hub_attrs[] = { + &dev_attr_always_powered_in_suspend.attr, + NULL, +}; +ATTRIBUTE_GROUPS(onboard_hub); + +static void onboard_hub_attach_usb_driver(struct work_struct *work) +{ + int err; + + err = driver_attach(&onboard_hub_usbdev_driver.drvwrap.driver); + if (err) + pr_err("Failed to attach USB driver: %d\n", err); +} + +static int onboard_hub_probe(struct platform_device *pdev) +{ + struct device *dev = &pdev->dev; + struct onboard_hub *hub; + int err; + + hub = devm_kzalloc(dev, sizeof(*hub), GFP_KERNEL); + if (!hub) + return -ENOMEM; + + hub->vdd = devm_regulator_get(dev, "vdd"); + if (IS_ERR(hub->vdd)) + return PTR_ERR(hub->vdd); + + hub->dev = dev; + mutex_init(&hub->lock); + INIT_LIST_HEAD(&hub->udev_list); + + dev_set_drvdata(dev, hub); + + err = onboard_hub_power_on(hub); + if (err) + return err; + + /* + * The USB driver might have been detached from the USB devices by + * onboard_hub_remove(), make sure to re-attach it if needed. + * + * This needs to be done deferred to avoid self-deadlocks on systems + * with nested onboard hubs. + */ + INIT_WORK(&hub->attach_usb_driver_work, onboard_hub_attach_usb_driver); + schedule_work(&hub->attach_usb_driver_work); + + return 0; +} + +static int onboard_hub_remove(struct platform_device *pdev) +{ + struct onboard_hub *hub = dev_get_drvdata(&pdev->dev); + struct usbdev_node *node; + struct usb_device *udev; + + hub->going_away = true; + + cancel_work_sync(&hub->attach_usb_driver_work); + + mutex_lock(&hub->lock); + + /* unbind the USB devices to avoid dangling references to this device */ + while (!list_empty(&hub->udev_list)) { + node = list_first_entry(&hub->udev_list, struct usbdev_node, list); + udev = node->udev; + + /* + * Unbinding the driver will call onboard_hub_remove_usbdev(), + * which acquires hub->lock. We must release the lock first. + */ + get_device(&udev->dev); + mutex_unlock(&hub->lock); + device_release_driver(&udev->dev); + put_device(&udev->dev); + mutex_lock(&hub->lock); + } + + mutex_unlock(&hub->lock); + + return onboard_hub_power_off(hub); +} + +MODULE_DEVICE_TABLE(of, onboard_hub_match); + +static const struct dev_pm_ops __maybe_unused onboard_hub_pm_ops = { + SET_LATE_SYSTEM_SLEEP_PM_OPS(onboard_hub_suspend, onboard_hub_resume) +}; + +static struct platform_driver onboard_hub_driver = { + .probe = onboard_hub_probe, + .remove = onboard_hub_remove, + + .driver = { + .name = "onboard-usb-hub", + .of_match_table = onboard_hub_match, + .pm = pm_ptr(&onboard_hub_pm_ops), + .dev_groups = onboard_hub_groups, + }, +}; + +/************************** USB driver **************************/ + +#define VENDOR_ID_REALTEK 0x0bda + +/* + * Returns the onboard_hub platform device that is associated with the USB + * device passed as parameter. + */ +static struct onboard_hub *_find_onboard_hub(struct device *dev) +{ + struct platform_device *pdev; + struct device_node *np; + struct onboard_hub *hub; + + pdev = of_find_device_by_node(dev->of_node); + if (!pdev) { + np = of_parse_phandle(dev->of_node, "companion-hub", 0); + if (!np) { + dev_err(dev, "failed to find device node for companion hub\n"); + return ERR_PTR(-EINVAL); + } + + pdev = of_find_device_by_node(np); + of_node_put(np); + + if (!pdev) + return ERR_PTR(-ENODEV); + } + + hub = dev_get_drvdata(&pdev->dev); + put_device(&pdev->dev); + + /* + * The presence of drvdata ('hub') indicates that the platform driver + * finished probing. This handles the case where (conceivably) we could + * be running at the exact same time as the platform driver's probe. If + * we detect the race we request probe