Re: [RFC PATCH 08/16] PCI: Introduce pci_scan_host_bridge() and pci_host_info

[Liviu Dudau <Liviu.Dudau@arm.com>]

On Wed, Nov 19, 2014 at 02:09:12AM +0000, Yijing Wang wrote:
> >>  struct pci_host_bridge *pci_create_host_bridge(
> >> -=09=09struct device *parent, u32 db,=20
> >> -=09=09struct pci_ops *ops, void *sysdata,=20
> >> -=09=09struct list_head *resources)
> >> +=09=09struct device *parent, u32 db, struct pci_ops *ops,=20
> >> +=09=09struct pci_host_info *info)
> >>  {
> >>  =09int error;
> >>  =09struct pci_bus *b;
> >>  =09struct pci_host_bridge *host, *h;
> >> -=09struct pci_host_bridge_window *window, *n;
> >> =20
> >>  =09down_read(&pci_host_bridge_sem);
> >>  =09list_for_each_entry(h, &pci_host_bridge_list, list) {
> >> @@ -53,7 +51,7 @@ struct pci_host_bridge *pci_create_host_bridge(
> >>  =09if (!host)
> >>  =09=09return NULL;
> >> =20
> >> -=09host->sysdata =3D sysdata;
> >> +=09host->sysdata =3D info->arg;
> >>  =09host->busnum =3D PCI_BUSNUM(db);
> >>  =09host->domain =3D PCI_DOMAIN(db);
> >>  =09host->ops =3D ops;
> >> @@ -63,18 +61,23 @@ struct pci_host_bridge *pci_create_host_bridge(
> >> =20
> >>  =09/* this is hack, just for build, will be removed later*/
> >=20
> > Why do you need this hack? Just for calling pci_domain_nr() ?
>=20
> Yes, it's temporary code, we need domain number here for pci host bridge =
register.
>=20
> >=20
> >>  =09b =3D kzalloc(sizeof(*b), GFP_KERNEL);
> >> -=09b->sysdata =3D sysdata;
> >> +=09b->sysdata =3D host->sysdata;
> >>  =09pci_bus_assign_domain_nr(b, parent);
> >>  =09host->domain =3D pci_domain_nr(b);
> >> +=09kfree(b);
> >> =20
> ...
> >> +static int pci_default_init_res(struct pci_host_bridge *host,
> >> +=09=09struct pci_host_info *info)
> >> +{
> >> +=09struct pci_host_bridge_window *window, *n;
> >> +
> >> +=09if (info->res_type !=3D PCI_HOST_RES_DEFAULT)=20
> >> +=09=09list_for_each_entry_safe(window, n, info->resources,
> >> +=09=09=09=09list)
> >> +=09=09=09list_move_tail(&window->list, &host->windows);
> >> +=09else
> >> +=09=09info->res_type =3D PCI_HOST_RES_DEFAULT;
> >=20
> > I'm confused about this assignment. Isn't this a nop as the else part
> > means info->res_type *is* PCI_HOST_RES_DEFAULT?
>=20
> No, in this patch, host drivers pass a pci host bridge resources init hoo=
k
> in pci_host_info *info, and we call this info->init_res() in pci_create_h=
ost_bridge().
>=20
> +struct pci_host_info {
> +=09u8 res_type;
> +=09void *arg;
> +=09struct list_head *resources; /*just for build, will clean up later */
> +=09int (*init_res)(struct pci_host_bridge *host,
> +=09=09=09struct pci_host_info *info);
> +};
> +

That's not what I've asked! Your code does:

=09if (info->res_type !=3D PCI_HOST_RES_DEFAULT)
=09=09....
=09else /* info->res_type =3D=3D PCI_HOST_RES_DEFAULT)
=09=09info->res_type =3D PCI_HOST_RES_DEFAULT;

info->res_type is already =3D=3D PCI_HOST_RES_DEFAULT in the else side, ass=
ignment is a NOP?


