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

Liviu Dudau
2014-11-18T15:30:20Z

On Mon, Nov 17, 2014 at 10:21:41AM +0000, Yijing Wang wrote:
> There are some common PCI infos like domain, msi_controller, these
> infos are saved in arch PCI sysdata, and lots arch specific functions
> like pci_domain_nr() and pcibios_msi_controller() required.
> We could separate pci_host_bridge creation out of pci_create_root_bus(),
> then we could put the common infos in, then we could eliminate
> the arch specifc functions.
>

Please Cc: Yinghai Lu and Jiang Liu on future versions.

More comments on the conversion of pci_create_root_bus():

> Signed-off-by: Yijing Wang <wangyijing@huawei.com>
> ---
> drivers/pci/host-bridge.c | 99 +++++++++++++++++++++++++++++++++
> drivers/pci/probe.c | 134 ++++++++++++++++----------------------------
> include/linux/pci.h | 11 +++-
> 3 files changed, 158 insertions(+), 86 deletions(-)
>
> diff --git a/drivers/pci/host-bridge.c b/drivers/pci/host-bridge.c
> index 0e5f3c9..e31604f 100644
> --- a/drivers/pci/host-bridge.c
> +++ b/drivers/pci/host-bridge.c
> @@ -8,6 +8,105 @@
>
> #include "pci.h"
>
> +LIST_HEAD(pci_host_bridge_list);
> +DECLARE_RWSEM(pci_host_bridge_sem);
> +
> +static struct resource busn_resource = {
> + .name = "PCI busn",
> + .start = 0,
> + .end = 255,
> + .flags = IORESOURCE_BUS,
> +};
> +
> +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 pci_ops *ops, void *sysdata,

I don't thinks it is worth moving the buses' pci_ops into pci_host_bridge. It
might be more useful to have pci_host_bridge specific ops here.

> + struct list_head *resources)
> +{
> + int error;
> + struct pci_bus *b;
> + struct pci_host_bridge *host, *h;
> + struct pci_host_bridge_window *window, *n;
> +
> + down_read(&pci_host_bridge_sem);
> + list_for_each_entry(h, &pci_host_bridge_list, list) {
> + if (h->domain == PCI_DOMAIN(db) &&
> + h->busnum == PCI_BUSNUM(db)) {
> + dev_dbg(&h->dev, "pci host bridge exist\n");
> + up_read(&pci_host_bridge_sem);
> + return NULL;
> + }
> + }
> + up_read(&pci_host_bridge_sem);
> +
> + host = kzalloc(sizeof(*host), GFP_KERNEL);
> + if (!host)
> + return NULL;
> +
> + host->sysdata = sysdata;
> + host->busnum = PCI_BUSNUM(db);
> + host->domain = PCI_DOMAIN(db);
> + host->ops = ops;
> + host->dev.parent = parent;
> + INIT_LIST_HEAD(&host->windows);
> + host->dev.release = pci_release_host_bridge_dev;
> +
> + /* this is hack, just for build, will be removed later*/
> + b = kzalloc(sizeof(*b), GFP_KERNEL);
> + b->sysdata = sysdata;
> + pci_bus_assign_domain_nr(b, parent);
> + host->domain = pci_domain_nr(b);
> +
> + if (!resources) {
> + /* Use default IO/MEM/BUS resources*/
> + pci_add_resource(&host->windows, &ioport_resource);
> + pci_add_resource(&host->windows, &iomem_resource);
> + pci_add_resource(&host->windows, &busn_resource);
> + } else {
> + list_for_each_entry_safe(window, n, resources, list)
> + list_move_tail(&window->list, &host->windows);
> + }
> +
> + dev_set_name(&host->dev, "pci%04x:%02x", host->domain,
> + host->busnum);
> + error = pcibios_root_bridge_prepare(host);
> + if(error) {
> + kfree(host);
> + return NULL;
> + }
> +
> + error = device_register(&host->dev);
> + if (error) {
> + put_device(&host->dev);
> + return NULL;
> + }
> +
> + down_write(&pci_host_bridge_sem);
> + list_add_tail(&host->list, &pci_host_bridge_list);
> + up_write(&pci_host_bridge_sem);
> + return host;
> +}
> +EXPORT_SYMBOL(pci_create_host_bridge);
> +
> +void pci_free_host_bridge(struct pci_host_bridge *host)
> +{
> + down_write(&pci_host_bridge_sem);
> + list_del(&host->list);
> + up_write(&pci_host_bridge_sem);
> +
> + device_unregister(&host->dev);
> +}
> +
> static struct pci_bus *find_pci_root_bus(struct pci_bus *bus)
> {
> while (bus->parent)
> diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
> index adf4d09..d472da4 100644
> --- a/drivers/pci/probe.c
> +++ b/drivers/pci/probe.c
> @@ -17,13 +17,6 @@
> #define CARDBUS_LATENCY_TIMER 176 /* secondary latency timer */
> #define CARDBUS_RESERVE_BUSNR 3
>
> -static struct resource busn_resource = {
> - .name = "PCI busn",
> - .start = 0,
> - .end = 255,
> - .flags = IORESOURCE_BUS,
> -};
> -
> /* Ugh. Need to stop exporting this to modules. */
> LIST_HEAD(pci_root_buses);
> EXPORT_SYMBOL(pci_root_buses);
> @@ -508,31 +501,6 @@ 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 */
> @@ -1895,52 +1863,33 @@ 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)
> +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.

> + 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.

Otherwise it looks to me like you are heading in the right direction.

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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