deferral and we'll come back and + * try again. + */ + if (!hub) + return ERR_PTR(-EPROBE_DEFER); + + return hub; +} + +static int onboard_hub_usbdev_probe(struct usb_device *udev) +{ + struct device *dev = &udev->dev; + struct onboard_hub *hub; + int err; + + /* ignore supported hubs without device tree node */ + if (!dev->of_node) + return -ENODEV; + + hub = _find_onboard_hub(dev); + if (IS_ERR(hub)) + return PTR_ERR(hub); + + dev_set_drvdata(dev, hub); + + err = onboard_hub_add_usbdev(hub, udev); + if (err) + return err; + + return 0; +} + +static void onboard_hub_usbdev_disconnect(struct usb_device *udev) +{ + struct onboard_hub *hub = dev_get_drvdata(&udev->dev); + + onboard_hub_remove_usbdev(hub, udev); +} + +static const struct usb_device_id onboard_hub_id_table[] = { + { USB_DEVICE(VENDOR_ID_REALTEK, 0x0411) }, /* RTS5411 USB 3.1 */ + { USB_DEVICE(VENDOR_ID_REALTEK, 0x5411) }, /* RTS5411 USB 2.1 */ + { USB_DEVICE(VENDOR_ID_REALTEK, 0x0414) }, /* RTS5414 USB 3.2 */ + { USB_DEVICE(VENDOR_ID_REALTEK, 0x5414) }, /* RTS5414 USB 2.1 */ + {} +}; +MODULE_DEVICE_TABLE(usb, onboard_hub_id_table); + +static struct usb_device_driver onboard_hub_usbdev_driver = { + .name = "onboard-usb-hub", + .probe = onboard_hub_usbdev_probe, + .disconnect = onboard_hub_usbdev_disconnect, + .generic_subclass = 1, + .supports_autosuspend = 1, + .id_table = onboard_hub_id_table, +}; + +static int __init onboard_hub_init(void) +{ + int ret; + + ret = platform_driver_register(&onboard_hub_driver); + if (ret) + return ret; + + ret = usb_register_device_driver(&onboard_hub_usbdev_driver, THIS_MODULE); + if (ret) + platform_driver_unregister(&onboard_hub_driver); + + return ret; +} +module_init(onboard_hub_init); + +static void __exit onboard_hub_exit(void) +{ + usb_deregister_device_driver(&onboard_hub_usbdev_driver); + platform_driver_unregister(&onboard_hub_driver); +} +module_exit(onboard_hub_exit); + +MODULE_AUTHOR("Matthias Kaehlcke <mka@chromium.org>"); +MODULE_DESCRIPTION("Driver for discrete onboard USB hubs"); +MODULE_LICENSE("GPL v2"); diff --git a/drivers/usb/misc/onboard_usb_hub.h b/drivers/usb/misc/onboard_usb_hub.h new file mode 100644 index 000000000000..d3a5b6938582 --- /dev/null +++ b/drivers/usb/misc/onboard_usb_hub.h @@ -0,0 +1,17 @@ +/* SPDX-License-Identifier: GPL-2.0+ */ +/* + * Copyright (c) 2022, Google LLC + */ + +#ifndef _USB_MISC_ONBOARD_USB_HUB_H +#define _USB_MISC_ONBOARD_USB_HUB_H + +static const struct of_device_id onboard_hub_match[] = { + { .compatible = "usbbda,411" }, + { .compatible = "usbbda,5411" }, + { .compatible = "usbbda,414" }, + { .compatible = "usbbda,5414" }, + {} +}; + +#endif /* _USB_MISC_ONBOARD_USB_HUB_H */ diff --git a/drivers/usb/misc/onboard_usb_hub_pdevs.c b/drivers/usb/misc/onboard_usb_hub_pdevs.c new file mode 100644 index 000000000000..8f38cca9e530 --- /dev/null +++ b/drivers/usb/misc/onboard_usb_hub_pdevs.c @@ -0,0 +1,129 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * API for creating and destroying USB onboard hub platform devices + * + * Copyright (c) 2022, Google LLC + */ + +#include <linux/device.h> +#include <linux/export.h> +#include <linux/kernel.h> +#include <linux/list.h> +#include <linux/of.h> +#include <linux/of_platform.h> +#include <linux/platform_device.h> +#include <linux/usb.h> +#include <linux/usb/hcd.h> +#include <linux/usb/of.h> + +#include "onboard_usb_hub.h" + +struct pdev_list_entry { + struct platform_device *pdev; + struct list_head node; +}; + +static bool of_is_onboard_usb_hub(const struct device_node *np) +{ + return !!of_match_node(onboard_hub_match, np); +} + +/** + * onboard_hub_create_pdevs -- create platform devices for onboard USB hubs + * @parent_hub : parent hub to scan for connected onboard hubs + * @pdev_list : list of onboard hub platform devices owned by the parent hub + * + * Creates a platform device for each supported onboard hub that is connected to + * the given parent hub. To keep track of the platform devices they are added to + * a list that is owned by the parent hub. + */ +void onboard_hub_create_pdevs(struct usb_device *parent_hub, struct list_head *pdev_list) +{ + int i; + struct usb_hcd *hcd = bus_to_hcd(parent_hub->bus); + struct device_node *np, *npc; + struct platform_device *pdev = NULL; + struct pdev_list_entry *pdle; + + if (!parent_hub->dev.of_node) + return; + + for (i = 1; i <= parent_hub->maxchild; i++) { + np = usb_of_get_device_node(parent_hub, i); + if (!np) + continue; + + if (!of_is_onboard_usb_hub(np)) + goto node_put; + + npc = of_parse_phandle(np, "companion-hub", 0); + if (npc) { + /* + * Hubs with companions share the same platform device. + * Create the plaform device only for the hub that is + * connected to the primary HCD (directly or through + * other hubs). + */ + if (!usb_hcd_is_primary_hcd(hcd)) { + of_node_put(npc); + goto node_put; + } + + pdev = of_find_device_by_node(npc); + of_node_put(npc); + } else { + /* + * For root hubs this function can be called multiple times + * for the same root hub node (the HCD node). Make sure only + * one platform device is created for this hub. + */ + if (!parent_hub->parent && !usb_hcd_is_primary_hcd(hcd)) + goto node_put; + } + + if (pdev) { + /* the companion hub already has a platform device, nothing to do here */ + put_device(&pdev->dev); + goto node_put; + } + + pdev = of_platform_device_create(np, NULL, &parent_hub->dev); + if (!pdev) { + dev_err(&parent_hub->dev, + "failed to create platform device for onboard hub '%pOF'\n", np); + goto node_put; + } + + pdle = kzalloc(sizeof(*pdle), GFP_KERNEL); + if (!pdle) { + of_platform_device_destroy(&pdev->dev, NULL); + goto node_put; + } + + pdle->pdev = pdev; + list_add(&pdle->node, pdev_list); + +node_put: + of_node_put(np); + } +} +EXPORT_SYMBOL_GPL(onboard_hub_create_pdevs); + +/** + * onboard_hub_destroy_pdevs -- free resources of onboard hub platform devices + * @pdev_list : list of onboard hub platform devices + * + * Destroys the platform devices in the given list and frees the memory associated + * with the list entry. + */ +void onboard_hub_destroy_pdevs(struct list_head *pdev_list) +{ + struct pdev_list_entry *pdle, *tmp; + + list_for_each_entry_safe(pdle, tmp, pdev_list, node) { + list_del(&pdle->node); + of_platform_device_destroy(&pdle->pdev->dev, NULL); + kfree(pdle); + } +} +EXPORT_SYMBOL_GPL(onboard_hub_destroy_pdevs); diff --git a/include/linux/usb/onboard_hub.h b/include/linux/usb/onboard_hub.h new file mode 100644 index 000000000000..d9373230556e --- /dev/null +++ b/include/linux/usb/onboard_hub.h @@ -0,0 +1,18 @@ +/* SPDX-License-Identifier: GPL-2.0 */ + +#ifndef __LINUX_USB_ONBOARD_HUB_H +#define __LINUX_USB_ONBOARD_HUB_H + +struct usb_device; +struct list_head; + +#if IS_ENABLED(CONFIG_USB_ONBOARD_HUB) +void onboard_hub_create_pdevs(struct usb_device *parent_hub, struct list_head *pdev_list); +void onboard_hub_destroy_pdevs(struct list_head *pdev_list); +#else +static inline void onboard_hub_create_pdevs(struct usb_device *parent_hub, + struct list_head *pdev_list) {} +static inline void onboard_hub_destroy_pdevs(struct list_head *pdev_list) {} +#endif + +#endif /* __LINUX_USB_ONBOARD_HUB_H */