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SubjectRe: [PATCH v6 12/30] PCI: Introduce pci_host_bridge_ops to support host specific operations
On Mon, Mar 09, 2015 at 10:34:09AM +0800, Yijing Wang wrote:
> Now we have weak functions like pcibios_root_bridge_prepare()
> to setup pci host bridge, We could introduce pci_host_bridge_ops
> which contain host bridge specific ops to setup pci_host_bridge.
> Then host bridge driver could add pci_host_bridge_ops hooks
> intead of weak function to setup pci_host_bridge.
> This patch add following pci_host_bridge_ops hooks:
>
> pci_host_bridge_ops {
> /* set root bus speed, some platform need this like powerpc */
> void (*set_root_bus_speed)(struct pci_host_bridge *host);
> /* setup pci_host_bridge before pci_host_bridge be added to driver core */
> int (*prepare)(struct pci_host_bridge *host);
> /* platform specific of scan hook to scan pci device */
> void (*scan_bus)(struct pci_host_bridge *);
> }
> We could easily extend it to support different host bridge
> specific operations.
>
> Signed-off-by: Yijing Wang <wangyijing@huawei.com>
> Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
> ---
> drivers/pci/host-bridge.c | 12 ++++++++++--
> drivers/pci/pci.h | 4 ++--
> drivers/pci/probe.c | 17 +++++++++++------
> include/linux/pci.h | 8 ++++++++
> 4 files changed, 31 insertions(+), 10 deletions(-)
>
> diff --git a/drivers/pci/host-bridge.c b/drivers/pci/host-bridge.c
> index 3c34c49..bc1de59 100644
> --- a/drivers/pci/host-bridge.c
> +++ b/drivers/pci/host-bridge.c
> @@ -23,8 +23,8 @@ static void pci_release_host_bridge_dev(struct device *dev)
> }
>
> struct pci_host_bridge *pci_create_host_bridge(
> - struct device *parent, u32 db,
> - struct list_head *resources, void *sysdata)
> + struct device *parent, u32 db, struct list_head *resources,
> + void *sysdata, struct pci_host_bridge_ops *ops)
> {
> int error;
> int bus = PCI_BUSNUM(db);
> @@ -56,6 +56,7 @@ struct pci_host_bridge *pci_create_host_bridge(
> }
> mutex_unlock(&phb_mutex);
>
> + host->ops = ops;
> host->dev.parent = parent;
> INIT_LIST_HEAD(&host->windows);
> host->dev.release = pci_release_host_bridge_dev;
> @@ -63,6 +64,13 @@ struct pci_host_bridge *pci_create_host_bridge(
> dev_set_name(&host->dev, "pci%04x:%02x", host->domain,
> host->busnum);
>
> + if (host->ops && host->ops->prepare) {
> + error = host->ops->prepare(host);
> + if (error) {
> + kfree(host);
> + return NULL;
> + }
> + }
> error = device_register(&host->dev);
> if (error) {
> put_device(&host->dev);
> diff --git a/drivers/pci/pci.h b/drivers/pci/pci.h
> index 79a8894..a1dc9f2 100644
> --- a/drivers/pci/pci.h
> +++ b/drivers/pci/pci.h
> @@ -324,8 +324,8 @@ static inline int pci_dev_specific_reset(struct pci_dev *dev, int probe)
> #endif
>
> struct pci_host_bridge *pci_create_host_bridge(
> - struct device *parent, u32 dombus,
> - struct list_head *resources, void *sysdata);
> + struct device *parent, u32 dombus, struct list_head *resources,
> + void *sysdata, struct pci_host_bridge_ops *ops);
>
> void pci_free_host_bridge(struct pci_host_bridge *host);
> #endif /* DRIVERS_PCI_H */
> diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
> index c8e074d..59d9be3 100644
> --- a/drivers/pci/probe.c
> +++ b/drivers/pci/probe.c
> @@ -1889,6 +1889,8 @@ static struct pci_bus *__pci_create_root_bus(
>
> bridge->bus = b;
> b->bridge = get_device(&bridge->dev);
> + if (bridge->ops && bridge->ops->set_root_bus_speed)
> + bridge->ops->set_root_bus_speed(bridge);

