/*
* Ultra Wide Band
* DRP availability management
*
* Copyright (C) 2005-2006 Intel Corporation
* Reinette Chatre <reinette.chatre@intel.com>
* Copyright (C) 2008 Cambridge Silicon Radio Ltd.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License version
* 2 as published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*
*
* Manage DRP Availability (the MAS available for DRP
* reservations). Thus:
*
* - Handle DRP Availability Change notifications
*
* - Allow the reservation manager to indicate MAS reserved/released
* by local (owned by/targeted at the radio controller)
* reservations.
*
* - Based on the two sources above, generate a DRP Availability IE to
* be included in the beacon.
*
* See also the documentation for struct uwb_drp_avail.
*/
#include <linux/errno.h>
#include <linux/module.h>
#include <linux/device.h>
#include <linux/bitmap.h>
#include "uwb-internal.h"
/**
* uwb_drp_avail_init - initialize an RC's MAS availability
*
* All MAS are available initially. The RC will inform use which
* slots are used for the BP (it may change in size).
*/
void uwb_drp_avail_init(struct uwb_rc *rc)
{
bitmap_fill(rc->drp_avail.global, UWB_NUM_MAS);
bitmap_fill(rc->drp_avail.local, UWB_NUM_MAS);
bitmap_fill(rc->drp_avail.pending, UWB_NUM_MAS);
}
/*
* Determine MAS available for new local reservations.
*
* avail = global & local & pending
*/
static void uwb_drp_available(struct uwb_rc *rc, struct uwb_mas_bm *avail)
{
bitmap_and(avail->bm, rc->drp_avail.global, rc->drp_avail.local, UWB_NUM_MAS);
bitmap_and(avail->bm, avail->bm, rc->drp_avail.pending, UWB_NUM_MAS);
}
/**
* uwb_drp_avail_reserve_pending - reserve MAS for a new reservation
* @rc: the radio controller
* @mas: the MAS to reserve
*
* Returns 0 on success, or -EBUSY if the MAS requested aren't available.
*/
int uwb_drp_avail_reserve_pending(struct uwb_rc *rc, struct uwb_mas_bm *mas)
{
struct uwb_mas_bm avail;
uwb_drp_available(rc, &avail);
if (!bitmap_subset(mas->bm, avail.bm, UWB_NUM_MAS))
return -EBUSY;
bitmap_andnot(rc->drp_avail.pending, rc->drp_avail.pending, mas->bm, UWB_NUM_MAS);
return 0;
}
/**
* uwb_drp_avail_reserve - reserve MAS for an established reservation
* @rc: the radio controller
* @mas: the MAS to reserve
*/
void uwb_drp_avail_reserve(struct uwb_rc *rc, struct uwb_mas_bm *mas)
{
bitmap_or(rc->drp_avail.pending, rc->drp_avail.pending, mas->bm, UWB_NUM_MAS);
bitmap_andnot(rc->drp_avail.local, rc->drp_avail.local, mas->bm, UWB_NUM_MAS);
rc->drp_avail.ie_valid = false;
}
/**
* uwb_drp_avail_release - release MAS from a pending or established reservation
* @rc: the radio controller
* @mas: the MAS to release
*/
void uwb_drp_avail_release(struct uwb_rc *rc, struct uwb_mas_bm *mas)
{
bitmap_or(rc->drp_avail.local, rc->drp_avail.local, mas->bm, UWB_NUM_MAS);
bitmap_or(rc->drp_avail.pending, rc->drp_avail.pending, mas->bm, UWB_NUM_MAS);
rc->drp_avail.ie_valid = false;
}
/**
* uwb_drp_avail_ie_update - update the DRP Availability IE
* @rc: the radio controller
*
* avail = global & local
*/
void uwb_drp_avail_ie_update(struct uwb_rc *rc)
{
struct uwb_mas_bm avail;
bitmap_and(avail.bm, rc->drp_avail.global, rc->drp_avail.local, UWB_NUM_MAS);
rc->drp_avail.ie.hdr.element_id = UWB_IE_DRP_AVAILABILITY;
rc->drp_avail.ie.hdr.length = UWB_NUM_MAS / 8;
uwb_mas_bm_copy_le(rc->drp_avail.ie.bmp, &avail);
rc->drp_avail.ie_valid = true;
}
/**
* Create an unsigned long from a buffer containing a byte stream.
*
* @array: pointer to buffer
* @itr: index of buffer from where we start
* @len: the buffer's remaining size may not be exact multiple of
* sizeof(unsigned long), @len is the length of buffer that needs
* to be converted. This will be sizeof(unsigned long) or smaller
* (BUG if not). If it is smaller then we will pad the remaining
* space of the result with zeroes.
