Re: [PATCH v6 09/30] PCI: Separate pci_host_bridge creation out of pci_create_root_bus()

From: Bjorn Helgaas
Date: Wed Mar 11 2015 - 23:52:14 EST

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In reply to: Yijing Wang: "[PATCH v6 09/30] PCI: Separate pci_host_bridge creation out of pci_create_root_bus()"
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On Mon, Mar 09, 2015 at 10:34:06AM +0800, Yijing Wang wrote:
> This patch separate pci_host_bridge creation out
> of pci_create_root_bus(), and try to make a generic
> pci_host_bridge, then we could place generic PCI
> infos like domain number in it. Also Ripping out
> pci_host_bridge creation from pci_create_root_bus()
> make code more better readability. Further more,
> we could use the generic pci_host_bridge to hold
> host bridge specific operations like
> pcibios_root_bridge_prepare(). The changes are
> transparent to platform host bridge drivers.
>
> Signed-off-by: Yijing Wang <wangyijing@xxxxxxxxxx>
> Signed-off-by: Bjorn Helgaas <bhelgaas@xxxxxxxxxx>
> ---
> drivers/pci/host-bridge.c | 55 ++++++++++++++++++++++
> drivers/pci/pci.h | 3 +
> drivers/pci/probe.c | 114 ++++++++++++++++++++-------------------------
> include/linux/pci.h | 1 +
> 4 files changed, 109 insertions(+), 64 deletions(-)
>
> diff --git a/drivers/pci/host-bridge.c b/drivers/pci/host-bridge.c
> index 39b2dbe..3bd45e7 100644
> --- a/drivers/pci/host-bridge.c
> +++ b/drivers/pci/host-bridge.c
> @@ -8,6 +8,61 @@
>
> #include "pci.h"
>
> +static void pci_release_host_bridge_dev(struct device *dev)
> +{
> + struct pci_host_bridge *bridge = to_pci_host_bridge(dev);
> +
> + if (bridge->release_fn)
> + bridge->release_fn(bridge);
> +
> + pci_free_resource_list(&bridge->windows);
> + kfree(bridge);
> +}
> +
> +struct pci_host_bridge *pci_create_host_bridge(
> + struct device *parent, u32 db, struct list_head *resources)
> +{
> + int error;
> + int bus = PCI_BUSNUM(db);
> + int domain = PCI_DOMAIN(db);
> + struct pci_host_bridge *host;
> + struct resource_entry *window, *n;
> +
> + host = kzalloc(sizeof(*host), GFP_KERNEL);
> + if (!host)
> + return NULL;
> +
> + host->busnum = bus;
> + host->domain = domain;
> + /* If support CONFIG_PCI_DOMAINS_GENERIC, use
> + * pci_host_assign_domain_nr() to assign domain
> + * number instead PCI_DOMAIN(db).
> + */

Follow the normal Linux comment style:

host->domain = domain;

/*
* If we support ...
*/

> + pci_host_assign_domain_nr(host);
> +
> + host->dev.parent = parent;
> + INIT_LIST_HEAD(&host->windows);
> + host->dev.release = pci_release_host_bridge_dev;
> + dev_set_name(&host->dev, "pci%04x:%02x", host->domain,
> + host->busnum);
> +
> + error = device_register(&host->dev);
> + if (error) {
> + put_device(&host->dev);
> + return NULL;
> + }
> +
> + resource_list_for_each_entry_safe(window, n, resources)
> + list_move_tail(&window->node, &host->windows);
> +
> + return host;
> +}
> +
> +void pci_free_host_bridge(struct pci_host_bridge *host)
> +{
> + device_unregister(&host->dev);
> +}
> +
> static struct pci_bus *find_pci_root_bus(struct pci_bus *bus)
> {
> while (bus->parent)
> diff --git a/drivers/pci/pci.h b/drivers/pci/pci.h
> index eeacab9..3de5e51 100644
> --- a/drivers/pci/pci.h
> +++ b/drivers/pci/pci.h
> @@ -323,4 +323,7 @@ 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 pci_free_host_bridge(struct pci_host_bridge *host);

A later patch adds another declaration and a blank line here. If you want
the blank line, add it here, when you're adding the first declarations in
this section.