>=20
> >=20
> >> +
> >> +=09return 0;
> >> +}
> ...
> >> @@ -2038,8 +2057,13 @@ struct pci_bus *pci_scan_root_bus(struct device=
 *parent, u32 db,
> >>  =09bool found =3D false;
> >>  =09struct pci_host_bridge *host;
> >>  =09int max;
> >> +=09struct pci_host_info info;
> >> +=09
> >> +=09info.arg =3D sysdata;
> >> +=09info.resources =3D resources;
> >> +=09info.init_res =3D pci_default_init_res;
> >=20
> > I have mixed feelings about this patch. While it is heading in the righ=
t direction
> > of moving pci_host_bridge relevant information towards the right user, =
I don't think
> > you picked up the right set to move. The resource list is going to be c=
opied into
> > internal pci_host_bridge list anyway, keeping another copy is not helpf=
ul *and*
> > you have increased the code size.
> >=20
> > I think for now we should aim to get the *missing* data into pci_host_b=
ridge: MSI
> > controllers and PCI domain/segment. Then we can do more cleanup.
>=20
> Hi Liviu, I agree with you here, the changes to resources stuff seems not=
 a perfect
> solution. In my patch 6, we could pass pci domain nr by u32 PCI_DOMBUS(do=
main, bus) argument,
> and store it in pci_host_bridge. For msi controller, we couldn't save the=
 msi_controller
> in pci_host_bridge. Before we assume one pci host bridge only had one msi=
_controller,
> but now something changes, Jiang introduce hierarchy irq domain in x86, a=
nd now
> one pci host bridge may has more than one msi_controller. So I prefer to =
add a
> function to pci_host_bridge something like
>=20
> struct msi_controller *pci_get_msi_controller(struct pci_dev *dev)

Yes, good idea.

>=20
> >=20
> >> =20
> >> -=09host =3D pci_create_host_bridge(parent, db, ops, sysdata, resource=
s);
> >> +=09host =3D pci_create_host_bridge(parent, db, ops, &info);
> >>  =09if (!host)
> >>  =09=09return NULL;
> >> =20
> >> @@ -2070,6 +2094,47 @@ struct pci_bus *pci_scan_root_bus(struct device=
 *parent, u32 db,
> >>  }
> >>  EXPORT_SYMBOL(pci_scan_root_bus);
> >> =20
> >> +struct pci_host_bridge *pci_scan_host_bridge(
> >> +=09=09struct device *parent, u32 db, struct pci_ops *ops,
> >> +=09=09struct pci_host_info *info)
> >> +{
> >> +=09struct pci_host_bridge_window *window;
> >> +=09bool found =3D false;
> >> +=09struct pci_host_bridge *host;
> >> +=09int max;
> >> +
> >> +=09host =3D pci_create_host_bridge(parent, db, ops, info);
> >> +=09if (!host)
> >> +=09=09return NULL;
> >> +
> >> +=09list_for_each_entry(window, &host->windows, list)
> >> +=09=09if (window->res->flags & IORESOURCE_BUS) {
> >> +=09=09=09found =3D true;
> >> +=09=09=09break;
> >> +=09=09}
> >> +
> >> +=09host->bus =3D __pci_create_root_bus(host);
> >> +=09if (!host->bus) {
> >> +=09=09pci_free_host_bridge(host);
> >> +=09=09return NULL;
> >> +=09}
> >> +
> >> +=09if (!found) {
> >> +=09=09dev_info(&host->bus->dev,
> >> +=09=09 "No busn resource found for root bus, will use [bus %02x-ff]\n=
",
> >> +=09=09=09host->busnum);
> >> +=09=09pci_bus_insert_busn_res(host->bus, host->busnum, 255);
> >> +=09}
> >> +
> >> +=09max =3D pci_scan_child_bus(host->bus);
> >> +=09if (!found)
> >> +=09=09pci_bus_update_busn_res_end(host->bus, max);
> >> +
> >> +=09return host;
> >> +
> >> +}
> >> +EXPORT_SYMBOL(pci_scan_host_bridge);
> >> +
> >>  /**
> >>   * pci_rescan_bus_bridge_resize - scan a PCI bus for devices.
> >>   * @bridge: PCI bridge for the bus to scan
> >> diff --git a/include/linux/pci.h b/include/linux/pci.h
> >> index daa7f40..a51f5f5 100644
> >> --- a/include/linux/pci.h
> >> +++ b/include/linux/pci.h
> >> @@ -412,6 +412,21 @@ struct pci_host_bridge {
> >>  =09void *release_data;
> >>  };
> >> =20
> >> +struct pci_host_info {
> >> +=09u8 res_type;
> >> +=09void *arg;
> >> +=09struct list_head *resources; /*just for build, will clean up later=
 */
> >> +=09int (*init_res)(struct pci_host_bridge *host,=20
> >> +=09=09=09struct pci_host_info *info);
> >> +};
> >> +
> >> +static inline void init_pci_host_info(struct pci_host_info *info)
> >> +{
> >> +=09memset(info, 0 , sizeof(*info));
> >> +}
> >=20
> > Where is this used?
>=20
> Host driver uses it to init pci_host_info.