Before this patch, can you do this:

- Rename the powerpc pcibios_root_bridge_prepare() to
pcibios_set_root_bus_speed() and add a call to it here

- Move the pcibios_root_bridge_prepare() call to pci_create_host_bridge()

Then this patch will make a lot more sense because it will look like this,
with the host bridge ops call right next to the matching pcibios call:

+ if (host->ops && host->ops->prepare) {
+ error = host->ops->prepare(host);
+ ...
+ }
pcibios_root_bridge_prepare(...);

+ if (bridge->ops && bridge->ops->set_root_bus_speed)
+ bridge->ops->set_root_bus_speed(bridge);
pcibios_set_root_bus_speed(...);

> error = pcibios_root_bridge_prepare(bridge);
> if (error)
> goto err_out;
> @@ -1954,7 +1956,7 @@ struct pci_bus *pci_create_root_bus(struct device *parent, u32 db,
> {
> struct pci_host_bridge *host;
>
> - host = pci_create_host_bridge(parent, db, resources, sysdata);
> + host = pci_create_host_bridge(parent, db, resources, sysdata, NULL);
> if (!host)
> return NULL;
>
> @@ -2051,10 +2053,13 @@ static struct pci_bus *__pci_scan_root_bus(
> pci_bus_insert_busn_res(b, b->number, 255);
> }
>
> - max = pci_scan_child_bus(b);
> -
> - if (!found)
> - pci_bus_update_busn_res_end(b, max);
> + if (host->ops && host->ops->scan_bus) {
> + host->ops->scan_bus(host);
> + } else {
> + max = pci_scan_child_bus(b);
> + if (!found)
> + pci_bus_update_busn_res_end(b, max);
> + }

I think host->ops->scan_bus() should have the same prototype as
pci_scan_child_bus(), and it should return max, and you should do the same
busn update as when you call pci_scan_child_bus(). So the code would look
like this:

if (host->ops && host->ops->scan_bus)
max = host->ops->scan_bus(b);
else
max = pci_scan_child_bus(b);

if (!found)
pci_bus_update_busn_res_end(b, max);

>
> return b;
> }
> @@ -2064,7 +2069,7 @@ struct pci_bus *pci_scan_root_bus(struct device *parent, u32 db,
> {
> struct pci_host_bridge *host;
>
> - host = pci_create_host_bridge(parent, db, resources, sysdata);
> + host = pci_create_host_bridge(parent, db, resources, sysdata, NULL);
> if (!host)
> return NULL;
>
> diff --git a/include/linux/pci.h b/include/linux/pci.h
> index b621f5b..e9922b1 100644
> --- a/include/linux/pci.h
> +++ b/include/linux/pci.h
> @@ -400,6 +400,13 @@ static inline int pci_channel_offline(struct pci_dev *pdev)
> return (pdev->error_state != pci_channel_io_normal);
> }
>
> +struct pci_host_bridge;
> +struct pci_host_bridge_ops {
> + void (*set_root_bus_speed)(struct pci_host_bridge *host);
> + int (*prepare)(struct pci_host_bridge *host);
> + void (*scan_bus)(struct pci_host_bridge *);

Needs an argument name to match the style of the other ops.

> +};
> +
> struct pci_host_bridge {
> u16 domain;
> u16 busnum;
> @@ -407,6 +414,7 @@ struct pci_host_bridge {
> struct pci_bus *bus; /* root bus */
> struct list_head windows; /* resource_entry */
> struct list_head list;
> + struct pci_host_bridge_ops *ops;
> void (*release_fn)(struct pci_host_bridge *);
> void *release_data;
> };
> --
> 1.7.1
>
> --
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