te
Copyright (c) 1996, Sun Microsystems, Inc. All Rights Reserved
The contents of this file are subject to the terms of the Common Development and Distribution License (the "License"). You may not use this file except in compliance with the License.
You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE or http://www.opensolaris.org/os/licensing. See the License for the specific language governing permissions and limitations under the License.
When distributing Covered Code, include this CDDL HEADER in each file and include the License file at usr/src/OPENSOLARIS.LICENSE. If applicable, add the following below this CDDL HEADER, with the fields enclosed by brackets "[]" replaced with your own identifying information: Portions Copyright [yyyy] [name of copyright owner]
devmap_map - device mapping create entry point

#include <sys/ddi.h>
#include <sys/sunddi.h>



int prefixdevmap_map(devmap_cookie_t dhp, dev_t dev,
 uint_t flags, offset_t off, size_t len, void **pvtp);

illumos DDI specific (illumos DDI). dhp dev flags off len pvtp The devmap_map() entry point is an optional routine that allows drivers to perform additional processing or to allocate private resources during the mapping setup time. For example, in order for device drivers to support context switching, the drivers allocate private mapping data and associate the private data with the mapping parameters in the devmap_map() entry point.

The system calls devmap_map() after the user mapping to device physical memory has been established. (For example, after the devmap(9E) entry point is called.)

devmap_map() receives a pointer to the driver private data for this mapping in pvtp. The system expects the driver to allocate its private data and set *pvtp to the allocated data. The driver must store off and len, which define the range of the mapping, in its private data. Later, when the system calls devmap_unmap(9E), the driver will use the off and len stored in pvtp to check if the entire mapping, or just a part of it, is being unmapped. If only a part of the mapping is being unmapped, the driver must allocate a new private data for the remaining mapping before freeing the old private data. The driver will receive *pvtp in subsequent event notification callbacks.

If the driver support context switching, it should store the mapping handle dhp in its private data *pvtp for later use in devmap_unload(9F).

For a driver that supports context switching, flags indicates whether or not the driver should allocate a private context for the mapping. For example, a driver may allocate a memory region to store the device context if flags is set to MAP_PRIVATE.

devmap_map() returns the following values: 0 Non-zero Example 1 devmap_map()implementation

The following shows an example implementation for devmap_map().

static int
xxdevmap_map(devmap_cookie_t dhp, dev_t dev, uint_t flags, \e
 offset_t off,size_t len, void **pvtp)
{
 struct xx_resources *pvt;
 struct xx_context *this_context;
 struct xx_softc *softc;
 softc = ddi_get_soft_state(statep, getminor(dev));

 this_context = get_context(softc, off, len);

 /* allocate resources for the mapping - Device dependent */
 pvt = kmem_zalloc(sizeof (struct xx_resources), KM_SLEEP);

 pvt->off = off;
 pvt->len = len;
 pvt->dhp = dhp;
 pvt->ctx = this_context;
 *pvtp = pvt;
}

devmap_unmap(9E), devmap_unload(9F), devmap_callback_ctl(9S)

Writing Device Drivers