Might be worth adding it that patch rather than here.

Best regards,
Liviu

>=20
> >=20
> >> +
> >> +#define PCI_HOST_RES_DEFAULT=090x2
> >> +
> >=20
> > Magic number?
>=20
> Hmmm, I will rework pci host bridge resources stuff.
>=20
> >=20
> > Best regards,
> > Liviu
> >=20
> >>  #define=09to_pci_host_bridge(n) container_of(n, struct pci_host_bridg=
e, dev)
> >>  void pci_set_host_bridge_release(struct pci_host_bridge *bridge,
> >>  =09=09     void (*release_fn)(struct pci_host_bridge *),
> >> @@ -420,7 +435,7 @@ void pci_set_host_bridge_release(struct pci_host_b=
ridge *bridge,
> >>  int pcibios_root_bridge_prepare(struct pci_host_bridge *bridge);
> >>  struct pci_host_bridge *pci_create_host_bridge(
> >>  =09=09struct device *parent, u32 db, struct pci_ops *ops,=20
> >> -=09=09void *sys, struct list_head *resources);
> >> +=09=09struct pci_host_info *info);
> >>  /*
> >>   * The first PCI_BRIDGE_RESOURCE_NUM PCI bus resources (those that co=
rrespond
> >>   * to P2P or CardBus bridge windows) go in a table.  Additional ones =
(for
> >> @@ -785,6 +800,9 @@ void pci_bus_release_busn_res(struct pci_bus *b);
> >>  struct pci_bus *pci_scan_root_bus(struct device *parent, u32 bus,
> >>  =09=09=09=09=09     struct pci_ops *ops, void *sysdata,
> >>  =09=09=09=09=09     struct list_head *resources);
> >> +struct pci_host_bridge *pci_scan_host_bridge(struct device *parent,
> >> +=09=09u32 db, struct pci_ops *ops,
> >> +=09=09struct pci_host_info *info);
> >>  struct pci_bus *pci_add_new_bus(struct pci_bus *parent, struct pci_de=
v *dev,
> >>  =09=09=09=09int busnr);
> >>  void pcie_update_link_speed(struct pci_bus *bus, u16 link_status);
> >> --=20
> >> 1.7.1
> >>
> >> --
> >> To unsubscribe from this list: send the line "unsubscribe linux-pci" i=
n
> >> the body of a message to majordomo@vger.kernel.org
> >> More majordomo info at  http://vger.kernel.org/majordomo-info.html
> >>
> >=20
>=20
>=20
> --=20
> Thanks!
> Yijing
>=20
> --
> To unsubscribe from this list: send the line "unsubscribe linux-pci" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html
>=20

--=20
=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