Re: [RFC PATCH 07/16] PCI: Separate pci_host_bridge creation out of pci_create_root_bus()

[Liviu Dudau]

On Fri, Nov 21, 2014 at 02:53:01AM +0000, Yijing Wang wrote:
> >>> pci_create_host_bridge() can get pci_host_bridge ops while pci_create_root_bus() gets
> >>> the bus ops. For find out the MSI controller, the domain number and any other HB
> >>> specific stuff, you use the HB ops. For config R/W acceses you use bus ops.
> >>>
> >>
> >> I want to unexport pci_create_root_bus() if we have pci_create_host_bridge().
> >
> > That's fine, but the function signature doesn't change, right? And I think we should keep
> > pci_scan_root_bus() with the current signature as well (except change sysdata into a
> > struct pci_host_bridge *). We create the host bridge in one step, stuff it with all the
> > data that we need for scanning the root and associated busses, and then call pci_scan_root_bus().
> > pci_host_bridge has the ops from pci_create_host_bridge() and the root bus from pci_scan_root_bus().
> 
> Liviu, could you have some draft patches about replace sysdata with pci_host_bridge, so we could
> discuss the details base it. :)

Sure, I'll try to send something soon.

Best regards,
Liviu

> 
> >
> > Hope this makes sense.
> >
> >>
> >>
> >>>>>> -struct pci_bus *pci_create_root_bus(struct device *parent, u32 db,
> >>>>>> -               struct pci_ops *ops, void *sysdata, struct list_head *resources)
> >>>>>> +struct pci_bus *__pci_create_root_bus(struct pci_host_bridge *bridge)
> >>>>>>  {
> >>>>>>         int error;
> >>>>>> -       struct pci_host_bridge *bridge;
> >>>>>>         struct pci_bus *b, *b2;
> >>>>>> -       struct pci_host_bridge_window *window, *n;
> >>>>>> +       struct pci_host_bridge_window *window;
> >>>>>>         struct resource *res;
> >>>>>>         resource_size_t offset;
> >>>>>>         char bus_addr[64];
> >>>>>>         char *fmt;
> >>>>>> -       u8      bus = PCI_BUSNUM(db);
> >>>>>> +       struct device *parent = bridge->dev.parent;
> >>>>>>
> >>>>>>         b = pci_alloc_bus(NULL);
> >>>>>>         if (!b)
> >>>>>>                 return NULL;
> >>>>>>
> >>>>>> -       b->sysdata = sysdata;
> >>>>>> -       b->ops = ops;
> >>>>>> -       b->number = b->busn_res.start = bus;
> >>>>>> +       b->sysdata = bridge->sysdata;
> >>>>>
> >>>>> I think bridge should be the b->sysdata here.
> >>>>
> >>>> ? what's the meaning?
> >>>
> >>> Currently, bus->sysdata holds a pointer to the arch/driver host bridge structure, as passed
> >>> in pci_create_root_bus(). If you agree with my idea of wrapping the host bridge driver
> >>> structure around the pci_host_bridge, then we will always have a way of retrieving that
> >>> information; but for backwards compatibility we could set bus->sysdata to be the bridge.
> >>> Then existing macros that convert sysdata to pci_controller can be reused after being
> >>> updated.
> >>
> >> I think wrapping the host bridge driver structure around the pci_host_bridge could help
> >> us to find the private pci_controller, but in this case, pci_host_bridge is not a pointer
> >> so we put all pci_host_bridge init stuff in host drivers ?
> >
> > Of course we put pci_host_bridge init *calls* in the host drivers because we need to do host
> > driver specific initialisation there anyway.
> >
> >> And if we still use arch spec
> >> macros convert ssydata to pci_controller, so what's the greatest advantage ?
> >
> > Agree, the macro is not useful unless we have a common pci_controller structure. Sorry about
> > the noise.
> >
> >>
> >> If we move domain and msi_chip out of sysdata, what's other things in sysdata still need us
> >> to convert in PCI core ?
> >
> > I've never said we need to keep sysdata. From my discussion with Bjorn a year ago the idea was
> > to put the sysdata members into pci_host_bridge structure and remove sysdata member from pci_bus.
> > pci_scan_root_bus() can still get a parameter called sysdata if we want, but it will be a
> > struct pci_host_bridge * type.
> 
> Fine.