*/
static
unsigned long get_val(u8 *array, size_t itr, size_t len)
{
unsigned long val = 0;
size_t top = itr + len;
BUG_ON(len > sizeof(val));
while (itr < top) {
val <<= 8;
val |= array[top - 1];
top--;
}
val <<= 8 * (sizeof(val) - len); /* padding */
return val;
}
/**
* Initialize bitmap from data buffer.
*
* The bitmap to be converted could come from a IE, for example a
* DRP Availability IE.
* From ECMA-368 1.0 [16.8.7]: "
* octets: 1 1 N * (0 to 32)
* Element ID Length (=N) DRP Availability Bitmap
*
* The DRP Availability Bitmap field is up to 256 bits long, one
* bit for each MAS in the superframe, where the least-significant
* bit of the field corresponds to the first MAS in the superframe
* and successive bits correspond to successive MASs."
*
* The DRP Availability bitmap is in octets from 0 to 32, so octet
* 32 contains bits for MAS 1-8, etc. If the bitmap is smaller than 32
* octets, the bits in octets not included at the end of the bitmap are
* treated as zero. In this case (when the bitmap is smaller than 32
* octets) the MAS represented range from MAS 1 to MAS (size of bitmap)
* with the last octet still containing bits for MAS 1-8, etc.
*
* For example:
* F00F0102 03040506 0708090A 0B0C0D0E 0F010203
* ^^^^
* ||||
* ||||
* |||\LSB of byte is MAS 9
* ||\MSB of byte is MAS 16
* |\LSB of first byte is MAS 1
* \ MSB of byte is MAS 8
*
* An example of this encoding can be found in ECMA-368 Annex-D [Table D.11]
*
* The resulting bitmap will have the following mapping:
* bit position 0 == MAS 1
* bit position 1 == MAS 2
* ...
* bit position (UWB_NUM_MAS - 1) == MAS UWB_NUM_MAS
*
* @bmp_itr: pointer to bitmap (can be declared with DECLARE_BITMAP)
* @buffer: pointer to buffer containing bitmap data in big endian
* format (MSB first)
* @buffer_size:number of bytes with which bitmap should be initialized
*/
static
void buffer_to_bmp(unsigned long *bmp_itr, void *_buffer,
size_t buffer_size)
{
u8 *buffer = _buffer;
size_t itr, len;
unsigned long val;
itr = 0;
while (itr < buffer_size) {
len = buffer_size - itr >= sizeof(val) ?
sizeof(val) : buffer_size - itr;
val = get_val(buffer, itr, len);
bmp_itr[itr / sizeof(val)] = val;
itr += sizeof(val);
}
}
/**
* Extract DRP Availability bitmap from the notification.
*
* The notification that comes in contains a bitmap of (UWB_NUM_MAS / 8) bytes
* We convert that to our internal representation.
*/
static
int uwbd_evt_get_drp_avail(struct uwb_event *evt, unsigned long *bmp)
{
struct device *dev = &evt->rc->uwb_dev.dev;
struct uwb_rc_evt_drp_avail *drp_evt;
int result = -EINVAL;
/* Is there enough data to decode the event? */
if (evt->notif.size < sizeof(*drp_evt)) {
dev_err(dev, "DRP Availability Change: Not enough "
"data to decode event [%zu bytes, %zu "
"needed]\n", evt->notif.size, sizeof(*drp_evt));
goto error;
}
drp_evt = container_of(evt->notif.rceb, struct uwb_rc_evt_drp_avail, rceb);
buffer_to_bmp(bmp, drp_evt->bmp, UWB_NUM_MAS/8);
result = 0;
error:
return result;
}
/**
* Process an incoming DRP Availability notification.
*
* @evt: Event information (packs the actual event data, which
* radio controller it came to, etc).
*
* @returns: 0 on success (so uwbd() frees the event buffer), < 0
* on error.
*
* According to ECMA-368 1.0 [16.8.7], bits set to ONE indicate that
* the MAS slot is available, bits set to ZERO indicate that the slot
* is busy.
*
* So we clear available slots, we set used slots :)
*
* The notification only marks non-availability based on the BP and
* received DRP IEs that are not for this radio controller. A copy of
* this bitmap is needed to generate the real availability (which
* includes local and pending reservations).
*
* The DRP Availability IE that this radio controller emits will need
* to be updated.
*/
int uwbd_evt_handle_rc_drp_avail(struct uwb_event *evt)
{
int result;
struct uwb_rc *rc = evt->rc;
DECLARE_BITMAP(bmp, UWB_NUM_MAS);
result = uwbd_evt_get_drp_avail(evt, bmp);
if (result < 0)
return result;
mutex_lock(&rc->rsvs_mutex);
bitmap_copy(rc->drp_avail.global, bmp, UWB_NUM_MAS);
rc->drp_avail.ie_valid = false;
mutex_unlock(&rc->rsvs_mutex);
uwb_rsv_sched_update(rc);
return 0;
}
