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

Yijing Wang
2014-11-21T02:53:01Z

>>> 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. :)

>
> 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
>>>>>>
>>>>>> --
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>>>>>> the body of a message to majordomo at vger.kernel.org
>>>>>> 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 at vger.kernel.org
>>>> More majordomo info at http://vger.kernel.org/majordomo-info.html
>>>>
>>>
>>
>>
>> --
>> Thanks!
>> Yijing
>>
>>
>

--
Thanks!
Yijing