On 2015/3/12 9:29, Bjorn Helgaas wrote:
On Mon, Mar 09, 2015 at 10:34:03AM +0800, Yijing Wang wrote:
Currently, we use int type for bus number in
pci_create_root_bus(), pci_scan_root_bus() and
pci_scan_bus_legacy. Because PCI bus number
always <= 255, so we could change the bus number
argument type to u32, and combine PCI domain and
bus number in one.
This makes no sense. Or rather, it only states the obvious: an 8-bit value
and a 16-bit value will both fit in a 32-bit value. But it doesn't say
*why* you think it's a good idea to pass a single value that contains both
domain and bus numbers. The obvious thing is to pass two separate values,
and you don't say why passing a single combined value is better.
Sorry for my poor description for this patch, I combined the domain and bus, because
I think now we have too many args at pci_scan_root_bus() or other scan functions,
struct pci_bus *pci_scan_root_bus(struct device *parent, int bus,
struct pci_ops *ops, void *sysdata, struct list_head *resources)
Now we have five args yet, plus the new introduced domain and pci_host_bridge_ops,
it will become 7.
I thought introduced a new structure which contain the necessary info to scan root bus/ host bridge,
E.g
struct pci_scan_info {
int bus;
struct device *parent;
struct pci_ops *ops;
void *sysdata;
struct list_head *resource;
int domain;
struct pci_host_bridge_ops;
}
Do you like this one or keep it like now ?
pci_scan_root_bus(struct device *parent, int domain, int bus,
struct pci_ops *ops, void *sysdata, struct list_head *resources, struct pci_host_bridge_ops *ops)
Also see whitespace mistakes below. I get a little testy when people don't
follow the whitespace convention of neighboring lines because if people are
sloppy about whitespace I assume they're sloppy about the code.
Sorry, I would be more careful.
int error;
@@ -1901,6 +1901,7 @@ struct pci_bus *pci_create_root_bus(struct device *parent, int bus,
resource_size_t offset;
char bus_addr[64];
char *fmt;
+ u8 bus = PCI_BUSNUM(db);
Whitespace botch.
b = pci_alloc_bus(NULL);
if (!b)
@@ -1921,6 +1922,7 @@ struct pci_bus *pci_create_root_bus(struct device *parent, int bus,
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);
@@ -2058,7 +2060,7 @@ 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, int bus,
+struct pci_bus *pci_scan_root_bus(struct device *parent, u32 db,
struct pci_ops *ops, void *sysdata, struct list_head *resources)
{
struct resource_entry *window;
@@ -2072,15 +2074,15 @@ struct pci_bus *pci_scan_root_bus(struct device *parent, int bus,
break;
}
- b = pci_create_root_bus(parent, bus, ops, sysdata, resources);
+ b = pci_create_root_bus(parent, db, ops, sysdata, resources);
if (!b)
return NULL;
if (!found) {
dev_info(&b->dev,
"No busn resource found for root bus, will use [bus %02x-ff]\n",
- bus);
- pci_bus_insert_busn_res(b, bus, 255);
+ PCI_BUSNUM(db));
+ pci_bus_insert_busn_res(b, PCI_BUSNUM(db), 255);
}
max = pci_scan_child_bus(b);
@@ -2092,7 +2094,7 @@ struct pci_bus *pci_scan_root_bus(struct device *parent, int bus,
}
EXPORT_SYMBOL(pci_scan_root_bus);
-struct pci_bus *pci_scan_bus(int bus, struct pci_ops *ops,
+struct pci_bus *pci_scan_bus(u32 db, struct pci_ops *ops,
void *sysdata)
{
LIST_HEAD(resources);
@@ -2101,7 +2103,7 @@ struct pci_bus *pci_scan_bus(int bus, struct pci_ops *ops,
pci_add_resource(&resources, &ioport_resource);
pci_add_resource(&resources, &iomem_resource);
pci_add_resource(&resources, &busn_resource);
- b = pci_create_root_bus(NULL, bus, ops, sysdata, &resources);
+ b = pci_create_root_bus(NULL, db, ops, sysdata, &resources);
if (b) {
pci_scan_child_bus(b);
} else {
diff --git a/include/linux/pci.h b/include/linux/pci.h
index 36effb8..8b3d245 100644
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -401,6 +401,7 @@ static inline int pci_channel_offline(struct pci_dev *pdev)
}
struct pci_host_bridge {
+ u16 domain;
Please follow the existing whitespace convention, i.e., use a space, not a
tab, between "u16 domain".
struct device dev;
struct pci_bus *bus; /* root bus */
struct list_head windows; /* resource_entry */
@@ -769,14 +770,14 @@ void pcibios_bus_to_resource(struct pci_bus *bus, struct resource *res,
void pcibios_scan_specific_bus(int busn);
struct pci_bus *pci_find_bus(int domain, int busnr);
void pci_bus_add_devices(const struct pci_bus *bus);
-struct pci_bus *pci_scan_bus(int bus, struct pci_ops *ops, void *sysdata);
-struct pci_bus *pci_create_root_bus(struct device *parent, int bus,
+struct pci_bus *pci_scan_bus(u32 dombus, struct pci_ops *ops, void *sysdata);
+struct pci_bus *pci_create_root_bus(struct device *parent, u32 dombus,
struct pci_ops *ops, void *sysdata,
struct list_head *resources);
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);
-struct pci_bus *pci_scan_root_bus(struct device *parent, int bus,
+struct pci_bus *pci_scan_root_bus(struct device *parent, u32 dombus,
struct pci_ops *ops, void *sysdata,
struct list_head *resources);
struct pci_bus *pci_add_new_bus(struct pci_bus *parent, struct pci_dev *dev,
diff --git a/include/uapi/linux/pci.h b/include/uapi/linux/pci.h
index 3c292bc..89c6f15 100644
--- a/include/uapi/linux/pci.h
+++ b/include/uapi/linux/pci.h
@@ -30,6 +30,9 @@
#define PCI_DEVFN(slot, func) ((((slot) & 0x1f) << 3) | ((func) & 0x07))
#define PCI_SLOT(devfn) (((devfn) >> 3) & 0x1f)
#define PCI_FUNC(devfn) ((devfn) & 0x07)
+#define PCI_DOMAIN(db) ((db) >> 16)
+#define PCI_BUSNUM(db) ((db) & 0xffff)
+#define PCI_DOMBUS(domain, bus) (((domain) << 16) | (bus))
/* Ioctls for /proc/bus/pci/X/Y nodes. */
#define PCIIOC_BASE ('P' << 24 | 'C' << 16 | 'I' << 8)
--
1.7.1
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--
Thanks!
Yijing
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