GSP
Quick Navigator

Search Site

Unix VPS
A - Starter
B - Basic
C - Preferred
D - Commercial
MPS - Dedicated
Previous VPSs
* Sign Up! *

Support
Contact Us
Online Help
Handbooks
Domain Status
Man Pages

FAQ
Virtual Servers
Pricing
Billing
Technical

Network
Facilities
Connectivity
Topology Map

Miscellaneous
Server Agreement
Year 2038
Credits
 

USA Flag

 

 

Man Pages
BUS_MAP_RESOURCE(9) FreeBSD Kernel Developer's Manual BUS_MAP_RESOURCE(9)

bus_map_resource, bus_unmap_resource, resource_init_map_request
map or unmap an active resource

#include <sys/param.h>
#include <sys/bus.h>

#include <machine/bus.h>
#include <sys/rman.h>
#include <machine/resource.h>
int
bus_map_resource(device_t dev, int type, struct resource *r, struct resource_map_request *args, struct resource_map *map);
int
bus_unmap_resource(device_t dev, int type, struct resource *r, struct resource_map *map);
void
resource_init_map_request(struct resource_map_request *args);

These functions create or destroy a mapping of a previously activated resource. Mappings permit CPU access to the resource via the bus_space(9) API.
The arguments are as follows:
dev
The device that owns the resource.
type
The type of resource to map. It is one of:
for I/O ports
for I/O memory
r
A pointer to the struct resource returned by bus_alloc_resource(9).
args
A set of optional properties to apply when creating a mapping. This argument can be set to NULL to request a mapping of the entire resource with the default properties.
map
The resource mapping to create or destroy.

Resource mappings are described by a struct resource_map object. This structure contains a bus_space(9) tag and handle in the r_bustag and r_bushandle members that can be used for CPU access to the mapping. The structure also contains a r_vaddr member which contains the virtual address of the mapping if one exists.
The wrapper API for struct resource objects described in bus_activate_resource(9) can also be used with struct resource_map. For example, a pointer to a mapping object can be passed as the first argument to bus_read_4(). This wrapper API is preferred over using the r_bustag and r_bushandle members directly.

The struct resource_map_request object passed in args can be used to specify optional properties of a mapping. The structure must be initialized by invoking resource_init_map_request(). Properties are then specified by setting one or more of these members:
offset, length
These two members specify a region of the resource to map. By default a mapping is created for the entire resource. The offset is relative to the start of the resource.
memattr
Specifies a memory attribute to use when mapping the resource. By default memory mappings use the VM_MEMATTR_UNCACHEABLE attribute.

Zero is returned on success, otherwise an error is returned.

This maps a PCI memory BAR with the write-combining memory attribute and reads the first 32-bit word:
	struct resource *r; 
	struct resource_map map; 
	struct resource_map_request req; 
	uint32_t val; 
	int rid; 
 
	rid = PCIR_BAR(0); 
	r = bus_alloc_resource_any(dev, SYS_RES_MEMORY, &rid, RF_ACTIVE | 
	    RF_UNMAPPED); 
	resource_init_map_request(&req); 
	req.memattr = VM_MEMATTR_WRITE_COMBINING; 
	bus_map_resource(dev, SYS_RES_MEMORY, r, &req, &map); 
	val = bus_read_4(&map, 0);

bus_activate_resource(9), bus_alloc_resource(9), bus_space(9), device(9), driver(9)

This manual page was written by John Baldwin <jhb@FreeBSD.org>.
February 5, 2018 FreeBSD 12.0-RELEASE

Search for    or go to Top of page |  Section 9 |  Main Index

Powered by GSP Visit the GSP FreeBSD Man Page Interface.
Output converted with ManDoc.