linux/drivers/pci/bus.c
Yinghai Lu 928bea9648 PCI: Delay enabling bridges until they're needed
We currently enable PCI bridges after scanning a bus and assigning
resources.  This is often done in arch code.

This patch changes this so we don't enable a bridge until necessary, i.e.,
until we enable a PCI device behind the bridge.  We do this in the generic
pci_enable_device() path, so this also removes the arch-specific code to
enable bridges.

[bhelgaas: changelog]
Signed-off-by: Yinghai Lu <yinghai@kernel.org>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
2013-07-25 12:35:03 -06:00

286 lines
6.7 KiB
C

/*
* drivers/pci/bus.c
*
* From setup-res.c, by:
* Dave Rusling (david.rusling@reo.mts.dec.com)
* David Mosberger (davidm@cs.arizona.edu)
* David Miller (davem@redhat.com)
* Ivan Kokshaysky (ink@jurassic.park.msu.ru)
*/
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/pci.h>
#include <linux/errno.h>
#include <linux/ioport.h>
#include <linux/proc_fs.h>
#include <linux/init.h>
#include <linux/slab.h>
#include "pci.h"
void pci_add_resource_offset(struct list_head *resources, struct resource *res,
resource_size_t offset)
{
struct pci_host_bridge_window *window;
window = kzalloc(sizeof(struct pci_host_bridge_window), GFP_KERNEL);
if (!window) {
printk(KERN_ERR "PCI: can't add host bridge window %pR\n", res);
return;
}
window->res = res;
window->offset = offset;
list_add_tail(&window->list, resources);
}
EXPORT_SYMBOL(pci_add_resource_offset);
void pci_add_resource(struct list_head *resources, struct resource *res)
{
pci_add_resource_offset(resources, res, 0);
}
EXPORT_SYMBOL(pci_add_resource);
void pci_free_resource_list(struct list_head *resources)
{
struct pci_host_bridge_window *window, *tmp;
list_for_each_entry_safe(window, tmp, resources, list) {
list_del(&window->list);
kfree(window);
}
}
EXPORT_SYMBOL(pci_free_resource_list);
void pci_bus_add_resource(struct pci_bus *bus, struct resource *res,
unsigned int flags)
{
struct pci_bus_resource *bus_res;
bus_res = kzalloc(sizeof(struct pci_bus_resource), GFP_KERNEL);
if (!bus_res) {
dev_err(&bus->dev, "can't add %pR resource\n", res);
return;
}
bus_res->res = res;
bus_res->flags = flags;
list_add_tail(&bus_res->list, &bus->resources);
}
struct resource *pci_bus_resource_n(const struct pci_bus *bus, int n)
{
struct pci_bus_resource *bus_res;
if (n < PCI_BRIDGE_RESOURCE_NUM)
return bus->resource[n];
n -= PCI_BRIDGE_RESOURCE_NUM;
list_for_each_entry(bus_res, &bus->resources, list) {
if (n-- == 0)
return bus_res->res;
}
return NULL;
}
EXPORT_SYMBOL_GPL(pci_bus_resource_n);
void pci_bus_remove_resources(struct pci_bus *bus)
{
int i;
struct pci_bus_resource *bus_res, *tmp;
for (i = 0; i < PCI_BRIDGE_RESOURCE_NUM; i++)
bus->resource[i] = NULL;
list_for_each_entry_safe(bus_res, tmp, &bus->resources, list) {
list_del(&bus_res->list);
kfree(bus_res);
}
}
/**
* pci_bus_alloc_resource - allocate a resource from a parent bus
* @bus: PCI bus
* @res: resource to allocate
* @size: size of resource to allocate
* @align: alignment of resource to allocate
* @min: minimum /proc/iomem address to allocate
* @type_mask: IORESOURCE_* type flags
* @alignf: resource alignment function
* @alignf_data: data argument for resource alignment function
*
* Given the PCI bus a device resides on, the size, minimum address,
* alignment and type, try to find an acceptable resource allocation
* for a specific device resource.
*/
int
pci_bus_alloc_resource(struct pci_bus *bus, struct resource *res,
resource_size_t size, resource_size_t align,