> 
> >
> > Best regards,
> > Liviu
> >
> >>
> >>
> >>
> >>>
> >>> Best regards,
> >>> Liviu
> >>>
> >>>>
> >>>>>
> >>>>>> +       b->ops = bridge->ops;
> >>>>>
> >>>>> See comment above why I don't think this is necessary.
> >>>>>
> >>>>>> +       b->number = b->busn_res.start = bridge->busnum;
> >>>>>>         pci_bus_assign_domain_nr(b, parent);
> >>>>>> -       b2 = pci_find_bus(pci_domain_nr(b), bus);
> >>>>>> +       bridge->domain = pci_domain_nr(b);
> >>>>>
> >>>>> Do you really want to overwrite the bridge's domain with the one from a bus that
> >>>>> could possibly be rejected a couple of lines further down?
> >>>>>
> >>>>> As an asside: if we are doing the split of pci_host_bridge from root bus creation
> >>>>> it is worth in my opinion to move the domain setup in pci_create_host_bridge()
> >>>>> and stop fiddling with it here.
> >>>>
> >>>>
> >>>> Hi Liviu, these lines just temporary, I will remove it after all host drivers
> >>>> save its domain in pci_host_bridge.
> >>>>
> >>>>
> >>>>>
> >>>>> Otherwise it looks to me like you are heading in the right direction.
> >>>>
> >>>> Thanks!
> >>>> Yijing.
> >>>>
> >>>>>
> >>>>> Best regards,
> >>>>> Liviu
> >>>>>
> >>>>>> +       b2 = pci_find_bus(pci_domain_nr(b), bridge->busnum);
> >>>>>>         if (b2) {
> >>>>>>                 /* If we already got to this bus through a different bridge, ignore it */
> >>>>>>                 dev_dbg(&b2->dev, "bus already known\n");
> >>>>>>                 goto err_out;
> >>>>>>         }
> >>>>>>
> >>>>>> -       bridge = pci_alloc_host_bridge(b);
> >>>>>> -       if (!bridge)
> >>>>>> -               goto err_out;
> >>>>>> -
> >>>>>> -       bridge->dev.parent = parent;
> >>>>>> -       bridge->dev.release = pci_release_host_bridge_dev;
> >>>>>> -       dev_set_name(&bridge->dev, "pci%04x:%02x", pci_domain_nr(b), bus);
> >>>>>> -       error = pcibios_root_bridge_prepare(bridge);
> >>>>>> -       if (error) {
> >>>>>> -               kfree(bridge);
> >>>>>> -               goto err_out;
> >>>>>> -       }
> >>>>>> -
> >>>>>> -       error = device_register(&bridge->dev);
> >>>>>> -       if (error) {
> >>>>>> -               put_device(&bridge->dev);
> >>>>>> -               goto err_out;
> >>>>>> -       }
> >>>>>>         b->bridge = get_device(&bridge->dev);
> >>>>>>         device_enable_async_suspend(b->bridge);
> >>>>>>         pci_set_bus_of_node(b);
> >>>>>> @@ -1950,7 +1899,7 @@ struct pci_bus *pci_create_root_bus(struct device *parent, u32 db,
> >>>>>>
> >>>>>>         b->dev.class = &pcibus_class;
> >>>>>>         b->dev.parent = b->bridge;
> >>>>>> -       dev_set_name(&b->dev, "%04x:%02x", pci_domain_nr(b), bus);
> >>>>>> +       dev_set_name(&b->dev, "%04x:%02x", pci_domain_nr(b), b->number);
> >>>>>>         error = device_register(&b->dev);
> >>>>>>         if (error)
> >>>>>>                 goto class_dev_reg_err;
> >>>>>> @@ -1966,12 +1915,11 @@ struct pci_bus *pci_create_root_bus(struct device *parent, u32 db,
> >>>>>>                 printk(KERN_INFO "PCI host bridge to bus %s\n", dev_name(&b->dev));
> >>>>>>
> >>>>>>         /* Add initial resources to the bus */
> >>>>>> -       list_for_each_entry_safe(window, n, resources, list) {
> >>>>>> -               list_move_tail(&window->list, &bridge->windows);
> >>>>>> +       list_for_each_entry(window, &bridge->windows, list) {
> >>>>>>                 res = window->res;
> >>>>>>                 offset = window->offset;