> #endif /* DRIVERS_PCI_H */
> diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
> index 3d6befd..27ec612 100644
> --- a/drivers/pci/probe.c
> +++ b/drivers/pci/probe.c
> @@ -503,31 +503,6 @@ static struct pci_bus *pci_alloc_bus(struct pci_bus *parent)
> return b;
> }
>
> -static void pci_release_host_bridge_dev(struct device *dev)
> -{
> - struct pci_host_bridge *bridge = to_pci_host_bridge(dev);
> -
> - if (bridge->release_fn)
> - bridge->release_fn(bridge);
> -
> - pci_free_resource_list(&bridge->windows);
> -
> - kfree(bridge);
> -}
> -
> -static struct pci_host_bridge *pci_alloc_host_bridge(struct pci_bus *b)
> -{
> - struct pci_host_bridge *bridge;
> -
> - bridge = kzalloc(sizeof(*bridge), GFP_KERNEL);
> - if (!bridge)
> - return NULL;
> -
> - INIT_LIST_HEAD(&bridge->windows);
> - bridge->bus = b;
> - return bridge;
> -}
> -
> static const unsigned char pcix_bus_speed[] = {
> PCI_SPEED_UNKNOWN, /* 0 */
> PCI_SPEED_66MHz_PCIX, /* 1 */
> @@ -1890,54 +1865,41 @@ void __weak pcibios_remove_bus(struct pci_bus *bus)
> {
> }
>
> -struct pci_bus *pci_create_root_bus(struct device *parent, u32 db,
> - struct pci_ops *ops, void *sysdata, struct list_head *resources)
> +static struct pci_bus *__pci_create_root_bus(
> + struct pci_host_bridge *bridge, struct pci_ops *ops,
> + void *sysdata)
> {
> int error;
> - struct pci_host_bridge *bridge;
> struct pci_bus *b, *b2;
> - struct resource_entry *window, *n;
> + struct resource_entry *window;
> + struct device *parent;
> struct resource *res;
> resource_size_t offset;
> char bus_addr[64];
> char *fmt;
> - u8 bus = PCI_BUSNUM(db);
>
> + 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->number = b->busn_res.start = bridge->busnum;
> pci_bus_assign_domain_nr(b, parent);
> - b2 = pci_find_bus(pci_domain_nr(b), bus);
> + b2 = pci_find_bus(pci_domain_nr(b), b->number);
> 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->domain = PCI_DOMAIN(db);
> - 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);
> + bridge->bus = b;
> + b->bridge = get_device(&bridge->dev);
> error = pcibios_root_bridge_prepare(bridge);
> - if (error) {
> - kfree(bridge);
> + if (error)
> 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);
>
> @@ -1946,10 +1908,11 @@ 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", bridge->domain,
> + b->number);
> error = device_register(&b->dev);
> if (error)
> - goto class_dev_reg_err;
> + goto err_out;
>
> pcibios_add_bus(b);
>
> @@ -1962,12 +1925,11 @@ 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 */
> - resource_list_for_each_entry_safe(window, n, resources) {
> - list_move_tail(&window->node, &bridge->windows);
> + resource_list_for_each_entry(window, &bridge->windows) {
> 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) {
> @@ -1989,14 +1951,23 @@ struct pci_bus *pci_create_root_bus(struct device *parent, u32 db,
>
> return b;
>
> -class_dev_reg_err:
> - put_device(&bridge->dev);
> - device_unregister(&bridge->dev);
> err_out:
> kfree(b);
> return NULL;
> }
>
> +struct pci_bus *pci_create_root_bus(struct device *parent, u32 db,
> + struct pci_ops *ops, void *sysdata, struct list_head *resources)
> +{
> + struct pci_host_bridge *host;
> +
> + host = pci_create_host_bridge(parent, db, resources);
> + if (!host)
> + return NULL;
> +
> + return __pci_create_root_bus(host, ops, sysdata);
> +}
> +
> int pci_bus_insert_busn_res(struct pci_bus *b, int bus, int bus_max)
> {
> struct resource *res = &b->busn_res;
> @@ -2060,29 +2031,32 @@ void pci_bus_release_busn_res(struct pci_bus *b)
> res, ret ? "can not be" : "is");
> }
>
> -struct pci_bus *pci_scan_root_bus(struct device *parent, u32 db,
> - struct pci_ops *ops, void *sysdata, struct list_head *resources)
> +static struct pci_bus *__pci_scan_root_bus(
> + struct pci_host_bridge *host, struct pci_ops *ops,
> + void *sysdata)
> {
> struct resource_entry *window;
> bool found = false;
> struct pci_bus *b;
> int max;
>
> - resource_list_for_each_entry(window, resources)
> + resource_list_for_each_entry(window, &host->windows)
> if (window->res->flags & IORESOURCE_BUS) {
> found = true;
> break;
> }
>
> - b = pci_create_root_bus(parent, db, ops, sysdata, resources);
> - if (!b)
> + b = __pci_create_root_bus(host, ops, sysdata);
> + if (!b) {
> + pci_free_host_bridge(host);
> return NULL;
> + }
>
> if (!found) {
> dev_info(&b->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);
> + host->busnum);
> + pci_bus_insert_busn_res(b, b->number, 255);
> }
>
> max = pci_scan_child_bus(b);
> @@ -2092,6 +2066,18 @@ struct pci_bus *pci_scan_root_bus(struct device *parent, u32 db,
>
> return b;
> }
> +
> +struct pci_bus *pci_scan_root_bus(struct device *parent, u32 db,
> + struct pci_ops *ops, void *sysdata, struct list_head *resources)
> +{
> + struct pci_host_bridge *host;
> +
> + host = pci_create_host_bridge(parent, db, resources);
> + if (!host)
> + return NULL;
> +
> + return __pci_scan_root_bus(host, ops, sysdata);
> +}
> EXPORT_SYMBOL(pci_scan_root_bus);
>
> struct pci_bus *pci_scan_bus(u32 db, struct pci_ops *ops,
> diff --git a/include/linux/pci.h b/include/linux/pci.h
> index 2b1b998..463eaa3 100644
> --- a/include/linux/pci.h
> +++ b/include/linux/pci.h
> @@ -402,6 +402,7 @@ static inline int pci_channel_offline(struct pci_dev *pdev)
>
> struct pci_host_bridge {
> u16 domain;
> + u16 busnum;

Why do we need this? host_bridge->bus->number and
host_bridge->bus->busn_res.start both already contain the same information,
and I hate to add a third place. I know pci_create_host_bridge() doesn't
have a struct pci_bus at the point where you initialize busnum, but it does
have the resource list, which contains the bus number range.

> struct device dev;
> struct pci_bus *bus; /* root bus */
> struct list_head windows; /* resource_entry */
> --
> 1.7.1
>
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Next message: Herbert Xu: "Re: linux-next: Tree for Mar 11 (powerpc build failure due to vmx crypto code)"
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In reply to: Yijing Wang: "[PATCH v6 09/30] PCI: Separate pci_host_bridge creation out of pci_create_root_bus()"
Next in thread: Yijing Wang: "Re: [PATCH v6 09/30] PCI: Separate pci_host_bridge creation out of pci_create_root_bus()"
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