resource_size_t min, unsigned int type_mask,
resource_size_t (*alignf)(void *,
const struct resource *,
resource_size_t,
resource_size_t),
void *alignf_data)
{
int i, ret = -ENOMEM;
struct resource *r;
resource_size_t max = -1;
type_mask |= IORESOURCE_IO | IORESOURCE_MEM;
/* don't allocate too high if the pref mem doesn't support 64bit*/
if (!(res->flags & IORESOURCE_MEM_64))
max = PCIBIOS_MAX_MEM_32;
pci_bus_for_each_resource(bus, r, i) {
if (!r)
continue;
/* type_mask must match */
if ((res->flags ^ r->flags) & type_mask)
continue;
/* We cannot allocate a non-prefetching resource
from a pre-fetching area */
if ((r->flags & IORESOURCE_PREFETCH) &&
!(res->flags & IORESOURCE_PREFETCH))
continue;
/* Ok, try it out.. */
ret = allocate_resource(r, res, size,
r->start ? : min,
max, align,
alignf, alignf_data);
if (ret == 0)
break;
}
return ret;
}
void __weak pcibios_resource_survey_bus(struct pci_bus *bus) { }
/**
* pci_bus_add_device - start driver for a single device
* @dev: device to add
*
* This adds add sysfs entries and start device drivers
*/
int pci_bus_add_device(struct pci_dev *dev)
{
int retval;
/*
* Can not put in pci_device_add yet because resources
* are not assigned yet for some devices.
*/
pci_fixup_device(pci_fixup_final, dev);
pci_create_sysfs_dev_files(dev);
dev->match_driver = true;
retval = device_attach(&dev->dev);
WARN_ON(retval < 0);
dev->is_added = 1;
return 0;
}
/**
* pci_bus_add_devices - start driver for PCI devices
* @bus: bus to check for new devices
*
* Start driver for PCI devices and add some sysfs entries.
*/
void pci_bus_add_devices(const struct pci_bus *bus)
{
struct pci_dev *dev;
struct pci_bus *child;
int retval;
list_for_each_entry(dev, &bus->devices, bus_list) {
/* Skip already-added devices */
if (dev->is_added)
continue;
retval = pci_bus_add_device(dev);
if (retval)
dev_err(&dev->dev, "Error adding device (%d)\n",
retval);
}
list_for_each_entry(dev, &bus->devices, bus_list) {
BUG_ON(!dev->is_added);
child = dev->subordinate;
if (child)
pci_bus_add_devices(child);
}
}
/** pci_walk_bus - walk devices on/under bus, calling callback.
* @top bus whose devices should be walked
* @cb callback to be called for each device found
* @userdata arbitrary pointer to be passed to callback.
*
* Walk the given bus, including any bridged devices
* on buses under this bus. Call the provided callback
* on each device found.
*
* We check the return of @cb each time. If it returns anything
* other than 0, we break out.
*
*/
void pci_walk_bus(struct pci_bus *top, int (*cb)(struct pci_dev *, void *),
void *userdata)
{
struct pci_dev *dev;
struct pci_bus *bus;
struct list_head *next;
int retval;
bus = top;
down_read(&pci_bus_sem);
next = top->devices.next;
for (;;) {
if (next == &bus->devices) {
/* end of this bus, go up or finish */
if (bus == top)
break;
next = bus->self->bus_list.next;
bus = bus->self->bus;
continue;
}
dev = list_entry(next, struct pci_dev, bus_list);
if (dev->subordinate) {
/* this is a pci-pci bridge, do its devices next */
next = dev->subordinate->devices.next;
bus = dev->subordinate;
} else
next = dev->bus_list.next;
retval = cb(dev, userdata);
if (retval)
break;
}
up_read(&pci_bus_sem);
}
EXPORT_SYMBOL_GPL(pci_walk_bus);
struct pci_bus *pci_bus_get(struct pci_bus *bus)
{
if (bus)
get_device(&bus->dev);
return bus;
}
EXPORT_SYMBOL(pci_bus_get);
void pci_bus_put(struct pci_bus *bus)
{
if (bus)
put_device(&bus->dev);
}
EXPORT_SYMBOL(pci_bus_put);
EXPORT_SYMBOL(pci_bus_alloc_resource);
EXPORT_SYMBOL_GPL(pci_bus_add_device);
EXPORT_SYMBOL(pci_bus_add_devices);