Re: [RFC PATCH 07/16] PCI: Separate pci_host_bridge creation out of... | linuxppc-dev

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

From: Liviu Dudau <Liviu.Dudau@arm.com>
Date: 2014-11-21 09:53:20
Also in: linux-arm-kernel, linux-pci, lkml

On Fri, Nov 21, 2014 at 02:53:01AM +0000, Yijing Wang wrote:

quoted

pci_create_host_bridge() can get pci_host_bridge ops while pci_create=

_root_bus() gets

quoted

the bus ops. For find out the MSI controller, the domain number and a=

ny other HB

quoted

specific stuff, you use the HB ops. For config R/W acceses you use bu=

s ops.

quoted

I want to unexport pci_create_root_bus() if we have pci_create_host_br=

idge().

quoted

That's fine, but the function signature doesn't change, right? And I th=

ink we should keep

quoted

pci_scan_root_bus() with the current signature as well (except change s=

ysdata into a

quoted

struct pci_host_bridge *). We create the host bridge in one step, stuff=

 it with all the

quoted

data that we need for scanning the root and associated busses, and then=

 call pci_scan_root_bus().

quoted

pci_host_bridge has the ops from pci_create_host_bridge() and the root =

bus from pci_scan_root_bus().

=20
Liviu, could you have some draft patches about replace sysdata with pci_h=

ost_bridge, so we could

discuss the details base it. :)

Sure, I'll try to send something soon.

Best regards,
Liviu

=20

quoted

Hope this makes sense.

quoted

-struct pci_bus *pci_create_root_bus(struct device *parent, u32 db=

quoted
quoted
quoted
quoted
quoted
quoted
-               struct pci_ops *ops, void *sysdata, struct list_he=

ad *resources)

quoted
quoted
quoted
quoted
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+struct pci_bus *__pci_create_root_bus(struct pci_host_bridge *bri=

dge)

quoted

 {
        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 =3D PCI_BUSNUM(db);
+       struct device *parent =3D bridge->dev.parent;

        b =3D pci_alloc_bus(NULL);
        if (!b)
                return NULL;

-       b->sysdata =3D sysdata;
-       b->ops =3D ops;
-       b->number =3D b->busn_res.start =3D bus;
+       b->sysdata =3D 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 bridg=

e structure, as passed

quoted

in pci_create_root_bus(). If you agree with my idea of wrapping the h=

ost bridge driver

quoted

structure around the pci_host_bridge, then we will always have a way =

of retrieving that

quoted

information; but for backwards compatibility we could set bus->sysdat=

a to be the bridge.

quoted

Then existing macros that convert sysdata to pci_controller can be re=

used after being

quoted

updated.

I think wrapping the host bridge driver structure around the pci_host_=

bridge could help

quoted

us to find the private pci_controller, but in this case, pci_host_brid=

ge is not a pointer

quoted

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 becau=

se we need to do host

quoted

driver specific initialisation there anyway.

quoted

And if we still use arch spec
macros convert ssydata to pci_controller, so what's the greatest advan=

tage ?

quoted

Agree, the macro is not useful unless we have a common pci_controller s=

tructure. Sorry about

quoted

the noise.

quoted

If we move domain and msi_chip out of sysdata, what's other things in =

sysdata still need us

quoted

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

quoted

to put the sysdata members into pci_host_bridge structure and remove sy=

sdata member from pci_bus.

quoted

pci_scan_root_bus() can still get a parameter called sysdata if we want=

, but it will be a

quoted

struct pci_host_bridge * type.

=20
Fine.
=20

quoted

Best regards,
Liviu

quoted

Best regards,
Liviu

quoted

+       b->ops =3D bridge->ops;

See comment above why I don't think this is necessary.

quoted

+       b->number =3D b->busn_res.start =3D bridge->busnum;
        pci_bus_assign_domain_nr(b, parent);
-       b2 =3D pci_find_bus(pci_domain_nr(b), bus);
+       bridge->domain =3D pci_domain_nr(b);

Do you really want to overwrite the bridge's domain with the one fr=

om a bus that

quoted

could possibly be rejected a couple of lines further down?

As an asside: if we are doing the split of pci_host_bridge from roo=

t bus creation

quoted
quoted
quoted
quoted
quoted
it is worth in my opinion to move the domain setup in pci_create_ho=

st_bridge()

quoted

and stop fiddling with it here.


