[Fwd: Memory layout question]
Oliver Korpilla
okorpil at fh-landshut.de
Wed May 26 21:56:03 EST 2004
Below I sketched out a function that may give an address from the bus the Tundra
Universe is on - it is designed to be used, where normally the
allocate_resource() call is used (e.g. in create_slsi_window()).
With kind regards,
Oliver Korpilla
/* Try getting a resource (range of PCI addresses) from the PCI bus we're on */
static int allocate_pci_resource(unsigned long size, unsigned long align,
struct resource *new_resource) {
/* Determine the bus the Tundra is on */
struct pci_bus *bus = universe_pci_dev->bus;
int i;
for (i=0; i<4; i++) {
int retval;
/* Get one of the bus address ranges */
struct resource *r = bus->resource[i];
/* Check if that resource "exists" */
if (!r)
continue;
/* If the resource is not I/O memory (e.g. I/O ports) */
if (! (r->flags & IORESOURCE_MEM))
continue;
#ifdef DEBUG
/* Print out name of resource for debugging */
if (r->name)
printk(KERN_INFO "Checking bus resource with name \"%s\".\n", r->name);
printk(KERN_INFO "resource.start: %08lX, resource.end: %08lX.\n",
r->start, r->end);
#endif
/* Try to allocate a new sub-resource from this
given the proper size and alignment*/
retval = allocate_resource(r, new_resource, size, 0, ~0,
align, NULL, NULL);
/* If this allocation fails, try with next resource
(and give debug message) */
if (retval < 0) {
#ifdef DEBUG
if (r->name)
printk(KERN_INFO
"Failed allocating from bus resource with name \"%s\".\n",
r->name);
else
printk(KERN_INFO
"Failed allocating from bus resource with number %d.\n", i);
#endif
continue;
}
/* If this allocation succeeds, return what allocate_resource() returned */
else
return retval;
}
/* return busy if no resource could be successfully allocated */
return -EBUSY;
}
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