> >>>>>>                 if (res->flags & IORESOURCE_BUS)
> >>>>>> -                       pci_bus_insert_busn_res(b, bus, res->end);
> >>>>>> +                       pci_bus_insert_busn_res(b, b->number, res->end);
> >>>>>>                 else
> >>>>>>                         pci_bus_add_resource(b, res, 0);
> >>>>>>                 if (offset) {
> >>>>>> @@ -2001,6 +1949,25 @@ err_out:
> >>>>>>         return NULL;
> >>>>>>  }
> >>>>>>
> >>>>>> +struct pci_bus *pci_create_root_bus(struct device *parent, u32 bus,
> >>>>>> +               struct pci_ops *ops, void *sysdata, struct list_head *resources)
> >>>>>> +{
> >>>>>> +       struct pci_host_bridge *host;
> >>>>>> +
> >>>>>> +       host = pci_create_host_bridge(parent, bus, ops,
> >>>>>> +                       sysdata ,resources);
> >>>>>> +       if (!host)
> >>>>>> +               return NULL;
> >>>>>> +
> >>>>>> +       host->bus = __pci_create_root_bus(host);
> >>>>>> +       if (!host->bus) {
> >>>>>> +               pci_free_host_bridge(host);
> >>>>>> +               return NULL;
> >>>>>> +       }
> >>>>>> +
> >>>>>> +       return host->bus;
> >>>>>> +}
> >>>>>> +
> >>>>>>  int pci_bus_insert_busn_res(struct pci_bus *b, int bus, int bus_max)
> >>>>>>  {
> >>>>>>         struct resource *res = &b->busn_res;
> >>>>>> @@ -2069,40 +2036,37 @@ struct pci_bus *pci_scan_root_bus(struct device *parent, u32 db,
> >>>>>>  {
> >>>>>>         struct pci_host_bridge_window *window;
> >>>>>>         bool found = false;
> >>>>>> -       struct pci_bus *b;
> >>>>>> -       LIST_HEAD(default_res);
> >>>>>> +       struct pci_host_bridge *host;
> >>>>>>         int max;
> >>>>>>
> >>>>>> -       if (!resources) {
> >>>>>> -               pci_add_resource(&default_res, &ioport_resource);
> >>>>>> -               pci_add_resource(&default_res, &iomem_resource);
> >>>>>> -               pci_add_resource(&default_res, &busn_resource);
> >>>>>> -       } else {
> >>>>>> -               list_for_each_entry(window, resources, list)
> >>>>>> -                       if (window->res->flags & IORESOURCE_BUS) {
> >>>>>> -                               found = true;
> >>>>>> -                               break;
> >>>>>> -                       }
> >>>>>> -       }
> >>>>>> +       host = pci_create_host_bridge(parent, db, ops, sysdata, resources);
> >>>>>> +       if (!host)
> >>>>>> +               return NULL;
> >>>>>>
> >>>>>> -       b = pci_create_root_bus(parent, db, ops, sysdata,
> >>>>>> -                       resources ? resources : &default_res);
> >>>>>> -       if (!b)
> >>>>>> +       list_for_each_entry(window, &host->windows, list)
> >>>>>> +               if (window->res->flags & IORESOURCE_BUS) {
> >>>>>> +                       found = true;
> >>>>>> +                       break;
> >>>>>> +               }
> >>>>>> +
> >>>>>> +       host->bus = __pci_create_root_bus(host);
> >>>>>> +       if (!host->bus) {
> >>>>>> +               pci_free_host_bridge(host);
> >>>>>>                 return NULL;
> >>>>>> +       }
> >>>>>>
> >>>>>>         if (!found) {
> >>>>>> -               dev_info(&b->dev,
> >>>>>> +               dev_info(&host->bus->dev,
> >>>>>>                  "No busn resource found for root bus, will use [bus %02x-ff]\n",
> >>>>>>                         PCI_BUSNUM(db));
> >>>>>> -               pci_bus_insert_busn_res(b, PCI_BUSNUM(db), 255);
> >>>>>> +               pci_bus_insert_busn_res(host->bus, PCI_BUSNUM(db), 255);
> >>>>>>         }
> >>>>>>