Hi Liviu, these lines just temporary, I will remove it after all hos=

t drivers

quoted

save its domain in pci_host_bridge.

quoted

Otherwise it looks to me like you are heading in the right directio=

n.

quoted

Thanks!
Yijing.

quoted

Best regards,
Liviu

quoted

+       b2 =3D pci_find_bus(pci_domain_nr(b), bridge->busnum);
        if (b2) {
                /* If we already got to this bus through a differe=

nt bridge, ignore it */

quoted

                dev_dbg(&b2->dev, "bus already known\n");
                goto err_out;
        }

-       bridge =3D pci_alloc_host_bridge(b);
-       if (!bridge)
-               goto err_out;
-
-       bridge->dev.parent =3D parent;
-       bridge->dev.release =3D pci_release_host_bridge_dev;
-       dev_set_name(&bridge->dev, "pci%04x:%02x", pci_domain_nr(b=

), bus);

quoted

-       error =3D pcibios_root_bridge_prepare(bridge);
-       if (error) {
-               kfree(bridge);
-               goto err_out;
-       }
-
-       error =3D device_register(&bridge->dev);
-       if (error) {
-               put_device(&bridge->dev);
-               goto err_out;
-       }
        b->bridge =3D 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 d=

evice *parent, u32 db,

quoted

        b->dev.class =3D &pcibus_class;
        b->dev.parent =3D 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->nu=

mber);

quoted

        error =3D 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,

quoted

                printk(KERN_INFO "PCI host bridge to bus %s\n", de=

v_name(&b->dev));

quoted

        /* 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 =3D window->res;
                offset =3D 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);

quoted

                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 bu=

s,

quoted
quoted
quoted
quoted
quoted
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+               struct pci_ops *ops, void *sysdata, struct list_he=

ad *resources)

quoted

+{
+       struct pci_host_bridge *host;
+
+       host =3D pci_create_host_bridge(parent, bus, ops,
+                       sysdata ,resources);
+       if (!host)
+               return NULL;
+
+       host->bus =3D __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_m=

ax)

quoted

 {
        struct resource *res =3D &b->busn_res;

@@ -2069,40 +2036,37 @@ struct pci_bus *pci_scan_root_bus(struct d=

evice *parent, u32 db,

quoted

 {
        struct pci_host_bridge_window *window;
        bool found =3D 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 =3D true;
-                               break;
-                       }
-       }
+       host =3D pci_create_host_bridge(parent, db, ops, sysdata, =

resources);

quoted

+       if (!host)
+               return NULL;

-       b =3D 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 =3D true;
+                       break;
+               }
+
+       host->bus =3D __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 [b=

us %02x-ff]\n",

quoted

                        PCI_BUSNUM(db));
-               pci_bus_insert_busn_res(b, PCI_BUSNUM(db), 255);
+               pci_bus_insert_busn_res(host->bus, PCI_BUSNUM(db),=

 255);

quoted

        }

-       max =3D pci_scan_child_bus(b);
-
+       max =3D 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=

*/

quoted

+       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_ho=

st_bridge *bridge,

quoted

                     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=

quoted

+               void *sys, struct list_head *resources);
 /*
  * The first PCI_BRIDGE_RESOURCE_NUM PCI bus resources (those tha=

t correspond

quoted
quoted
quoted
quoted
quoted
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  * to P2P or CardBus bridge windows) go in a table.  Additional o=

nes (for

quoted
quoted
quoted
quoted
quoted
quoted
@@ -770,6 +777,8 @@ void pci_bus_add_devices(const struct pci_bus =

*bus);

quoted
quoted
quoted
quoted
quoted
quoted
 struct pci_bus *pci_create_root_bus(struct device *parent, u32 bu=

s,

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                                    struct pci_ops *ops, void *sys=

data,

quoted

                                    struct list_head *resources);
+struct pci_bus *__pci_create_root_bus(struct pci_host_bridge *hos=

t);

quoted

+void pci_free_host_bridge(struct pci_host_bridge *host);
 int pci_bus_insert_busn_res(struct pci_bus *b, int bus, int busma=

x);

quoted

 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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--
Thanks!
Yijing

--
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--
Thanks!
Yijing

=20
=20
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Thanks!
Yijing
=20
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=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D
| I would like to |
| fix the world,  |
| but they're not |
| giving me the   |
 \ source code!  /
  ---------------
    =C2=AF\_(=E3=83=84)_/=C2=AF

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