> >>>>>> -       max = pci_scan_child_bus(b);
> >>>>>> -
> >>>>>> +       max = pci_scan_child_bus(host->bus);
> >>>>>>         if (!found)
> >>>>>> -               pci_bus_update_busn_res_end(b, max);
> >>>>>> +               pci_bus_update_busn_res_end(host->bus, max);
> >>>>>>
> >>>>>> -       return b;
> >>>>>> +       return host->bus;
> >>>>>>  }
> >>>>>>  EXPORT_SYMBOL(pci_scan_root_bus);
> >>>>>>
> >>>>>> diff --git a/include/linux/pci.h b/include/linux/pci.h
> >>>>>> index 8b11b38..daa7f40 100644
> >>>>>> --- a/include/linux/pci.h
> >>>>>> +++ b/include/linux/pci.h
> >>>>>> @@ -402,7 +402,12 @@ struct pci_host_bridge_window {
> >>>>>>  struct pci_host_bridge {
> >>>>>>         struct device dev;
> >>>>>>         struct pci_bus *bus;            /* root bus */
> >>>>>> +       struct list_head list;
> >>>>>>         struct list_head windows;       /* pci_host_bridge_windows */
> >>>>>> +       int busnum;
> >>>>>> +       int domain;
> >>>>>> +       void *sysdata;
> >>>>>> +       struct pci_ops *ops;
> >>>>>>         void (*release_fn)(struct pci_host_bridge *);
> >>>>>>         void *release_data;
> >>>>>>  };
> >>>>>> @@ -413,7 +418,9 @@ void pci_set_host_bridge_release(struct pci_host_bridge *bridge,
> >>>>>>                      void *release_data);
> >>>>>>
> >>>>>>  int pcibios_root_bridge_prepare(struct pci_host_bridge *bridge);
> >>>>>> -
> >>>>>> +struct pci_host_bridge *pci_create_host_bridge(
> >>>>>> +               struct device *parent, u32 db, struct pci_ops *ops,
> >>>>>> +               void *sys, struct list_head *resources);
> >>>>>>  /*
> >>>>>>   * The first PCI_BRIDGE_RESOURCE_NUM PCI bus resources (those that correspond
> >>>>>>   * to P2P or CardBus bridge windows) go in a table.  Additional ones (for
> >>>>>> @@ -770,6 +777,8 @@ void pci_bus_add_devices(const struct pci_bus *bus);
> >>>>>>  struct pci_bus *pci_create_root_bus(struct device *parent, u32 bus,
> >>>>>>                                     struct pci_ops *ops, void *sysdata,
> >>>>>>                                     struct list_head *resources);
> >>>>>> +struct pci_bus *__pci_create_root_bus(struct pci_host_bridge *host);
> >>>>>> +void pci_free_host_bridge(struct pci_host_bridge *host);
> >>>>>>  int pci_bus_insert_busn_res(struct pci_bus *b, int bus, int busmax);
> >>>>>>  int pci_bus_update_busn_res_end(struct pci_bus *b, int busmax);
> >>>>>>  void pci_bus_release_busn_res(struct pci_bus *b);
> >>>>>> --
> >>>>>> 1.7.1
> >>>>>>
> >>>>>> --
> >>>>>> To unsubscribe from this list: send the line "unsubscribe linux-pci" in
> >>>>>> the body of a message to majordomo@xxxxxxxxxxxxxxx
> >>>>>> More majordomo info at  http://vger.kernel.org/majordomo-info.html
> >>>>>>
> >>>>>
> >>>>
> >>>>
> >>>> --
> >>>> Thanks!
> >>>> Yijing
> >>>>
> >>>> --
> >>>> To unsubscribe from this list: send the line "unsubscribe linux-pci" in
> >>>> the body of a message to majordomo@xxxxxxxxxxxxxxx
> >>>> More majordomo info at  http://vger.kernel.org/majordomo-info.html
> >>>>
> >>>
> >>
> >>
> >> --
> >> Thanks!
> >> Yijing
> >>
> >>
> >
> 
> 
> --
> Thanks!
> Yijing
> 
> --
> To unsubscribe from this list: send the line "unsubscribe linux-pci" in
> the body of a message to majordomo@xxxxxxxxxxxxxxx
> More majordomo info at  http://vger.kernel.org/majordomo-info.html
> 

-- 
====================
| I would like to |
| fix the world,  |
| but they're not |
| giving me the   |
 \ source code!  /
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